egui/crates/egui/src/context.rs

3905 lines
144 KiB
Rust

#![warn(missing_docs)] // Let's keep `Context` well-documented.
use std::{borrow::Cow, cell::RefCell, panic::Location, sync::Arc, time::Duration};
use containers::area::AreaState;
use epaint::{
emath::{self, TSTransform},
mutex::RwLock,
pos2,
stats::PaintStats,
tessellator,
text::Fonts,
util::OrderedFloat,
vec2, ClippedPrimitive, ClippedShape, Color32, ImageData, ImageDelta, Pos2, Rect,
TessellationOptions, TextureAtlas, TextureId, Vec2,
};
use crate::{
animation_manager::AnimationManager,
containers,
data::output::PlatformOutput,
epaint, hit_test,
input_state::{InputState, MultiTouchInfo, PointerEvent},
interaction,
layers::GraphicLayers,
load,
load::{Bytes, Loaders, SizedTexture},
memory::{Options, Theme},
menu,
os::OperatingSystem,
output::FullOutput,
pass_state::PassState,
resize, scroll_area,
util::IdTypeMap,
viewport::ViewportClass,
Align2, CursorIcon, DeferredViewportUiCallback, FontDefinitions, Grid, Id, ImmediateViewport,
ImmediateViewportRendererCallback, Key, KeyboardShortcut, Label, LayerId, Memory,
ModifierNames, NumExt, Order, Painter, RawInput, Response, RichText, ScrollArea, Sense, Style,
TextStyle, TextureHandle, TextureOptions, Ui, ViewportBuilder, ViewportCommand, ViewportId,
ViewportIdMap, ViewportIdPair, ViewportIdSet, ViewportOutput, Widget, WidgetRect, WidgetText,
};
#[cfg(feature = "accesskit")]
use crate::IdMap;
use self::{hit_test::WidgetHits, interaction::InteractionSnapshot};
/// Information given to the backend about when it is time to repaint the ui.
///
/// This is given in the callback set by [`Context::set_request_repaint_callback`].
#[derive(Clone, Copy, Debug)]
pub struct RequestRepaintInfo {
/// This is used to specify what viewport that should repaint.
pub viewport_id: ViewportId,
/// Repaint after this duration. If zero, repaint as soon as possible.
pub delay: Duration,
/// The number of fully completed passes, of the entire lifetime of the [`Context`].
///
/// This can be compared to [`Context::cumulative_pass_nr`] to see if we we still
/// need another repaint (ui pass / frame), or if one has already happened.
pub current_cumulative_pass_nr: u64,
}
// ----------------------------------------------------------------------------
thread_local! {
static IMMEDIATE_VIEWPORT_RENDERER: RefCell<Option<Box<ImmediateViewportRendererCallback>>> = Default::default();
}
// ----------------------------------------------------------------------------
struct WrappedTextureManager(Arc<RwLock<epaint::TextureManager>>);
impl Default for WrappedTextureManager {
fn default() -> Self {
let mut tex_mngr = epaint::textures::TextureManager::default();
// Will be filled in later
let font_id = tex_mngr.alloc(
"egui_font_texture".into(),
epaint::FontImage::new([0, 0]).into(),
Default::default(),
);
assert_eq!(font_id, TextureId::default());
Self(Arc::new(RwLock::new(tex_mngr)))
}
}
// ----------------------------------------------------------------------------
/// Generic event callback.
pub type ContextCallback = Arc<dyn Fn(&Context) + Send + Sync>;
#[derive(Clone)]
struct NamedContextCallback {
debug_name: &'static str,
callback: ContextCallback,
}
/// Callbacks that users can register
#[derive(Clone, Default)]
struct Plugins {
pub on_begin_pass: Vec<NamedContextCallback>,
pub on_end_pass: Vec<NamedContextCallback>,
}
impl Plugins {
fn call(ctx: &Context, _cb_name: &str, callbacks: &[NamedContextCallback]) {
crate::profile_scope!("plugins", _cb_name);
for NamedContextCallback {
debug_name: _name,
callback,
} in callbacks
{
crate::profile_scope!("plugin", _name);
(callback)(ctx);
}
}
fn on_begin_pass(&self, ctx: &Context) {
Self::call(ctx, "on_begin_pass", &self.on_begin_pass);
}
fn on_end_pass(&self, ctx: &Context) {
Self::call(ctx, "on_end_pass", &self.on_end_pass);
}
}
// ----------------------------------------------------------------------------
/// Repaint-logic
impl ContextImpl {
/// This is where we update the repaint logic.
fn begin_pass_repaint_logic(&mut self, viewport_id: ViewportId) {
let viewport = self.viewports.entry(viewport_id).or_default();
std::mem::swap(
&mut viewport.repaint.prev_causes,
&mut viewport.repaint.causes,
);
viewport.repaint.causes.clear();
viewport.repaint.prev_pass_paint_delay = viewport.repaint.repaint_delay;
if viewport.repaint.outstanding == 0 {
// We are repainting now, so we can wait a while for the next repaint.
viewport.repaint.repaint_delay = Duration::MAX;
} else {
viewport.repaint.repaint_delay = Duration::ZERO;
viewport.repaint.outstanding -= 1;
if let Some(callback) = &self.request_repaint_callback {
(callback)(RequestRepaintInfo {
viewport_id,
delay: Duration::ZERO,
current_cumulative_pass_nr: viewport.repaint.cumulative_pass_nr,
});
}
}
}
fn request_repaint(&mut self, viewport_id: ViewportId, cause: RepaintCause) {
self.request_repaint_after(Duration::ZERO, viewport_id, cause);
}
fn request_repaint_after(
&mut self,
mut delay: Duration,
viewport_id: ViewportId,
cause: RepaintCause,
) {
let viewport = self.viewports.entry(viewport_id).or_default();
if delay == Duration::ZERO {
// Each request results in two repaints, just to give some things time to settle.
// This solves some corner-cases of missing repaints on frame-delayed responses.
viewport.repaint.outstanding = 1;
} else {
// For non-zero delays, we only repaint once, because
// otherwise we would just schedule an immediate repaint _now_,
// which would then clear the delay and repaint again.
// Hovering a tooltip is a good example of a case where we want to repaint after a delay.
}
if let Ok(predicted_frame_time) = Duration::try_from_secs_f32(viewport.input.predicted_dt) {
// Make it less likely we over-shoot the target:
delay = delay.saturating_sub(predicted_frame_time);
}
viewport.repaint.causes.push(cause);
// We save some CPU time by only calling the callback if we need to.
// If the new delay is greater or equal to the previous lowest,
// it means we have already called the callback, and don't need to do it again.
if delay < viewport.repaint.repaint_delay {
viewport.repaint.repaint_delay = delay;
if let Some(callback) = &self.request_repaint_callback {
(callback)(RequestRepaintInfo {
viewport_id,
delay,
current_cumulative_pass_nr: viewport.repaint.cumulative_pass_nr,
});
}
}
}
#[must_use]
fn requested_immediate_repaint_prev_pass(&self, viewport_id: &ViewportId) -> bool {
self.viewports
.get(viewport_id)
.map_or(false, |v| v.repaint.requested_immediate_repaint_prev_pass())
}
#[must_use]
fn has_requested_repaint(&self, viewport_id: &ViewportId) -> bool {
self.viewports.get(viewport_id).map_or(false, |v| {
0 < v.repaint.outstanding || v.repaint.repaint_delay < Duration::MAX
})
}
}
// ----------------------------------------------------------------------------
/// State stored per viewport.
///
/// Mostly for internal use.
/// Things here may move and change without warning.
#[derive(Default)]
pub struct ViewportState {
/// The type of viewport.
///
/// This will never be [`ViewportClass::Embedded`],
/// since those don't result in real viewports.
pub class: ViewportClass,
/// The latest delta
pub builder: ViewportBuilder,
/// The user-code that shows the GUI, used for deferred viewports.
///
/// `None` for immediate viewports.
pub viewport_ui_cb: Option<Arc<DeferredViewportUiCallback>>,
pub input: InputState,
/// State that is collected during a pass and then cleared.
pub this_pass: PassState,
/// The final [`PassState`] from last pass.
///
/// Only read from.
pub prev_pass: PassState,
/// Has this viewport been updated this pass?
pub used: bool,
/// State related to repaint scheduling.
repaint: ViewportRepaintInfo,
// ----------------------
// Updated at the start of the pass:
//
/// Which widgets are under the pointer?
pub hits: WidgetHits,
/// What widgets are being interacted with this pass?
///
/// Based on the widgets from last pass, and input in this pass.
pub interact_widgets: InteractionSnapshot,
// ----------------------
// The output of a pass:
//
pub graphics: GraphicLayers,
// Most of the things in `PlatformOutput` are not actually viewport dependent.
pub output: PlatformOutput,
pub commands: Vec<ViewportCommand>,
// ----------------------
// Cross-frame statistics:
pub num_multipass_in_row: usize,
}
/// What called [`Context::request_repaint`] or [`Context::request_discard`]?
#[derive(Clone, PartialEq, Eq, Hash)]
pub struct RepaintCause {
/// What file had the call that requested the repaint?
pub file: &'static str,
/// What line number of the call that requested the repaint?
pub line: u32,
/// Explicit reason; human readable.
pub reason: Cow<'static, str>,
}
impl std::fmt::Debug for RepaintCause {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
write!(f, "{}:{} {}", self.file, self.line, self.reason)
}
}
impl std::fmt::Display for RepaintCause {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
write!(f, "{}:{} {}", self.file, self.line, self.reason)
}
}
impl RepaintCause {
/// Capture the file and line number of the call site.
#[allow(clippy::new_without_default)]
#[track_caller]
pub fn new() -> Self {
let caller = Location::caller();
Self {
file: caller.file(),
line: caller.line(),
reason: "".into(),
}
}
/// Capture the file and line number of the call site,
/// as well as add a reason.
#[allow(clippy::new_without_default)]
#[track_caller]
pub fn new_reason(reason: impl Into<Cow<'static, str>>) -> Self {
let caller = Location::caller();
Self {
file: caller.file(),
line: caller.line(),
reason: reason.into(),
}
}
}
/// Per-viewport state related to repaint scheduling.
struct ViewportRepaintInfo {
/// Monotonically increasing counter.
cumulative_pass_nr: u64,
/// The duration which the backend will poll for new events
/// before forcing another egui update, even if there's no new events.
///
/// Also used to suppress multiple calls to the repaint callback during the same pass.
///
/// This is also returned in [`crate::ViewportOutput`].
repaint_delay: Duration,
/// While positive, keep requesting repaints. Decrement at the start of each pass.
outstanding: u8,
/// What caused repaints during this pass?
causes: Vec<RepaintCause>,
/// What triggered a repaint the previous pass?
/// (i.e: why are we updating now?)
prev_causes: Vec<RepaintCause>,
/// What was the output of `repaint_delay` on the previous pass?
///
/// If this was zero, we are repainting as quickly as possible
/// (as far as we know).
prev_pass_paint_delay: Duration,
}
impl Default for ViewportRepaintInfo {
fn default() -> Self {
Self {
cumulative_pass_nr: 0,
// We haven't scheduled a repaint yet.
repaint_delay: Duration::MAX,
// Let's run a couple of frames at the start, because why not.
outstanding: 1,
causes: Default::default(),
prev_causes: Default::default(),
prev_pass_paint_delay: Duration::MAX,
}
}
}
impl ViewportRepaintInfo {
pub fn requested_immediate_repaint_prev_pass(&self) -> bool {
self.prev_pass_paint_delay == Duration::ZERO
}
}
// ----------------------------------------------------------------------------
#[derive(Default)]
struct ContextImpl {
/// Since we could have multiple viewports across multiple monitors with
/// different `pixels_per_point`, we need a `Fonts` instance for each unique
/// `pixels_per_point`.
/// This is because the `Fonts` depend on `pixels_per_point` for the font atlas
/// as well as kerning, font sizes, etc.
fonts: std::collections::BTreeMap<OrderedFloat<f32>, Fonts>,
font_definitions: FontDefinitions,
memory: Memory,
animation_manager: AnimationManager,
plugins: Plugins,
/// All viewports share the same texture manager and texture namespace.
///
/// In all viewports, [`TextureId::default`] is special, and points to the font atlas.
/// The font-atlas texture _may_ be different across viewports, as they may have different
/// `pixels_per_point`, so we do special book-keeping for that.
/// See <https://github.com/emilk/egui/issues/3664>.
tex_manager: WrappedTextureManager,
/// Set during the pass, becomes active at the start of the next pass.
new_zoom_factor: Option<f32>,
os: OperatingSystem,
/// How deeply nested are we?
viewport_stack: Vec<ViewportIdPair>,
/// What is the last viewport rendered?
last_viewport: ViewportId,
paint_stats: PaintStats,
request_repaint_callback: Option<Box<dyn Fn(RequestRepaintInfo) + Send + Sync>>,
viewport_parents: ViewportIdMap<ViewportId>,
viewports: ViewportIdMap<ViewportState>,
embed_viewports: bool,
#[cfg(feature = "accesskit")]
is_accesskit_enabled: bool,
loaders: Arc<Loaders>,
}
impl ContextImpl {
fn begin_pass(&mut self, mut new_raw_input: RawInput) {
let viewport_id = new_raw_input.viewport_id;
let parent_id = new_raw_input
.viewports
.get(&viewport_id)
.and_then(|v| v.parent)
.unwrap_or_default();
let ids = ViewportIdPair::from_self_and_parent(viewport_id, parent_id);
let is_outermost_viewport = self.viewport_stack.is_empty(); // not necessarily root, just outermost immediate viewport
self.viewport_stack.push(ids);
self.begin_pass_repaint_logic(viewport_id);
let viewport = self.viewports.entry(viewport_id).or_default();
if is_outermost_viewport {
if let Some(new_zoom_factor) = self.new_zoom_factor.take() {
let ratio = self.memory.options.zoom_factor / new_zoom_factor;
self.memory.options.zoom_factor = new_zoom_factor;
let input = &viewport.input;
// This is a bit hacky, but is required to avoid jitter:
let mut rect = input.screen_rect;
rect.min = (ratio * rect.min.to_vec2()).to_pos2();
rect.max = (ratio * rect.max.to_vec2()).to_pos2();
new_raw_input.screen_rect = Some(rect);
// We should really scale everything else in the input too,
// but the `screen_rect` is the most important part.
