egui/crates/epaint/src/text/fonts.rs

1317 lines
45 KiB
Rust

use std::{
collections::BTreeMap,
sync::{
Arc,
atomic::{AtomicU64, Ordering},
},
};
use crate::{
AlphaFromCoverage, TextureAtlas,
text::{
Galley, LayoutJob, LayoutSection,
font::{Font, FontImpl, GlyphInfo},
},
};
use emath::{NumExt as _, OrderedFloat};
#[cfg(feature = "default_fonts")]
use epaint_default_fonts::{EMOJI_ICON, HACK_REGULAR, NOTO_EMOJI_REGULAR, UBUNTU_LIGHT};
// ----------------------------------------------------------------------------
/// How to select a sized font.
#[derive(Clone, Debug, PartialEq)]
#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
pub struct FontId {
/// Height in points.
pub size: f32,
/// What font family to use.
pub family: FontFamily,
// TODO(emilk): weight (bold), italics, …
}
impl Default for FontId {
#[inline]
fn default() -> Self {
Self {
size: 14.0,
family: FontFamily::Proportional,
}
}
}
impl FontId {
#[inline]
pub const fn new(size: f32, family: FontFamily) -> Self {
Self { size, family }
}
#[inline]
pub const fn proportional(size: f32) -> Self {
Self::new(size, FontFamily::Proportional)
}
#[inline]
pub const fn monospace(size: f32) -> Self {
Self::new(size, FontFamily::Monospace)
}
}
impl std::hash::Hash for FontId {
#[inline(always)]
fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
let Self { size, family } = self;
emath::OrderedFloat(*size).hash(state);
family.hash(state);
}
}
// ----------------------------------------------------------------------------
/// Font of unknown size.
///
/// Which style of font: [`Monospace`][`FontFamily::Monospace`], [`Proportional`][`FontFamily::Proportional`],
/// or by user-chosen name.
#[derive(Clone, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd)]
#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
pub enum FontFamily {
/// A font where some characters are wider than other (e.g. 'w' is wider than 'i').
///
/// Proportional fonts are easier to read and should be the preferred choice in most situations.
#[default]
Proportional,
/// A font where each character is the same width (`w` is the same width as `i`).
///
/// Useful for code snippets, or when you need to align numbers or text.
Monospace,
/// One of the names in [`FontDefinitions::families`].
///
/// ```
/// # use epaint::FontFamily;
/// // User-chosen names:
/// FontFamily::Name("arial".into());
/// FontFamily::Name("serif".into());
/// ```
Name(Arc<str>),
}
impl std::fmt::Display for FontFamily {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self {
Self::Monospace => "Monospace".fmt(f),
Self::Proportional => "Proportional".fmt(f),
Self::Name(name) => (*name).fmt(f),
}
}
}
// ----------------------------------------------------------------------------
/// A `.ttf` or `.otf` file and a font face index.
#[derive(Clone, Debug, PartialEq)]
#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
pub struct FontData {
/// The content of a `.ttf` or `.otf` file.
pub font: std::borrow::Cow<'static, [u8]>,
/// Which font face in the file to use.
/// When in doubt, use `0`.
pub index: u32,
/// Extra scale and vertical tweak to apply to all text of this font.
pub tweak: FontTweak,
}
impl FontData {
pub fn from_static(font: &'static [u8]) -> Self {
Self {
font: std::borrow::Cow::Borrowed(font),
index: 0,
tweak: Default::default(),
}
}
pub fn from_owned(font: Vec<u8>) -> Self {
Self {
font: std::borrow::Cow::Owned(font),
index: 0,
tweak: Default::default(),
}
}
pub fn tweak(self, tweak: FontTweak) -> Self {
Self { tweak, ..self }
}
}
impl AsRef<[u8]> for FontData {
fn as_ref(&self) -> &[u8] {
self.font.as_ref()
}
}
// ----------------------------------------------------------------------------
/// Extra scale and vertical tweak to apply to all text of a certain font.
#[derive(Copy, Clone, Debug, PartialEq)]
#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
pub struct FontTweak {
/// Scale the font's glyphs by this much.
/// this is only a visual effect and does not affect the text layout.
///
/// Default: `1.0` (no scaling).
pub scale: f32,
/// Shift font's glyphs downwards by this fraction of the font size (in points).
/// this is only a visual effect and does not affect the text layout.
///
/// Affects larger font sizes more.
///
/// A positive value shifts the text downwards.
/// A negative value shifts it upwards.
///
/// Example value: `-0.2`.
pub y_offset_factor: f32,
/// Shift font's glyphs downwards by this amount of logical points.
/// this is only a visual effect and does not affect the text layout.
///
/// Affects all font sizes equally.
