This can be used, for instance, to:
* Render things to offscreen buffers.
* Read the pixel buffer from the previous frame (glow::Context::read_pixels).
* Render things behind the egui windows.
The purpose of this is to expose `frame.storage()` and `frame.storage_mut()` so users can save/load app state from the `App::update` function, without having to add another parameter to that function.
Changes:
* Added `Frame::storage()` and `Frame::storage_mut()`
* `App::update` now takes a `&mut Frame` rather than just `&Frame`
* `Frame` is no longer `Clone` or `Sync` (doesn't have to be since https://github.com/emilk/egui/pull/1366)
This adds a callback (set by `Context::set_request_repaint_callback`)
which integration can use to wake up the UI thread.
eframe (egui_web and egui_glow) will use this, replacing
`epi::Frame::request_repaint`.
Existing code calling `epi::Frame::request_repaint` should be changed
to instead call `egui::Context::request_repaint`.
This is the first callback added to the egui API, which otherwise is
completely driven by data.
The purpose of this is to remove the confusion between the two
`request_repaint` methods (by removing one). Furthermore, it makes
`epi::Frame` a lot simpler, allowing future simplifications to it
(perhaps no longer having it be `Send+Sync+Clone`).
* Add Shape::Callback to do custom rendering inside of an egui UI
* Use Rc<glow::Context> everywhere
* Remove trait WebPainter
* Add glow::Context to epi::App::setup
* egui_web: use tracing crate
* egui_glow: use tracing crate
* Log at the debug level
* egui_demo_app: enable tracing to log to stdout
* Use tracing in egui-winit
* Add opt-in tracing support to egui
* 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
* Move texture allocation into epaint/egui proper
* Add TextureHandle
* egui_glow: cast using bytemuck instead of unsafe code
* Optimize glium painter
* Optimize WebGL
* Add example of loading an image from file
* Move window building to egui-winit
* Move icon loading to egui-winit
* `use glow::HasContext;` -> `use glow::HasContext as _;`
* Move FileStorage into epi behind a feature flag
* De-duplicate screen_size_in_pixels and native_pixels_per_point
* Move creation of FileStorage to epi
* Handle epi app output (window size changes etc) in egui-winit
* Move app and memory persistence and autosave logic to egui-winit
* fix check.sh
* Make the epi backend opt-in for egui_glium and egui_glow
* Fix persistence
* Add integration name to epi::IntegrationInfo and the demo
* Clean up Cargo.toml files and fix making egui_glium optional
* fix typo
* Make egui_glium compile without the `epi` feature