}
}
let native_pixels_per_point = new_raw_input
.viewport()
.native_pixels_per_point
.unwrap_or(1.0);
let pixels_per_point = self.memory.options.zoom_factor * native_pixels_per_point;
let all_viewport_ids: ViewportIdSet = self.all_viewport_ids();
let viewport = self.viewports.entry(self.viewport_id()).or_default();
self.memory.begin_pass(&new_raw_input, &all_viewport_ids);
viewport.input = std::mem::take(&mut viewport.input).begin_pass(
new_raw_input,
viewport.repaint.requested_immediate_repaint_prev_pass(),
pixels_per_point,
&self.memory.options,
);
let screen_rect = viewport.input.screen_rect;
viewport.this_pass.begin_pass(screen_rect);
{
let area_order = self.memory.areas().order_map();
let mut layers: Vec<LayerId> = viewport.prev_pass.widgets.layer_ids().collect();
layers.sort_by(|a, b| {
if a.order == b.order {
// Maybe both are windows, so respect area order:
area_order.get(a).cmp(&area_order.get(b))
} else {
// comparing e.g. background to tooltips
a.order.cmp(&b.order)
}
});
viewport.hits = if let Some(pos) = viewport.input.pointer.interact_pos() {
let interact_radius = self.memory.options.style().interaction.interact_radius;
crate::hit_test::hit_test(
&viewport.prev_pass.widgets,
&layers,
&self.memory.layer_transforms,
pos,
interact_radius,
)
} else {
WidgetHits::default()
};
viewport.interact_widgets = crate::interaction::interact(
&viewport.interact_widgets,
&viewport.prev_pass.widgets,
&viewport.hits,
&viewport.input,
self.memory.interaction_mut(),
);
}
// Ensure we register the background area so panels and background ui can catch clicks:
self.memory.areas_mut().set_state(
LayerId::background(),
AreaState {
pivot_pos: Some(screen_rect.left_top()),
pivot: Align2::LEFT_TOP,
size: Some(screen_rect.size()),
interactable: true,
last_became_visible_at: None,
},
);
#[cfg(feature = "accesskit")]
if self.is_accesskit_enabled {
crate::profile_scope!("accesskit");
use crate::pass_state::AccessKitPassState;
let id = crate::accesskit_root_id();
let mut builder = accesskit::NodeBuilder::new(accesskit::Role::Window);
let pixels_per_point = viewport.input.pixels_per_point();
builder.set_transform(accesskit::Affine::scale(pixels_per_point.into()));
let mut node_builders = IdMap::default();
node_builders.insert(id, builder);
viewport.this_pass.accesskit_state = Some(AccessKitPassState {
node_builders,
parent_stack: vec![id],
});
}
self.update_fonts_mut();
}
/// Load fonts unless already loaded.
fn update_fonts_mut(&mut self) {
crate::profile_function!();
let input = &self.viewport().input;
let pixels_per_point = input.pixels_per_point();
let max_texture_side = input.max_texture_side;
if let Some(font_definitions) = self.memory.new_font_definitions.take() {
// New font definition loaded, so we need to reload all fonts.
self.fonts.clear();
self.font_definitions = font_definitions;
#[cfg(feature = "log")]
log::trace!("Loading new font definitions");
}
let mut is_new = false;
let fonts = self
.fonts
.entry(pixels_per_point.into())
.or_insert_with(|| {
#[cfg(feature = "log")]
log::trace!("Creating new Fonts for pixels_per_point={pixels_per_point}");
is_new = true;
crate::profile_scope!("Fonts::new");
Fonts::new(
pixels_per_point,
max_texture_side,
self.font_definitions.clone(),
)
});
{
crate::profile_scope!("Fonts::begin_pass");
fonts.begin_pass(pixels_per_point, max_texture_side);
}
if is_new && self.memory.options.preload_font_glyphs {
crate::profile_scope!("preload_font_glyphs");
// Preload the most common characters for the most common fonts.
// This is not very important to do, but may save a few GPU operations.
for font_id in self.memory.options.style().text_styles.values() {
fonts.lock().fonts.font(font_id).preload_common_characters();
}
}
}
#[cfg(feature = "accesskit")]
fn accesskit_node_builder(&mut self, id: Id) -> &mut accesskit::NodeBuilder {
let state = self.viewport().this_pass.accesskit_state.as_mut().unwrap();
let builders = &mut state.node_builders;
if let std::collections::hash_map::Entry::Vacant(entry) = builders.entry(id) {
entry.insert(Default::default());
let parent_id = state.parent_stack.last().unwrap();
let parent_builder = builders.get_mut(parent_id).unwrap();
parent_builder.push_child(id.accesskit_id());
}
builders.get_mut(&id).unwrap()
}
fn pixels_per_point(&mut self) -> f32 {
self.viewport().input.pixels_per_point
}
/// Return the `ViewportId` of the current viewport.
///
/// For the root viewport this will return [`ViewportId::ROOT`].
pub(crate) fn viewport_id(&self) -> ViewportId {
self.viewport_stack.last().copied().unwrap_or_default().this
}
/// Return the `ViewportId` of his parent.
///
/// For the root viewport this will return [`ViewportId::ROOT`].
pub(crate) fn parent_viewport_id(&self) -> ViewportId {
let viewport_id = self.viewport_id();
*self
.viewport_parents
.get(&viewport_id)
.unwrap_or(&ViewportId::ROOT)
}
fn all_viewport_ids(&self) -> ViewportIdSet {
self.viewports
.keys()
.copied()
.chain([ViewportId::ROOT])
.collect()
}
/// The current active viewport
pub(crate) fn viewport(&mut self) -> &mut ViewportState {
self.viewports.entry(self.viewport_id()).or_default()
}
fn viewport_for(&mut self, viewport_id: ViewportId) -> &mut ViewportState {
self.viewports.entry(viewport_id).or_default()
}
}
// ----------------------------------------------------------------------------
/// Your handle to egui.
///
/// This is the first thing you need when working with egui.
/// Contains the [`InputState`], [`Memory`], [`PlatformOutput`], and more.
///
/// [`Context`] is cheap to clone, and any clones refers to the same mutable data
/// ([`Context`] uses refcounting internally).
///
/// ## Locking
/// All methods are marked `&self`; [`Context`] has interior mutability protected by an [`RwLock`].
///
/// To access parts of a `Context` you need to use some of the helper functions that take closures:
///
/// ```
/// # let ctx = egui::Context::default();
/// if ctx.input(|i| i.key_pressed(egui::Key::A)) {
/// ctx.output_mut(|o| o.copied_text = "Hello!".to_string());
/// }
/// ```
///
/// Within such a closure you may NOT recursively lock the same [`Context`], as that can lead to a deadlock.
/// Therefore it is important that any lock of [`Context`] is short-lived.
///
/// These are effectively transactional accesses.
///
/// [`Ui`] has many of the same accessor functions, and the same applies there.
///
/// ## Example:
///
/// ``` no_run
/// # fn handle_platform_output(_: egui::PlatformOutput) {}
/// # fn paint(textures_delta: egui::TexturesDelta, _: Vec<egui::ClippedPrimitive>) {}
/// let mut ctx = egui::Context::default();
///
/// // Game loop:
/// loop {
/// let raw_input = egui::RawInput::default();
/// let full_output = ctx.run(raw_input, |ctx| {
/// egui::CentralPanel::default().show(&ctx, |ui| {
/// ui.label("Hello world!");
/// if ui.button("Click me").clicked() {
/// // take some action here
/// }
/// });
/// });
/// handle_platform_output(full_output.platform_output);
/// let clipped_primitives = ctx.tessellate(full_output.shapes, full_output.pixels_per_point);
/// paint(full_output.textures_delta, clipped_primitives);
/// }
/// ```
#[derive(Clone)]
pub struct Context(Arc<RwLock<ContextImpl>>);
impl std::fmt::Debug for Context {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.debug_struct("Context").finish_non_exhaustive()
}
}
impl std::cmp::PartialEq for Context {
fn eq(&self, other: &Self) -> bool {
Arc::ptr_eq(&self.0, &other.0)
}
}
impl Default for Context {
fn default() -> Self {
let ctx_impl = ContextImpl {
embed_viewports: true,
..Default::default()
};
let ctx = Self(Arc::new(RwLock::new(ctx_impl)));
// Register built-in plugins:
crate::debug_text::register(&ctx);
crate::text_selection::LabelSelectionState::register(&ctx);
crate::DragAndDrop::register(&ctx);
ctx
}
}
impl Context {
/// Do read-only (shared access) transaction on Context
fn read<R>(&self, reader: impl FnOnce(&ContextImpl) -> R) -> R {
reader(&self.0.read())
}
/// Do read-write (exclusive access) transaction on Context
fn write<R>(&self, writer: impl FnOnce(&mut ContextImpl) -> R) -> R {
writer(&mut self.0.write())
}
/// Run the ui code for one 1.
///
/// At most [`Options::max_passes`] calls will be issued to `run_ui`,
/// and only on the rare occasion that [`Context::request_discard`] is called.
/// Usually, it `run_ui` will only be called once.
///
/// Put your widgets into a [`crate::SidePanel`], [`crate::TopBottomPanel`], [`crate::CentralPanel`], [`crate::Window`] or [`crate::Area`].
///
/// Instead of calling `run`, you can alternatively use [`Self::begin_pass`] and [`Context::end_pass`].
///
/// ```
/// // One egui context that you keep reusing:
/// let mut ctx = egui::Context::default();
///
/// // Each frame:
/// let input = egui::RawInput::default();
/// let full_output = ctx.run(input, |ctx| {
/// egui::CentralPanel::default().show(&ctx, |ui| {
/// ui.label("Hello egui!");
/// });
/// });
/// // handle full_output
/// ```
#[must_use]
pub fn run(&self, mut new_input: RawInput, mut run_ui: impl FnMut(&Self)) -> FullOutput {
crate::profile_function!();
let viewport_id = new_input.viewport_id;
let max_passes = self.write(|ctx| ctx.memory.options.max_passes.get());
let mut output = FullOutput::default();
debug_assert_eq!(output.platform_output.num_completed_passes, 0);
loop {
crate::profile_scope!(
"pass",
output.platform_output.num_completed_passes.to_string()
);
// We must move the `num_passes` (back) to the viewport output so that [`Self::will_discard`]
// has access to the latest pass count.
self.write(|ctx| {
let viewport = ctx.viewport_for(viewport_id);
viewport.output.num_completed_passes =
std::mem::take(&mut output.platform_output.num_completed_passes);
output.platform_output.request_discard_reasons.clear();
});
self.begin_pass(new_input.take());
run_ui(self);
output.append(self.end_pass());
debug_assert!(0 < output.platform_output.num_completed_passes);
if !output.platform_output.requested_discard() {
break; // no need for another pass
}
if max_passes <= output.platform_output.num_completed_passes {
#[cfg(feature = "log")]
log::debug!("Ignoring call request_discard, because max_passes={max_passes}. Requested from {:?}", output.platform_output.request_discard_reasons);
break;
}
}
self.write(|ctx| {
let did_multipass = 1 < output.platform_output.num_completed_passes;
let viewport = ctx.viewport_for(viewport_id);
if did_multipass {
viewport.num_multipass_in_row += 1;
} else {
viewport.num_multipass_in_row = 0;
}
});
output
}
/// An alternative to calling [`Self::run`].
///
/// It is usually better to use [`Self::run`], because
/// `run` supports multi-pass layout using [`Self::request_discard`].
///
/// ```
/// // One egui context that you keep reusing:
/// let mut ctx = egui::Context::default();
///
/// // Each frame:
/// let input = egui::RawInput::default();
/// ctx.begin_pass(input);
///
/// egui::CentralPanel::default().show(&ctx, |ui| {
/// ui.label("Hello egui!");
/// });
///
/// let full_output = ctx.end_pass();
/// // handle full_output
/// ```
pub fn begin_pass(&self, new_input: RawInput) {
crate::profile_function!();
self.write(|ctx| ctx.begin_pass(new_input));
// Plugins run just after the pass starts:
self.read(|ctx| ctx.plugins.clone()).on_begin_pass(self);
}
/// See [`Self::begin_pass`].
#[deprecated = "Renamed begin_pass"]
pub fn begin_frame(&self, new_input: RawInput) {
self.begin_pass(new_input);
}
}
/// ## Borrows parts of [`Context`]
/// These functions all lock the [`Context`].
/// Please see the documentation of [`Context`] for how locking works!
impl Context {
/// Read-only access to [`InputState`].
///
/// Note that this locks the [`Context`].
///
/// ```
/// # let mut ctx = egui::Context::default();
/// ctx.input(|i| {
/// // ⚠️ Using `ctx` (even from other `Arc` reference) again here will lead to a deadlock!
/// });
///
/// if let Some(pos) = ctx.input(|i| i.pointer.hover_pos()) {
/// // This is fine!
/// }
/// ```
#[inline]
pub fn input<R>(&self, reader: impl FnOnce(&InputState) -> R) -> R {
self.write(move |ctx| reader(&ctx.viewport().input))
}
/// This will create a `InputState::default()` if there is no input state for that viewport
#[inline]
pub fn input_for<R>(&self, id: ViewportId, reader: impl FnOnce(&InputState) -> R) -> R {
self.write(move |ctx| reader(&ctx.viewport_for(id).input))
}
/// Read-write access to [`InputState`].
#[inline]
pub fn input_mut<R>(&self, writer: impl FnOnce(&mut InputState) -> R) -> R {
self.input_mut_for(self.viewport_id(), writer)
}
/// This will create a `InputState::default()` if there is no input state for that viewport
#[inline]
pub fn input_mut_for<R>(&self, id: ViewportId, writer: impl FnOnce(&mut InputState) -> R) -> R {
self.write(move |ctx| writer(&mut ctx.viewport_for(id).input))
}
/// Read-only access to [`Memory`].
#[inline]
pub fn memory<R>(&self, reader: impl FnOnce(&Memory) -> R) -> R {
self.read(move |ctx| reader(&ctx.memory))
}
/// Read-write access to [`Memory`].
#[inline]
pub fn memory_mut<R>(&self, writer: impl FnOnce(&mut Memory) -> R) -> R {
self.write(move |ctx| writer(&mut ctx.memory))
}
/// Read-only access to [`IdTypeMap`], which stores superficial widget state.
#[inline]
pub fn data<R>(&self, reader: impl FnOnce(&IdTypeMap) -> R) -> R {
self.read(move |ctx| reader(&ctx.memory.data))
}
/// Read-write access to [`IdTypeMap`], which stores superficial widget state.
#[inline]
pub fn data_mut<R>(&self, writer: impl FnOnce(&mut IdTypeMap) -> R) -> R {
self.write(move |ctx| writer(&mut ctx.memory.data))
}
/// Read-write access to [`GraphicLayers`], where painted [`crate::Shape`]s are written to.
#[inline]
pub fn graphics_mut<R>(&self, writer: impl FnOnce(&mut GraphicLayers) -> R) -> R {
self.write(move |ctx| writer(&mut ctx.viewport().graphics))
}
/// Read-only access to [`GraphicLayers`], where painted [`crate::Shape`]s are written to.
#[inline]
pub fn graphics<R>(&self, reader: impl FnOnce(&GraphicLayers) -> R) -> R {
self.write(move |ctx| reader(&ctx.viewport().graphics))
}
/// Read-only access to [`PlatformOutput`].
///
/// This is what egui outputs each pass and frame.
///
/// ```
/// # let mut ctx = egui::Context::default();
/// ctx.output_mut(|o| o.cursor_icon = egui::CursorIcon::Progress);
/// ```
#[inline]
pub fn output<R>(&self, reader: impl FnOnce(&PlatformOutput) -> R) -> R {
self.write(move |ctx| reader(&ctx.viewport().output))
}
/// Read-write access to [`PlatformOutput`].
#[inline]
pub fn output_mut<R>(&self, writer: impl FnOnce(&mut PlatformOutput) -> R) -> R {
self.write(move |ctx| writer(&mut ctx.viewport().output))
}
/// Read-only access to [`PassState`].
///
/// This is only valid during the call to [`Self::run`] (between [`Self::begin_pass`] and [`Self::end_pass`]).
#[inline]
pub(crate) fn pass_state<R>(&self, reader: impl FnOnce(&PassState) -> R) -> R {
self.write(move |ctx| reader(&ctx.viewport().this_pass))
}
/// Read-write access to [`PassState`].
///
/// This is only valid during the call to [`Self::run`] (between [`Self::begin_pass`] and [`Self::end_pass`]).
#[inline]
pub(crate) fn pass_state_mut<R>(&self, writer: impl FnOnce(&mut PassState) -> R) -> R {
self.write(move |ctx| writer(&mut ctx.viewport().this_pass))
}
/// Read-only access to the [`PassState`] from the previous pass.
///
/// This is swapped at the end of each pass.