///
/// Example value: `2.0`.
pub y_offset: f32,
}
impl Default for FontTweak {
fn default() -> Self {
Self {
scale: 1.0,
y_offset_factor: 0.0,
y_offset: 0.0,
}
}
}
// ----------------------------------------------------------------------------
fn ab_glyph_font_from_font_data(name: &str, data: &FontData) -> ab_glyph::FontArc {
match &data.font {
std::borrow::Cow::Borrowed(bytes) => {
ab_glyph::FontRef::try_from_slice_and_index(bytes, data.index)
.map(ab_glyph::FontArc::from)
}
std::borrow::Cow::Owned(bytes) => {
ab_glyph::FontVec::try_from_vec_and_index(bytes.clone(), data.index)
.map(ab_glyph::FontArc::from)
}
}
.unwrap_or_else(|err| panic!("Error parsing {name:?} TTF/OTF font file: {err}"))
}
/// Describes the font data and the sizes to use.
///
/// Often you would start with [`FontDefinitions::default()`] and then add/change the contents.
///
/// This is how you install your own custom fonts:
/// ```
/// # use {epaint::text::{FontDefinitions, FontFamily, FontData}};
/// # struct FakeEguiCtx {};
/// # impl FakeEguiCtx { fn set_fonts(&self, _: FontDefinitions) {} }
/// # let egui_ctx = FakeEguiCtx {};
/// let mut fonts = FontDefinitions::default();
///
/// // Install my own font (maybe supporting non-latin characters):
/// fonts.font_data.insert("my_font".to_owned(),
/// std::sync::Arc::new(
/// // .ttf and .otf supported
/// FontData::from_static(include_bytes!("../../../epaint_default_fonts/fonts/Ubuntu-Light.ttf"))
/// )
/// );
///
/// // Put my font first (highest priority):
/// fonts.families.get_mut(&FontFamily::Proportional).unwrap()
/// .insert(0, "my_font".to_owned());
///
/// // Put my font as last fallback for monospace:
/// fonts.families.get_mut(&FontFamily::Monospace).unwrap()
/// .push("my_font".to_owned());
///
/// egui_ctx.set_fonts(fonts);
/// ```
#[derive(Clone, Debug, PartialEq)]
#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
#[cfg_attr(feature = "serde", serde(default))]
pub struct FontDefinitions {
/// List of font names and their definitions.
///
/// `epaint` has built-in-default for these, but you can override them if you like.
pub font_data: BTreeMap<String, Arc<FontData>>,
/// Which fonts (names) to use for each [`FontFamily`].
///
/// The list should be a list of keys into [`Self::font_data`].
/// When looking for a character glyph `epaint` will start with
/// the first font and then move to the second, and so on.
/// So the first font is the primary, and then comes a list of fallbacks in order of priority.
pub families: BTreeMap<FontFamily, Vec<String>>,
}
#[derive(Debug, Clone)]
pub struct FontInsert {
/// Font name
pub name: String,
/// A `.ttf` or `.otf` file and a font face index.
pub data: FontData,
/// Sets the font family and priority
pub families: Vec<InsertFontFamily>,
}
#[derive(Debug, Clone)]
pub struct InsertFontFamily {
/// Font family
pub family: FontFamily,
/// Fallback or Primary font
pub priority: FontPriority,
}
#[derive(Debug, Clone)]
pub enum FontPriority {
/// Prefer this font before all existing ones.
///
/// If a desired glyph exists in this font, it will be used.
Highest,
/// Use this font as a fallback, after all existing ones.
///
/// This font will only be used if the glyph is not found in any of the previously installed fonts.
Lowest,
}
impl FontInsert {
pub fn new(name: &str, data: FontData, families: Vec<InsertFontFamily>) -> Self {
Self {
name: name.to_owned(),
data,
families,
}
}
}
impl Default for FontDefinitions {
/// Specifies the default fonts if the feature `default_fonts` is enabled,
/// otherwise this is the same as [`Self::empty`].
#[cfg(not(feature = "default_fonts"))]
fn default() -> Self {
Self::empty()
}
/// Specifies the default fonts if the feature `default_fonts` is enabled,
/// otherwise this is the same as [`Self::empty`].
#[cfg(feature = "default_fonts")]
fn default() -> Self {
let mut font_data: BTreeMap<String, Arc<FontData>> = BTreeMap::new();
let mut families = BTreeMap::new();
font_data.insert(
"Hack".to_owned(),
Arc::new(FontData::from_static(HACK_REGULAR)),
);
// Some good looking emojis. Use as first priority:
font_data.insert(
"NotoEmoji-Regular".to_owned(),
Arc::new(FontData::from_static(NOTO_EMOJI_REGULAR).tweak(FontTweak {
scale: 0.81, // Make smaller
..Default::default()
})),
);
font_data.insert(
"Ubuntu-Light".to_owned(),
Arc::new(FontData::from_static(UBUNTU_LIGHT)),
);
// Bigger emojis, and more. <http://jslegers.github.io/emoji-icon-font/>:
font_data.insert(
"emoji-icon-font".to_owned(),
Arc::new(FontData::from_static(EMOJI_ICON).tweak(FontTweak {
scale: 0.90, // Make smaller
..Default::default()
})),
);
families.insert(
FontFamily::Monospace,
vec![
"Hack".to_owned(),
"Ubuntu-Light".to_owned(), // fallback for √ etc
"NotoEmoji-Regular".to_owned(),
"emoji-icon-font".to_owned(),
],
);
families.insert(
FontFamily::Proportional,
vec![
"Ubuntu-Light".to_owned(),
"NotoEmoji-Regular".to_owned(),
"emoji-icon-font".to_owned(),
],
);
Self {
font_data,
families,
}
}
}
impl FontDefinitions {
/// No fonts.
