Bug 1505743 - [Wayland] Clear Wayland buffer when GtkWindow is mapped. r=jhorak

Differential Revision: https://phabricator.services.mozilla.com/D11999

--HG--
extra : moz-landing-system : lando

widget/gtk/WindowSurfaceWayland.cpp

@@ -475,6 +475,11 @@ void WindowBackBuffer::Release()
   mWidth = mHeight = 0;
 }
 
+void WindowBackBuffer::Clear()
+{
+  memset(mShmPool.GetImageData(), 0, mHeight * mWidth * BUFFER_BPP);
+}
+
 WindowBackBuffer::WindowBackBuffer(nsWaylandDisplay* aWaylandDisplay,
                                    int aWidth, int aHeight)
  : mShmPool(aWaylandDisplay, aWidth*aHeight*BUFFER_BPP)
@@ -674,15 +679,19 @@ WindowSurfaceWayland::GetWaylandBufferToDraw(int aWidth, int aHeight)
 }
 
 already_AddRefed<gfx::DrawTarget>
-WindowSurfaceWayland::LockWaylandBuffer(int aWidth, int aHeight)
+WindowSurfaceWayland::LockWaylandBuffer(int aWidth, int aHeight, bool aClearBuffer)
 {
   WindowBackBuffer* buffer = GetWaylandBufferToDraw(aWidth, aHeight);
-  if (buffer) {
-    return buffer->Lock();
+  if (!buffer) {
+    NS_WARNING("WindowSurfaceWayland::LockWaylandBuffer(): No buffer available");
+    return nullptr;
   }
 
-  NS_WARNING("WindowSurfaceWayland::LockWaylandBuffer(): No buffer available");
-  return nullptr;
+  if (aClearBuffer) {
+    buffer->Clear();
+  }
+
+  return buffer->Lock();
 }
 
 already_AddRefed<gfx::DrawTarget>
@@ -733,7 +742,8 @@ WindowSurfaceWayland::Lock(const LayoutDeviceIntRegion& aRegion)
 
   if (mDrawToWaylandBufferDirectly) {
     RefPtr<gfx::DrawTarget> dt = LockWaylandBuffer(screenRect.width,
-                                                   screenRect.height);
+                                                   screenRect.height,
+                                                   mWindow->WaylandSurfaceNeedsClear());
     if (dt) {
       return dt.forget();
     }
@@ -760,7 +770,8 @@ WindowSurfaceWayland::CommitImageSurfaceToWaylandBuffer(const LayoutDeviceIntReg
   }
 
   RefPtr<gfx::DrawTarget> dt = LockWaylandBuffer(screenRect.width,
-                                                 screenRect.height);
+                                                 screenRect.height,
+                                                 mWindow->WaylandSurfaceNeedsClear());
   RefPtr<gfx::SourceSurface> surf =
     gfx::Factory::CreateSourceSurfaceForCairoSurface(mImageSurface->CairoSurface(),
                                                      mImageSurface->GetSize(),

widget/gtk/WindowSurfaceWayland.h

@@ -75,6 +75,7 @@ public:
   void Detach();
   bool IsAttached() { return mAttached; }
 
+  void Clear();
   bool Resize(int aWidth, int aHeight);
   bool SetImageDataFromBuffer(class WindowBackBuffer* aSourceBuffer);
 
@@ -118,7 +119,8 @@ public:
 private:
   WindowBackBuffer*         GetWaylandBufferToDraw(int aWidth, int aHeight);
 
-  already_AddRefed<gfx::DrawTarget> LockWaylandBuffer(int aWidth, int aHeight);
+  already_AddRefed<gfx::DrawTarget> LockWaylandBuffer(int aWidth, int aHeight,
+                                                      bool aClearBuffer);
   already_AddRefed<gfx::DrawTarget> LockImageSurface(const gfx::IntSize& aLockSize);
   bool                      CommitImageSurfaceToWaylandBuffer(const LayoutDeviceIntRegion& aRegion);
   void                      CommitWaylandBuffer();

widget/gtk/mozcontainer.cpp

@@ -213,6 +213,7 @@ moz_container_init (MozContainer *container)
       container->subsurface = nullptr;
       container->eglwindow = nullptr;
       container->parent_surface_committed = false;
+      container->needs_clear = true;
 
       GdkDisplay *gdk_display = gtk_widget_get_display(GTK_WIDGET(container));
       if (!GDK_IS_X11_DISPLAY(gdk_display)) {
@@ -266,8 +267,9 @@ moz_container_map_surface(MozContainer *container)
     if (GDK_IS_X11_DISPLAY(display))
         return false;
 
-    if (container->subsurface && container->surface)
+    if (container->subsurface && container->surface) {
         return true;
+    }
 
     if (!container->parent_surface_committed) {
         if (!container->parent_surface_committed_handler) {
@@ -313,6 +315,8 @@ moz_container_map_surface(MozContainer *container)
         wl_region* region = wl_compositor_create_region(compositor);
         wl_surface_set_input_region(container->surface, region);
         wl_region_destroy(region);
+
+        container->needs_clear = true;
     }
     return true;
 }
@@ -337,7 +341,6 @@ moz_container_unmap_surface(MozContainer *container)
     }
     container->parent_surface_committed = false;
 }
-
 #endif
 
 void
@@ -641,4 +644,12 @@ moz_container_has_wl_egl_window(MozContainer *container)
 {
     return container->eglwindow ? true : false;
 }
+
+gboolean
+moz_container_needs_clear(MozContainer *container)
+{
+    gboolean state = container->needs_clear;
+    container->needs_clear = false;
+    return state;
+}
 #endif

widget/gtk/mozcontainer.h

@@ -73,6 +73,7 @@ struct _MozContainer
     struct wl_surface       *surface;
     struct wl_subsurface    *subsurface;
     struct wl_egl_window    *eglwindow;
+    gboolean                 needs_clear;
     gboolean                 parent_surface_committed;
     gulong                   parent_surface_committed_handler;
 #endif
@@ -100,6 +101,7 @@ void       moz_container_move          (MozContainer *container,
 struct wl_surface* moz_container_get_wl_surface(MozContainer *container);
 struct wl_egl_window* moz_container_get_wl_egl_window(MozContainer *container);
 gboolean moz_container_has_wl_egl_window(MozContainer *container);
+gboolean moz_container_needs_clear(MozContainer *container);
 #endif
 
 #endif /* __MOZ_CONTAINER_H__ */

widget/gtk/nsWindow.cpp

@@ -7323,6 +7323,17 @@ nsWindow::GetWaylandSurface()
   NS_WARNING("nsWindow::GetWaylandSurfaces(): We don't have any mContainer for drawing!");
   return nullptr;
 }
+
+bool
+nsWindow::WaylandSurfaceNeedsClear()
+{
+  if (mContainer) {
+    return moz_container_needs_clear(MOZ_CONTAINER(mContainer));
+  }
+
+  NS_WARNING("nsWindow::WaylandSurfaceNeedsClear(): We don't have any mContainer!");
+  return false;
+}
 #endif
 
 #ifdef MOZ_X11

widget/gtk/nsWindow.h

@@ -388,6 +388,7 @@ public:
 #ifdef MOZ_WAYLAND
     wl_display* GetWaylandDisplay();
     wl_surface* GetWaylandSurface();
+    bool WaylandSurfaceNeedsClear();
 #endif
     virtual void GetCompositorWidgetInitData(mozilla::widget::CompositorWidgetInitData* aInitData) override;