#[inline]
pub(crate) fn prev_pass_state<R>(&self, reader: impl FnOnce(&PassState) -> R) -> R {
self.write(move |ctx| reader(&ctx.viewport().prev_pass))
}
/// Read-only access to [`Fonts`].
///
/// Not valid until first call to [`Context::run()`].
/// That's because since we don't know the proper `pixels_per_point` until then.
#[inline]
pub fn fonts<R>(&self, reader: impl FnOnce(&Fonts) -> R) -> R {
self.write(move |ctx| {
let pixels_per_point = ctx.pixels_per_point();
reader(
ctx.fonts
.get(&pixels_per_point.into())
.expect("No fonts available until first call to Context::run()"),
)
})
}
/// Read-only access to [`Options`].
#[inline]
pub fn options<R>(&self, reader: impl FnOnce(&Options) -> R) -> R {
self.read(move |ctx| reader(&ctx.memory.options))
}
/// Read-write access to [`Options`].
#[inline]
pub fn options_mut<R>(&self, writer: impl FnOnce(&mut Options) -> R) -> R {
self.write(move |ctx| writer(&mut ctx.memory.options))
}
/// Read-only access to [`TessellationOptions`].
#[inline]
pub fn tessellation_options<R>(&self, reader: impl FnOnce(&TessellationOptions) -> R) -> R {
self.read(move |ctx| reader(&ctx.memory.options.tessellation_options))
}
/// Read-write access to [`TessellationOptions`].
#[inline]
pub fn tessellation_options_mut<R>(
&self,
writer: impl FnOnce(&mut TessellationOptions) -> R,
) -> R {
self.write(move |ctx| writer(&mut ctx.memory.options.tessellation_options))
}
/// If the given [`Id`] has been used previously the same pass at different position,
/// then an error will be printed on screen.
///
/// This function is already called for all widgets that do any interaction,
/// but you can call this from widgets that store state but that does not interact.
///
/// The given [`Rect`] should be approximately where the widget will be.
/// The most important thing is that [`Rect::min`] is approximately correct,
/// because that's where the warning will be painted. If you don't know what size to pick, just pick [`Vec2::ZERO`].
pub fn check_for_id_clash(&self, id: Id, new_rect: Rect, what: &str) {
let prev_rect = self.pass_state_mut(move |state| state.used_ids.insert(id, new_rect));
if !self.options(|opt| opt.warn_on_id_clash) {
return;
}
let Some(prev_rect) = prev_rect else { return };
// It is ok to reuse the same ID for e.g. a frame around a widget,
// or to check for interaction with the same widget twice:
let is_same_rect = prev_rect.expand(0.1).contains_rect(new_rect)
|| new_rect.expand(0.1).contains_rect(prev_rect);
if is_same_rect {
return;
}
let show_error = |widget_rect: Rect, text: String| {
let screen_rect = self.screen_rect();
let text = format!("🔥 {text}");
let color = self.style().visuals.error_fg_color;
let painter = self.debug_painter();
painter.rect_stroke(widget_rect, 0.0, (1.0, color));
let below = widget_rect.bottom() + 32.0 < screen_rect.bottom();
let text_rect = if below {
painter.debug_text(
widget_rect.left_bottom() + vec2(0.0, 2.0),
Align2::LEFT_TOP,
color,
text,
)
} else {
painter.debug_text(
widget_rect.left_top() - vec2(0.0, 2.0),
Align2::LEFT_BOTTOM,
color,
text,
)
};
if let Some(pointer_pos) = self.pointer_hover_pos() {
if text_rect.contains(pointer_pos) {
let tooltip_pos = if below {
text_rect.left_bottom() + vec2(2.0, 4.0)
} else {
text_rect.left_top() + vec2(2.0, -4.0)
};
painter.error(
tooltip_pos,
format!("Widget is {} this text.\n\n\
ID clashes happens when things like Windows or CollapsingHeaders share names,\n\
or when things like Plot and Grid:s aren't given unique id_salt:s.\n\n\
Sometimes the solution is to use ui.push_id.",
if below { "above" } else { "below" })
);
}
}
};
let id_str = id.short_debug_format();
if prev_rect.min.distance(new_rect.min) < 4.0 {
show_error(new_rect, format!("Double use of {what} ID {id_str}"));
} else {
show_error(prev_rect, format!("First use of {what} ID {id_str}"));
show_error(new_rect, format!("Second use of {what} ID {id_str}"));
}
}
// ---------------------------------------------------------------------
/// Create a widget and check for interaction.
///
/// If this is not called, the widget doesn't exist.
///
/// You should use [`Ui::interact`] instead.
///
/// If the widget already exists, its state (sense, Rect, etc) will be updated.
///
/// `allow_focus` should usually be true, unless you call this function multiple times with the
/// same widget, then `allow_focus` should only be true once (like in [`Ui::new`] (true) and [`Ui::remember_min_rect`] (false)).
#[allow(clippy::too_many_arguments)]
pub(crate) fn create_widget(&self, w: WidgetRect, allow_focus: bool) -> Response {
// Remember this widget
self.write(|ctx| {
let viewport = ctx.viewport();
// We add all widgets here, even non-interactive ones,
// because we need this list not only for checking for blocking widgets,
// but also to know when we have reached the widget we are checking for cover.
viewport.this_pass.widgets.insert(w.layer_id, w);
if allow_focus && w.sense.focusable {
ctx.memory.interested_in_focus(w.id);
}
});
if allow_focus && (!w.enabled || !w.sense.focusable || !w.layer_id.allow_interaction()) {
// Not interested or allowed input:
self.memory_mut(|mem| mem.surrender_focus(w.id));
}
if w.sense.interactive() || w.sense.focusable {
self.check_for_id_clash(w.id, w.rect, "widget");
}
#[allow(clippy::let_and_return)]
let res = self.get_response(w);
#[cfg(feature = "accesskit")]
if allow_focus && w.sense.focusable {
// Make sure anything that can receive focus has an AccessKit node.
// TODO(mwcampbell): For nodes that are filled from widget info,
// some information is written to the node twice.
self.accesskit_node_builder(w.id, |builder| res.fill_accesskit_node_common(builder));
}
res
}
/// Read the response of some widget, which may be called _before_ creating the widget (!).
///
/// This is because widget interaction happens at the start of the pass, using the widget rects from the previous pass.
///
/// If the widget was not visible the previous pass (or this pass), this will return `None`.
pub fn read_response(&self, id: Id) -> Option<Response> {
self.write(|ctx| {
let viewport = ctx.viewport();
viewport
.this_pass
.widgets
.get(id)
.or_else(|| viewport.prev_pass.widgets.get(id))
.copied()
})
.map(|widget_rect| self.get_response(widget_rect))
}
/// Returns `true` if the widget with the given `Id` contains the pointer.
#[deprecated = "Use Response.contains_pointer or Context::read_response instead"]
pub fn widget_contains_pointer(&self, id: Id) -> bool {
self.read_response(id)
.map_or(false, |response| response.contains_pointer)
}
/// Do all interaction for an existing widget, without (re-)registering it.
pub(crate) fn get_response(&self, widget_rect: WidgetRect) -> Response {
let WidgetRect {
id,
layer_id,
rect,
interact_rect,
sense,
enabled,
} = widget_rect;
// previous pass + "highlight next pass" == "highlight this pass"
let highlighted = self.prev_pass_state(|fs| fs.highlight_next_pass.contains(&id));
let mut res = Response {
ctx: self.clone(),
layer_id,
id,
rect,
interact_rect,
sense,
enabled,
contains_pointer: false,
hovered: false,
highlighted,
clicked: false,
fake_primary_click: false,
long_touched: false,
drag_started: false,
dragged: false,
drag_stopped: false,
is_pointer_button_down_on: false,
interact_pointer_pos: None,
changed: false,
intrinsic_size: None,
};
self.write(|ctx| {
let viewport = ctx.viewports.entry(ctx.viewport_id()).or_default();
res.contains_pointer = viewport.interact_widgets.contains_pointer.contains(&id);
let input = &viewport.input;
let memory = &mut ctx.memory;
if enabled
&& sense.click
&& memory.has_focus(id)
&& (input.key_pressed(Key::Space) || input.key_pressed(Key::Enter))
{
// Space/enter works like a primary click for e.g. selected buttons
res.fake_primary_click = true;
}
#[cfg(feature = "accesskit")]
if enabled
&& sense.click
&& input.has_accesskit_action_request(id, accesskit::Action::Default)
{
res.fake_primary_click = true;
}
if enabled && sense.click && Some(id) == viewport.interact_widgets.long_touched {
res.long_touched = true;
}
let interaction = memory.interaction();
res.is_pointer_button_down_on = interaction.potential_click_id == Some(id)
|| interaction.potential_drag_id == Some(id);
if res.enabled {
res.hovered = viewport.interact_widgets.hovered.contains(&id);
res.dragged = Some(id) == viewport.interact_widgets.dragged;
res.drag_started = Some(id) == viewport.interact_widgets.drag_started;
res.drag_stopped = Some(id) == viewport.interact_widgets.drag_stopped;
}
let clicked = Some(id) == viewport.interact_widgets.clicked;
let mut any_press = false;
for pointer_event in &input.pointer.pointer_events {
match pointer_event {
PointerEvent::Moved(_) => {}
PointerEvent::Pressed { .. } => {
any_press = true;
}
PointerEvent::Released { click, .. } => {
if enabled && sense.click && clicked && click.is_some() {
res.clicked = true;
}
res.is_pointer_button_down_on = false;
res.dragged = false;
}
}
}
// is_pointer_button_down_on is false when released, but we want interact_pointer_pos
// to still work.
let is_interacted_with =
res.is_pointer_button_down_on || res.long_touched || clicked || res.drag_stopped;
if is_interacted_with {
res.interact_pointer_pos = input.pointer.interact_pos();
if let (Some(transform), Some(pos)) = (
memory.layer_transforms.get(&res.layer_id),
&mut res.interact_pointer_pos,
) {
*pos = transform.inverse() * *pos;
}
}
if input.pointer.any_down() && !is_interacted_with {
// We don't hover widgets while interacting with *other* widgets:
res.hovered = false;
}
let pointer_pressed_elsewhere = any_press && !res.hovered;
if pointer_pressed_elsewhere && memory.has_focus(id) {
memory.surrender_focus(id);
}
});
res
}
/// This is called by [`Response::widget_info`], but can also be called directly.
///
/// With some debug flags it will store the widget info in [`crate::WidgetRects`] for later display.
#[inline]
pub fn register_widget_info(&self, id: Id, make_info: impl Fn() -> crate::WidgetInfo) {
#[cfg(debug_assertions)]
self.write(|ctx| {
if ctx.memory.options.style().debug.show_interactive_widgets {
ctx.viewport().this_pass.widgets.set_info(id, make_info());
}
});
#[cfg(not(debug_assertions))]
{
_ = (self, id, make_info);
}
}
/// Get a full-screen painter for a new or existing layer
pub fn layer_painter(&self, layer_id: LayerId) -> Painter {
let screen_rect = self.screen_rect();
Painter::new(self.clone(), layer_id, screen_rect)
}
/// Paint on top of everything else
pub fn debug_painter(&self) -> Painter {
Self::layer_painter(self, LayerId::debug())
}
/// Print this text next to the cursor at the end of the pass.
///
/// If you call this multiple times, the text will be appended.
///
/// This only works if compiled with `debug_assertions`.
///
/// ```
/// # let ctx = egui::Context::default();
/// # let state = true;
/// ctx.debug_text(format!("State: {state:?}"));
/// ```
///
/// This is just a convenience for calling [`crate::debug_text::print`].
#[track_caller]
pub fn debug_text(&self, text: impl Into<WidgetText>) {
crate::debug_text::print(self, text);
}
/// What operating system are we running on?
///
/// When compiling natively, this is
/// figured out from the `target_os`.
///
/// For web, this can be figured out from the user-agent,
/// and is done so by [`eframe`](https://github.com/emilk/egui/tree/master/crates/eframe).
pub fn os(&self) -> OperatingSystem {
self.read(|ctx| ctx.os)
}
/// Set the operating system we are running on.
///
/// If you are writing wasm-based integration for egui you
/// may want to set this based on e.g. the user-agent.
pub fn set_os(&self, os: OperatingSystem) {
self.write(|ctx| ctx.os = os);
}
/// Set the cursor icon.
///
/// Equivalent to:
/// ```
/// # let ctx = egui::Context::default();
/// ctx.output_mut(|o| o.cursor_icon = egui::CursorIcon::PointingHand);
/// ```
pub fn set_cursor_icon(&self, cursor_icon: CursorIcon) {
self.output_mut(|o| o.cursor_icon = cursor_icon);
}
/// Open an URL in a browser.
///
/// Equivalent to:
/// ```
/// # let ctx = egui::Context::default();
/// # let open_url = egui::OpenUrl::same_tab("http://www.example.com");
/// ctx.output_mut(|o| o.open_url = Some(open_url));
/// ```
pub fn open_url(&self, open_url: crate::OpenUrl) {
self.output_mut(|o| o.open_url = Some(open_url));
}
/// Copy the given text to the system clipboard.
///
/// Empty strings are ignored.
///
/// Equivalent to:
/// ```
/// # let ctx = egui::Context::default();
/// ctx.output_mut(|o| o.copied_text = "Copy this".to_owned());
/// ```
pub fn copy_text(&self, text: String) {
self.output_mut(|o| o.copied_text = text);
}
/// Format the given shortcut in a human-readable way (e.g. `Ctrl+Shift+X`).
///
/// Can be used to get the text for [`crate::Button::shortcut_text`].
pub fn format_shortcut(&self, shortcut: &KeyboardShortcut) -> String {
let os = self.os();
let is_mac = matches!(os, OperatingSystem::Mac | OperatingSystem::IOS);
let can_show_symbols = || {
let ModifierNames {
alt,
ctrl,
shift,
mac_cmd,
..
} = ModifierNames::SYMBOLS;
let font_id = TextStyle::Body.resolve(&self.style());
self.fonts(|f| {
let mut lock = f.lock();
let font = lock.fonts.font(&font_id);
font.has_glyphs(alt)
&& font.has_glyphs(ctrl)
&& font.has_glyphs(shift)
&& font.has_glyphs(mac_cmd)
})
};
if is_mac && can_show_symbols() {
shortcut.format(&ModifierNames::SYMBOLS, is_mac)
} else {
shortcut.format(&ModifierNames::NAMES, is_mac)
}
}
/// The total number of completed passes (usually there is one pass per rendered frame).
///
/// Starts at zero, and is incremented for each completed pass inside of [`Self::run`] (usually once).
pub fn cumulative_pass_nr(&self) -> u64 {
self.cumulative_pass_nr_for(self.viewport_id())
}
/// The total number of completed passes (usually there is one pass per rendered frame).
///
/// Starts at zero, and is incremented for each completed pass inside of [`Self::run`] (usually once).
pub fn cumulative_pass_nr_for(&self, id: ViewportId) -> u64 {
self.read(|ctx| {
ctx.viewports
.get(&id)
.map_or(0, |v| v.repaint.cumulative_pass_nr)
})
}
/// Call this if there is need to repaint the UI, i.e. if you are showing an animation.
///
/// If this is called at least once in a frame, then there will be another frame right after this.
/// Call as many times as you wish, only one repaint will be issued.
///
/// To request repaint with a delay, use [`Self::request_repaint_after`].
///
/// If called from outside the UI thread, the UI thread will wake up and run,
/// provided the egui integration has set that up via [`Self::set_request_repaint_callback`]
/// (this will work on `eframe`).
///
/// This will repaint the current viewport.
#[track_caller]
pub fn request_repaint(&self) {
self.request_repaint_of(self.viewport_id());
}
/// Call this if there is need to repaint the UI, i.e. if you are showing an animation.