pub fn empty() -> Self {
let mut families = BTreeMap::new();
families.insert(FontFamily::Monospace, vec![]);
families.insert(FontFamily::Proportional, vec![]);
Self {
font_data: Default::default(),
families,
}
}
/// List of all the builtin font names used by `epaint`.
#[cfg(feature = "default_fonts")]
pub fn builtin_font_names() -> &'static [&'static str] {
&[
"Ubuntu-Light",
"NotoEmoji-Regular",
"emoji-icon-font",
"Hack",
]
}
/// List of all the builtin font names used by `epaint`.
#[cfg(not(feature = "default_fonts"))]
pub fn builtin_font_names() -> &'static [&'static str] {
&[]
}
}
/// Unique ID for looking up a single font face/file.
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
pub(crate) struct FontFaceKey(u64);
impl FontFaceKey {
pub const INVALID: Self = Self(0);
fn new() -> Self {
static KEY_COUNTER: AtomicU64 = AtomicU64::new(1);
Self(crate::util::hash(
KEY_COUNTER.fetch_add(1, Ordering::Relaxed),
))
}
}
// Safe, because we hash the value in the constructor.
impl nohash_hasher::IsEnabled for FontFaceKey {}
/// Cached data for working with a font family (e.g. doing character lookups).
#[derive(Debug)]
pub(super) struct CachedFamily {
pub fonts: Vec<FontFaceKey>,
/// Lazily calculated.
pub characters: Option<BTreeMap<char, Vec<String>>>,
pub replacement_glyph: (FontFaceKey, GlyphInfo),
pub glyph_info_cache: ahash::HashMap<char, (FontFaceKey, GlyphInfo)>,
}
impl CachedFamily {
fn new(
fonts: Vec<FontFaceKey>,
fonts_by_id: &mut nohash_hasher::IntMap<FontFaceKey, FontImpl>,
) -> Self {
if fonts.is_empty() {
return Self {
fonts,
characters: None,
replacement_glyph: (FontFaceKey::INVALID, GlyphInfo::INVISIBLE),
glyph_info_cache: Default::default(),
};
}
let mut slf = Self {
fonts,
characters: None,
replacement_glyph: (FontFaceKey::INVALID, GlyphInfo::INVISIBLE),
glyph_info_cache: Default::default(),
};
const PRIMARY_REPLACEMENT_CHAR: char = '◻'; // white medium square
const FALLBACK_REPLACEMENT_CHAR: char = '?'; // fallback for the fallback
let replacement_glyph = slf
.glyph_info_no_cache_or_fallback(PRIMARY_REPLACEMENT_CHAR, fonts_by_id)
.or_else(|| slf.glyph_info_no_cache_or_fallback(FALLBACK_REPLACEMENT_CHAR, fonts_by_id))
.unwrap_or_else(|| {
#[cfg(feature = "log")]
log::warn!(
"Failed to find replacement characters {PRIMARY_REPLACEMENT_CHAR:?} or {FALLBACK_REPLACEMENT_CHAR:?}. Will use empty glyph."
);
(FontFaceKey::INVALID, GlyphInfo::INVISIBLE)
});
slf.replacement_glyph = replacement_glyph;
slf
}
pub(crate) fn glyph_info_no_cache_or_fallback(
&mut self,
c: char,
fonts_by_id: &mut nohash_hasher::IntMap<FontFaceKey, FontImpl>,
) -> Option<(FontFaceKey, GlyphInfo)> {
for font_key in &self.fonts {
let font_impl = fonts_by_id.get_mut(font_key).expect("Nonexistent font ID");
if let Some(glyph_info) = font_impl.glyph_info(c) {
self.glyph_info_cache.insert(c, (*font_key, glyph_info));
return Some((*font_key, glyph_info));
}
}
None
}
}
// ----------------------------------------------------------------------------
/// The collection of fonts used by `epaint`.
///
/// Required in order to paint text. Create one and reuse. Cheap to clone.
///
/// Each [`Fonts`] comes with a font atlas textures that needs to be used when painting.
///
/// If you are using `egui`, use `egui::Context::set_fonts` and `egui::Context::fonts`.
///
/// You need to call [`Self::begin_pass`] and [`Self::font_image_delta`] once every frame.
pub struct Fonts {
pub fonts: FontsImpl,
galley_cache: GalleyCache,
}
impl Fonts {
/// Create a new [`Fonts`] for text layout.
