egui/crates/eframe/src/web/mod.rs

370 lines
12 KiB
Rust

//! [`egui`] bindings for web apps (compiling to WASM).
#![allow(clippy::missing_errors_doc)] // So many `-> Result<_, JsValue>`
mod app_runner;
mod backend;
mod events;
mod input;
mod panic_handler;
mod text_agent;
mod web_logger;
mod web_runner;
/// Access to the browser screen reader.
#[cfg(feature = "web_screen_reader")]
pub mod screen_reader;
/// Access to local browser storage.
pub mod storage;
pub(crate) use app_runner::AppRunner;
pub use panic_handler::{PanicHandler, PanicSummary};
pub use web_logger::WebLogger;
pub use web_runner::WebRunner;
#[cfg(not(any(feature = "glow", feature = "wgpu")))]
compile_error!("You must enable either the 'glow' or 'wgpu' feature");
mod web_painter;
#[cfg(feature = "glow")]
mod web_painter_glow;
#[cfg(feature = "glow")]
pub(crate) type ActiveWebPainter = web_painter_glow::WebPainterGlow;
#[cfg(feature = "wgpu")]
mod web_painter_wgpu;
#[cfg(all(feature = "wgpu", not(feature = "glow")))]
pub(crate) type ActiveWebPainter = web_painter_wgpu::WebPainterWgpu;
pub use backend::*;
use wasm_bindgen::prelude::*;
use web_sys::{Document, MediaQueryList, Node};
use input::{
button_from_mouse_event, modifiers_from_kb_event, modifiers_from_mouse_event,
modifiers_from_wheel_event, pos_from_mouse_event, primary_touch_pos, push_touches,
text_from_keyboard_event, translate_key,
};
// ----------------------------------------------------------------------------
/// Debug browser resizing?
const DEBUG_RESIZE: bool = false;
pub(crate) fn string_from_js_value(value: &JsValue) -> String {
value.as_string().unwrap_or_else(|| format!("{value:#?}"))
}
/// Returns the `Element` with active focus.
///
/// Elements can only be focused if they are:
/// - `<a>`/`<area>` with an `href` attribute
/// - `<input>`/`<select>`/`<textarea>`/`<button>` which aren't `disabled`
/// - any other element with a `tabindex` attribute
pub(crate) fn focused_element(root: &Node) -> Option<web_sys::Element> {
if let Some(document) = root.dyn_ref::<Document>() {
document.active_element()
} else if let Some(shadow) = root.dyn_ref::<web_sys::ShadowRoot>() {
shadow.active_element()
} else {
None
}
}
pub(crate) fn has_focus<T: JsCast>(element: &T) -> bool {
fn try_has_focus<T: JsCast>(element: &T) -> Option<bool> {
let element = element.dyn_ref::<web_sys::Element>()?;
let root = element.get_root_node();
let focused_element = focused_element(&root)?;
Some(element == &focused_element)
}
try_has_focus(element).unwrap_or(false)
}
/// Current time in seconds (since undefined point in time).
///
/// Monotonically increasing.
pub fn now_sec() -> f64 {
web_sys::window()
.expect("should have a Window")
.performance()
.expect("should have a Performance")
.now()
/ 1000.0
}
/// The native GUI scale factor, taking into account the browser zoom.
///
/// Corresponds to [`window.devicePixelRatio`](https://developer.mozilla.org/en-US/docs/Web/API/Window/devicePixelRatio) in JavaScript.
pub fn native_pixels_per_point() -> f32 {
let pixels_per_point = web_sys::window().unwrap().device_pixel_ratio() as f32;
if pixels_per_point > 0.0 && pixels_per_point.is_finite() {
pixels_per_point
} else {
1.0
}
}
/// Ask the browser about the preferred system theme.
///
/// `None` means unknown.
pub fn system_theme() -> Option<egui::Theme> {
let dark_mode = prefers_color_scheme_dark(&web_sys::window()?)
.ok()??