///
/// If this is called at least once in a frame, then there will be another frame right after this.
/// Call as many times as you wish, only one repaint will be issued.
///
/// To request repaint with a delay, use [`Self::request_repaint_after_for`].
///
/// If called from outside the UI thread, the UI thread will wake up and run,
/// provided the egui integration has set that up via [`Self::set_request_repaint_callback`]
/// (this will work on `eframe`).
///
/// This will repaint the specified viewport.
#[track_caller]
pub fn request_repaint_of(&self, id: ViewportId) {
let cause = RepaintCause::new();
self.write(|ctx| ctx.request_repaint(id, cause));
}
/// Request repaint after at most the specified duration elapses.
///
/// The backend can chose to repaint sooner, for instance if some other code called
/// this method with a lower duration, or if new events arrived.
///
/// The function can be multiple times, but only the *smallest* duration will be considered.
/// So, if the function is called two times with `1 second` and `2 seconds`, egui will repaint
/// after `1 second`
///
/// This is primarily useful for applications who would like to save battery by avoiding wasted
/// redraws when the app is not in focus. But sometimes the GUI of the app might become stale
/// and outdated if it is not updated for too long.
///
/// Let's say, something like a stopwatch widget that displays the time in seconds. You would waste
/// resources repainting multiple times within the same second (when you have no input),
/// just calculate the difference of duration between current time and next second change,
/// and call this function, to make sure that you are displaying the latest updated time, but
/// not wasting resources on needless repaints within the same second.
///
/// ### Quirk:
/// Duration begins at the next frame. Let's say for example that it's a very inefficient app
/// and takes 500 milliseconds per frame at 2 fps. The widget / user might want a repaint in
/// next 500 milliseconds. Now, app takes 1000 ms per frame (1 fps) because the backend event
/// timeout takes 500 milliseconds AFTER the vsync swap buffer.
/// So, it's not that we are requesting repaint within X duration. We are rather timing out
/// during app idle time where we are not receiving any new input events.
///
/// This repaints the current viewport.
#[track_caller]
pub fn request_repaint_after(&self, duration: Duration) {
self.request_repaint_after_for(duration, self.viewport_id());
}
/// Repaint after this many seconds.
///
/// See [`Self::request_repaint_after`] for details.
#[track_caller]
pub fn request_repaint_after_secs(&self, seconds: f32) {
if let Ok(duration) = std::time::Duration::try_from_secs_f32(seconds) {
self.request_repaint_after(duration);
}
}
/// Request repaint after at most the specified duration elapses.
///
/// The backend can chose to repaint sooner, for instance if some other code called
/// this method with a lower duration, or if new events arrived.
///
/// The function can be multiple times, but only the *smallest* duration will be considered.
/// So, if the function is called two times with `1 second` and `2 seconds`, egui will repaint
/// after `1 second`
///
/// This is primarily useful for applications who would like to save battery by avoiding wasted
/// redraws when the app is not in focus. But sometimes the GUI of the app might become stale
/// and outdated if it is not updated for too long.
///
/// Let's say, something like a stopwatch widget that displays the time in seconds. You would waste
/// resources repainting multiple times within the same second (when you have no input),
/// just calculate the difference of duration between current time and next second change,
/// and call this function, to make sure that you are displaying the latest updated time, but
/// not wasting resources on needless repaints within the same second.
///
/// ### Quirk:
/// Duration begins at the next frame. Let's say for example that it's a very inefficient app
/// and takes 500 milliseconds per frame at 2 fps. The widget / user might want a repaint in
/// next 500 milliseconds. Now, app takes 1000 ms per frame (1 fps) because the backend event
/// timeout takes 500 milliseconds AFTER the vsync swap buffer.
/// So, it's not that we are requesting repaint within X duration. We are rather timing out
/// during app idle time where we are not receiving any new input events.
///
/// This repaints the specified viewport.
#[track_caller]
pub fn request_repaint_after_for(&self, duration: Duration, id: ViewportId) {
let cause = RepaintCause::new();
self.write(|ctx| ctx.request_repaint_after(duration, id, cause));
}
/// Was a repaint requested last pass for the current viewport?
#[must_use]
pub fn requested_repaint_last_pass(&self) -> bool {
self.requested_repaint_last_pass_for(&self.viewport_id())
}
/// Was a repaint requested last pass for the given viewport?
#[must_use]
pub fn requested_repaint_last_pass_for(&self, viewport_id: &ViewportId) -> bool {
self.read(|ctx| ctx.requested_immediate_repaint_prev_pass(viewport_id))
}
/// Has a repaint been requested for the current viewport?
#[must_use]
pub fn has_requested_repaint(&self) -> bool {
self.has_requested_repaint_for(&self.viewport_id())
}
/// Has a repaint been requested for the given viewport?
#[must_use]
pub fn has_requested_repaint_for(&self, viewport_id: &ViewportId) -> bool {
self.read(|ctx| ctx.has_requested_repaint(viewport_id))
}
/// Why are we repainting?
///
/// This can be helpful in debugging why egui is constantly repainting.
pub fn repaint_causes(&self) -> Vec<RepaintCause> {
self.read(|ctx| {
ctx.viewports
.get(&ctx.viewport_id())
.map(|v| v.repaint.prev_causes.clone())
})
.unwrap_or_default()
}
/// For integrations: this callback will be called when an egui user calls [`Self::request_repaint`] or [`Self::request_repaint_after`].
///
/// This lets you wake up a sleeping UI thread.
///
/// Note that only one callback can be set. Any new call overrides the previous callback.
pub fn set_request_repaint_callback(
&self,
callback: impl Fn(RequestRepaintInfo) + Send + Sync + 'static,
) {
let callback = Box::new(callback);
self.write(|ctx| ctx.request_repaint_callback = Some(callback));
}
/// Request to discard the visual output of this pass,
/// and to immediately do another one.
///
/// This can be called to cover up visual glitches during a "sizing pass".
/// For instance, when a [`crate::Grid`] is first shown we don't yet know the
/// width and heights of its columns and rows. egui will do a best guess,
/// but it will likely be wrong. Next pass it can read the sizes from the previous
/// pass, and from there on the widths will be stable.
/// This means the first pass will look glitchy, and ideally should not be shown to the user.
/// So [`crate::Grid`] calls [`Self::request_discard`] to cover up this glitches.
///
/// There is a limit to how many passes egui will perform, set by [`Options::max_passes`].
/// Therefore, the request might be declined.
///
/// You can check if the current pass will be discarded with [`Self::will_discard`].
///
/// You should be very conservative with when you call [`Self::request_discard`],
/// as it will cause an extra ui pass, potentially leading to extra CPU use and frame judder.
///
/// The given reason should be a human-readable string that explains why `request_discard`
/// was called. This will be shown in certain debug situations, to help you figure out
/// why a pass was discarded.
#[track_caller]
pub fn request_discard(&self, reason: impl Into<Cow<'static, str>>) {
let cause = RepaintCause::new_reason(reason);
self.output_mut(|o| o.request_discard_reasons.push(cause));
#[cfg(feature = "log")]
log::trace!(
"request_discard: {}",
if self.will_discard() {
"allowed"
} else {
"denied"
}
);
}
/// Will the visual output of this pass be discarded?
///
/// If true, you can early-out from expensive graphics operations.
///
/// See [`Self::request_discard`] for more.
pub fn will_discard(&self) -> bool {
self.write(|ctx| {
let vp = ctx.viewport();
// NOTE: `num_passes` is incremented
vp.output.requested_discard()
&& vp.output.num_completed_passes + 1 < ctx.memory.options.max_passes.get()
})
}
}
/// Callbacks
impl Context {
/// Call the given callback at the start of each pass of each viewport.
///
/// This can be used for egui _plugins_.
/// See [`crate::debug_text`] for an example.
pub fn on_begin_pass(&self, debug_name: &'static str, cb: ContextCallback) {
let named_cb = NamedContextCallback {
debug_name,
callback: cb,
};
self.write(|ctx| ctx.plugins.on_begin_pass.push(named_cb));
}
/// Call the given callback at the end of each pass of each viewport.
///
/// This can be used for egui _plugins_.
/// See [`crate::debug_text`] for an example.
pub fn on_end_pass(&self, debug_name: &'static str, cb: ContextCallback) {
let named_cb = NamedContextCallback {
debug_name,
callback: cb,
};
self.write(|ctx| ctx.plugins.on_end_pass.push(named_cb));
}
}
impl Context {
/// Tell `egui` which fonts to use.
///
/// The default `egui` fonts only support latin and cyrillic alphabets,
/// but you can call this to install additional fonts that support e.g. korean characters.
///
/// The new fonts will become active at the start of the next pass.
pub fn set_fonts(&self, font_definitions: FontDefinitions) {
crate::profile_function!();
let pixels_per_point = self.pixels_per_point();
let mut update_fonts = true;
self.read(|ctx| {
if let Some(current_fonts) = ctx.fonts.get(&pixels_per_point.into()) {
// NOTE: this comparison is expensive since it checks TTF data for equality
if current_fonts.lock().fonts.definitions() == &font_definitions {
update_fonts = false; // no need to update
}
}
});
if update_fonts {
self.memory_mut(|mem| mem.new_font_definitions = Some(font_definitions));
}
}
/// Does the OS use dark or light mode?
/// This is used when the theme preference is set to [`crate::ThemePreference::System`].
pub fn system_theme(&self) -> Option<Theme> {
self.memory(|mem| mem.options.system_theme)
}
/// The [`Theme`] used to select the appropriate [`Style`] (dark or light)
/// used by all subsequent windows, panels etc.
pub fn theme(&self) -> Theme {
self.options(|opt| opt.theme())
}
/// The [`Theme`] used to select between dark and light [`Self::style`]
/// as the active style used by all subsequent windows, panels etc.
///
/// Example:
/// ```
/// # let mut ctx = egui::Context::default();
/// ctx.set_theme(egui::Theme::Light); // Switch to light mode
/// ```
pub fn set_theme(&self, theme_preference: impl Into<crate::ThemePreference>) {
self.options_mut(|opt| opt.theme_preference = theme_preference.into());
}
/// The currently active [`Style`] used by all subsequent windows, panels etc.
pub fn style(&self) -> Arc<Style> {
self.options(|opt| opt.style().clone())
}
/// Mutate the currently active [`Style`] used by all subsequent windows, panels etc.
/// Use [`Self::all_styles_mut`] to mutate both dark and light mode styles.
///
/// Example:
/// ```
/// # let mut ctx = egui::Context::default();
/// ctx.style_mut(|style| {
/// style.spacing.item_spacing = egui::vec2(10.0, 20.0);
/// });
/// ```
pub fn style_mut(&self, mutate_style: impl FnOnce(&mut Style)) {
self.options_mut(|opt| mutate_style(Arc::make_mut(opt.style_mut())));
}
/// The currently active [`Style`] used by all new windows, panels etc.
///
/// Use [`Self::all_styles_mut`] to mutate both dark and light mode styles.
///
/// You can also change this using [`Self::style_mut`].
///
/// You can use [`Ui::style_mut`] to change the style of a single [`Ui`].
pub fn set_style(&self, style: impl Into<Arc<Style>>) {
self.options_mut(|opt| *opt.style_mut() = style.into());
}
/// Mutate the [`Style`]s used by all subsequent windows, panels etc. in both dark and light mode.
///
/// Example:
/// ```
/// # let mut ctx = egui::Context::default();
/// ctx.all_styles_mut(|style| {
/// style.spacing.item_spacing = egui::vec2(10.0, 20.0);
/// });
/// ```
pub fn all_styles_mut(&self, mut mutate_style: impl FnMut(&mut Style)) {
self.options_mut(|opt| {
mutate_style(Arc::make_mut(&mut opt.dark_style));
mutate_style(Arc::make_mut(&mut opt.light_style));
});
}
/// The [`Style`] used by all subsequent windows, panels etc.
pub fn style_of(&self, theme: Theme) -> Arc<Style> {
self.options(|opt| match theme {
Theme::Dark => opt.dark_style.clone(),
Theme::Light => opt.light_style.clone(),
})
}
/// Mutate the [`Style`] used by all subsequent windows, panels etc.
///
/// Example:
/// ```
/// # let mut ctx = egui::Context::default();
/// ctx.style_mut_of(egui::Theme::Dark, |style| {
/// style.spacing.item_spacing = egui::vec2(10.0, 20.0);
/// });
/// ```
pub fn style_mut_of(&self, theme: Theme, mutate_style: impl FnOnce(&mut Style)) {
self.options_mut(|opt| match theme {
Theme::Dark => mutate_style(Arc::make_mut(&mut opt.dark_style)),
Theme::Light => mutate_style(Arc::make_mut(&mut opt.light_style)),
});
}
/// The [`Style`] used by all new windows, panels etc.
/// Use [`Self::set_theme`] to choose between dark and light mode.
///
/// You can also change this using [`Self::style_mut_of`].
///
/// You can use [`Ui::style_mut`] to change the style of a single [`Ui`].
pub fn set_style_of(&self, theme: Theme, style: impl Into<Arc<Style>>) {
let style = style.into();
self.options_mut(|opt| match theme {
Theme::Dark => opt.dark_style = style,
Theme::Light => opt.light_style = style,
});
}
/// The [`crate::Visuals`] used by all subsequent windows, panels etc.
///
/// You can also use [`Ui::visuals_mut`] to change the visuals of a single [`Ui`].
///
/// Example:
/// ```
/// # let mut ctx = egui::Context::default();
/// ctx.set_visuals_of(egui::Theme::Dark, egui::Visuals { panel_fill: egui::Color32::RED, ..Default::default() });
/// ```
pub fn set_visuals_of(&self, theme: Theme, visuals: crate::Visuals) {
self.style_mut_of(theme, |style| style.visuals = visuals);
}
/// The [`crate::Visuals`] used by all subsequent windows, panels etc.
///
/// You can also use [`Ui::visuals_mut`] to change the visuals of a single [`Ui`].
///
/// Example:
/// ```
/// # let mut ctx = egui::Context::default();
/// ctx.set_visuals(egui::Visuals { panel_fill: egui::Color32::RED, ..Default::default() });
/// ```
pub fn set_visuals(&self, visuals: crate::Visuals) {
self.style_mut_of(self.theme(), |style| style.visuals = visuals);
}
/// The number of physical pixels for each logical point.
///
/// This is calculated as [`Self::zoom_factor`] * [`Self::native_pixels_per_point`]
#[inline(always)]
pub fn pixels_per_point(&self) -> f32 {
self.input(|i| i.pixels_per_point)
}
/// Set the number of physical pixels for each logical point.
/// Will become active at the start of the next pass.
///
/// This will actually translate to a call to [`Self::set_zoom_factor`].
pub fn set_pixels_per_point(&self, pixels_per_point: f32) {
if pixels_per_point != self.pixels_per_point() {
self.set_zoom_factor(pixels_per_point / self.native_pixels_per_point().unwrap_or(1.0));
}
}
/// The number of physical pixels for each logical point on this monitor.
///
/// This is given as input to egui via [`crate::ViewportInfo::native_pixels_per_point`]
/// and cannot be changed.
#[inline(always)]
pub fn native_pixels_per_point(&self) -> Option<f32> {
self.input(|i| i.viewport().native_pixels_per_point)
}
/// Global zoom factor of the UI.
///
/// This is used to calculate the `pixels_per_point`
/// for the UI as `pixels_per_point = zoom_factor * native_pixels_per_point`.
///
/// The default is 1.0.
/// Make larger to make everything larger.