/// This call is expensive, so only create one [`Fonts`] and then reuse it.
///
/// * `max_texture_side`: largest supported texture size (one side).
pub fn new(
max_texture_side: usize,
text_alpha_from_coverage: AlphaFromCoverage,
definitions: FontDefinitions,
) -> Self {
Self {
fonts: FontsImpl::new(max_texture_side, text_alpha_from_coverage, definitions),
galley_cache: Default::default(),
}
}
/// Call at the start of each frame with the latest known
/// `pixels_per_point`, `max_texture_side`, and `text_alpha_from_coverage`.
///
/// Call after painting the previous frame, but before using [`Fonts`] for the new frame.
///
/// This function will react to changes in `pixels_per_point`, `max_texture_side`, and `text_alpha_from_coverage`,
/// as well as notice when the font atlas is getting full, and handle that.
pub fn begin_pass(
&mut self,
max_texture_side: usize,
text_alpha_from_coverage: AlphaFromCoverage,
) {
let max_texture_side_changed = self.fonts.max_texture_side != max_texture_side;
let text_alpha_from_coverage_changed =
self.fonts.atlas.text_alpha_from_coverage != text_alpha_from_coverage;
let font_atlas_almost_full = self.fonts.atlas.fill_ratio() > 0.8;
let needs_recreate =
max_texture_side_changed || text_alpha_from_coverage_changed || font_atlas_almost_full;
if needs_recreate {
let definitions = self.fonts.definitions.clone();
*self = Self {
fonts: FontsImpl::new(max_texture_side, text_alpha_from_coverage, definitions),
galley_cache: Default::default(),
};
}
self.galley_cache.flush_cache();
}
/// Call at the end of each frame (before painting) to get the change to the font texture since last call.
pub fn font_image_delta(&mut self) -> Option<crate::ImageDelta> {
self.fonts.atlas.take_delta()
}
#[inline]
pub fn max_texture_side(&self) -> usize {
self.fonts.max_texture_side
}
#[inline]
pub fn definitions(&self) -> &FontDefinitions {
&self.fonts.definitions
}
/// The font atlas.
/// Pass this to [`crate::Tessellator`].
pub fn texture_atlas(&self) -> &TextureAtlas {
&self.fonts.atlas
}
/// The full font atlas image.
#[inline]
pub fn image(&self) -> crate::ColorImage {
self.fonts.atlas.image().clone()
}
/// Current size of the font image.
/// Pass this to [`crate::Tessellator`].
pub fn font_image_size(&self) -> [usize; 2] {
self.fonts.atlas.size()
}
/// Can we display this glyph?
pub fn has_glyph(&mut self, font_id: &FontId, c: char) -> bool {
self.fonts.font(&font_id.family).has_glyph(c)
}
/// Can we display all the glyphs in this text?
pub fn has_glyphs(&mut self, font_id: &FontId, s: &str) -> bool {
self.fonts.font(&font_id.family).has_glyphs(s)
}
pub fn num_galleys_in_cache(&self) -> usize {
self.galley_cache.num_galleys_in_cache()
}
/// How full is the font atlas?
///
/// This increases as new fonts and/or glyphs are used,
/// but can also decrease in a call to [`Self::begin_pass`].
pub fn font_atlas_fill_ratio(&self) -> f32 {
self.fonts.atlas.fill_ratio()
}
/// Returns a [`FontsView`] with the given `pixels_per_point` that can be used to do text layout.
pub fn with_pixels_per_point(&mut self, pixels_per_point: f32) -> FontsView<'_> {
FontsView {
fonts: &mut self.fonts,
galley_cache: &mut self.galley_cache,
pixels_per_point,
}
}
}
// ----------------------------------------------------------------------------
/// The context's collection of fonts, with this context's `pixels_per_point`. This is what you use to do text layout.
pub struct FontsView<'a> {
pub fonts: &'a mut FontsImpl,
galley_cache: &'a mut GalleyCache,
pixels_per_point: f32,
}
impl FontsView<'_> {
#[inline]
pub fn max_texture_side(&self) -> usize {
self.fonts.max_texture_side
}
#[inline]
pub fn definitions(&self) -> &FontDefinitions {
&self.fonts.definitions
}
/// The full font atlas image.
#[inline]
pub fn image(&self) -> crate::ColorImage {
self.fonts.atlas.image().clone()
}
/// Current size of the font image.
/// Pass this to [`crate::Tessellator`].
pub fn font_image_size(&self) -> [usize; 2] {
self.fonts.atlas.size()
}
/// Width of this character in points.
///
/// If the font doesn't exist, this will return `0.0`.
pub fn glyph_width(&mut self, font_id: &FontId, c: char) -> f32 {
self.fonts
.font(&font_id.family)
.glyph_width(c, font_id.size)
}
/// Can we display this glyph?
pub fn has_glyph(&mut self, font_id: &FontId, c: char) -> bool {
self.fonts.font(&font_id.family).has_glyph(c)
}
/// Can we display all the glyphs in this text?
pub fn has_glyphs(&mut self, font_id: &FontId, s: &str) -> bool {
self.fonts.font(&font_id.family).has_glyphs(s)
}
/// Height of one row of text in points.
