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When layer transforms are present, the `Response::hover_pos` function in
egui returns `transform * pos` instead of `transform.inverse() * pos`.
This is incorrect and isn't consistent with [how egui calculates other
interaction
positions](https://github.com/emilk/egui/blob/master/crates/egui/src/context.rs#L1193).
See:
https://github.com/emilk/egui/blob/master/crates/egui/src/response.rs#L471
This PR fixes this bug, changing `transform` to `transform.inverse()`.
Nothing fancy here, just a one-line change. `scripts/check.sh` runs
successfully.
Below are videos of before and after with a modified version of the web
demo. I added another entry after
https://github.com/emilk/egui/blob/master/crates/egui_demo_lib/src/demo/pan_zoom.rs#L108
with a debug rectangle drawn at the return value of `hover_pos`:
```rust
(
egui::Pos2::new(120.0, 120.0),
Box::new(|ui, _state| {
let response =
ui.allocate_response(egui::Vec2::splat(128.0), egui::Sense::hover());
ui.painter().rect_filled(
egui::Rect::from_center_size(
response.hover_pos().unwrap_or_default(),
egui::Vec2::splat(8.0),
),
egui::Rounding::ZERO,
egui::Color32::DEBUG_COLOR,
);
response
}),
),
```
Without the fix:
https://github.com/emilk/egui/assets/104604363/241cfcab-88ab-459b-8f4d-3367da3aa392
With the fix:
https://github.com/emilk/egui/assets/104604363/e52a7263-44c7-42c1-be46-1ecadc025625
cd3e9ea5b6