tor-browser

commit 9ea357021925d50a7d3c203011a0c75d54cbad04
parent 198098e9253e65e98ecf5c16f34d0aa29b0a01c7
Author: Martin Stransky <stransky@redhat.com>
Date:   Mon, 15 Dec 2025 08:47:36 +0000

Bug 2004350 [KDE] Don't use stable subsurface rounding on KDE r=emilio

'Stable' Wayland subsurface rounding algorithm is used by all compositors except KDE.
See https://gitlab.freedesktop.org/wayland/wayland-protocols/-/merge_requests/143#note_1343171 for details.

Differential Revision: https://phabricator.services.mozilla.com/D275962

Diffstat:
M
widget/gtk/WaylandSurface.cpp
 | 
5
++++-
M
widget/gtk/nsWindow.cpp
 | 
9
++++++++-
M
widget/gtk/nsWindow.h
 | 
8
++++++++

3 files changed, 20 insertions(+), 2 deletions(-)
diff --git a/widget/gtk/WaylandSurface.cpp b/widget/gtk/WaylandSurface.cpp
@@ -941,9 +941,12 @@ bool WaylandSurface::RemoveOpaqueSurfaceHandlerLocked(
 
 LayoutDeviceIntSize WaylandSurface::GetScaledSize(
     const DesktopIntSize& aSize) const {
-  DesktopIntRect rect(mSubsurfacePosition, aSize);
+  DesktopIntRect rect(
+      gUseStableRounding ? mSubsurfacePosition : DesktopIntPoint(), aSize);
+
   auto scaledRect =
       LayoutDeviceIntRect::Round(rect * DesktopToLayoutDeviceScale(GetScale()));
+
   LOGVERBOSE(
       "WaylandSurface::GetScaledSize() pos [%d, %d] size [%d x %d] scale %f "
       "scaled [%d x %d]",
diff --git a/widget/gtk/nsWindow.cpp b/widget/gtk/nsWindow.cpp
@@ -357,6 +357,7 @@ static nsWindow* gFocusWindow = nullptr;
 static bool gBlockActivateEvent = false;
 static bool gGlobalsInitialized = false;
 static bool gUseAspectRatio = true;
+bool gUseStableRounding = true;
 static uint32_t gLastTouchID = 0;
 // See Bug 1777269 for details. We don't know if the suspected leave notify
 // event is a correct one when we get it.
@@ -592,7 +593,10 @@ void nsWindow::DispatchResized() {
     return;
   }
 
-  auto clientSize = GetClientSize();
+  auto clientSize = gUseStableRounding
+                        ? GetClientSize()
+                        : LayoutDeviceIntSize::Round(mClientArea.Size() *
+                                                     GetDesktopToDeviceScale());
 
   LOG("nsWindow::DispatchResized() client scaled size [%d, %d]",
       (int)clientSize.width, (int)clientSize.height);
@@ -8804,6 +8808,9 @@ static nsresult initialize_prefs(void) {
   } else {
     gUseAspectRatio = IsGnomeDesktopEnvironment() || IsKdeDesktopEnvironment();
   }
+  // 'Stable' Wayland subsurface rounding algorithm is used by all compositors
+  // except KDE.
+  gUseStableRounding = !IsKdeDesktopEnvironment() || GdkIsX11Display();
   return NS_OK;
 }
 
diff --git a/widget/gtk/nsWindow.h b/widget/gtk/nsWindow.h
@@ -108,6 +108,14 @@ struct _GdkEventTouchpadPinch;
 typedef struct _GdkEventTouchpadPinch GdkEventTouchpadPinch;
 #endif
 
+// 'Stable' Wayland subsurface rounding algorithm is used by all compositors
+// except KDE.
+// See
+// https://gitlab.freedesktop.org/wayland/wayland-protocols/-/merge_requests/143#note_1343171
+// for details.
+// We want to replace it by wp-fractional-scale-v2 when it's available.
+extern bool gUseStableRounding;
+
 #if !GTK_CHECK_VERSION(3, 22, 0)
 typedef enum {
   GDK_ANCHOR_FLIP_X = 1 << 0,