///
/// Returns a value rounded to [`emath::GUI_ROUNDING`].
pub fn row_height(&mut self, font_id: &FontId) -> f32 {
self.fonts
.font(&font_id.family)
.scaled_metrics(self.pixels_per_point, font_id.size)
.row_height
}
/// List of all known font families.
pub fn families(&self) -> Vec<FontFamily> {
self.fonts.definitions.families.keys().cloned().collect()
}
/// Layout some text.
///
/// This is the most advanced layout function.
/// See also [`Self::layout`], [`Self::layout_no_wrap`] and
/// [`Self::layout_delayed_color`].
///
/// The implementation uses memoization so repeated calls are cheap.
#[inline]
pub fn layout_job(&mut self, job: LayoutJob) -> Arc<Galley> {
let allow_split_paragraphs = true; // Optimization for editing text with many paragraphs.
self.galley_cache.layout(
self.fonts,
self.pixels_per_point,
job,
allow_split_paragraphs,
)
}
pub fn num_galleys_in_cache(&self) -> usize {
self.galley_cache.num_galleys_in_cache()
}
/// How full is the font atlas?
///
/// This increases as new fonts and/or glyphs are used,
/// but can also decrease in a call to [`Fonts::begin_pass`].
pub fn font_atlas_fill_ratio(&self) -> f32 {
self.fonts.atlas.fill_ratio()
}
/// Will wrap text at the given width and line break at `\n`.
///
/// The implementation uses memoization so repeated calls are cheap.
pub fn layout(
&mut self,
text: String,
font_id: FontId,
color: crate::Color32,
wrap_width: f32,
) -> Arc<Galley> {
let job = LayoutJob::simple(text, font_id, color, wrap_width);
self.layout_job(job)
}
/// Will line break at `\n`.
///
/// The implementation uses memoization so repeated calls are cheap.
pub fn layout_no_wrap(
&mut self,
text: String,
font_id: FontId,
color: crate::Color32,
) -> Arc<Galley> {
let job = LayoutJob::simple(text, font_id, color, f32::INFINITY);
self.layout_job(job)
}
/// Like [`Self::layout`], made for when you want to pick a color for the text later.
///
/// The implementation uses memoization so repeated calls are cheap.
pub fn layout_delayed_color(
&mut self,
text: String,
font_id: FontId,
wrap_width: f32,
) -> Arc<Galley> {
self.layout(text, font_id, crate::Color32::PLACEHOLDER, wrap_width)
}
}
// ----------------------------------------------------------------------------
/// The collection of fonts used by `epaint`.
///
/// Required in order to paint text.
pub struct FontsImpl {
max_texture_side: usize,
definitions: FontDefinitions,
atlas: TextureAtlas,
fonts_by_id: nohash_hasher::IntMap<FontFaceKey, FontImpl>,
fonts_by_name: ahash::HashMap<String, FontFaceKey>,
family_cache: ahash::HashMap<FontFamily, CachedFamily>,
}
impl FontsImpl {
/// Create a new [`FontsImpl`] for text layout.
/// This call is expensive, so only create one [`FontsImpl`] and then reuse it.
pub fn new(
max_texture_side: usize,
text_alpha_from_coverage: AlphaFromCoverage,
definitions: FontDefinitions,
) -> Self {
let texture_width = max_texture_side.at_most(16 * 1024);
let initial_height = 32; // Keep initial font atlas small, so it is fast to upload to GPU. This will expand as needed anyways.
let atlas = TextureAtlas::new([texture_width, initial_height], text_alpha_from_coverage);
let mut fonts_by_id: nohash_hasher::IntMap<FontFaceKey, FontImpl> = Default::default();
let mut font_impls: ahash::HashMap<String, FontFaceKey> = Default::default();
for (name, font_data) in &definitions.font_data {
let tweak = font_data.tweak;
let ab_glyph = ab_glyph_font_from_font_data(name, font_data);
let font_impl = FontImpl::new(name.clone(), ab_glyph, tweak);
let key = FontFaceKey::new();
fonts_by_id.insert(key, font_impl);
font_impls.insert(name.clone(), key);
}
Self {
max_texture_side,
definitions,
atlas,
fonts_by_id,
fonts_by_name: font_impls,
family_cache: Default::default(),
}
}
/// Get the right font implementation from [`FontFamily`].
pub fn font(&mut self, family: &FontFamily) -> Font<'_> {
let cached_family = self.family_cache.entry(family.clone()).or_insert_with(|| {
let fonts = &self.definitions.families.get(family);
let fonts =
fonts.unwrap_or_else(|| panic!("FontFamily::{family:?} is not bound to any fonts"));
let fonts: Vec<FontFaceKey> = fonts
.iter()
.map(|font_name| {
*self
.fonts_by_name
.get(font_name)
.unwrap_or_else(|| panic!("No font data found for {font_name:?}"))
})
.collect();
CachedFamily::new(fonts, &mut self.fonts_by_id)
});
Font {
fonts_by_id: &mut self.fonts_by_id,
cached_family,
atlas: &mut self.atlas,
}
}
}
// ----------------------------------------------------------------------------
struct CachedGalley {
/// When it was last used
last_used: u32,
/// Hashes of all other entries this one depends on for quick re-layout.
