On Windows with Windows Ink (WM_POINTER), winit drops penFlags (PEN_FLAG_BARREL) and reports stylus contact as WindowEvent::Touch, which egui-winit maps exclusively to PointerButton::Primary. Additionally, Windows Ink does not update GetAsyncKeyState(VK_RBUTTON) when pressing the pen barrel button. Consequently, Alt + Barrel Button drag was recognized as Alt + Left Drag (triggering the eyedropper and painting strokes instead of brush resize), and right-clicks with the stylus were treated as left-clicks.
This commit resolves the issue by:
1. Adding a native Windows message hook (WH_GETMESSAGE) in crates/tablet/src/windows.rs calling GetPointerPenInfo to intercept PEN_FLAG_BARREL (0x00000001) and POINTER_FLAG_SECONDBUTTON.
2. Exposing
ight_button_down in Services combining the pointer hook and GetAsyncKeyState(VK_RBUTTON).
3. Updating canvas.rs and paint_mouse.rs to prevent strokes_live and alt_eyedropper from hijacking the stylus gesture when the barrel button is held, and correctly routing resize events.
4. Adding tests asserting that Alt + stylus barrel drag resizes diameter horizontally and adjusts hardness vertically without triggering eyedropper or painting.
Anim86