Changeset 126095 in webkit

Timestamp:

Aug 20, 2012 4:57:24 PM (12 years ago)

Author:

abarth@webkit.org

Message:

WebWidget should be able to paint into a zoomed canvas without aliasing
​https://bugs.webkit.org/show_bug.cgi?id=92043

Reviewed by James Robinson.

If accelerated compositing is enabled, WebWidget::paint reads back from
the compositor rather than re-painting the widget. That approach works
well if the canvas we're rendering into is at a similar resolution to
the pixels in the compositor, but if the canvas has been scaled (e.g.,
to help the user disambiguate links), then reading back from the
compositor will cause aliasing artifacts.

This patch adds an option to paint to let the embedder request a
software re-rendering of the widget to avoid these aliasing artifacts.

• public/WebWidget.h:

(WebKit::WebWidget::paint):

• src/WebPagePopupImpl.cpp:

(WebKit::WebPagePopupImpl::paint):

• src/WebPagePopupImpl.h:

(WebPagePopupImpl):

• src/WebPopupMenuImpl.cpp:

(WebKit::WebPopupMenuImpl::paint):

• src/WebPopupMenuImpl.h:
• src/WebViewImpl.cpp:

(WebKit::canvasBackgroundForTransparencey):
(WebKit):
(WebKit::WebViewImpl::paint):

• src/WebViewImpl.h:

(WebViewImpl):

Location:

trunk/Source/WebKit/chromium

Files:

• ChangeLog (modified) (1 diff)
• public/WebWidget.h (modified) (2 diffs)
• src/WebPagePopupImpl.cpp (modified) (1 diff)
• src/WebPagePopupImpl.h (modified) (1 diff)
• src/WebPopupMenuImpl.cpp (modified) (1 diff)
• src/WebPopupMenuImpl.h (modified) (1 diff)
• src/WebViewImpl.cpp (modified) (3 diffs)
• src/WebViewImpl.h (modified) (1 diff)

trunk/Source/WebKit/chromium/ChangeLog

@@ +1 @@
+2012-08-20  Adam Barth  <abarth@webkit.org>
+
+        WebWidget should be able to paint into a zoomed canvas without aliasing
+        https://bugs.webkit.org/show_bug.cgi?id=92043
+
+        Reviewed by James Robinson.
+
+        If accelerated compositing is enabled, WebWidget::paint reads back from
+        the compositor rather than re-painting the widget. That approach works
+        well if the canvas we're rendering into is at a similar resolution to
+        the pixels in the compositor, but if the canvas has been scaled (e.g.,
+        to help the user disambiguate links), then reading back from the
+        compositor will cause aliasing artifacts.
+
+        This patch adds an option to paint to let the embedder request a
+        software re-rendering of the widget to avoid these aliasing artifacts.
+
+        * public/WebWidget.h:
+        (WebKit::WebWidget::paint):
+        * src/WebPagePopupImpl.cpp:
+        (WebKit::WebPagePopupImpl::paint):
+        * src/WebPagePopupImpl.h:
+        (WebPagePopupImpl):
+        * src/WebPopupMenuImpl.cpp:
+        (WebKit::WebPopupMenuImpl::paint):
+        * src/WebPopupMenuImpl.h:
+        * src/WebViewImpl.cpp:
+        (WebKit::canvasBackgroundForTransparencey):
+        (WebKit):
+        (WebKit::WebViewImpl::paint):
+        * src/WebViewImpl.h:
+        (WebViewImpl):
+
 2012-08-20  James Robinson  <jamesr@chromium.org>
 

trunk/Source/WebKit/chromium/public/WebWidget.h

@@ -91 +91 @@
     virtual void layout() { }
 
+    enum PaintOptions {
+        // Attempt to fulfill the painting request by reading back from the
+        // compositor, assuming we're using a compositor to render.
+        ReadbackFromCompositorIfAvailable,
+
+        // Force the widget to rerender onto the canvas using software. This
+        // mode ignores 3d transforms and ignores GPU-resident content, such
+        // as video, canvas, and WebGL.
+        //
+        // Note: This option exists on OS(ANDROID) and will hopefully be
+        //       removed once the link disambiguation feature renders using
+        //       the compositor.
+        ForceSoftwareRenderingAndIgnoreGPUResidentContent,
+    };
+
     // Called to paint the rectangular region within the WebWidget
     // onto the specified canvas at (viewPort.x,viewPort.y). You MUST call
@@ -98 +113 @@
     // processed, it should be assumed that another call to layout is
     // warranted before painting again).
-    virtual void paint(WebCanvas*, const WebRect& viewPort) { }
+    virtual void paint(WebCanvas*, const WebRect& viewPort, PaintOptions = ReadbackFromCompositorIfAvailable) { }
 
