Move paint code from RenderMultiColumnSet to MultiColumnSetPainter.

Source/core/paint/MultiColumnSetPainter.cpp

Index: Source/core/paint/MultiColumnSetPainter.cpp
diff --git a/Source/core/paint/MultiColumnSetPainter.cpp b/Source/core/paint/MultiColumnSetPainter.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..3035051c813e6263f76f890598cad9b3719bcb89
--- /dev/null
+++ b/Source/core/paint/MultiColumnSetPainter.cpp
@@ -0,0 +1,88 @@
+// 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/MultiColumnSetPainter.h"
+
+#include "core/paint/BlockPainter.h"
+#include "core/paint/BoxPainter.h"
+#include "core/rendering/PaintInfo.h"
+#include "core/rendering/RenderMultiColumnSet.h"
+#include "platform/geometry/LayoutPoint.h"
+
+namespace blink {
+
+void MultiColumnSetPainter::paintObject(PaintInfo& paintInfo, const LayoutPoint& paintOffset)
+{
+    if (m_renderMultiColumnSet.style()->visibility() != VISIBLE)
+        return;
+
+    BlockPainter(m_renderMultiColumnSet).paintObject(paintInfo, paintOffset);
+
+    // FIXME: Right now we're only painting in the foreground phase.
+    // Columns should technically respect phases and allow for background/float/foreground overlap etc., just like
+    // RenderBlocks do. Note this is a pretty minor issue, since the old column implementation clipped columns
+    // anyway, thus making it impossible for them to overlap one another. It's also really unlikely that the columns
+    // would overlap another block.
+    if (!m_renderMultiColumnSet.flowThread() || !m_renderMultiColumnSet.isValid() || (paintInfo.phase != PaintPhaseForeground && paintInfo.phase != PaintPhaseSelection))
+        return;
+
+    paintColumnRules(paintInfo, paintOffset);
+}
+
+void MultiColumnSetPainter::paintColumnRules(PaintInfo& paintInfo, const LayoutPoint& paintOffset)
+{
+    if (m_renderMultiColumnSet.flowThread()->isRenderPagedFlowThread())
+        return;
+
+    RenderStyle* blockStyle = m_renderMultiColumnSet.multiColumnBlockFlow()->style();
+    const Color& ruleColor = m_renderMultiColumnSet.resolveColor(blockStyle, CSSPropertyWebkitColumnRuleColor);
+    bool ruleTransparent = blockStyle->columnRuleIsTransparent();
+    EBorderStyle ruleStyle = blockStyle->columnRuleStyle();
+    LayoutUnit ruleThickness = blockStyle->columnRuleWidth();
+    LayoutUnit colGap = m_renderMultiColumnSet.columnGap();
+    bool renderRule = ruleStyle > BHIDDEN && !ruleTransparent;
+    if (!renderRule)
+        return;
+
+    unsigned colCount = m_renderMultiColumnSet.actualColumnCount();
+    if (colCount <= 1)
+        return;
+
+    bool antialias = BoxPainter::shouldAntialiasLines(paintInfo.context);
+
+    bool leftToRight = m_renderMultiColumnSet.style()->isLeftToRightDirection();
+    LayoutUnit currLogicalLeftOffset = leftToRight ? LayoutUnit() : m_renderMultiColumnSet.contentLogicalWidth();
+    LayoutUnit ruleAdd = m_renderMultiColumnSet.borderAndPaddingLogicalLeft();
+    LayoutUnit ruleLogicalLeft = leftToRight ? LayoutUnit() : m_renderMultiColumnSet.contentLogicalWidth();
+    LayoutUnit inlineDirectionSize = m_renderMultiColumnSet.pageLogicalWidth();
+    BoxSide boxSide = m_renderMultiColumnSet.isHorizontalWritingMode()
+        ? leftToRight ? BSLeft : BSRight
+        : leftToRight ? BSTop : BSBottom;
+
+    for (unsigned i = 0; i < colCount; i++) {
+        // Move to the next position.
+        if (leftToRight) {
+            ruleLogicalLeft += inlineDirectionSize + colGap / 2;
+            currLogicalLeftOffset += inlineDirectionSize + colGap;
+        } else {
+            ruleLogicalLeft -= (inlineDirectionSize + colGap / 2);
+            currLogicalLeftOffset -= (inlineDirectionSize + colGap);
+        }
+
+        // Now paint the column rule.
+        if (i < colCount - 1) {
+            LayoutUnit ruleLeft = m_renderMultiColumnSet.isHorizontalWritingMode() ? paintOffset.x() + ruleLogicalLeft - ruleThickness / 2 + ruleAdd : paintOffset.x() + m_renderMultiColumnSet.borderLeft() + m_renderMultiColumnSet.paddingLeft();
+            LayoutUnit ruleRight = m_renderMultiColumnSet.isHorizontalWritingMode() ? ruleLeft + ruleThickness : ruleLeft + m_renderMultiColumnSet.contentWidth();
+            LayoutUnit ruleTop = m_renderMultiColumnSet.isHorizontalWritingMode() ? paintOffset.y() + m_renderMultiColumnSet.borderTop() + m_renderMultiColumnSet.paddingTop() : paintOffset.y() + ruleLogicalLeft - ruleThickness / 2 + ruleAdd;
+            LayoutUnit ruleBottom = m_renderMultiColumnSet.isHorizontalWritingMode() ? ruleTop + m_renderMultiColumnSet.contentHeight() : ruleTop + ruleThickness;
+            IntRect pixelSnappedRuleRect = pixelSnappedIntRectFromEdges(ruleLeft, ruleTop, ruleRight, ruleBottom);
+            ObjectPainter::drawLineForBoxSide(paintInfo.context, pixelSnappedRuleRect.x(), pixelSnappedRuleRect.y(), pixelSnappedRuleRect.maxX(), pixelSnappedRuleRect.maxY(), boxSide, ruleColor, ruleStyle, 0, 0, antialias);
+        }
+
+        ruleLogicalLeft = currLogicalLeftOffset;
+    }
+}
+
+} // namespace blink