void RenderMultiColumnSet::prepareForLayout()
{
RenderBlockFlow* multicolBlock = toRenderBlockFlow(parent());
const RenderStyle& multicolStyle = multicolBlock->style();
// Set box logical top.
ASSERT(!previousSiblingBox() || !previousSiblingBox()->isRenderMultiColumnSet()); // FIXME: multiple set not implemented; need to examine previous set to calculate the correct logical top.
setLogicalTop(multicolBlock->borderAndPaddingBefore());
// Set box width.
updateLogicalWidth();
if (multicolBlock->multiColumnFlowThread()->requiresBalancing()) {
// Set maximum column height. We will not stretch beyond this.
m_maxColumnHeight = RenderFlowThread::maxLogicalHeight();
if (!multicolStyle.logicalHeight().isAuto()) {
m_maxColumnHeight = multicolBlock->computeContentLogicalHeight(multicolStyle.logicalHeight());
if (m_maxColumnHeight == -1)
m_maxColumnHeight = RenderFlowThread::maxLogicalHeight();
}
if (!multicolStyle.logicalMaxHeight().isUndefined()) {
LayoutUnit logicalMaxHeight = multicolBlock->computeContentLogicalHeight(multicolStyle.logicalMaxHeight());
if (logicalMaxHeight != -1 && m_maxColumnHeight > logicalMaxHeight)
m_maxColumnHeight = logicalMaxHeight;
}
m_maxColumnHeight = heightAdjustedForSetOffset(m_maxColumnHeight);
m_computedColumnHeight = 0; // Restart balancing.
} else
setAndConstrainColumnHeight(heightAdjustedForSetOffset(multicolBlock->multiColumnFlowThread()->columnHeightAvailable()));
clearForcedBreaks();
// Nuke previously stored minimum column height. Contents may have changed for all we know.
m_minimumColumnHeight = 0;
}
LayoutUnit RenderMultiColumnSet::calculateMaxColumnHeight() const
{
RenderBlockFlow* multicolBlock = multiColumnBlockFlow();
RenderStyle* multicolStyle = multicolBlock->style();
LayoutUnit availableHeight = multiColumnFlowThread()->columnHeightAvailable();
LayoutUnit maxColumnHeight = availableHeight ? availableHeight : RenderFlowThread::maxLogicalHeight();
if (!multicolStyle->logicalMaxHeight().isUndefined()) {
LayoutUnit logicalMaxHeight = multicolBlock->computeContentLogicalHeight(multicolStyle->logicalMaxHeight(), -1);
if (logicalMaxHeight != -1 && maxColumnHeight > logicalMaxHeight)
maxColumnHeight = logicalMaxHeight;
}
return heightAdjustedForSetOffset(maxColumnHeight);
}
void RenderMultiColumnSet::resetColumnHeight()
{
// Nuke previously stored minimum column height. Contents may have changed for all we know.
m_minimumColumnHeight = 0;
m_maxColumnHeight = calculateMaxColumnHeight();
LayoutUnit oldColumnHeight = pageLogicalHeight();
if (multiColumnFlowThread()->requiresBalancing())
m_columnHeight = 0;
else
setAndConstrainColumnHeight(heightAdjustedForSetOffset(multiColumnFlowThread()->columnHeightAvailable()));
if (pageLogicalHeight() != oldColumnHeight)
setChildNeedsLayout(MarkOnlyThis);
// Content runs are only needed in the initial layout pass, in order to find an initial column
// height, and should have been deleted afterwards. We're about to rebuild the content runs, so
// the list needs to be empty.
ASSERT(m_contentRuns.isEmpty());
}
