third_party/WebKit/Source/core/paint/MultiColumnSetPainter.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 "core/paint/MultiColumnSetPainter.h"

#include "core/layout/LayoutMultiColumnSet.h"
#include "core/paint/BlockPainter.h"
#include "core/paint/BoxPainter.h"
#include "core/paint/LayoutObjectDrawingRecorder.h"
#include "core/paint/ObjectPainter.h"
#include "core/paint/PaintInfo.h"
#include "platform/geometry/LayoutPoint.h"

namespace blink {

void MultiColumnSetPainter::paintObject(const PaintInfo& paintInfo, const LayoutPoint& paintOffset)
{
    if (m_layoutMultiColumnSet.style()->visibility() != EVisibility::Visible)
        return;

    BlockPainter(m_layoutMultiColumnSet).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
    // LayoutBlocks 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_layoutMultiColumnSet.flowThread() || (paintInfo.phase != PaintPhaseForeground && paintInfo.phase != PaintPhaseSelection))
        return;

    paintColumnRules(paintInfo, paintOffset);
}

void MultiColumnSetPainter::paintColumnRules(const PaintInfo& paintInfo, const LayoutPoint& paintOffset)
{
    Vector<LayoutRect> columnRuleBounds;
    if (!m_layoutMultiColumnSet.computeColumnRuleBounds(paintOffset, columnRuleBounds))
        return;

    if (LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(paintInfo.context, m_layoutMultiColumnSet, DisplayItem::kColumnRules))
        return;

    LayoutRect paintRect = m_layoutMultiColumnSet.visualOverflowRect();
    paintRect.moveBy(paintOffset);
    LayoutObjectDrawingRecorder drawingRecorder(paintInfo.context, m_layoutMultiColumnSet, DisplayItem::kColumnRules, paintRect);

    const ComputedStyle& blockStyle = m_layoutMultiColumnSet.multiColumnBlockFlow()->styleRef();
    EBorderStyle ruleStyle = blockStyle.columnRuleStyle();
    bool leftToRight = m_layoutMultiColumnSet.style()->isLeftToRightDirection();
    BoxSide boxSide = m_layoutMultiColumnSet.isHorizontalWritingMode()
        ? leftToRight ? BSLeft : BSRight
        : leftToRight ? BSTop : BSBottom;
    const Color& ruleColor = m_layoutMultiColumnSet.resolveColor(blockStyle, CSSPropertyColumnRuleColor);

    for (auto& bound : columnRuleBounds) {
        IntRect pixelSnappedRuleRect = pixelSnappedIntRect(bound);
        ObjectPainter::drawLineForBoxSide(paintInfo.context, pixelSnappedRuleRect.x(), pixelSnappedRuleRect.y(), pixelSnappedRuleRect.maxX(), pixelSnappedRuleRect.maxY(), boxSide, ruleColor, ruleStyle, 0, 0, true);
    }
}

} // namespace blink