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/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);
     }