#[inline(always)]
pub fn zoom_factor(&self) -> f32 {
self.options(|o| o.zoom_factor)
}
/// Sets zoom factor of the UI.
/// Will become active at the start of the next pass.
///
/// Note that calling this will not update [`Self::zoom_factor`] until the end of the pass.
///
/// This is used to calculate the `pixels_per_point`
/// for the UI as `pixels_per_point = zoom_fator * native_pixels_per_point`.
///
/// The default is 1.0.
/// Make larger to make everything larger.
///
/// It is better to call this than modifying
/// [`Options::zoom_factor`].
#[inline(always)]
pub fn set_zoom_factor(&self, zoom_factor: f32) {
let cause = RepaintCause::new();
self.write(|ctx| {
if ctx.memory.options.zoom_factor != zoom_factor {
ctx.new_zoom_factor = Some(zoom_factor);
for viewport_id in ctx.all_viewport_ids() {
ctx.request_repaint(viewport_id, cause.clone());
}
}
});
}
/// Useful for pixel-perfect rendering of lines that are one pixel wide (or any odd number of pixels).
#[inline]
pub(crate) fn round_to_pixel_center(&self, point: f32) -> f32 {
let pixels_per_point = self.pixels_per_point();
((point * pixels_per_point - 0.5).round() + 0.5) / pixels_per_point
}
/// Useful for pixel-perfect rendering of lines that are one pixel wide (or any odd number of pixels).
#[inline]
pub(crate) fn round_pos_to_pixel_center(&self, point: Pos2) -> Pos2 {
pos2(
self.round_to_pixel_center(point.x),
self.round_to_pixel_center(point.y),
)
}
/// Useful for pixel-perfect rendering of filled shapes
#[inline]
pub(crate) fn round_to_pixel(&self, point: f32) -> f32 {
let pixels_per_point = self.pixels_per_point();
(point * pixels_per_point).round() / pixels_per_point
}
/// Useful for pixel-perfect rendering of filled shapes
#[inline]
pub(crate) fn round_pos_to_pixels(&self, pos: Pos2) -> Pos2 {
pos2(self.round_to_pixel(pos.x), self.round_to_pixel(pos.y))
}
/// Useful for pixel-perfect rendering of filled shapes
#[inline]
pub(crate) fn round_vec_to_pixels(&self, vec: Vec2) -> Vec2 {
vec2(self.round_to_pixel(vec.x), self.round_to_pixel(vec.y))
}
/// Useful for pixel-perfect rendering of filled shapes
#[inline]
pub(crate) fn round_rect_to_pixels(&self, rect: Rect) -> Rect {
Rect {
min: self.round_pos_to_pixels(rect.min),
max: self.round_pos_to_pixels(rect.max),
}
}
/// Allocate a texture.
///
/// This is for advanced users.
/// Most users should use [`crate::Ui::image`] or [`Self::try_load_texture`]
/// instead.
///
/// In order to display an image you must convert it to a texture using this function.
/// The function will hand over the image data to the egui backend, which will
/// upload it to the GPU.
///
/// ⚠️ Make sure to only call this ONCE for each image, i.e. NOT in your main GUI code.
/// The call is NOT immediate safe.
///
/// The given name can be useful for later debugging, and will be visible if you call [`Self::texture_ui`].
///
/// For how to load an image, see [`crate::ImageData`] and [`crate::ColorImage::from_rgba_unmultiplied`].
///
/// ```
/// struct MyImage {
/// texture: Option<egui::TextureHandle>,
/// }
///
/// impl MyImage {
/// fn ui(&mut self, ui: &mut egui::Ui) {
/// let texture: &egui::TextureHandle = self.texture.get_or_insert_with(|| {
/// // Load the texture only once.
/// ui.ctx().load_texture(
/// "my-image",
/// egui::ColorImage::example(),
/// Default::default()
/// )
/// });
///
/// // Show the image:
/// ui.image((texture.id(), texture.size_vec2()));
/// }
/// }
/// ```
///
/// See also [`crate::ImageData`], [`crate::Ui::image`] and [`crate::Image`].
pub fn load_texture(
&self,
name: impl Into<String>,
image: impl Into<ImageData>,
options: TextureOptions,
) -> TextureHandle {
let name = name.into();
let image = image.into();
let max_texture_side = self.input(|i| i.max_texture_side);
debug_assert!(
image.width() <= max_texture_side && image.height() <= max_texture_side,
"Texture {:?} has size {}x{}, but the maximum texture side is {}",
name,
image.width(),
image.height(),
max_texture_side
);
let tex_mngr = self.tex_manager();
let tex_id = tex_mngr.write().alloc(name, image, options);
TextureHandle::new(tex_mngr, tex_id)
}
/// Low-level texture manager.
///
/// In general it is easier to use [`Self::load_texture`] and [`TextureHandle`].
///
/// You can show stats about the allocated textures using [`Self::texture_ui`].
pub fn tex_manager(&self) -> Arc<RwLock<epaint::textures::TextureManager>> {
self.read(|ctx| ctx.tex_manager.0.clone())
}
// ---------------------------------------------------------------------
/// Constrain the position of a window/area so it fits within the provided boundary.
pub(crate) fn constrain_window_rect_to_area(&self, window: Rect, area: Rect) -> Rect {
let mut pos = window.min;
// Constrain to screen, unless window is too large to fit:
let margin_x = (window.width() - area.width()).at_least(0.0);
let margin_y = (window.height() - area.height()).at_least(0.0);
pos.x = pos.x.at_most(area.right() + margin_x - window.width()); // move left if needed
pos.x = pos.x.at_least(area.left() - margin_x); // move right if needed
pos.y = pos.y.at_most(area.bottom() + margin_y - window.height()); // move right if needed
pos.y = pos.y.at_least(area.top() - margin_y); // move down if needed
pos = self.round_pos_to_pixels(pos);
Rect::from_min_size(pos, window.size())
}
}
impl Context {
/// Call at the end of each frame if you called [`Context::begin_pass`].
#[must_use]
pub fn end_pass(&self) -> FullOutput {
crate::profile_function!();
if self.options(|o| o.zoom_with_keyboard) {
crate::gui_zoom::zoom_with_keyboard(self);
}
// Plugins run just before the pass ends.
self.read(|ctx| ctx.plugins.clone()).on_end_pass(self);
#[cfg(debug_assertions)]
self.debug_painting();
self.write(|ctx| ctx.end_pass())
}
/// Call at the end of each frame if you called [`Context::begin_pass`].
#[must_use]
#[deprecated = "Renamed end_pass"]
pub fn end_frame(&self) -> FullOutput {
self.end_pass()
}
/// Called at the end of the pass.
#[cfg(debug_assertions)]
fn debug_painting(&self) {
let paint_widget = |widget: &WidgetRect, text: &str, color: Color32| {
let rect = widget.interact_rect;
if rect.is_positive() {
let painter = Painter::new(self.clone(), widget.layer_id, Rect::EVERYTHING);
painter.debug_rect(rect, color, text);
}
};
let paint_widget_id = |id: Id, text: &str, color: Color32| {
if let Some(widget) =
self.write(|ctx| ctx.viewport().this_pass.widgets.get(id).copied())
{
paint_widget(&widget, text, color);
}
};
if self.style().debug.show_interactive_widgets {
// Show all interactive widgets:
let rects = self.write(|ctx| ctx.viewport().this_pass.widgets.clone());
for (layer_id, rects) in rects.layers() {
let painter = Painter::new(self.clone(), *layer_id, Rect::EVERYTHING);
for rect in rects {
if rect.sense.interactive() {
let (color, text) = if rect.sense.click && rect.sense.drag {
(Color32::from_rgb(0x88, 0, 0x88), "click+drag")
} else if rect.sense.click {
(Color32::from_rgb(0x88, 0, 0), "click")
} else if rect.sense.drag {
(Color32::from_rgb(0, 0, 0x88), "drag")
} else {
// unreachable since we only show interactive
(Color32::from_rgb(0, 0, 0x88), "hover")
};
painter.debug_rect(rect.interact_rect, color, text);
}
}
}
// Show the ones actually interacted with:
{
let interact_widgets = self.write(|ctx| ctx.viewport().interact_widgets.clone());
let InteractionSnapshot {
clicked,
long_touched: _,
drag_started: _,
dragged,
drag_stopped: _,
contains_pointer,
hovered,
} = interact_widgets;
if true {
for &id in &contains_pointer {
paint_widget_id(id, "contains_pointer", Color32::BLUE);
}
let widget_rects = self.write(|w| w.viewport().this_pass.widgets.clone());
let mut contains_pointer: Vec<Id> = contains_pointer.iter().copied().collect();
contains_pointer.sort_by_key(|&id| {
widget_rects
.order(id)
.map(|(layer_id, order_in_layer)| (layer_id.order, order_in_layer))
});
let mut debug_text = "Widgets in order:\n".to_owned();
for id in contains_pointer {
let mut widget_text = format!("{id:?}");
if let Some(rect) = widget_rects.get(id) {
widget_text += &format!(" {:?} {:?}", rect.rect, rect.sense);
}
if let Some(info) = widget_rects.info(id) {
widget_text += &format!(" {info:?}");
}
debug_text += &format!("{widget_text}\n");
}
self.debug_text(debug_text);
}
if true {
for widget in hovered {
paint_widget_id(widget, "hovered", Color32::WHITE);
}
}
if let Some(widget) = clicked {
paint_widget_id(widget, "clicked", Color32::RED);
}
if let Some(widget) = dragged {
paint_widget_id(widget, "dragged", Color32::GREEN);
}
}
}
if self.style().debug.show_widget_hits {
let hits = self.write(|ctx| ctx.viewport().hits.clone());
let WidgetHits {
contains_pointer,
click,
drag,
} = hits;
if true {
for widget in &contains_pointer {
paint_widget(widget, "contains_pointer", Color32::BLUE);
}
}
if let Some(widget) = &click {
paint_widget(widget, "click", Color32::RED);
}
if let Some(widget) = &drag {
paint_widget(widget, "drag", Color32::GREEN);
}
}
if let Some(debug_rect) = self.pass_state_mut(|fs| fs.debug_rect.take()) {
debug_rect.paint(&self.debug_painter());
}
let num_multipass_in_row = self.viewport(|vp| vp.num_multipass_in_row);
if 3 <= num_multipass_in_row {
// If you see this message, it means we've been paying the cost of multi-pass for multiple frames in a row.
// This is likely a bug. `request_discard` should only be called in rare situations, when some layout changes.
let mut warning = format!("egui PERF WARNING: request_discard has been called {num_multipass_in_row} frames in a row");
self.viewport(|vp| {
for reason in &vp.output.request_discard_reasons {
warning += &format!("\n {reason}");
}
});
self.debug_painter()
.debug_text(Pos2::ZERO, Align2::LEFT_TOP, Color32::RED, warning);
}
}
}
impl ContextImpl {
fn end_pass(&mut self) -> FullOutput {
let ended_viewport_id = self.viewport_id();
let viewport = self.viewports.entry(ended_viewport_id).or_default();
let pixels_per_point = viewport.input.pixels_per_point;
viewport.repaint.cumulative_pass_nr += 1;
self.memory.end_pass(&viewport.this_pass.used_ids);
if let Some(fonts) = self.fonts.get(&pixels_per_point.into()) {
let tex_mngr = &mut self.tex_manager.0.write();
if let Some(font_image_delta) = fonts.font_image_delta() {
// A partial font atlas update, e.g. a new glyph has been entered.
tex_mngr.set(TextureId::default(), font_image_delta);
}
if 1 < self.fonts.len() {
// We have multiple different `pixels_per_point`,
// e.g. because we have many viewports spread across
// monitors with different DPI scaling.
// All viewports share the same texture namespace and renderer,
// so the all use `TextureId::default()` for the font texture.
// This is a problem.
// We solve this with a hack: we always upload the full font atlas
// every frame, for all viewports.
// This ensures it is up-to-date, solving
// https://github.com/emilk/egui/issues/3664
// at the cost of a lot of performance.
// (This will override any smaller delta that was uploaded above.)
crate::profile_scope!("full_font_atlas_update");
let full_delta = ImageDelta::full(fonts.image(), TextureAtlas::texture_options());
tex_mngr.set(TextureId::default(), full_delta);
}
}
// Inform the backend of all textures that have been updated (including font atlas).
let textures_delta = self.tex_manager.0.write().take_delta();
#[cfg_attr(not(feature = "accesskit"), allow(unused_mut))]
let mut platform_output: PlatformOutput = std::mem::take(&mut viewport.output);
#[cfg(feature = "accesskit")]
{
crate::profile_scope!("accesskit");
let state = viewport.this_pass.accesskit_state.take();
if let Some(state) = state {
let root_id = crate::accesskit_root_id().accesskit_id();
let nodes = {
state
.node_builders
.into_iter()
.map(|(id, builder)| (id.accesskit_id(), builder.build()))
.collect()
};
let focus_id = self
.memory
.focused()
.map_or(root_id, |id| id.accesskit_id());
platform_output.accesskit_update = Some(accesskit::TreeUpdate {
nodes,
tree: Some(accesskit::Tree::new(root_id)),
focus: focus_id,
});
}
}
let shapes = viewport
.graphics
.drain(self.memory.areas().order(), &self.memory.layer_transforms);
let mut repaint_needed = false;
if self.memory.options.repaint_on_widget_change {
crate::profile_function!("compare-widget-rects");
if viewport.prev_pass.widgets != viewport.this_pass.widgets {
repaint_needed = true; // Some widget has moved
}
}
std::mem::swap(&mut viewport.prev_pass, &mut viewport.this_pass);
if repaint_needed {
self.request_repaint(ended_viewport_id, RepaintCause::new());
} else if let Some(delay) = viewport.input.wants_repaint_after() {
self.request_repaint_after(delay, ended_viewport_id, RepaintCause::new());
}
// -------------------
let all_viewport_ids = self.all_viewport_ids();
self.last_viewport = ended_viewport_id;
self.viewports.retain(|&id, viewport| {
let parent = *self.viewport_parents.entry(id).or_default();
if !all_viewport_ids.contains(&parent) {
#[cfg(feature = "log")]
log::debug!(
"Removing viewport {:?} ({:?}): the parent is gone",
id,
viewport.builder.title
);
return false;
}
let is_our_child = parent == ended_viewport_id && id != ViewportId::ROOT;
if is_our_child {
if !viewport.used {
#[cfg(feature = "log")]
log::debug!(
"Removing viewport {:?} ({:?}): it was never used this pass",
id,
viewport.builder.title
);
return false; // Only keep children that have been updated this pass
}
viewport.used = false; // reset so we can check again next pass
}
true
});
// If we are an immediate viewport, this will resume the previous viewport.
self.viewport_stack.pop();
// The last viewport is not necessarily the root viewport,
// just the top _immediate_ viewport.
let is_last = self.viewport_stack.is_empty();
let viewport_output = self
.viewports
.iter_mut()
.map(|(&id, viewport)| {
let parent = *self.viewport_parents.entry(id).or_default();
let commands = if is_last {
// Let the primary immediate viewport handle the commands of its children too.
