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/*
* Copyright (C) 2017-2020 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "LayoutIntegrationPagination.h"
#include "FontCascade.h"
#include "InlineIteratorLineBox.h"
#include "RenderBlockFlow.h"
#include "RenderStyleInlines.h"
#include "RenderTableCell.h"
namespace WebCore {
namespace LayoutIntegration {
Vector<LineAdjustment> computeAdjustmentsForPagination(const InlineContent& inlineContent, RenderBlockFlow& flow)
{
auto lineCount = inlineContent.displayContent().lines.size();
Vector<LineAdjustment> adjustments { lineCount };
std::optional<size_t> previousPageBreakIndex;
size_t widows = flow.style().hasAutoWidows() ? 0 : flow.style().widows();
size_t orphans = flow.style().orphans();
auto accumulatedOffset = 0_lu;
for (size_t lineIndex = 0; lineIndex < lineCount;) {
auto line = InlineIterator::lineBoxFor(inlineContent, lineIndex);
auto adjustment = flow.computeLineAdjustmentForPagination(line, accumulatedOffset);
if (adjustment.isFirstAfterPageBreak) {
auto remainingLines = lineCount - lineIndex;
// Ignore the last line if it is completely empty.
if (inlineContent.displayContent().lines.last().lineBoxRect().isEmpty())
remainingLines--;
// See if there are enough lines left to meet the widow requirement.
if (remainingLines < widows && !flow.didBreakAtLineToAvoidWidow()) {
auto previousPageLineCount = lineIndex - previousPageBreakIndex.value_or(0);
auto neededLines = widows - remainingLines;
auto availableLines = previousPageLineCount > orphans ? previousPageLineCount - orphans : 0;
auto breakIndex = lineIndex - std::min(neededLines, availableLines);
// Set the widow break and recompute the adjustments starting from that line.
flow.setBreakAtLineToAvoidWidow(breakIndex + 1);
lineIndex = breakIndex;
continue;
}
previousPageBreakIndex = lineIndex;
}
accumulatedOffset += adjustment.strut;
adjustments[lineIndex] = LineAdjustment { accumulatedOffset, adjustment.isFirstAfterPageBreak };
++lineIndex;
}
flow.clearDidBreakAtLineToAvoidWidow();
if (!previousPageBreakIndex)
return { };
return adjustments;
}
void adjustLinePositionsForPagination(InlineContent& inlineContent, const Vector<LineAdjustment>& adjustments)
{
if (adjustments.isEmpty())
return;
inlineContent.isPaginated = true;
auto& displayContent = inlineContent.displayContent();
for (size_t lineIndex = 0; lineIndex < displayContent.lines.size(); ++lineIndex) {
auto& line = displayContent.lines[lineIndex];
auto& adjustment = adjustments[lineIndex];
line.moveVertically(adjustment.offset);
if (adjustment.isFirstAfterPageBreak)
line.setIsFirstAfterPageBreak();
}
for (auto& box : displayContent.boxes)
box.moveVertically(adjustments[box.lineIndex()].offset);
inlineContent.firstLinePaginationOffset = adjustments[0].offset;
}
}
}
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