/// Their `last_used`s should be updated alongside this one to make sure they're
/// not evicted.
children: Option<Arc<[u64]>>,
galley: Arc<Galley>,
}
#[derive(Default)]
struct GalleyCache {
/// Frame counter used to do garbage collection on the cache
generation: u32,
cache: nohash_hasher::IntMap<u64, CachedGalley>,
}
impl GalleyCache {
fn layout_internal(
&mut self,
fonts: &mut FontsImpl,
mut job: LayoutJob,
pixels_per_point: f32,
allow_split_paragraphs: bool,
) -> (u64, Arc<Galley>) {
if job.wrap.max_width.is_finite() {
// Protect against rounding errors in egui layout code.
// Say the user asks to wrap at width 200.0.
// The text layout wraps, and reports that the final width was 196.0 points.
// This then trickles up the `Ui` chain and gets stored as the width for a tooltip (say).
// On the next frame, this is then set as the max width for the tooltip,
// and we end up calling the text layout code again, this time with a wrap width of 196.0.
// Except, somewhere in the `Ui` chain with added margins etc, a rounding error was introduced,
// so that we actually set a wrap-width of 195.9997 instead.
// Now the text that fit perfrectly at 196.0 needs to wrap one word earlier,
// and so the text re-wraps and reports a new width of 185.0 points.
// And then the cycle continues.
// So we limit max_width to integers.
// Related issues:
// * https://github.com/emilk/egui/issues/4927
// * https://github.com/emilk/egui/issues/4928
// * https://github.com/emilk/egui/issues/5084
// * https://github.com/emilk/egui/issues/5163
job.wrap.max_width = job.wrap.max_width.round();
}
let hash = crate::util::hash((&job, OrderedFloat(pixels_per_point))); // TODO(emilk): even faster hasher?
let galley = match self.cache.entry(hash) {
std::collections::hash_map::Entry::Occupied(entry) => {
// The job was found in cache - no need to re-layout.
let cached = entry.into_mut();
cached.last_used = self.generation;
let galley = cached.galley.clone();
if let Some(children) = &cached.children {
// The point of `allow_split_paragraphs` is to split large jobs into paragraph,
// and then cache each paragraph individually.
// That way, if we edit a single paragraph, only that paragraph will be re-layouted.
// For that to work we need to keep all the child/paragraph
// galleys alive while the parent galley is alive:
for child_hash in children.clone().iter() {
if let Some(cached_child) = self.cache.get_mut(child_hash) {
cached_child.last_used = self.generation;
}
}
}
galley
}
std::collections::hash_map::Entry::Vacant(entry) => {
let job = Arc::new(job);
if allow_split_paragraphs && should_cache_each_paragraph_individually(&job) {
let (child_galleys, child_hashes) =
self.layout_each_paragraph_individually(fonts, &job, pixels_per_point);
debug_assert_eq!(
child_hashes.len(),
child_galleys.len(),
"Bug in `layout_each_paragraph_individuallly`"
);
let galley = Arc::new(Galley::concat(job, &child_galleys, pixels_per_point));
self.cache.insert(
hash,
CachedGalley {
last_used: self.generation,
children: Some(child_hashes.into()),
galley: galley.clone(),
},
);
galley
} else {
let galley = super::layout(fonts, pixels_per_point, job);
let galley = Arc::new(galley);
entry.insert(CachedGalley {
last_used: self.generation,
children: None,
galley: galley.clone(),
});
galley
}
}
};
(hash, galley)
}
fn layout(
&mut self,
fonts: &mut FontsImpl,
pixels_per_point: f32,
job: LayoutJob,
allow_split_paragraphs: bool,
) -> Arc<Galley> {
self.layout_internal(fonts, job, pixels_per_point, allow_split_paragraphs)
.1
}
/// Split on `\n` and lay out (and cache) each paragraph individually.
fn layout_each_paragraph_individually(
&mut self,
fonts: &mut FontsImpl,
job: &LayoutJob,
pixels_per_point: f32,
) -> (Vec<Arc<Galley>>, Vec<u64>) {
profiling::function_scope!();
let mut current_section = 0;
let mut start = 0;
let mut max_rows_remaining = job.wrap.max_rows;
let mut child_galleys = Vec::new();
let mut child_hashes = Vec::new();
while start < job.text.len() {
let is_first_paragraph = start == 0;
// `end` will not include the `\n` since we don't want to create an empty row in our
// split galley
let mut end = job.text[start..]
