Choose your own font and size (#1154)

* Refactor text layout: don't need &Fonts in all functions
* Replace indexing in Fonts with member function
* Wrap Fonts in a Mutex
* Remove mutex for Font::glyph_info_cache
* Remove RwLock around Font::characters
* Put FontsImpl and GalleyCache behind the same Mutex
* Round font sizes to whole pixels before deduplicating them
* Make TextStyle !Copy
* Implement user-named TextStyle:s
* round font size earlier
* Cache fonts based on family and size
* Move TextStyle into egui and Style
* Remove body_text_style
* Query graphics about max texture size and use that as font atlas size
* Recreate texture atlas when it is getting full

egui_web/src/backend.rs

@@ -143,6 +143,8 @@ impl AppRunner {
             textures_delta: Default::default(),
         };
 
+        runner.input.raw.max_texture_side = runner.painter.max_texture_side();
+
         {
             runner
                 .app

egui_web/src/glow_wrapping.rs

@@ -40,6 +40,10 @@ impl WrappedGlowPainter {
 }
 
 impl crate::Painter for WrappedGlowPainter {
+    fn max_texture_side(&self) -> usize {
+        self.painter.max_texture_side()
+    }
+
     fn set_texture(&mut self, tex_id: egui::TextureId, delta: &egui::epaint::ImageDelta) {
         self.painter.set_texture(&self.glow_ctx, tex_id, delta);
     }

egui_web/src/painter.rs

@@ -1,6 +1,9 @@
 use wasm_bindgen::prelude::JsValue;
 
 pub trait Painter {
+    /// Max size of one side of a texture.
+    fn max_texture_side(&self) -> usize;
+
     fn set_texture(&mut self, tex_id: egui::TextureId, delta: &egui::epaint::ImageDelta);
 
     fn free_texture(&mut self, tex_id: egui::TextureId);

egui_web/src/webgl1.rs

@@ -289,6 +289,21 @@ impl epi::NativeTexture for WebGlPainter {
 }
 
 impl crate::Painter for WebGlPainter {
+    fn max_texture_side(&self) -> usize {
+        if let Ok(max_texture_side) = self
+            .gl
+            .get_parameter(web_sys::WebGlRenderingContext::MAX_TEXTURE_SIZE)
+        {
+            if let Some(max_texture_side) = max_texture_side.as_f64() {
+                return max_texture_side as usize;
+            }
+        }
+
+        crate::console_error("Failed to query max texture size");
+
+        2048
+    }
+
     fn set_texture(&mut self, tex_id: egui::TextureId, delta: &egui::epaint::ImageDelta) {
         match &delta.image {
             egui::ImageData::Color(image) => {

egui_web/src/webgl2.rs

@@ -273,6 +273,21 @@ impl epi::NativeTexture for WebGl2Painter {
 }
 
 impl crate::Painter for WebGl2Painter {
+    fn max_texture_side(&self) -> usize {
+        if let Ok(max_texture_side) = self
+            .gl
+            .get_parameter(web_sys::WebGl2RenderingContext::MAX_TEXTURE_SIZE)
+        {
+            if let Some(max_texture_side) = max_texture_side.as_f64() {
+                return max_texture_side as usize;
+            }
+        }
+
+        crate::console_error("Failed to query max texture size");
+
+        2048
+    }
+
     fn set_texture(&mut self, tex_id: egui::TextureId, delta: &egui::epaint::ImageDelta) {
         match &delta.image {
             egui::ImageData::Color(image) => {