// This can make things easier for the backend, as otherwise we may get commands
// that affect a viewport while its egui logic is running.
std::mem::take(&mut viewport.commands)
} else {
vec![]
};
(
id,
ViewportOutput {
parent,
class: viewport.class,
builder: viewport.builder.clone(),
viewport_ui_cb: viewport.viewport_ui_cb.clone(),
commands,
repaint_delay: viewport.repaint.repaint_delay,
},
)
})
.collect();
if is_last {
// Remove dead viewports:
self.viewports.retain(|id, _| all_viewport_ids.contains(id));
self.viewport_parents
.retain(|id, _| all_viewport_ids.contains(id));
} else {
let viewport_id = self.viewport_id();
self.memory.set_viewport_id(viewport_id);
}
let active_pixels_per_point: std::collections::BTreeSet<OrderedFloat<f32>> = self
.viewports
.values()
.map(|v| v.input.pixels_per_point.into())
.collect();
self.fonts.retain(|pixels_per_point, _| {
if active_pixels_per_point.contains(pixels_per_point) {
true
} else {
#[cfg(feature = "log")]
log::trace!(
"Freeing Fonts with pixels_per_point={} because it is no longer needed",
pixels_per_point.into_inner()
);
false
}
});
platform_output.num_completed_passes += 1;
FullOutput {
platform_output,
textures_delta,
shapes,
pixels_per_point,
viewport_output,
}
}
}
impl Context {
/// Tessellate the given shapes into triangle meshes.
///
/// `pixels_per_point` is used for feathering (anti-aliasing).
/// For this you can use [`FullOutput::pixels_per_point`], [`Self::pixels_per_point`],
/// or whatever is appropriate for your viewport.
pub fn tessellate(
&self,
shapes: Vec<ClippedShape>,
pixels_per_point: f32,
) -> Vec<ClippedPrimitive> {
crate::profile_function!();
// A tempting optimization is to reuse the tessellation from last frame if the
// shapes are the same, but just comparing the shapes takes about 50% of the time
// it takes to tessellate them, so it is not a worth optimization.
self.write(|ctx| {
let tessellation_options = ctx.memory.options.tessellation_options;
let texture_atlas = if let Some(fonts) = ctx.fonts.get(&pixels_per_point.into()) {
fonts.texture_atlas()
} else {
#[cfg(feature = "log")]
log::warn!("No font size matching {pixels_per_point} pixels per point found.");
ctx.fonts
.iter()
.next()
.expect("No fonts loaded")
.1
.texture_atlas()
};
let (font_tex_size, prepared_discs) = {
let atlas = texture_atlas.lock();
(atlas.size(), atlas.prepared_discs())
};
let paint_stats = PaintStats::from_shapes(&shapes);
let clipped_primitives = {
crate::profile_scope!("tessellator::tessellate_shapes");
tessellator::Tessellator::new(
pixels_per_point,
tessellation_options,
font_tex_size,
prepared_discs,
)
.tessellate_shapes(shapes)
};
ctx.paint_stats = paint_stats.with_clipped_primitives(&clipped_primitives);
clipped_primitives
})
}
// ---------------------------------------------------------------------
/// Position and size of the egui area.
pub fn screen_rect(&self) -> Rect {
self.input(|i| i.screen_rect())
}
/// How much space is still available after panels has been added.
///
/// This is the "background" area, what egui doesn't cover with panels (but may cover with windows).
/// This is also the area to which windows are constrained.
pub fn available_rect(&self) -> Rect {
self.pass_state(|s| s.available_rect())
}
/// How much space is used by panels and windows.
pub fn used_rect(&self) -> Rect {
self.write(|ctx| {
let mut used = ctx.viewport().this_pass.used_by_panels;
for (_id, window) in ctx.memory.areas().visible_windows() {
used = used.union(window.rect());
}
used
})
}
/// How much space is used by panels and windows.
///
/// You can shrink your egui area to this size and still fit all egui components.
pub fn used_size(&self) -> Vec2 {
self.used_rect().max - Pos2::ZERO
}
// ---------------------------------------------------------------------
/// Is the pointer (mouse/touch) over any egui area?
pub fn is_pointer_over_area(&self) -> bool {
let pointer_pos = self.input(|i| i.pointer.interact_pos());
if let Some(pointer_pos) = pointer_pos {
if let Some(layer) = self.layer_id_at(pointer_pos) {
if layer.order == Order::Background {
!self.pass_state(|state| state.unused_rect.contains(pointer_pos))
} else {
true
}
} else {
false
}
} else {
false
}
}
/// True if egui is currently interested in the pointer (mouse or touch).
///
/// Could be the pointer is hovering over a [`crate::Window`] or the user is dragging a widget.
/// If `false`, the pointer is outside of any egui area and so
/// you may be interested in what it is doing (e.g. controlling your game).
/// Returns `false` if a drag started outside of egui and then moved over an egui area.
pub fn wants_pointer_input(&self) -> bool {
self.is_using_pointer()
|| (self.is_pointer_over_area() && !self.input(|i| i.pointer.any_down()))
}
/// Is egui currently using the pointer position (e.g. dragging a slider)?
///
/// NOTE: this will return `false` if the pointer is just hovering over an egui area.
pub fn is_using_pointer(&self) -> bool {
self.memory(|m| m.interaction().is_using_pointer())
}
/// If `true`, egui is currently listening on text input (e.g. typing text in a [`crate::TextEdit`]).
pub fn wants_keyboard_input(&self) -> bool {
self.memory(|m| m.focused().is_some())
}
/// Highlight this widget, to make it look like it is hovered, even if it isn't.
///
/// If you call this after the widget has been fully rendered,
/// then it won't be highlighted until the next ui pass.
///
/// See also [`Response::highlight`].
pub fn highlight_widget(&self, id: Id) {
self.pass_state_mut(|fs| fs.highlight_next_pass.insert(id));
}
/// Is an egui context menu open?
pub fn is_context_menu_open(&self) -> bool {
self.data(|d| {
d.get_temp::<crate::menu::BarState>(menu::CONTEXT_MENU_ID_STR.into())
.map_or(false, |state| state.has_root())
})
}
}
// Ergonomic methods to forward some calls often used in 'if let' without holding the borrow
impl Context {
/// Latest reported pointer position.
///
/// When tapping a touch screen, this will be `None`.
#[inline(always)]
pub fn pointer_latest_pos(&self) -> Option<Pos2> {
self.input(|i| i.pointer.latest_pos())
}
/// If it is a good idea to show a tooltip, where is pointer?
#[inline(always)]
pub fn pointer_hover_pos(&self) -> Option<Pos2> {
self.input(|i| i.pointer.hover_pos())
}
/// If you detect a click or drag and wants to know where it happened, use this.
///
/// Latest position of the mouse, but ignoring any [`crate::Event::PointerGone`]
/// if there were interactions this pass.
/// When tapping a touch screen, this will be the location of the touch.
#[inline(always)]
pub fn pointer_interact_pos(&self) -> Option<Pos2> {
self.input(|i| i.pointer.interact_pos())
}
/// Calls [`InputState::multi_touch`].
pub fn multi_touch(&self) -> Option<MultiTouchInfo> {
self.input(|i| i.multi_touch())
}
}
impl Context {
/// Transform the graphics of the given layer.
///
/// This will also affect input.
///
/// This is a sticky setting, remembered from one frame to the next.
///
/// Can be used to implement pan and zoom (see relevant demo).
///
/// For a temporary transform, use [`Self::transform_layer_shapes`] instead.
pub fn set_transform_layer(&self, layer_id: LayerId, transform: TSTransform) {
self.memory_mut(|m| {
if transform == TSTransform::IDENTITY {
m.layer_transforms.remove(&layer_id)
} else {
m.layer_transforms.insert(layer_id, transform)
}
});
}
/// Move all the graphics at the given layer.
///
/// Is used to implement drag-and-drop preview.
///
/// This only applied to the existing graphics at the layer, not to new graphics added later.
///
/// For a persistent transform, use [`Self::set_transform_layer`] instead.
#[deprecated = "Use `transform_layer_shapes` instead"]
pub fn translate_layer(&self, layer_id: LayerId, delta: Vec2) {
if delta != Vec2::ZERO {
let transform = emath::TSTransform::from_translation(delta);
self.transform_layer_shapes(layer_id, transform);
}
}
/// Transform all the graphics at the given layer.
///
/// Is used to implement drag-and-drop preview.
///
/// This only applied to the existing graphics at the layer, not to new graphics added later.
///
/// For a persistent transform, use [`Self::set_transform_layer`] instead.
pub fn transform_layer_shapes(&self, layer_id: LayerId, transform: TSTransform) {
if transform != TSTransform::IDENTITY {
self.graphics_mut(|g| g.entry(layer_id).transform(transform));
}
}
/// Top-most layer at the given position.
pub fn layer_id_at(&self, pos: Pos2) -> Option<LayerId> {
self.memory(|mem| mem.layer_id_at(pos))
}
/// Moves the given area to the top in its [`Order`].
///
/// [`crate::Area`]:s and [`crate::Window`]:s also do this automatically when being clicked on or interacted with.
pub fn move_to_top(&self, layer_id: LayerId) {
self.memory_mut(|mem| mem.areas_mut().move_to_top(layer_id));
}
/// Mark the `child` layer as a sublayer of `parent`.
///
/// Sublayers are moved directly above the parent layer at the end of the frame. This is mainly
/// intended for adding a new [`crate::Area`] inside a [`crate::Window`].
///
/// This currently only supports one level of nesting. If `parent` is a sublayer of another
/// layer, the behavior is unspecified.
pub fn set_sublayer(&self, parent: LayerId, child: LayerId) {
self.memory_mut(|mem| mem.areas_mut().set_sublayer(parent, child));
}
/// Retrieve the [`LayerId`] of the top level windows.
pub fn top_layer_id(&self) -> Option<LayerId> {
self.memory(|mem| mem.areas().top_layer_id(Order::Middle))
}
/// Does the given rectangle contain the mouse pointer?
///
/// Will return false if some other area is covering the given layer.
///
/// The given rectangle is assumed to have been clipped by its parent clip rect.
///
/// See also [`Response::contains_pointer`].
pub fn rect_contains_pointer(&self, layer_id: LayerId, rect: Rect) -> bool {
let rect =
if let Some(transform) = self.memory(|m| m.layer_transforms.get(&layer_id).copied()) {
transform * rect
} else {
rect
};
if !rect.is_positive() {
return false;
}
let pointer_pos = self.input(|i| i.pointer.interact_pos());
let Some(pointer_pos) = pointer_pos else {
return false;
};
if !rect.contains(pointer_pos) {
return false;
}
if self.layer_id_at(pointer_pos) != Some(layer_id) {
return false;
}
true
}
// ---------------------------------------------------------------------
/// Whether or not to debug widget layout on hover.
#[cfg(debug_assertions)]
pub fn debug_on_hover(&self) -> bool {
self.options(|opt| opt.style().debug.debug_on_hover)
}
/// Turn on/off whether or not to debug widget layout on hover.
#[cfg(debug_assertions)]
pub fn set_debug_on_hover(&self, debug_on_hover: bool) {
self.all_styles_mut(|style| style.debug.debug_on_hover = debug_on_hover);
}
}
/// ## Animation
impl Context {
/// Returns a value in the range [0, 1], to indicate "how on" this thing is.
///
/// The first time called it will return `if value { 1.0 } else { 0.0 }`
/// Calling this with `value = true` will always yield a number larger than zero, quickly going towards one.
/// Calling this with `value = false` will always yield a number less than one, quickly going towards zero.
///
/// The function will call [`Self::request_repaint()`] when appropriate.
///
/// The animation time is taken from [`Style::animation_time`].
#[track_caller] // To track repaint cause
pub fn animate_bool(&self, id: Id, value: bool) -> f32 {
let animation_time = self.style().animation_time;
self.animate_bool_with_time_and_easing(id, value, animation_time, emath::easing::linear)
}
/// Like [`Self::animate_bool`], but uses an easing function that makes the value move
/// quickly in the beginning and slow down towards the end.
///
/// The exact easing function may come to change in future versions of egui.
#[track_caller] // To track repaint cause
pub fn animate_bool_responsive(&self, id: Id, value: bool) -> f32 {
self.animate_bool_with_easing(id, value, emath::easing::cubic_out)
}
/// Like [`Self::animate_bool`] but allows you to control the easing function.
#[track_caller] // To track repaint cause
pub fn animate_bool_with_easing(&self, id: Id, value: bool, easing: fn(f32) -> f32) -> f32 {
let animation_time = self.style().animation_time;
self.animate_bool_with_time_and_easing(id, value, animation_time, easing)
}
/// Like [`Self::animate_bool`] but allows you to control the animation time.
#[track_caller] // To track repaint cause
pub fn animate_bool_with_time(&self, id: Id, target_value: bool, animation_time: f32) -> f32 {
self.animate_bool_with_time_and_easing(
id,
target_value,
animation_time,
emath::easing::linear,
)
}
/// Like [`Self::animate_bool`] but allows you to control the animation time and easing function.
///
/// Use e.g. [`emath::easing::quadratic_out`]
/// for a responsive start and a slow end.
///
/// The easing function flips when `target_value` is `false`,
/// so that when going back towards 0.0, we get
#[track_caller] // To track repaint cause
pub fn animate_bool_with_time_and_easing(
&self,
id: Id,
target_value: bool,
animation_time: f32,
easing: fn(f32) -> f32,
) -> f32 {
let animated_value = self.write(|ctx| {
ctx.animation_manager.animate_bool(
&ctx.viewports.entry(ctx.viewport_id()).or_default().input,
animation_time,
id,
target_value,
)
});
let animation_in_progress = 0.0 < animated_value && animated_value < 1.0;
if animation_in_progress {
self.request_repaint();
}
if target_value {
easing(animated_value)
} else {
1.0 - easing(1.0 - animated_value)
}
}
/// Smoothly animate an `f32` value.
///
/// At the first call the value is written to memory.
/// When it is called with a new value, it linearly interpolates to it in the given time.
