tor-browser

commit e8e17d4083171071da0f32e686942cb525ca42e1
parent ed5d8b39aa223d2c9f083c958bc46d44f884d56d
Author: stransky <stransky@redhat.com>
Date:   Wed,  3 Dec 2025 08:32:07 +0000

Bug 2000769 [Wayland] Follow 'stable rounding' algorithm for fractionaly scaled subsurfaces r=emilio

Calculate scaled subsurface size from both position and size as described by:
https://gitlab.freedesktop.org/wayland/wayland-protocols/-/merge_requests/143#note_1343171
which is supposed to be used by all tree major Wayland compositors (Mutter, KWin, WlRoots).

Differential Revision: https://phabricator.services.mozilla.com/D274266

Diffstat:
M
widget/gtk/WaylandSurface.cpp
 | 
33
++++++++++++++++++++++++---------
M
widget/gtk/WaylandSurface.h
 | 
8
++++++--

2 files changed, 30 insertions(+), 11 deletions(-)
diff --git a/widget/gtk/WaylandSurface.cpp b/widget/gtk/WaylandSurface.cpp
@@ -16,6 +16,7 @@
 #include "ScreenHelperGTK.h"
 #include "DMABufFormats.h"
 #include "mozilla/gfx/gfxVars.h"
+#include "mozilla/gfx/Logging.h"
 #ifdef MOZ_LOGGING
 #  include "EncoderConfig.h"
 #endif
@@ -92,6 +93,8 @@ WaylandSurface::WaylandSurface(RefPtr<WaylandSurface> aParent)
              mParent ? mParent->GetLoggingWidget() : nullptr);
   struct wl_compositor* compositor = WaylandDisplayGet()->GetCompositor();
   mSurface = wl_compositor_create_surface(compositor);
+  LOGWAYLAND("    created surface %p ID %d", (void*)mSurface,
+             wl_proxy_get_id((struct wl_proxy*)mSurface));
   MOZ_RELEASE_ASSERT(mSurface, "Can't create wl_surface!");
 }
 
@@ -464,8 +467,6 @@ bool WaylandSurface::MapLocked(const WaylandSurfaceLock& aProofOfLock,
     EnableDMABufFormatsLocked(aProofOfLock, mDMABufFormatRefreshCallback);
   }
 
-  LOGWAYLAND("    created surface %p ID %d", (void*)mSurface,
-             wl_proxy_get_id((struct wl_proxy*)mSurface));
   return true;
 }
 
@@ -952,14 +953,26 @@ bool WaylandSurface::RemoveOpaqueSurfaceHandlerLocked(
   return true;
 }
 
+LayoutDeviceIntSize WaylandSurface::GetScaledSize(
+    const DesktopIntSize& aSize) const {
+  DesktopIntRect rect(mSubsurfacePosition, aSize);
+  auto scaledRect =
+      LayoutDeviceIntRect::Round(rect * DesktopToLayoutDeviceScale(GetScale()));
+  LOGVERBOSE(
+      "WaylandSurface::GetScaledSize() pos [%d, %d] size [%d x %d] scale %f "
+      "scaled [%d x %d]",
+      (int)mSubsurfacePosition.x, (int)mSubsurfacePosition.y, aSize.width,
+      aSize.height, GetScale(), scaledRect.width, scaledRect.height);
+  return scaledRect.Size();
+}
+
 wl_egl_window* WaylandSurface::GetEGLWindow(DesktopIntSize aSize) {
   LOGWAYLAND("WaylandSurface::GetEGLWindow() eglwindow %p", (void*)mEGLWindow);
 
   WaylandSurfaceLock lock(this);
   MOZ_DIAGNOSTIC_ASSERT(mSurface, "Missing wl_surface!");
 
-  auto scaledSize = LayoutDeviceIntSize::Round(
-      aSize * DesktopToLayoutDeviceScale(GetScale()));
+  auto scaledSize = GetScaledSize(aSize);
 
   if (!mEGLWindow) {
     mEGLWindow =
@@ -967,6 +980,10 @@ wl_egl_window* WaylandSurface::GetEGLWindow(DesktopIntSize aSize) {
     LOGWAYLAND(
         "WaylandSurface::GetEGLWindow() created eglwindow [%p] size %d x %d",
         (void*)mEGLWindow, scaledSize.width, scaledSize.height);
+    if (!mEGLWindow) {
+      gfxCriticalError()
+          << "Failed to create EGLWindow - we can't paint anything!";
+    }
   } else {
     LOGWAYLAND("WaylandSurface::GetEGLWindow() resized to %d x %d",
                scaledSize.width, scaledSize.height);
@@ -980,8 +997,7 @@ wl_egl_window* WaylandSurface::GetEGLWindow(DesktopIntSize aSize) {
 void WaylandSurface::SetSize(DesktopIntSize aSize) {
   WaylandSurfaceLock lock(this);
 
-  auto scaledSize = LayoutDeviceIntSize::Round(
-      aSize * DesktopToLayoutDeviceScale(GetScale()));
+  auto scaledSize = GetScaledSize(aSize);
 
   LOGVERBOSE(
       "WaylandSurface::SetSize() size [%d x %d] "
@@ -1080,8 +1096,7 @@ bool WaylandSurface::AttachLocked(const WaylandSurfaceLock& aSurfaceLock,
 
   auto scale = GetScale();
   LayoutDeviceIntSize bufferSize = aBuffer->GetSize();
-  DesktopIntSize surfaceSize((int)round(mSize.width * scale),
-                             (int)round(mSize.height * scale));
+  auto surfaceSize = GetScaledSize(mSize);
   bool sizeMatches = bufferSize.width == surfaceSize.width &&
                      bufferSize.height == surfaceSize.height;
   LOGWAYLAND(
@@ -1182,7 +1197,7 @@ GdkWindow* WaylandSurface::GetGdkWindow() const {
   return mGdkWindow;
 }
 
-double WaylandSurface::GetScale() {
+double WaylandSurface::GetScale() const {
 #ifdef MOZ_LOGGING
   static float lastLoggedScale = 0.0;
 #endif
diff --git a/widget/gtk/WaylandSurface.h b/widget/gtk/WaylandSurface.h
@@ -197,7 +197,7 @@ class WaylandSurface final {
   // Returns scale as float point number. If WaylandSurface is not mapped,
   // return fractional scale of parent surface or monitor.
   static constexpr const double sNoScale = -1;
-  double GetScale();
+  double GetScale() const;
 
   // Called when screen ceiled scale changed or set initial scale before we map
   // and paint the surface.
@@ -301,6 +301,10 @@ class WaylandSurface final {
 
   void ClearScaleLocked(const WaylandSurfaceLock& aProofOfLock);
 
+  // Calculate 'stable' rounded size for subsurface based
+  // on its size and position.
+  LayoutDeviceIntSize GetScaledSize(const DesktopIntSize& aSize) const;
+
   // Weak ref to owning widget (nsWindow or NativeLayerWayland),
   // used for diagnostics/logging only.
   void* mLoggingWidget = nullptr;
@@ -347,7 +351,7 @@ class WaylandSurface final {
   bool mSubsurfaceDesync = true;
 
   wl_subsurface* mSubsurface = nullptr;
-  DesktopIntPoint mSubsurfacePosition{-1, -1};
+  DesktopIntPoint mSubsurfacePosition;
 
   // Wayland buffers recently attached to this surface or held by
   // Wayland compositor.