.matches();
Some(theme_from_dark_mode(dark_mode))
}
fn prefers_color_scheme_dark(window: &web_sys::Window) -> Result<Option<MediaQueryList>, JsValue> {
window.match_media("(prefers-color-scheme: dark)")
}
fn theme_from_dark_mode(dark_mode: bool) -> egui::Theme {
if dark_mode {
egui::Theme::Dark
} else {
egui::Theme::Light
}
}
/// Returns the canvas in client coordinates.
fn canvas_content_rect(canvas: &web_sys::HtmlCanvasElement) -> egui::Rect {
let bounding_rect = canvas.get_bounding_client_rect();
let mut rect = egui::Rect::from_min_max(
egui::pos2(bounding_rect.left() as f32, bounding_rect.top() as f32),
egui::pos2(bounding_rect.right() as f32, bounding_rect.bottom() as f32),
);
// We need to subtract padding and border:
if let Some(window) = web_sys::window() {
if let Ok(Some(style)) = window.get_computed_style(canvas) {
let get_property = |name: &str| -> Option<f32> {
let property = style.get_property_value(name).ok()?;
property.trim_end_matches("px").parse::<f32>().ok()
};
rect.min.x += get_property("padding-left").unwrap_or_default();
rect.min.y += get_property("padding-top").unwrap_or_default();
rect.max.x -= get_property("padding-right").unwrap_or_default();
rect.max.y -= get_property("padding-bottom").unwrap_or_default();
}
}
rect
}
fn canvas_size_in_points(canvas: &web_sys::HtmlCanvasElement, ctx: &egui::Context) -> egui::Vec2 {
// ctx.pixels_per_point can be outdated
let pixels_per_point = ctx.zoom_factor() * native_pixels_per_point();
egui::vec2(
canvas.width() as f32 / pixels_per_point,
canvas.height() as f32 / pixels_per_point,
)
}
// ----------------------------------------------------------------------------
/// Set the cursor icon.
fn set_cursor_icon(cursor: egui::CursorIcon) -> Option<()> {
let document = web_sys::window()?.document()?;
document
.body()?
.style()
.set_property("cursor", cursor_web_name(cursor))
.ok()
}
/// Set the clipboard text.
fn set_clipboard_text(s: &str) {
if let Some(window) = web_sys::window() {
if !window.is_secure_context() {
log::error!(
"Clipboard is not available because we are not in a secure context. \
See https://developer.mozilla.org/en-US/docs/Web/Security/Secure_Contexts"
);
return;
}
let promise = window.navigator().clipboard().write_text(s);
let future = wasm_bindgen_futures::JsFuture::from(promise);
let future = async move {
if let Err(err) = future.await {
log::error!("Copy/cut action failed: {}", string_from_js_value(&err));
}
};
wasm_bindgen_futures::spawn_local(future);
}
}
/// Set the clipboard image.
fn set_clipboard_image(image: &egui::ColorImage) {
if let Some(window) = web_sys::window() {
if !window.is_secure_context() {
log::error!(
"Clipboard is not available because we are not in a secure context. \
See https://developer.mozilla.org/en-US/docs/Web/Security/Secure_Contexts"
);
return;
}
let png_bytes = to_image(image).and_then(|image| to_png_bytes(&image));
let png_bytes = match png_bytes {
Ok(png_bytes) => png_bytes,
Err(err) => {
log::error!("Failed to encode image to png: {err}");
return;
}
};
let mime = "image/png";
let item = match create_clipboard_item(mime, &png_bytes) {
Ok(item) => item,
Err(err) => {
log::error!("Failed to copy image: {}", string_from_js_value(&err));
return;
}
};
let items = js_sys::Array::of1(&item);
let promise = window.navigator().clipboard().write(&items);
let future = wasm_bindgen_futures::JsFuture::from(promise);
let future = async move {
if let Err(err) = future.await {
log::error!(
"Copy/cut image action failed: {}",
string_from_js_value(&err)
);
}
};
wasm_bindgen_futures::spawn_local(future);
}
}
fn to_image(image: &egui::ColorImage) -> Result<image::RgbaImage, String> {
profiling::function_scope!();
image::RgbaImage::from_raw(
image.width() as _,
image.height() as _,
bytemuck::cast_slice(&image.pixels).to_vec(),
)
.ok_or_else(|| "Invalid IconData".to_owned())
}
fn to_png_bytes(image: &image::RgbaImage) -> Result<Vec<u8>, String> {
profiling::function_scope!();
let mut png_bytes: Vec<u8> = Vec::new();
image
.write_to(
&mut std::io::Cursor::new(&mut png_bytes),
image::ImageFormat::Png,
)
.map_err(|err| err.to_string())?;
Ok(png_bytes)
}
fn create_clipboard_item(mime: &str, bytes: &[u8]) -> Result<web_sys::ClipboardItem, JsValue> {
let array = js_sys::Uint8Array::from(bytes);
let blob_parts = js_sys::Array::new();
blob_parts.push(&array);
let options = web_sys::BlobPropertyBag::new();
options.set_type(mime);
let blob = web_sys::Blob::new_with_u8_array_sequence_and_options(&blob_parts, &options)?;
let items = js_sys::Object::new();
// SAFETY: I hope so
#[allow(unsafe_code, unused_unsafe)] // Weird false positive
unsafe {
js_sys::Reflect::set(&items, &JsValue::from_str(mime), &blob)?
