Refactor root element background painting

Source/core/paint/FrameSetPainter.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/paint/FrameSetPainter.h"
 
 #include "core/html/HTMLFrameSetElement.h"
 #include "core/layout/LayoutFrameSet.h"
 #include "core/paint/LayoutObjectDrawingRecorder.h"
@@ skipping 23 matching lines @@
 
     // FIXME: We should do something clever when borders from distinct framesets meet at a join.
 
     // Fill first.
     GraphicsContext* context = paintInfo.context;
     context->fillRect(borderRect, m_layoutFrameSet.frameSet()->hasBorderColor() ? m_layoutFrameSet.resolveColor(CSSPropertyBorderLeftColor) : borderFillColor());
 
     // Now stroke the edges but only if we have enough room to paint both edges with a little
     // bit of the fill color showing through.
     if (borderRect.width() >= 3) {
-        context->fillRect(IntRect(borderRect.location(), IntSize(1, m_layoutFrameSet.size().height())), borderStartEdgeColor());
-        context->fillRect(IntRect(IntPoint(borderRect.maxX() - 1, borderRect.y()), IntSize(1, m_layoutFrameSet.size().height())), borderEndEdgeColor());
+        context->fillRect(IntRect(borderRect.location(), IntSize(1, borderRect.height())), borderStartEdgeColor());

[chrishtr, 2015/06/03 18:15:15]

Why the changes in this file?

[trchen, 2015/06/03 23:15:24]

There is an over-paint with column border. Without the fix, column borders will
stick into frames.

My CL revealed this bug because sub-frames no longer paint base background.
(which is incorrect when the main frame has background, and is redundant too,
painting unnecessary pixels.)

Comment added to the commit message.

+        context->fillRect(IntRect(IntPoint(borderRect.maxX() - 1, borderRect.y()), IntSize(1, borderRect.height())), borderEndEdgeColor());
     }
 }
 
 void FrameSetPainter::paintRowBorder(const PaintInfo& paintInfo, const IntRect& borderRect)
 {
     // FIXME: We should do something clever when borders from distinct framesets meet at a join.
 
     // Fill first.
     GraphicsContext* context = paintInfo.context;
     context->fillRect(borderRect, m_layoutFrameSet.frameSet()->hasBorderColor() ? m_layoutFrameSet.resolveColor(CSSPropertyBorderLeftColor) : borderFillColor());
 
     // Now stroke the edges but only if we have enough room to paint both edges with a little
     // bit of the fill color showing through.
     if (borderRect.height() >= 3) {
-        context->fillRect(IntRect(borderRect.location(), IntSize(m_layoutFrameSet.size().width(), 1)), borderStartEdgeColor());
-        context->fillRect(IntRect(IntPoint(borderRect.x(), borderRect.maxY() - 1), IntSize(m_layoutFrameSet.size().width(), 1)), borderEndEdgeColor());
+        context->fillRect(IntRect(borderRect.location(), IntSize(borderRect.width(), 1)), borderStartEdgeColor());
+        context->fillRect(IntRect(IntPoint(borderRect.x(), borderRect.maxY() - 1), IntSize(borderRect.width(), 1)), borderEndEdgeColor());
     }
 }
 
 void FrameSetPainter::paintBorders(const PaintInfo& paintInfo, const LayoutPoint& adjustedPaintOffset)
 {
     LayoutRect adjustedFrameRect(adjustedPaintOffset, m_layoutFrameSet.size());
     LayoutObjectDrawingRecorder recorder(*paintInfo.context, m_layoutFrameSet, paintInfo.phase, adjustedFrameRect);
     if (recorder.canUseCachedDrawing())
         return;
 
     LayoutObject* child = m_layoutFrameSet.firstChild();
     size_t rows = m_layoutFrameSet.rows().m_sizes.size();
     size_t cols = m_layoutFrameSet.columns().m_sizes.size();
     LayoutUnit borderThickness = m_layoutFrameSet.frameSet()->border();
     LayoutUnit yPos = 0;
     for (size_t r = 0; r < rows; r++) {
         LayoutUnit xPos = 0;
         for (size_t c = 0; c < cols; c++) {
             xPos += m_layoutFrameSet.columns().m_sizes[c];
             if (borderThickness && m_layoutFrameSet.columns().m_allowBorder[c + 1]) {
                 paintColumnBorder(paintInfo, pixelSnappedIntRect(
-                    LayoutRect(adjustedPaintOffset.x() + xPos, adjustedPaintOffset.y() + yPos, borderThickness, m_layoutFrameSet.size().height())));
+                    LayoutRect(adjustedPaintOffset.x() + xPos, adjustedPaintOffset.y() + yPos, borderThickness, m_layoutFrameSet.size().height() - yPos)));
                 xPos += borderThickness;
             }
             child = child->nextSibling();
             if (!child)
                 return;
         }
         yPos += m_layoutFrameSet.rows().m_sizes[r];
         if (borderThickness && m_layoutFrameSet.rows().m_allowBorder[r + 1]) {
             paintRowBorder(paintInfo, pixelSnappedIntRect(
                 LayoutRect(adjustedPaintOffset.x(), adjustedPaintOffset.y() + yPos, m_layoutFrameSet.size().width(), borderThickness)));
@@ skipping 28 matching lines @@
     LayoutObject* child = m_layoutFrameSet.firstChild();
     if (!child)
         return;
 
     LayoutPoint adjustedPaintOffset = paintOffset + m_layoutFrameSet.location();
     paintChildren(paintInfo, adjustedPaintOffset);
     paintBorders(paintInfo, adjustedPaintOffset);
 }
 
 } // namespace blink