[Qt] Enable tiled shadow blur for inset box shadows

https://bugs.webkit.org/show_bug.cgi?id=111736

Reviewed by Noam Rosenthal.

Paint inset box-shadows using the optimized tiled shadow blur, instead of
applying shadow blur to the entire painted rect.

This optimizes the default CSS on common pastebin sites.

Tested by existing tests.

* platform/graphics/GraphicsContext.cpp:
* platform/graphics/ShadowBlur.cpp:
(WebCore::ShadowBlur::drawInsetShadowWithTiling):
    Must set fill color before calling clearShadow, as that might clear m_color.
(WebCore::ShadowBlur::drawLayerPieces):
    Ditto.
* platform/graphics/qt/GraphicsContextQt.cpp:
(WebCore::GraphicsContext::fillPath):
(WebCore::GraphicsContext::fillRectWithRoundedHole):

Change-Id: Idc563ff997f8150ef9553d8fe3d164e488f16e9f
git-svn-id: http://svn.webkit.org/repository/webkit/trunk@145366 268f45cc-cd09-0410-ab3c-d52691b4dbfc
Reviewed-by: Jocelyn Turcotte <jocelyn.turcotte@digia.com>

1 files changed, 31 insertions, 0 deletions

diff --git a/Source/WebCore/platform/graphics/qt/GraphicsContextQt.cpp b/Source/WebCore/platform/graphics/qt/GraphicsContextQt.cpp
index e91c2d287..ec992d648 100644
--- a/Source/WebCore/platform/graphics/qt/GraphicsContextQt.cpp
+++ b/Source/WebCore/platform/graphics/qt/GraphicsContextQt.cpp
@@ -791,6 +791,37 @@ void GraphicsContext::fillRoundedRect(const IntRect& rect, const IntSize& topLef
     p->fillPath(path.platformPath(), QColor(color));
 }
 
+void GraphicsContext::fillRectWithRoundedHole(const IntRect& rect, const RoundedRect& roundedHoleRect, const Color& color, ColorSpace colorSpace)
+{
+    if (paintingDisabled() || !color.isValid())
+        return;
+
+    Path path;
+    path.addRect(rect);
+    if (!roundedHoleRect.radii().isZero())
+        path.addRoundedRect(roundedHoleRect);
+    else
+        path.addRect(roundedHoleRect.rect());
+
+    QPainterPath platformPath = path.platformPath();
+    platformPath.setFillRule(Qt::OddEvenFill);
+
+    QPainter* p = m_data->p();
+    if (hasShadow()) {
+        ShadowBlur* shadow = shadowBlur();
+        if (shadow->mustUseShadowBlur(this))
+            shadow->drawInsetShadow(this, rect, roundedHoleRect.rect(), roundedHoleRect.radii());
+        else {
+            const QPointF shadowOffset(m_state.shadowOffset.width(), m_state.shadowOffset.height());
+            p->translate(shadowOffset);
+            p->fillPath(platformPath, QColor(m_state.shadowColor));
+            p->translate(-shadowOffset);
+        }
+    }
+
+    p->fillPath(platformPath, QColor(color));
+}
+
 bool GraphicsContext::isInTransparencyLayer() const
 {
     return m_data->layerCount;