.find('\n')
.map_or(job.text.len(), |i| start + i);
if end == job.text.len() - 1 && job.text.ends_with('\n') {
end += 1; // If the text ends with a newline, we include it in the last paragraph.
}
let mut paragraph_job = LayoutJob {
text: job.text[start..end].to_owned(),
wrap: crate::text::TextWrapping {
max_rows: max_rows_remaining,
..job.wrap
},
sections: Vec::new(),
break_on_newline: job.break_on_newline,
halign: job.halign,
justify: job.justify,
first_row_min_height: if is_first_paragraph {
job.first_row_min_height
} else {
0.0
},
round_output_to_gui: job.round_output_to_gui,
};
// Add overlapping sections:
for section in &job.sections[current_section..job.sections.len()] {
let LayoutSection {
leading_space,
byte_range: section_range,
format,
} = section;
// `start` and `end` are the byte range of the current paragraph.
// How does the current section overlap with the paragraph range?
if section_range.end <= start {
// The section is behind us
current_section += 1;
} else if end < section_range.start {
break; // Haven't reached this one yet.
} else {
// Section range overlaps with paragraph range
debug_assert!(
section_range.start <= section_range.end,
"Bad byte_range: {section_range:?}"
);
let new_range = section_range.start.saturating_sub(start)
..(section_range.end.at_most(end)).saturating_sub(start);
debug_assert!(
new_range.start <= new_range.end,
"Bad new section range: {new_range:?}"
);
paragraph_job.sections.push(LayoutSection {
leading_space: if start <= section_range.start {
*leading_space
} else {
0.0
},
byte_range: new_range,
format: format.clone(),
});
}
}
// TODO(emilk): we could lay out each paragraph in parallel to get a nice speedup on multicore machines.
let (hash, galley) =
self.layout_internal(fonts, paragraph_job, pixels_per_point, false);
child_hashes.push(hash);
// This will prevent us from invalidating cache entries unnecessarily:
if max_rows_remaining != usize::MAX {
max_rows_remaining -= galley.rows.len();
}
let elided = galley.elided;
child_galleys.push(galley);
if elided {
break;
}
start = end + 1;
}
(child_galleys, child_hashes)
}
pub fn num_galleys_in_cache(&self) -> usize {
self.cache.len()
}
/// Must be called once per frame to clear the [`Galley`] cache.
pub fn flush_cache(&mut self) {
let current_generation = self.generation;
self.cache.retain(|_key, cached| {
cached.last_used == current_generation // only keep those that were used this frame
});
self.generation = self.generation.wrapping_add(1);
}
}
/// If true, lay out and cache each paragraph (sections separated by newlines) individually.
///
/// This makes it much faster to re-layout the full text when only a portion of it has changed since last frame, i.e. when editing somewhere in a file with thousands of lines/paragraphs.
fn should_cache_each_paragraph_individually(job: &LayoutJob) -> bool {
// We currently don't support this elided text, i.e. when `max_rows` is set.
// Most often, elided text is elided to one row,
// and so will always be fast to lay out.
job.break_on_newline && job.wrap.max_rows == usize::MAX && job.text.contains('\n')
}
#[cfg(feature = "default_fonts")]
#[cfg(test)]
mod tests {
use core::f32;
use super::*;
use crate::text::{TextWrapping, layout};
use crate::{Stroke, text::TextFormat};
use ecolor::Color32;
use emath::Align;
fn jobs() -> Vec<LayoutJob> {
vec![
LayoutJob::simple(
String::default(),
FontId::new(14.0, FontFamily::Monospace),
Color32::WHITE,
f32::INFINITY,
),
LayoutJob::simple(
"ends with newlines\n\n".to_owned(),
FontId::new(14.0, FontFamily::Monospace),
Color32::WHITE,
f32::INFINITY,
),
LayoutJob::simple(
"Simple test.".to_owned(),
FontId::new(14.0, FontFamily::Monospace),
Color32::WHITE,
f32::INFINITY,
),
{
let mut job = LayoutJob::simple(
"hi".to_owned(),
FontId::default(),
Color32::WHITE,
f32::INFINITY,
);
job.append("\n", 0.0, TextFormat::default());
job.append("\n", 0.0, TextFormat::default());
job.append("world", 0.0, TextFormat::default());
job.wrap.max_rows = 2;
job
},
{
let mut job = LayoutJob::simple(
"Test text with a lot of words\n and a newline.".to_owned(),
FontId::new(14.0, FontFamily::Monospace),
Color32::WHITE,
40.0,
);
job.first_row_min_height = 30.0;
job
},
LayoutJob::simple(
"This some text that may be long.\nDet kanske också finns lite ÅÄÖ här.".to_owned(),
FontId::new(14.0, FontFamily::Proportional),
