Transparency

third_party/WebKit/WebCore/rendering/RenderThemeChromiumWin.cpp

Index: third_party/WebKit/WebCore/rendering/RenderThemeChromiumWin.cpp
===================================================================
--- third_party/WebKit/WebCore/rendering/RenderThemeChromiumWin.cpp	(revision 10194)
+++ third_party/WebKit/WebCore/rendering/RenderThemeChromiumWin.cpp	(working copy)
@@ -38,7 +38,7 @@
 #include "RenderBox.h"
 #include "ScrollbarTheme.h"
 #include "SkiaUtils.h"
-#include "ThemeHelperChromiumWin.h"
+#include "TransparencyWin.h"
 #include "UserAgentStyleSheets.h"
 #include "WindowsVersion.h"
 
@@ -53,6 +53,43 @@
 
 namespace WebCore {
 
+namespace {
+
+bool canvasHasMultipleLayers(const SkCanvas* canvas)
+{
+    SkCanvas::LayerIter iter(const_cast<SkCanvas*>(canvas), false);
+    iter.next();  // There is always at least one layer.
+    return !iter.done();  // There is > 1 layer if the the iterator can stil advance.
+}
+
+class ThemePainter : public TransparencyWin {
+public:
+    ThemePainter(GraphicsContext* context, const IntRect& r) {
+        // Compute the transform mode.
+        TransformMode transformMode;
+        const TransformationMatrix& matrix = context->getCTM();
+        if (matrix.b() != 0 || matrix.c() != 0)  // Skew.
+            transformMode = Untransform;
+        else if (matrix.a() != 1.0 || matrix.d() != 1.0)  // Scale.
+            transformMode = ScaleTransform;
+        else  // Nothing interesting.
+            transformMode = KeepTransform;
+
+        // Compute the layer mode.
+        LayerMode layerMode;
+        if (context->platformContext()->isDrawingToImageBuffer())  // Might have transparent background.
+            layerMode = WhiteLayer;
+        else if (canvasHasMultipleLayers(context->platformContext()->canvas()))  // Needs antialiasing help.
+            layerMode = OpaqueCompositeLayer;
+        else  // Nothing interesting.
+            layerMode = transformMode == KeepTransform ? NoLayer : OpaqueCompositeLayer;
+
+        init(context, layerMode, transformMode, r);
+    }
+};
+
+}  // namespace
+
 static void getNonClientMetrics(NONCLIENTMETRICS* metrics) {
     static UINT size = WebCore::isVistaOrNewer() ?
         sizeof(NONCLIENTMETRICS) : NONCLIENTMETRICS_SIZE_PRE_VISTA;
@@ -373,12 +410,12 @@
 {
     const ThemeData& themeData = getThemeData(o);
 
-    WebCore::ThemeHelperWin helper(i.context, r);
-    ChromiumBridge::paintButton(helper.context(),
+    WebCore::ThemePainter painter(i.context, r);
+    ChromiumBridge::paintButton(painter.context(),
                                 themeData.m_part,
                                 themeData.m_state,
                                 themeData.m_classicState,
-                                helper.rect());
+                                painter.drawRect());
     return false;
 }
 
@@ -441,12 +478,12 @@
                  r.height() - (spacingTop + spacingBottom));
 
     // Get the correct theme data for a textfield and paint the menu.
-    WebCore::ThemeHelperWin helper(i.context, rect);
-    ChromiumBridge::paintMenuList(helper.context(),
+    WebCore::ThemePainter painter(i.context, rect);
+    ChromiumBridge::paintMenuList(painter.context(),
                                   CP_DROPDOWNBUTTON,
                                   determineState(o),
                                   determineClassicState(o),
-                                  helper.rect());
+                                  painter.drawRect());
     return false;
 }
 
@@ -563,9 +600,9 @@
 }
 
 bool RenderThemeChromiumWin::paintTextFieldInternal(RenderObject* o,
-                                            const RenderObject::PaintInfo& i,
-                                            const IntRect& r,
-                                            bool drawEdges)
+                                                    const RenderObject::PaintInfo& i,
+                                                    const IntRect& r,
+                                                    bool drawEdges)
 {
     // Nasty hack to make us not paint the border on text fields with a
     // border-radius. Webkit paints elements with border-radius for us.
@@ -577,12 +614,12 @@
 
     const ThemeData& themeData = getThemeData(o);
 
-    WebCore::ThemeHelperWin helper(i.context, r);
-    ChromiumBridge::paintTextField(helper.context(),
+    WebCore::ThemePainter painter(i.context, r);
+    ChromiumBridge::paintTextField(painter.context(),
                                    themeData.m_part,
                                    themeData.m_state,
                                    themeData.m_classicState,
-                                   helper.rect(),
+                                   painter.drawRect(),
                                    o->style()->backgroundColor(),
                                    true,
                                    drawEdges);