};
let clipboard_item = web_sys::ClipboardItem::new_with_record_from_str_to_blob_promise(&items)?;
Ok(clipboard_item)
}
fn cursor_web_name(cursor: egui::CursorIcon) -> &'static str {
match cursor {
egui::CursorIcon::Alias => "alias",
egui::CursorIcon::AllScroll => "all-scroll",
egui::CursorIcon::Cell => "cell",
egui::CursorIcon::ContextMenu => "context-menu",
egui::CursorIcon::Copy => "copy",
egui::CursorIcon::Crosshair => "crosshair",
egui::CursorIcon::Default => "default",
egui::CursorIcon::Grab => "grab",
egui::CursorIcon::Grabbing => "grabbing",
egui::CursorIcon::Help => "help",
egui::CursorIcon::Move => "move",
egui::CursorIcon::NoDrop => "no-drop",
egui::CursorIcon::None => "none",
egui::CursorIcon::NotAllowed => "not-allowed",
egui::CursorIcon::PointingHand => "pointer",
egui::CursorIcon::Progress => "progress",
egui::CursorIcon::ResizeHorizontal => "ew-resize",
egui::CursorIcon::ResizeNeSw => "nesw-resize",
egui::CursorIcon::ResizeNwSe => "nwse-resize",
egui::CursorIcon::ResizeVertical => "ns-resize",
egui::CursorIcon::ResizeEast => "e-resize",
egui::CursorIcon::ResizeSouthEast => "se-resize",
egui::CursorIcon::ResizeSouth => "s-resize",
egui::CursorIcon::ResizeSouthWest => "sw-resize",
egui::CursorIcon::ResizeWest => "w-resize",
egui::CursorIcon::ResizeNorthWest => "nw-resize",
egui::CursorIcon::ResizeNorth => "n-resize",
egui::CursorIcon::ResizeNorthEast => "ne-resize",
egui::CursorIcon::ResizeColumn => "col-resize",
egui::CursorIcon::ResizeRow => "row-resize",
egui::CursorIcon::Text => "text",
egui::CursorIcon::VerticalText => "vertical-text",
egui::CursorIcon::Wait => "wait",
egui::CursorIcon::ZoomIn => "zoom-in",
egui::CursorIcon::ZoomOut => "zoom-out",
}
}
/// Open the given url in the browser.
pub fn open_url(url: &str, new_tab: bool) -> Option<()> {
let name = if new_tab { "_blank" } else { "_self" };
web_sys::window()?
.open_with_url_and_target(url, name)
.ok()?;
Some(())
}
/// e.g. "#fragment" part of "www.example.com/index.html#fragment",
///
/// Percent decoded
pub fn location_hash() -> String {
percent_decode(
&web_sys::window()
.unwrap()
.location()
.hash()
.unwrap_or_default(),
)
}
/// Percent-decodes a string.
pub fn percent_decode(s: &str) -> String {
percent_encoding::percent_decode_str(s)
.decode_utf8_lossy()
.to_string()
}
/// Are we running inside the Safari browser?
pub fn is_safari_browser() -> bool {
web_sys::window().is_some_and(|window| window.has_own_property(&JsValue::from("safari")))
}