Color32::WHITE,
50.0,
),
{
let mut job = LayoutJob {
first_row_min_height: 20.0,
..Default::default()
};
job.append(
"1st paragraph has underline and strikethrough, and has some non-ASCII characters:\n ÅÄÖ.",
0.0,
TextFormat {
font_id: FontId::new(15.0, FontFamily::Monospace),
underline: Stroke::new(1.0, Color32::RED),
strikethrough: Stroke::new(1.0, Color32::GREEN),
..Default::default()
},
);
job.append(
"2nd paragraph has some leading space.\n",
16.0,
TextFormat {
font_id: FontId::new(14.0, FontFamily::Proportional),
..Default::default()
},
);
job.append(
"3rd paragraph is kind of boring, but has italics.\nAnd a newline",
0.0,
TextFormat {
font_id: FontId::new(10.0, FontFamily::Proportional),
italics: true,
..Default::default()
},
);
job
},
{
// Regression test for <https://github.com/emilk/egui/issues/7378>
let mut job = LayoutJob::default();
job.append("\n", 0.0, TextFormat::default());
job.append("", 0.0, TextFormat::default());
job
},
]
}
#[expect(clippy::print_stdout)]
#[test]
fn test_split_paragraphs() {
for pixels_per_point in [1.0, 2.0_f32.sqrt(), 2.0] {
let max_texture_side = 4096;
let mut fonts = FontsImpl::new(
max_texture_side,
AlphaFromCoverage::default(),
FontDefinitions::default(),
);
for halign in [Align::Min, Align::Center, Align::Max] {
for justify in [false, true] {
for mut job in jobs() {
job.halign = halign;
job.justify = justify;
let whole = GalleyCache::default().layout(
&mut fonts,
pixels_per_point,
job.clone(),
false,
);
let split = GalleyCache::default().layout(
&mut fonts,
pixels_per_point,
job.clone(),
true,
);
for (i, row) in whole.rows.iter().enumerate() {
println!(
"Whole row {i}: section_index_at_start={}, first glyph section_index: {:?}",
row.row.section_index_at_start,
row.row.glyphs.first().map(|g| g.section_index)
);
}
for (i, row) in split.rows.iter().enumerate() {
println!(
"Split row {i}: section_index_at_start={}, first glyph section_index: {:?}",
row.row.section_index_at_start,
row.row.glyphs.first().map(|g| g.section_index)
);
}
// Don't compare for equaliity; but format with a specific precision and make sure we hit that.
// NOTE: we use a rather low precision, because as long as we're within a pixel I think it's good enough.
similar_asserts::assert_eq!(
format!("{:#.1?}", split),
format!("{:#.1?}", whole),
"pixels_per_point: {pixels_per_point:.2}, input text: '{}'",
job.text
);
}
}
}
}
}
#[test]
fn test_intrinsic_size() {
let pixels_per_point = [1.0, 1.3, 2.0, 0.867];
let max_widths = [40.0, 80.0, 133.0, 200.0];
let rounded_output_to_gui = [false, true];
for pixels_per_point in pixels_per_point {
let mut fonts = FontsImpl::new(
1024,
AlphaFromCoverage::default(),
FontDefinitions::default(),
);
for &max_width in &max_widths {
for round_output_to_gui in rounded_output_to_gui {
for mut job in jobs() {
job.wrap = TextWrapping::wrap_at_width(max_width);
job.round_output_to_gui = round_output_to_gui;
let galley_wrapped =
layout(&mut fonts, pixels_per_point, job.clone().into());
job.wrap = TextWrapping::no_max_width();
let text = job.text.clone();
let galley_unwrapped = layout(&mut fonts, pixels_per_point, job.into());
let intrinsic_size = galley_wrapped.intrinsic_size();
let unwrapped_size = galley_unwrapped.size();
let difference = (intrinsic_size - unwrapped_size).length().abs();
similar_asserts::assert_eq!(
format!("{intrinsic_size:.4?}"),
format!("{unwrapped_size:.4?}"),
"Wrapped intrinsic size should almost match unwrapped size. Intrinsic: {intrinsic_size:.8?} vs unwrapped: {unwrapped_size:.8?}
Difference: {difference:.8?}
wrapped rows: {}, unwrapped rows: {}
pixels_per_point: {pixels_per_point}, text: {text:?}, max_width: {max_width}, round_output_to_gui: {round_output_to_gui}",
galley_wrapped.rows.len(),
galley_unwrapped.rows.len()
);
similar_asserts::assert_eq!(
format!("{intrinsic_size:.4?}"),
format!("{unwrapped_size:.4?}"),
"Unwrapped galley intrinsic size should exactly match its size. \
{:.8?} vs {:8?}",
galley_unwrapped.intrinsic_size(),
galley_unwrapped.size(),
);
}
}
}
}
}
#[test]
fn test_fallback_glyph_width() {
let mut fonts = Fonts::new(1024, AlphaFromCoverage::default(), FontDefinitions::empty());
let mut view = fonts.with_pixels_per_point(1.0);
let width = view.glyph_width(&FontId::new(12.0, FontFamily::Proportional), ' ');
assert_eq!(width, 0.0);
}
}