mirror of
https://github.com/storytold/egui.git
synced 2026-11-06 18:42:08 +00:00
Lucas Meurer
416dd85acb
Migration guide for the changelog:
`ViewportCommand::Screenshot` was changed to be callback based.
Previously you needed to iter the input events to check for the
screenshot (but didn't need interior mutability):
```rs
[derive(Default)]
struct MyApp {
screenshot: Option<Arc<egui::ColorImage>>,
}
impl eframe::App for MyApp {
fn ui(&mut self, ui: &mut egui::Ui, _frame: &mut eframe::Frame) {
if ui.button("Screenshot").clicked() {
ui.send_viewport_cmd(ViewportCommand::Screenshot(UserData::default()));
}
let image = ui.input(|i| {
i.events
.iter()
.filter_map(|e| {
if let egui::Event::Screenshot { image, .. } = e {
Some(Arc::clone(image))
} else {
None
}
})
.next_back()
});
if let Some(image) = image {
self.screenshot = Some(image);
}
}
}
```
Now you need to use a mutex, channel, or some other sync primitive to
get the result:
```rs
#[derive(Default)]
struct MyApp {
screenshot: Arc<Mutex<Option<Arc<egui::ColorImage>>>>,
}
impl eframe::App for MyApp {
fn ui(&mut self, ui: &mut egui::Ui, _frame: &mut eframe::Frame) {
if ui.button("Screenshot").clicked() {
let ctx = ui.ctx().clone();
let screenshot_mutex = self.screenshot.clone();
ui.request_screenshot(move |screenshot| {
screenshot_mutex.lock().replace(screenshot);
ctx.request_repaint();
});
}
}
}
```
----
This implements a callback-based screenshot api for egui
Upsides over `ViewportCommand::Screenshot`:
- More convenient api: `ctx.request_screenshot(|screnshot| ...)` (and no
need to downcast UserData)
- Reading screenshot data doesn't require rendering another frame
- Should allow us to add recording as a plugin without special hooks in
egui_kittest (otherwise capturing the last frame would have required
custom hooks in kittest)
- This was also a problem in
[kittest_inspector](https://github.com/rerun-io/kittest_inspector): When
streaming a real app, the frame seen was always a couple frames behind
when the app was idle
Example how to take screenshots and display them with eframe/egui.
cargo run -p screenshot