#[track_caller] // To track repaint cause
pub fn animate_value_with_time(&self, id: Id, target_value: f32, animation_time: f32) -> f32 {
let animated_value = self.write(|ctx| {
ctx.animation_manager.animate_value(
&ctx.viewports.entry(ctx.viewport_id()).or_default().input,
animation_time,
id,
target_value,
)
});
let animation_in_progress = animated_value != target_value;
if animation_in_progress {
self.request_repaint();
}
animated_value
}
/// Clear memory of any animations.
pub fn clear_animations(&self) {
self.write(|ctx| ctx.animation_manager = Default::default());
}
}
impl Context {
/// Show a ui for settings (style and tessellation options).
pub fn settings_ui(&self, ui: &mut Ui) {
let prev_options = self.options(|o| o.clone());
let mut options = prev_options.clone();
ui.collapsing("🔠 Font tweak", |ui| {
self.fonts_tweak_ui(ui);
});
options.ui(ui);
if options != prev_options {
self.options_mut(move |o| *o = options);
}
}
fn fonts_tweak_ui(&self, ui: &mut Ui) {
let mut font_definitions = self.write(|ctx| ctx.font_definitions.clone());
let mut changed = false;
for (name, data) in &mut font_definitions.font_data {
ui.collapsing(name, |ui| {
if data.tweak.ui(ui).changed() {
changed = true;
}
});
}
if changed {
self.set_fonts(font_definitions);
}
}
/// Show the state of egui, including its input and output.
pub fn inspection_ui(&self, ui: &mut Ui) {
use crate::containers::CollapsingHeader;
ui.label(format!("Is using pointer: {}", self.is_using_pointer()))
.on_hover_text(
"Is egui currently using the pointer actively (e.g. dragging a slider)?",
);
ui.label(format!("Wants pointer input: {}", self.wants_pointer_input()))
.on_hover_text("Is egui currently interested in the location of the pointer (either because it is in use, or because it is hovering over a window).");
ui.label(format!(
"Wants keyboard input: {}",
self.wants_keyboard_input()
))
.on_hover_text("Is egui currently listening for text input?");
ui.label(format!(
"Keyboard focus widget: {}",
self.memory(|m| m.focused())
.as_ref()
.map(Id::short_debug_format)
.unwrap_or_default()
))
.on_hover_text("Is egui currently listening for text input?");
let pointer_pos = self
.pointer_hover_pos()
.map_or_else(String::new, |pos| format!("{pos:?}"));
ui.label(format!("Pointer pos: {pointer_pos}"));
let top_layer = self
.pointer_hover_pos()
.and_then(|pos| self.layer_id_at(pos))
.map_or_else(String::new, |layer| layer.short_debug_format());
ui.label(format!("Top layer under mouse: {top_layer}"));
ui.add_space(16.0);
ui.label(format!(
"There are {} text galleys in the layout cache",
self.fonts(|f| f.num_galleys_in_cache())
))
.on_hover_text("This is approximately the number of text strings on screen");
ui.add_space(16.0);
CollapsingHeader::new("🔃 Repaint Causes")
.default_open(false)
.show(ui, |ui| {
ui.set_min_height(120.0);
ui.label("What caused egui to repaint:");
ui.add_space(8.0);
let causes = ui.ctx().repaint_causes();
for cause in causes {
ui.label(cause.to_string());
}
});
CollapsingHeader::new("📥 Input")
.default_open(false)
.show(ui, |ui| {
let input = ui.input(|i| i.clone());
input.ui(ui);
});
CollapsingHeader::new("📊 Paint stats")
.default_open(false)
.show(ui, |ui| {
let paint_stats = self.read(|ctx| ctx.paint_stats);
paint_stats.ui(ui);
});
CollapsingHeader::new("🖼 Textures")
.default_open(false)
.show(ui, |ui| {
self.texture_ui(ui);
});
CollapsingHeader::new("🔠 Font texture")
.default_open(false)
.show(ui, |ui| {
let font_image_size = self.fonts(|f| f.font_image_size());
crate::introspection::font_texture_ui(ui, font_image_size);
});
CollapsingHeader::new("Label text selection state")
.default_open(false)
.show(ui, |ui| {
ui.label(format!(
"{:#?}",
crate::text_selection::LabelSelectionState::load(ui.ctx())
));
});
CollapsingHeader::new("Interaction")
.default_open(false)
.show(ui, |ui| {
let interact_widgets = self.write(|ctx| ctx.viewport().interact_widgets.clone());
interact_widgets.ui(ui);
});
}
/// Show stats about the allocated textures.
pub fn texture_ui(&self, ui: &mut crate::Ui) {
let tex_mngr = self.tex_manager();
let tex_mngr = tex_mngr.read();
let mut textures: Vec<_> = tex_mngr.allocated().collect();
textures.sort_by_key(|(id, _)| *id);
let mut bytes = 0;
for (_, tex) in &textures {
bytes += tex.bytes_used();
}
ui.label(format!(
"{} allocated texture(s), using {:.1} MB",
textures.len(),
bytes as f64 * 1e-6
));
let max_preview_size = vec2(48.0, 32.0);
ui.group(|ui| {
ScrollArea::vertical()
.max_height(300.0)
.auto_shrink([false, true])
.show(ui, |ui| {
ui.style_mut().override_text_style = Some(TextStyle::Monospace);
Grid::new("textures")
.striped(true)
.num_columns(4)
.spacing(vec2(16.0, 2.0))
.min_row_height(max_preview_size.y)
.show(ui, |ui| {
for (&texture_id, meta) in textures {
let [w, h] = meta.size;
let mut size = vec2(w as f32, h as f32);
size *= (max_preview_size.x / size.x).min(1.0);
size *= (max_preview_size.y / size.y).min(1.0);
ui.image(SizedTexture::new(texture_id, size))
.on_hover_ui(|ui| {
// show larger on hover
let max_size = 0.5 * ui.ctx().screen_rect().size();
let mut size = vec2(w as f32, h as f32);
size *= max_size.x / size.x.max(max_size.x);
size *= max_size.y / size.y.max(max_size.y);
ui.image(SizedTexture::new(texture_id, size));
});
ui.label(format!("{w} x {h}"));
ui.label(format!("{:.3} MB", meta.bytes_used() as f64 * 1e-6));
ui.label(format!("{:?}", meta.name));
ui.end_row();
}
});
});
});
}
/// Shows the contents of [`Self::memory`].
pub fn memory_ui(&self, ui: &mut crate::Ui) {
if ui
.button("Reset all")
.on_hover_text("Reset all egui state")
.clicked()
{
self.memory_mut(|mem| *mem = Default::default());
}
let (num_state, num_serialized) = self.data(|d| (d.len(), d.count_serialized()));
ui.label(format!(
"{num_state} widget states stored (of which {num_serialized} are serialized)."
));
ui.horizontal(|ui| {
ui.label(format!(
"{} areas (panels, windows, popups, …)",
self.memory(|mem| mem.areas().count())
));
if ui.button("Reset").clicked() {
self.memory_mut(|mem| *mem.areas_mut() = Default::default());
}
});
ui.indent("areas", |ui| {
ui.label("Visible areas, ordered back to front.");
ui.label("Hover to highlight");
let layers_ids: Vec<LayerId> = self.memory(|mem| mem.areas().order().to_vec());
for layer_id in layers_ids {
let area = AreaState::load(self, layer_id.id);
if let Some(area) = area {
let is_visible = self.memory(|mem| mem.areas().is_visible(&layer_id));
if !is_visible {
continue;
}
let text = format!("{} - {:?}", layer_id.short_debug_format(), area.rect(),);
// TODO(emilk): `Sense::hover_highlight()`
if ui
.add(Label::new(RichText::new(text).monospace()).sense(Sense::click()))
.hovered
&& is_visible
{
ui.ctx()
.debug_painter()
.debug_rect(area.rect(), Color32::RED, "");
}
}
}
});
ui.horizontal(|ui| {
ui.label(format!(
"{} collapsing headers",
self.data(|d| d.count::<containers::collapsing_header::InnerState>())
));
if ui.button("Reset").clicked() {
self.data_mut(|d| d.remove_by_type::<containers::collapsing_header::InnerState>());
}
});
ui.horizontal(|ui| {
ui.label(format!(
"{} menu bars",
self.data(|d| d.count::<menu::BarState>())
));
if ui.button("Reset").clicked() {
self.data_mut(|d| d.remove_by_type::<menu::BarState>());
}
});
ui.horizontal(|ui| {
ui.label(format!(
"{} scroll areas",
self.data(|d| d.count::<scroll_area::State>())
));
if ui.button("Reset").clicked() {
self.data_mut(|d| d.remove_by_type::<scroll_area::State>());
}
});
ui.horizontal(|ui| {
ui.label(format!(
"{} resize areas",
self.data(|d| d.count::<resize::State>())
));
if ui.button("Reset").clicked() {
self.data_mut(|d| d.remove_by_type::<resize::State>());
}
});
ui.shrink_width_to_current(); // don't let the text below grow this window wider
ui.label("NOTE: the position of this window cannot be reset from within itself.");
ui.collapsing("Interaction", |ui| {
let interaction = self.memory(|mem| mem.interaction().clone());
interaction.ui(ui);
});
}
}
impl Context {
/// Edit the [`Style`].
pub fn style_ui(&self, ui: &mut Ui, theme: Theme) {
let mut style: Style = (*self.style_of(theme)).clone();
style.ui(ui);
self.set_style_of(theme, style);
}
}
/// ## Accessibility
impl Context {
/// Call the provided function with the given ID pushed on the stack of
/// parent IDs for accessibility purposes. If the `accesskit` feature
/// is disabled or if AccessKit support is not active for this frame,
/// the function is still called, but with no other effect.
///
/// No locks are held while the given closure is called.
#[allow(clippy::unused_self, clippy::let_and_return)]
#[inline]
pub fn with_accessibility_parent<R>(&self, _id: Id, f: impl FnOnce() -> R) -> R {
// TODO(emilk): this isn't thread-safe - another thread can call this function between the push/pop calls
#[cfg(feature = "accesskit")]
self.pass_state_mut(|fs| {
if let Some(state) = fs.accesskit_state.as_mut() {
state.parent_stack.push(_id);
}
});
let result = f();
#[cfg(feature = "accesskit")]
self.pass_state_mut(|fs| {
if let Some(state) = fs.accesskit_state.as_mut() {
assert_eq!(state.parent_stack.pop(), Some(_id));
}
});
result
}
/// If AccessKit support is active for the current frame, get or create
/// a node builder with the specified ID and return a mutable reference to it.
/// For newly created nodes, the parent is the node with the ID at the top
/// of the stack managed by [`Context::with_accessibility_parent`].
///
/// The `Context` lock is held while the given closure is called!
///
/// Returns `None` if acesskit is off.
// TODO(emilk): consider making both read-only and read-write versions
#[cfg(feature = "accesskit")]
pub fn accesskit_node_builder<R>(
&self,
id: Id,
writer: impl FnOnce(&mut accesskit::NodeBuilder) -> R,
) -> Option<R> {
self.write(|ctx| {
ctx.viewport()
.this_pass
.accesskit_state
.is_some()
.then(|| ctx.accesskit_node_builder(id))
.map(writer)
})
}
/// Enable generation of AccessKit tree updates in all future frames.
#[cfg(feature = "accesskit")]
pub fn enable_accesskit(&self) {
self.write(|ctx| ctx.is_accesskit_enabled = true);
}
/// Disable generation of AccessKit tree updates in all future frames.
#[cfg(feature = "accesskit")]
pub fn disable_accesskit(&self) {
self.write(|ctx| ctx.is_accesskit_enabled = false);
}
}
/// ## Image loading
impl Context {
/// Associate some static bytes with a `uri`.
///
/// The same `uri` may be passed to [`Ui::image`] later to load the bytes as an image.
///
/// By convention, the `uri` should start with `bytes://`.
/// Following that convention will lead to better error messages.
pub fn include_bytes(&self, uri: impl Into<Cow<'static, str>>, bytes: impl Into<Bytes>) {
self.loaders().include.insert(uri, bytes);
}
/// Returns `true` if the chain of bytes, image, or texture loaders
/// contains a loader with the given `id`.
pub fn is_loader_installed(&self, id: &str) -> bool {
let loaders = self.loaders();
loaders.bytes.lock().iter().any(|l| l.id() == id)
|| loaders.image.lock().iter().any(|l| l.id() == id)
|| loaders.texture.lock().iter().any(|l| l.id() == id)
}
/// Add a new bytes loader.
///
/// It will be tried first, before any already installed loaders.
///
/// See [`load`] for more information.
pub fn add_bytes_loader(&self, loader: Arc<dyn load::BytesLoader + Send + Sync + 'static>) {
self.loaders().bytes.lock().push(loader);
}
/// Add a new image loader.
///
/// It will be tried first, before any already installed loaders.
///
/// See [`load`] for more information.
pub fn add_image_loader(&self, loader: Arc<dyn load::ImageLoader + Send + Sync + 'static>) {
self.loaders().image.lock().push(loader);
}
/// Add a new texture loader.
///
/// It will be tried first, before any already installed loaders.
///
/// See [`load`] for more information.
pub fn add_texture_loader(&self, loader: Arc<dyn load::TextureLoader + Send + Sync + 'static>) {
self.loaders().texture.lock().push(loader);
}
/// Release all memory and textures related to the given image URI.
///
/// If you attempt to load the image again, it will be reloaded from scratch.
pub fn forget_image(&self, uri: &str) {
use load::BytesLoader as _;
crate::profile_function!();
let loaders = self.loaders();
loaders.include.forget(uri);
for loader in loaders.bytes.lock().iter() {
loader.forget(uri);
}
for loader in loaders.image.lock().iter() {
loader.forget(uri);
}
for loader in loaders.texture.lock().iter() {
loader.forget(uri);
}
}
/// Release all memory and textures related to images used in [`Ui::image`] or [`crate::Image`].
///
/// If you attempt to load any images again, they will be reloaded from scratch.
pub fn forget_all_images(&self) {
use load::BytesLoader as _;
crate::profile_function!();
let loaders = self.loaders();
loaders.include.forget_all();
for loader in loaders.bytes.lock().iter() {
loader.forget_all();
}
for loader in loaders.image.lock().iter() {
loader.forget_all();
}
for loader in loaders.texture.lock().iter() {
loader.forget_all();
}
}
/// Try loading the bytes from the given uri using any available bytes loaders.
///
/// Loaders are expected to cache results, so that this call is immediate-mode safe.
///
/// This calls the loaders one by one in the order in which they were registered.
/// If a loader returns [`LoadError::NotSupported`][not_supported],
/// then the next loader is called. This process repeats until all loaders have
/// been exhausted, at which point this returns [`LoadError::NotSupported`][not_supported].
///
/// # Errors
/// This may fail with:
/// - [`LoadError::NotSupported`][not_supported] if none of the registered loaders support loading the given `uri`.
/// - [`LoadError::Loading`][custom] if one of the loaders _does_ support loading the `uri`, but the loading process failed.
///
/// ⚠ May deadlock if called from within a `BytesLoader`!
///
/// [not_supported]: crate::load::LoadError::NotSupported
/// [custom]: crate::load::LoadError::Loading
pub fn try_load_bytes(&self, uri: &str) -> load::BytesLoadResult {
crate::profile_function!(uri);
let loaders = self.loaders();
let bytes_loaders = loaders.bytes.lock();
// Try most recently added loaders first (hence `.rev()`)
for loader in bytes_loaders.iter().rev() {
match loader.load(self, uri) {
Err(load::LoadError::NotSupported) => continue,
result => return result,
}
}
Err(load::LoadError::NoMatchingBytesLoader)
}
/// Try loading the image from the given uri using any available image loaders.
///
/// Loaders are expected to cache results, so that this call is immediate-mode safe.
///
/// This calls the loaders one by one in the order in which they were registered.
/// If a loader returns [`LoadError::NotSupported`][not_supported],
/// then the next loader is called. This process repeats until all loaders have
/// been exhausted, at which point this returns [`LoadError::NotSupported`][not_supported].
///
/// # Errors
/// This may fail with:
/// - [`LoadError::NoImageLoaders`][no_image_loaders] if tbere are no registered image loaders.
/// - [`LoadError::NotSupported`][not_supported] if none of the registered loaders support loading the given `uri`.
/// - [`LoadError::Loading`][custom] if one of the loaders _does_ support loading the `uri`, but the loading process failed.
///
/// ⚠ May deadlock if called from within an `ImageLoader`!
///
/// [no_image_loaders]: crate::load::LoadError::NoImageLoaders
/// [not_supported]: crate::load::LoadError::NotSupported
/// [custom]: crate::load::LoadError::Loading
pub fn try_load_image(&self, uri: &str, size_hint: load::SizeHint) -> load::ImageLoadResult {
crate::profile_function!(uri);
let loaders = self.loaders();
let image_loaders = loaders.image.lock();
if image_loaders.is_empty() {
return Err(load::LoadError::NoImageLoaders);
}
// Try most recently added loaders first (hence `.rev()`)
for loader in image_loaders.iter().rev() {
match loader.load(self, uri, size_hint) {
Err(load::LoadError::NotSupported) => continue,
result => return result,
}
}
Err(load::LoadError::NoMatchingImageLoader)
}
/// Try loading the texture from the given uri using any available texture loaders.
///
/// Loaders are expected to cache results, so that this call is immediate-mode safe.
///
/// This calls the loaders one by one in the order in which they were registered.
/// If a loader returns [`LoadError::NotSupported`][not_supported],
/// then the next loader is called. This process repeats until all loaders have
/// been exhausted, at which point this returns [`LoadError::NotSupported`][not_supported].
///
/// # Errors
/// This may fail with:
/// - [`LoadError::NotSupported`][not_supported] if none of the registered loaders support loading the given `uri`.
