void RenderFlowThread::pushFlowThreadLayoutState(const RenderObject& object)
{
if (const RenderBox* currentBoxDescendant = currentStatePusherRenderBox()) {
LayoutState* layoutState = currentBoxDescendant->view()->layoutState();
if (layoutState && layoutState->isPaginated()) {
ASSERT(layoutState->renderer() == currentBoxDescendant);
LayoutSize offsetDelta = layoutState->layoutOffset() - layoutState->pageOffset();
setOffsetFromLogicalTopOfFirstRegion(currentBoxDescendant, currentBoxDescendant->isHorizontalWritingMode() ? offsetDelta.height() : offsetDelta.width());
}
}
m_statePusherObjectsStack.add(&object);
}
void RenderMultiColumnFlowThread::computeLineGridPaginationOrigin(LayoutState& layoutState) const
{
if (!progressionIsInline())
return;
// We need to cache a line grid pagination origin so that we understand how to reset the line grid
// at the top of each column.
// Get the current line grid and offset.
const auto lineGrid = layoutState.lineGrid();
if (!lineGrid)
return;
// Get the hypothetical line box used to establish the grid.
auto lineGridBox = lineGrid->lineGridBox();
if (!lineGridBox)
return;
bool isHorizontalWritingMode = lineGrid->isHorizontalWritingMode();
LayoutUnit lineGridBlockOffset = isHorizontalWritingMode ? layoutState.lineGridOffset().height() : layoutState.lineGridOffset().width();
// Now determine our position on the grid. Our baseline needs to be adjusted to the nearest baseline multiple
// as established by the line box.
// FIXME: Need to handle crazy line-box-contain values that cause the root line box to not be considered. I assume
// the grid should honor line-box-contain.
LayoutUnit gridLineHeight = lineGridBox->lineBottomWithLeading() - lineGridBox->lineTopWithLeading();
if (!gridLineHeight)
return;
LayoutUnit firstLineTopWithLeading = lineGridBlockOffset + lineGridBox->lineTopWithLeading();
if (layoutState.isPaginated() && layoutState.pageLogicalHeight()) {
LayoutUnit pageLogicalTop = isHorizontalWritingMode ? layoutState.pageOffset().height() : layoutState.pageOffset().width();
if (pageLogicalTop > firstLineTopWithLeading) {
// Shift to the next highest line grid multiple past the page logical top. Cache the delta
// between this new value and the page logical top as the pagination origin.
LayoutUnit remainder = roundToInt(pageLogicalTop - firstLineTopWithLeading) % roundToInt(gridLineHeight);
LayoutUnit paginationDelta = gridLineHeight - remainder;
if (isHorizontalWritingMode)
layoutState.setLineGridPaginationOrigin(LayoutSize(layoutState.lineGridPaginationOrigin().width(), paginationDelta));
else
layoutState.setLineGridPaginationOrigin(LayoutSize(paginationDelta, layoutState.lineGridPaginationOrigin().height()));
}
}
}
LayoutUnit RenderFlowThread::offsetFromLogicalTopOfFirstRegion(const RenderBlock* currentBlock) const
{
// First check if we cached the offset for the block if it's an ancestor containing block of the box
// being currently laid out.
LayoutUnit offset;
if (cachedOffsetFromLogicalTopOfFirstRegion(currentBlock, offset))
return offset;
// If it's the current box being laid out, use the layout state.
const RenderBox* currentBoxDescendant = currentStatePusherRenderBox();
if (currentBlock == currentBoxDescendant) {
LayoutState* layoutState = view()->layoutState();
ASSERT(layoutState->renderer() == currentBlock);
ASSERT(layoutState && layoutState->isPaginated());
LayoutSize offsetDelta = layoutState->layoutOffset() - layoutState->pageOffset();
return currentBoxDescendant->isHorizontalWritingMode() ? offsetDelta.height() : offsetDelta.width();
}
// As a last resort, take the slow path.
LayoutRect blockRect(0, 0, currentBlock->width(), currentBlock->height());
while (currentBlock && !currentBlock->isRenderFlowThread()) {
RenderBlock* containerBlock = currentBlock->containingBlock();
ASSERT(containerBlock);
if (!containerBlock)
return 0;
LayoutPoint currentBlockLocation = currentBlock->location();
if (containerBlock->style()->writingMode() != currentBlock->style()->writingMode()) {
// We have to put the block rect in container coordinates
// and we have to take into account both the container and current block flipping modes
if (containerBlock->style()->isFlippedBlocksWritingMode()) {
if (containerBlock->isHorizontalWritingMode())
blockRect.setY(currentBlock->height() - blockRect.maxY());
else
blockRect.setX(currentBlock->width() - blockRect.maxX());
}
currentBlock->flipForWritingMode(blockRect);
}
blockRect.moveBy(currentBlockLocation);
currentBlock = containerBlock;
}
return currentBlock->isHorizontalWritingMode() ? blockRect.y() : blockRect.x();
}
