ltk: convert physical sizes to logical for overlays and input regions on HiDPI

Overlay `set_size` and input regions were handed physical (layout-space) pixels straight to layer-shell and `wl_region`, both of which expect logical coordinates. They only coincide at scale 1, so on a scale-2 output every overlay requested a surface twice its intended size and the input region covered the wrong area.
`apply_input_region` now takes the surface scale and divides each `Rect` down to logical before adding it to the region; the four draw paths (software and gles, full and partial) forward their scale. `reconcile_overlays` converts `OverlaySpec::size` to logical for both `set_size` and the initial `OverlayConfig` (0 = fill survives the divide), and seeds the new surface's `scale_factor` from the parent so the first configure allocates a HiDPI buffer instead of rendering at scale 1 until `scale_factor_changed` lands a frame or two later.

src/draw/chrome.rs

@@ -84,15 +84,23 @@ pub( crate ) fn apply_input_region(
 	wl_surface:   &WlSurface,
 	compositor:   &CompositorState,
 	input_region: Option<&[Rect]>,
+	scale:        u32,
 )
 {
 	if let Some( regions ) = input_region
 	{
 		if let Ok( region ) = Region::new( compositor )
 		{
+			// `Rect`s are physical (layout space); `wl_region` is logical.
+			let s = scale.max( 1 ) as f32;
 			for r in regions
 			{
-				region.add( r.x as i32, r.y as i32, r.width as i32, r.height as i32 );
+				region.add(
+					( r.x      / s ).round() as i32,
+					( r.y      / s ).round() as i32,
+					( r.width  / s ).round() as i32,
+					( r.height / s ).round() as i32,
+				);
 			}
 			wl_surface.set_input_region( Some( region.wl_region() ) );
 		}

src/draw/gles.rs

@@ -141,7 +141,7 @@ pub( crate ) fn draw_surface_full_gpu<Msg: Clone>(
 	ss.content_dirty   = false;
 
 	let wl_surface = ss.surface.wl_surface();
-	apply_input_region( wl_surface, compositor, input_region );
+	apply_input_region( wl_surface, compositor, input_region, scale );
 	// Frame callback request must precede the implicit commit done by
 	// `swap_buffers_with_damage`, so the compositor can attach it to this
 	// frame and not the previous one.
@@ -241,7 +241,7 @@ pub( crate ) fn draw_surface_partial_gpu<Msg: Clone>(
 	ss.content_dirty   = false;
 
 	let wl_surface = ss.surface.wl_surface();
-	apply_input_region( wl_surface, compositor, input_region );
+	apply_input_region( wl_surface, compositor, input_region, scale );
 	request_frame( wl_surface );
 	// Convert top-left dirty rects to EGL bottom-left coords for the
 	// swap-with-damage call.

src/draw/software.rs

@@ -167,7 +167,7 @@ pub( crate ) fn draw_surface_full<Msg: Clone>(
 		}
 	}
 
-	apply_input_region( wl_surface, compositor, input_region );
+	apply_input_region( wl_surface, compositor, input_region, scale );
 	// Request a frame callback BEFORE commit so the compositor schedules it
 	// against this exact frame; sets `frame_pending` so the run loop won't
 	// try to draw this surface again until the callback fires.
@@ -282,7 +282,7 @@ pub( crate ) fn draw_surface_partial<Msg: Clone>(
 		wl_surface.damage_buffer( r.x as i32, r.y as i32, r.width as i32, r.height as i32 );
 	}
 
-	apply_input_region( wl_surface, compositor, input_region );
+	apply_input_region( wl_surface, compositor, input_region, scale );
 	request_frame( wl_surface );
 	wl_surface.commit();
 	ss.frame_pending = true;