fix: scale borderless resizing inset based on scale_factor, closes #376…

… (#379)

.changes/scaled-resize-borderless.md

@@ -0,0 +1,5 @@
+---
+"tao": patch
+---
+
+On Windows and Linux, increase the resizing area for borderless windows based on scale factor.

src/platform_impl/linux/window.rs

@@ -700,11 +700,13 @@ pub fn hit_test(window: &gdk::Window, cx: f64, cy: f64) -> WindowEdge {
   const BOTTOMLEFT: i32 = BOTTOM | LEFT;
   const BOTTOMRIGHT: i32 = BOTTOM | RIGHT;
 
+  let inset = BORDERLESS_RESIZE_INSET * window.scale_factor();
   #[rustfmt::skip]
-  let result = (LEFT * (if cx < (left + BORDERLESS_RESIZE_INSET) { 1 } else { 0 }))
-    | (RIGHT * (if cx >= (right - BORDERLESS_RESIZE_INSET) { 1 } else { 0 }))
-    | (TOP * (if cy < (top + BORDERLESS_RESIZE_INSET) { 1 } else { 0 }))
-    | (BOTTOM * (if cy >= (bottom - BORDERLESS_RESIZE_INSET) { 1 } else { 0 }));
+  let result =
+      (LEFT * (if cx < (left + inset) { 1 } else { 0 }))
+    | (RIGHT * (if cx >= (right - inset) { 1 } else { 0 }))
+    | (TOP * (if cy < (top + inset) { 1 } else { 0 }))
+    | (BOTTOM * (if cy >= (bottom - inset) { 1 } else { 0 }));
 
   match result {
     LEFT => WindowEdge::West,

src/platform_impl/windows/window.rs

@@ -1163,11 +1163,16 @@ pub fn hit_test(hwnd: HWND, cx: i32, cy: i32) -> LRESULT {
         top,
       } = window_rect;
 
+      let dpi = hwnd_dpi(hwnd);
+      let scale_factor = dpi_to_scale_factor(dpi);
+      let inset = (BORDERLESS_RESIZE_INSET as f64 * scale_factor) as i32;
+
       #[rustfmt::skip]
-      let result = (LEFT * (if cx < (left + BORDERLESS_RESIZE_INSET) { 1 } else { 0 }))
-        | (RIGHT * (if cx >= (right - BORDERLESS_RESIZE_INSET) { 1 } else { 0 }))
-        | (TOP * (if cy < (top + BORDERLESS_RESIZE_INSET) { 1 } else { 0 }))
-        | (BOTTOM * (if cy >= (bottom - BORDERLESS_RESIZE_INSET) { 1 } else { 0 }));
+      let result =
+          (LEFT * (if cx < (left + inset) { 1 } else { 0 }))
+        | (RIGHT * (if cx >= (right - inset) { 1 } else { 0 }))
+        | (TOP * (if cy < (top + inset) { 1 } else { 0 }))
+        | (BOTTOM * (if cy >= (bottom - inset) { 1 } else { 0 }));
 
       LRESULT(match result {
         CLIENT => HTCLIENT,

src/window.rs

@@ -1061,4 +1061,5 @@ impl Default for UserAttentionType {
 }
 
 /// A constant used to determine how much inside the window, the resize handler should appear (only used in Linux(gtk) and Windows).
+/// You probably need to scale it by the scale_factor of the window.
 pub const BORDERLESS_RESIZE_INSET: i32 = 5;