/// - [`LoadError::Loading`][custom] if one of the loaders _does_ support loading the `uri`, but the loading process failed.
///
/// ⚠ May deadlock if called from within a `TextureLoader`!
///
/// [not_supported]: crate::load::LoadError::NotSupported
/// [custom]: crate::load::LoadError::Loading
pub fn try_load_texture(
&self,
uri: &str,
texture_options: TextureOptions,
size_hint: load::SizeHint,
) -> load::TextureLoadResult {
crate::profile_function!(uri);
let loaders = self.loaders();
let texture_loaders = loaders.texture.lock();
// Try most recently added loaders first (hence `.rev()`)
for loader in texture_loaders.iter().rev() {
match loader.load(self, uri, texture_options, size_hint) {
Err(load::LoadError::NotSupported) => continue,
result => return result,
}
}
Err(load::LoadError::NoMatchingTextureLoader)
}
/// The loaders of bytes, images, and textures.
pub fn loaders(&self) -> Arc<Loaders> {
crate::profile_function!();
self.read(|this| this.loaders.clone())
}
}
/// ## Viewports
impl Context {
/// Return the `ViewportId` of the current viewport.
///
/// If this is the root viewport, this will return [`ViewportId::ROOT`].
///
/// Don't use this outside of `Self::run`, or after `Self::end_pass`.
pub fn viewport_id(&self) -> ViewportId {
self.read(|ctx| ctx.viewport_id())
}
/// Return the `ViewportId` of his parent.
///
/// If this is the root viewport, this will return [`ViewportId::ROOT`].
///
/// Don't use this outside of `Self::run`, or after `Self::end_pass`.
pub fn parent_viewport_id(&self) -> ViewportId {
self.read(|ctx| ctx.parent_viewport_id())
}
/// Read the state of the current viewport.
pub fn viewport<R>(&self, reader: impl FnOnce(&ViewportState) -> R) -> R {
self.write(|ctx| reader(ctx.viewport()))
}
/// Read the state of a specific current viewport.
pub fn viewport_for<R>(
&self,
viewport_id: ViewportId,
reader: impl FnOnce(&ViewportState) -> R,
) -> R {
self.write(|ctx| reader(ctx.viewport_for(viewport_id)))
}
/// For integrations: Set this to render a sync viewport.
///
/// This will only set the callback for the current thread,
/// which most likely should be the main thread.
///
/// When an immediate viewport is created with [`Self::show_viewport_immediate`] it will be rendered by this function.
///
/// When called, the integration needs to:
/// * Check if there already is a window for this viewport id, and if not open one
/// * Set the window attributes (position, size, …) based on [`ImmediateViewport::builder`].
/// * Call [`Context::run`] with [`ImmediateViewport::viewport_ui_cb`].
/// * Handle the output from [`Context::run`], including rendering
#[allow(clippy::unused_self)]
pub fn set_immediate_viewport_renderer(
callback: impl for<'a> Fn(&Self, ImmediateViewport<'a>) + 'static,
) {
let callback = Box::new(callback);
IMMEDIATE_VIEWPORT_RENDERER.with(|render_sync| {
render_sync.replace(Some(callback));
});
}
/// If `true`, [`Self::show_viewport_deferred`] and [`Self::show_viewport_immediate`] will
/// embed the new viewports inside the existing one, instead of spawning a new native window.
///
/// `eframe` sets this to `false` on supported platforms, but the default value is `true`.
pub fn embed_viewports(&self) -> bool {
self.read(|ctx| ctx.embed_viewports)
}
/// If `true`, [`Self::show_viewport_deferred`] and [`Self::show_viewport_immediate`] will
/// embed the new viewports inside the existing one, instead of spawning a new native window.
///
/// `eframe` sets this to `false` on supported platforms, but the default value is `true`.
pub fn set_embed_viewports(&self, value: bool) {
self.write(|ctx| ctx.embed_viewports = value);
}
/// Send a command to the current viewport.
///
/// This lets you affect the current viewport, e.g. resizing the window.
pub fn send_viewport_cmd(&self, command: ViewportCommand) {
self.send_viewport_cmd_to(self.viewport_id(), command);
}
/// Send a command to a specific viewport.
///
/// This lets you affect another viewport, e.g. resizing its window.
pub fn send_viewport_cmd_to(&self, id: ViewportId, command: ViewportCommand) {
self.request_repaint_of(id);
if command.requires_parent_repaint() {
self.request_repaint_of(self.parent_viewport_id());
}
self.write(|ctx| ctx.viewport_for(id).commands.push(command));
}
/// Show a deferred viewport, creating a new native window, if possible.
///
/// The given id must be unique for each viewport.
///
/// You need to call this each pass when the child viewport should exist.
///
/// You can check if the user wants to close the viewport by checking the
/// [`crate::ViewportInfo::close_requested`] flags found in [`crate::InputState::viewport`].
///
/// The given callback will be called whenever the child viewport needs repainting,
/// e.g. on an event or when [`Self::request_repaint`] is called.
/// This means it may be called multiple times, for instance while the
/// parent viewport (the caller) is sleeping but the child viewport is animating.
///
/// You will need to wrap your viewport state in an `Arc<RwLock<T>>` or `Arc<Mutex<T>>`.
/// When this is called again with the same id in `ViewportBuilder` the render function for that viewport will be updated.
///
/// You can also use [`Self::show_viewport_immediate`], which uses a simpler `FnOnce`
/// with no need for `Send` or `Sync`. The downside is that it will require
/// the parent viewport (the caller) to repaint anytime the child is repainted,
/// and vice versa.
///
/// If [`Context::embed_viewports`] is `true` (e.g. if the current egui
/// backend does not support multiple viewports), the given callback
/// will be called immediately, embedding the new viewport in the current one.
/// You can check this with the [`ViewportClass`] given in the callback.
/// If you find [`ViewportClass::Embedded`], you need to create a new [`crate::Window`] for you content.
///
/// See [`crate::viewport`] for more information about viewports.
pub fn show_viewport_deferred(
&self,
new_viewport_id: ViewportId,
viewport_builder: ViewportBuilder,
viewport_ui_cb: impl Fn(&Self, ViewportClass) + Send + Sync + 'static,
) {
crate::profile_function!();
if self.embed_viewports() {
viewport_ui_cb(self, ViewportClass::Embedded);
} else {
self.write(|ctx| {
ctx.viewport_parents
.insert(new_viewport_id, ctx.viewport_id());
let viewport = ctx.viewports.entry(new_viewport_id).or_default();
viewport.class = ViewportClass::Deferred;
viewport.builder = viewport_builder;
viewport.used = true;
viewport.viewport_ui_cb = Some(Arc::new(move |ctx| {
(viewport_ui_cb)(ctx, ViewportClass::Deferred);
}));
});
}
}
/// Show an immediate viewport, creating a new native window, if possible.
///
/// This is the easier type of viewport to use, but it is less performant
/// at it requires both parent and child to repaint if any one of them needs repainting,
/// which effectively produce double work for two viewports, and triple work for three viewports, etc.
/// To avoid this, use [`Self::show_viewport_deferred`] instead.
///
/// The given id must be unique for each viewport.
///
/// You need to call this each pass when the child viewport should exist.
///
/// You can check if the user wants to close the viewport by checking the
/// [`crate::ViewportInfo::close_requested`] flags found in [`crate::InputState::viewport`].
///
/// The given ui function will be called immediately.
/// This may only be called on the main thread.
/// This call will pause the current viewport and render the child viewport in its own window.
/// This means that the child viewport will not be repainted when the parent viewport is repainted, and vice versa.
///
/// If [`Context::embed_viewports`] is `true` (e.g. if the current egui
/// backend does not support multiple viewports), the given callback
/// will be called immediately, embedding the new viewport in the current one.
/// You can check this with the [`ViewportClass`] given in the callback.
/// If you find [`ViewportClass::Embedded`], you need to create a new [`crate::Window`] for you content.
///
/// See [`crate::viewport`] for more information about viewports.
pub fn show_viewport_immediate<T>(
&self,
new_viewport_id: ViewportId,
builder: ViewportBuilder,
mut viewport_ui_cb: impl FnMut(&Self, ViewportClass) -> T,
) -> T {
crate::profile_function!();
if self.embed_viewports() {
return viewport_ui_cb(self, ViewportClass::Embedded);
}
IMMEDIATE_VIEWPORT_RENDERER.with(|immediate_viewport_renderer| {
let immediate_viewport_renderer = immediate_viewport_renderer.borrow();
let Some(immediate_viewport_renderer) = immediate_viewport_renderer.as_ref() else {
// This egui backend does not support multiple viewports.
return viewport_ui_cb(self, ViewportClass::Embedded);
};
let ids = self.write(|ctx| {
let parent_viewport_id = ctx.viewport_id();
ctx.viewport_parents
.insert(new_viewport_id, parent_viewport_id);
let viewport = ctx.viewports.entry(new_viewport_id).or_default();
viewport.builder = builder.clone();
viewport.used = true;
viewport.viewport_ui_cb = None; // it is immediate
ViewportIdPair::from_self_and_parent(new_viewport_id, parent_viewport_id)
});
let mut out = None;
{
let out = &mut out;
let viewport = ImmediateViewport {
ids,
builder,
viewport_ui_cb: Box::new(move |context| {
*out = Some(viewport_ui_cb(context, ViewportClass::Immediate));
}),
};
immediate_viewport_renderer(self, viewport);
}
out.expect(
"egui backend is implemented incorrectly - the user callback was never called",
)
})
}
}
/// ## Interaction
impl Context {
/// Read you what widgets are currently being interacted with.
pub fn interaction_snapshot<R>(&self, reader: impl FnOnce(&InteractionSnapshot) -> R) -> R {
self.write(|w| reader(&w.viewport().interact_widgets))
}
/// The widget currently being dragged, if any.
///
/// For widgets that sense both clicks and drags, this will
/// not be set until the mouse cursor has moved a certain distance.
///
/// NOTE: if the widget was released this pass, this will be `None`.
/// Use [`Self::drag_stopped_id`] instead.
pub fn dragged_id(&self) -> Option<Id> {
self.interaction_snapshot(|i| i.dragged)
}
/// Is this specific widget being dragged?
///
/// A widget that sense both clicks and drags is only marked as "dragged"
/// when the mouse has moved a bit
///
/// See also: [`crate::Response::dragged`].
pub fn is_being_dragged(&self, id: Id) -> bool {
self.dragged_id() == Some(id)
}
/// This widget just started being dragged this pass.
///
/// The same widget should also be found in [`Self::dragged_id`].
pub fn drag_started_id(&self) -> Option<Id> {
self.interaction_snapshot(|i| i.drag_started)
}
/// This widget was being dragged, but was released this pass
pub fn drag_stopped_id(&self) -> Option<Id> {
self.interaction_snapshot(|i| i.drag_stopped)
}
/// Set which widget is being dragged.
pub fn set_dragged_id(&self, id: Id) {
self.write(|ctx| {
let vp = ctx.viewport();
let i = &mut vp.interact_widgets;
if i.dragged != Some(id) {
i.drag_stopped = i.dragged.or(i.drag_stopped);
i.dragged = Some(id);
i.drag_started = Some(id);
}
ctx.memory.interaction_mut().potential_drag_id = Some(id);
});
}
/// Stop dragging any widget.
pub fn stop_dragging(&self) {
self.write(|ctx| {
let vp = ctx.viewport();
let i = &mut vp.interact_widgets;
if i.dragged.is_some() {
i.drag_stopped = i.dragged;
i.dragged = None;
}
ctx.memory.interaction_mut().potential_drag_id = None;
});
}
/// Is something else being dragged?
///
/// Returns true if we are dragging something, but not the given widget.
#[inline(always)]
pub fn dragging_something_else(&self, not_this: Id) -> bool {
let dragged = self.dragged_id();
dragged.is_some() && dragged != Some(not_this)
}
}
#[test]
fn context_impl_send_sync() {
fn assert_send_sync<T: Send + Sync>() {}
assert_send_sync::<Context>();
}
#[cfg(test)]
mod test {
use super::Context;
#[test]
fn test_single_pass() {
let ctx = Context::default();
ctx.options_mut(|o| o.max_passes = 1.try_into().unwrap());
// A single call, no request to discard:
{
let mut num_calls = 0;
let output = ctx.run(Default::default(), |ctx| {
num_calls += 1;
assert_eq!(ctx.output(|o| o.num_completed_passes), 0);
assert!(!ctx.output(|o| o.requested_discard()));
assert!(!ctx.will_discard());
});
assert_eq!(num_calls, 1);
assert_eq!(output.platform_output.num_completed_passes, 1);
assert!(!output.platform_output.requested_discard());
}
// A single call, with a denied request to discard:
{
let mut num_calls = 0;
let output = ctx.run(Default::default(), |ctx| {
num_calls += 1;
ctx.request_discard("test");
assert!(!ctx.will_discard(), "The request should have been denied");
});
assert_eq!(num_calls, 1);
assert_eq!(output.platform_output.num_completed_passes, 1);
assert!(
output.platform_output.requested_discard(),
"The request should be reported"
);
assert_eq!(
output
.platform_output
.request_discard_reasons
.first()
.unwrap()
.reason,
"test"
);
}
}
#[test]
fn test_dual_pass() {
let ctx = Context::default();
ctx.options_mut(|o| o.max_passes = 2.try_into().unwrap());
// Normal single pass:
{
let mut num_calls = 0;
let output = ctx.run(Default::default(), |ctx| {
assert_eq!(ctx.output(|o| o.num_completed_passes), 0);
assert!(!ctx.output(|o| o.requested_discard()));
assert!(!ctx.will_discard());
num_calls += 1;
});
assert_eq!(num_calls, 1);
assert_eq!(output.platform_output.num_completed_passes, 1);
assert!(!output.platform_output.requested_discard());
}
// Request discard once:
{
let mut num_calls = 0;
let output = ctx.run(Default::default(), |ctx| {
assert_eq!(ctx.output(|o| o.num_completed_passes), num_calls);
assert!(!ctx.will_discard());
if num_calls == 0 {
ctx.request_discard("test");
assert!(ctx.will_discard());
}
num_calls += 1;
});
assert_eq!(num_calls, 2);
assert_eq!(output.platform_output.num_completed_passes, 2);
assert!(
!output.platform_output.requested_discard(),
"The request should have been cleared when fulfilled"
);
}
// Request discard twice:
{
let mut num_calls = 0;
let output = ctx.run(Default::default(), |ctx| {
assert_eq!(ctx.output(|o| o.num_completed_passes), num_calls);
assert!(!ctx.will_discard());
ctx.request_discard("test");
if num_calls == 0 {
assert!(ctx.will_discard(), "First request granted");
} else {
assert!(!ctx.will_discard(), "Second request should be denied");
}
num_calls += 1;
});
assert_eq!(num_calls, 2);
assert_eq!(output.platform_output.num_completed_passes, 2);
assert!(
output.platform_output.requested_discard(),
"The unfulfilled request should be reported"
);
}
}
#[test]
fn test_multi_pass() {
let ctx = Context::default();
ctx.options_mut(|o| o.max_passes = 10.try_into().unwrap());
// Request discard three times:
{
let mut num_calls = 0;
let output = ctx.run(Default::default(), |ctx| {
assert_eq!(ctx.output(|o| o.num_completed_passes), num_calls);
assert!(!ctx.will_discard());
if num_calls <= 2 {
ctx.request_discard("test");
assert!(ctx.will_discard());
}
num_calls += 1;
});
assert_eq!(num_calls, 4);
assert_eq!(output.platform_output.num_completed_passes, 4);
assert!(
!output.platform_output.requested_discard(),
"The request should have been cleared when fulfilled"
);
}
}
}