Color emojis 🦀

crates/epaint/src/text/font.rs

@@ -4,7 +4,7 @@ use std::sync::Arc;
 use emath::{GuiRounding as _, Vec2, vec2};
 
 use crate::{
-    TextureAtlas,
+    ColorImage, TextureAtlas,
     mutex::{Mutex, RwLock},
     text::FontTweak,
 };
@@ -261,6 +261,49 @@ impl FontImpl {
         self.ascent
     }
 
+    pub fn allocate_custom_glyph(&self, c: char, image: ColorImage) -> GlyphInfo {
+        let glyph_pos = {
+            let atlas = &mut self.atlas.lock();
+            let (glyph_pos, atlas_image) = atlas.allocate((image.width(), image.height()));
+
+            for x in 0..image.width() {
+                for y in 0..image.height() {
+                    let px = glyph_pos.0 + x;
+                    let py = glyph_pos.1 + y;
+                    atlas_image[(px, py)] = image[(x, y)];
+                }
+            }
+
+            glyph_pos
+        };
+
+        let glyph_width = image.width();
+        let glyph_height = image.height();
+
+        let offset = vec2(0.0, -self.height_in_points / 1.3);
+
+        let height = self.height_in_points;
+        let width = height * (glyph_width as f32 / glyph_height as f32);
+
+        let uv_rect = UvRect {
+            offset,
+            size: vec2(width, height),
+            min: [glyph_pos.0 as u16, glyph_pos.1 as u16],
+            max: [
+                (glyph_pos.0 + glyph_width) as u16,
+                (glyph_pos.1 + glyph_height) as u16,
+            ],
+        };
+
+        let advance_width = width;
+
+        GlyphInfo {
+            id: ab_glyph::GlyphId(0),
+            advance_width: advance_width as f32,
+            uv_rect,
+        }
+    }
+
     fn allocate_glyph(&self, glyph_id: ab_glyph::GlyphId) -> GlyphInfo {
         assert!(glyph_id.0 != 0, "Can't allocate glyph for id 0");
         use ab_glyph::{Font as _, ScaleFont as _};
@@ -386,6 +429,16 @@ impl Font {
         }
     }
 
+    pub fn allocate_custom_glyph(&mut self, c: char, image: ColorImage) -> GlyphInfo {
+        if let Some(font_impl) = self.fonts.first() {
+            let glyph_info = font_impl.allocate_custom_glyph(c, image);
+            self.glyph_info_cache.insert(c, (0, glyph_info));
+            glyph_info
+        } else {
+            GlyphInfo::default()
+        }
+    }
+
     pub fn preload_common_characters(&mut self) {
         // Preload the printable ASCII characters [32, 126] (which excludes control codes):
         const FIRST_ASCII: usize = 32; // 32 == space

examples/hello_world/src/main.rs

@@ -2,6 +2,10 @@
 #![allow(rustdoc::missing_crate_level_docs)] // it's an example
 
 use eframe::egui;
+use eframe::egui::{
+    Color32, ColorImage, FontFamily, FontId, FontSelection, RichText, TextEdit,
+    global_theme_preference_switch, include_image,
+};
 
 fn main() -> eframe::Result {
     env_logger::init(); // Log to stderr (if you run with `RUST_LOG=debug`).
@@ -26,10 +30,14 @@ struct MyApp {
     age: u32,
 }
 
+fn font_id() -> FontId {
+    FontId::new(30.0, FontFamily::Proportional)
+}
+
 impl Default for MyApp {
     fn default() -> Self {
         Self {
-            name: "Arthur".to_owned(),
+            name: "Ferris :crab:".to_owned(),
             age: 42,
         }
     }
@@ -38,21 +46,28 @@ impl Default for MyApp {
 impl eframe::App for MyApp {
     fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
         egui::CentralPanel::default().show(ctx, |ui| {
-            ui.heading("My egui Application");
-            ui.horizontal(|ui| {
-                let name_label = ui.label("Your name: ");
-                ui.text_edit_singleline(&mut self.name)
-                    .labelled_by(name_label.id);
-            });
-            ui.add(egui::Slider::new(&mut self.age, 0..=120).text("age"));
-            if ui.button("Increment").clicked() {
-                self.age += 1;
-            }
-            ui.label(format!("Hello '{}', age {}", self.name, self.age));
+            global_theme_preference_switch(ui);
 
-            ui.image(egui::include_image!(
-                "../../../crates/egui/assets/ferris.png"
-            ));
+            ctx.fonts(|f| {
+                let mut fonts = f.lock();
+                let font = fonts.fonts.font(&font_id());
+                if !font.has_glyph('🦀') {
+                    let image = include_bytes!("../../../crates/egui/assets/ferris.png");
+
+                    let image = egui_extras::image::load_image_bytes(image).unwrap();
+
+                    font.allocate_custom_glyph('🦀', image);
+                }
+            });
+
+            TextEdit::singleline(&mut self.name)
+                .font(FontSelection::FontId(font_id()))
+                .text_color(Color32::WHITE)
+                .show(ui);
+
+            self.name = self.name.replace(":crab:", "🦀");
+
+            ui.label(RichText::new(&self.name).font(font_id()).strong());
         });
     }
 }