     // In non-threaded compositing mode, triggers compositing of the current

trunk/Source/WebKit/chromium/src/WebPagePopupImpl.cpp

@@ -226 +226 @@
 }
 
-void WebPagePopupImpl::paint(WebCanvas* canvas, const WebRect& rect)
+void WebPagePopupImpl::paint(WebCanvas* canvas, const WebRect& rect, PaintOptions)
 {
     PageWidgetDelegate::paint(m_page.get(), 0, canvas, rect, PageWidgetDelegate::Opaque);

trunk/Source/WebKit/chromium/src/WebPagePopupImpl.h

@@ -73 +73 @@
     virtual void composite(bool) OVERRIDE;
     virtual void layout() OVERRIDE;
-    virtual void paint(WebCanvas*, const WebRect&) OVERRIDE;
+    virtual void paint(WebCanvas*, const WebRect&, PaintOptions = ReadbackFromCompositorIfAvailable) OVERRIDE;
     virtual void resize(const WebSize&) OVERRIDE;
     virtual void close() OVERRIDE;

trunk/Source/WebKit/chromium/src/WebPopupMenuImpl.cpp

@@ -194 +194 @@
 }
 
-void WebPopupMenuImpl::paint(WebCanvas* canvas, const WebRect& rect)
+void WebPopupMenuImpl::paint(WebCanvas* canvas, const WebRect& rect, PaintOptions)
 {
     if (!m_widget)

trunk/Source/WebKit/chromium/src/WebPopupMenuImpl.h

@@ -74 +74 @@
     virtual void animate(double frameBeginTime) OVERRIDE;
     virtual void layout() OVERRIDE;
-    virtual void paint(WebCanvas*, const WebRect&) OVERRIDE;
+    virtual void paint(WebCanvas*, const WebRect&, PaintOptions = ReadbackFromCompositorIfAvailable) OVERRIDE;
     virtual void themeChanged() OVERRIDE;
     virtual void setCompositorSurfaceReady() OVERRIDE;

trunk/Source/WebKit/chromium/src/WebViewImpl.cpp

@@ -1687 +1687 @@
 #endif
 
-void WebViewImpl::paint(WebCanvas* canvas, const WebRect& rect)
-{
-    if (isAcceleratedCompositingActive()) {
+void WebViewImpl::paint(WebCanvas* canvas, const WebRect& rect, PaintOptions option)
+{
+#if !OS(ANDROID)
+    // ReadbackFromCompositorIfAvailable is the only option available on non-Android.
+    // Ideally, Android would always use ReadbackFromCompositorIfAvailable as well.
+    ASSERT(option == ReadbackFromCompositorIfAvailable);
+#endif
+
+    if (option == ReadbackFromCompositorIfAvailable && isAcceleratedCompositingActive()) {
 #if USE(ACCELERATED_COMPOSITING)
         // If a canvas was passed in, we use it to grab a copy of the
@@ -1701 +1707 @@
 #endif
     } else {
+        FrameView* view = page()->mainFrame()->view();
+        PaintBehavior oldPaintBehavior = view->paintBehavior();
+        if (isAcceleratedCompositingActive()) {
+            ASSERT(option == ForceSoftwareRenderingAndIgnoreGPUResidentContent);            
+            view->setPaintBehavior(oldPaintBehavior | PaintBehaviorFlattenCompositingLayers);
+        }
+
         double paintStart = currentTime();
         PageWidgetDelegate::paint(m_page.get(), pageOverlays(), canvas, rect, isTransparent() ? PageWidgetDelegate::Translucent : PageWidgetDelegate::Opaque);
@@ -1707 +1720 @@
         WebKit::Platform::current()->histogramCustomCounts("Renderer4.SoftwarePaintDurationMS", (paintEnd - paintStart) * 1000, 0, 120, 30);
         WebKit::Platform::current()->histogramCustomCounts("Renderer4.SoftwarePaintMegapixPerSecond", pixelsPerSec / 1000000, 10, 210, 30);
+
+        if (isAcceleratedCompositingActive()) {
+            ASSERT(option == ForceSoftwareRenderingAndIgnoreGPUResidentContent);            
+            view->setPaintBehavior(oldPaintBehavior);
+        }
     }
 }

trunk/Source/WebKit/chromium/src/WebViewImpl.h

@@ -144 +144 @@
     virtual void animate(double);
     virtual void layout(); // Also implements WebLayerTreeViewClient::layout()
-    virtual void paint(WebCanvas*, const WebRect&);
+    virtual void paint(WebCanvas*, const WebRect&, PaintOptions = ReadbackFromCompositorIfAvailable);
     virtual void themeChanged();
     virtual void composite(bool finish);