зеркало из https://github.com/mozilla/gecko-dev.git
441 строка
18 KiB
C++
441 строка
18 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/* class that a parent frame uses to reflow a block frame */
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#include "nsBlockReflowContext.h"
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#include "BlockReflowState.h"
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#include "nsFloatManager.h"
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#include "nsColumnSetFrame.h"
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#include "nsContainerFrame.h"
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#include "nsBlockFrame.h"
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#include "nsLineBox.h"
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#include "nsLayoutUtils.h"
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using namespace mozilla;
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#ifdef DEBUG
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# include "nsBlockDebugFlags.h" // For NOISY_BLOCK_DIR_MARGINS
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#endif
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nsBlockReflowContext::nsBlockReflowContext(nsPresContext* aPresContext,
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const ReflowInput& aParentRI)
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: mPresContext(aPresContext),
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mOuterReflowInput(aParentRI),
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mFrame(nullptr),
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mSpace(aParentRI.GetWritingMode()),
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mICoord(0),
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mBCoord(0),
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mMetrics(aParentRI) {}
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static nsIFrame* DescendIntoBlockLevelFrame(nsIFrame* aFrame) {
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LayoutFrameType type = aFrame->Type();
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if (type == LayoutFrameType::ColumnSet) {
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static_cast<nsColumnSetFrame*>(aFrame)->DrainOverflowColumns();
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nsIFrame* child = aFrame->PrincipalChildList().FirstChild();
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if (child) {
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return DescendIntoBlockLevelFrame(child);
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}
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}
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return aFrame;
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}
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bool nsBlockReflowContext::ComputeCollapsedBStartMargin(
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const ReflowInput& aRI, nsCollapsingMargin* aMargin,
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nsIFrame* aClearanceFrame, bool* aMayNeedRetry, bool* aBlockIsEmpty) {
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WritingMode wm = aRI.GetWritingMode();
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WritingMode parentWM = mMetrics.GetWritingMode();
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// Include block-start element of frame's margin
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aMargin->Include(aRI.ComputedLogicalMargin(parentWM).BStart(parentWM));
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// The inclusion of the block-end margin when empty is done by the caller
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// since it doesn't need to be done by the top-level (non-recursive)
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// caller.
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#ifdef NOISY_BLOCK_DIR_MARGINS
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aRI.mFrame->ListTag(stdout);
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printf(": %d => %d\n", aRI.ComputedLogicalMargin(wm).BStart(wm),
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aMargin->get());
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#endif
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bool dirtiedLine = false;
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bool setBlockIsEmpty = false;
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// Calculate the frame's generational block-start-margin from its child
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// blocks. Note that if the frame has a non-zero block-start-border or
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// block-start-padding then this step is skipped because it will be a margin
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// root. It is also skipped if the frame is a margin root for other
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// reasons.
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nsIFrame* frame = DescendIntoBlockLevelFrame(aRI.mFrame);
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nsPresContext* prescontext = frame->PresContext();
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nsBlockFrame* block = nullptr;
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if (0 == aRI.ComputedLogicalBorderPadding(wm).BStart(wm)) {
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block = do_QueryFrame(frame);
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if (block) {
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bool bStartMarginRoot, unused;
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block->IsMarginRoot(&bStartMarginRoot, &unused);
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if (bStartMarginRoot) {
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block = nullptr;
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}
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}
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}
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// iterate not just through the lines of 'block' but also its
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// overflow lines and the normal and overflow lines of its next in
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// flows. Note that this will traverse some frames more than once:
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// for example, if A contains B and A->nextinflow contains
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// B->nextinflow, we'll traverse B->nextinflow twice. But this is
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// OK because our traversal is idempotent.
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for (; block; block = static_cast<nsBlockFrame*>(block->GetNextInFlow())) {
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for (int overflowLines = 0; overflowLines <= 1; ++overflowLines) {
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nsBlockFrame::LineIterator line;
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nsBlockFrame::LineIterator line_end;
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bool anyLines = true;
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if (overflowLines) {
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nsBlockFrame::FrameLines* frames = block->GetOverflowLines();
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nsLineList* lines = frames ? &frames->mLines : nullptr;
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if (!lines) {
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anyLines = false;
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} else {
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line = lines->begin();
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line_end = lines->end();
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}
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} else {
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line = block->LinesBegin();
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line_end = block->LinesEnd();
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}
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for (; anyLines && line != line_end; ++line) {
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if (!aClearanceFrame && line->HasClearance()) {
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// If we don't have a clearance frame, then we're computing
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// the collapsed margin in the first pass, assuming that all
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// lines have no clearance. So clear their clearance flags.
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line->ClearHasClearance();
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line->MarkDirty();
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dirtiedLine = true;
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}
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bool isEmpty;
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if (line->IsInline()) {
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isEmpty = line->IsEmpty();
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} else {
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nsIFrame* kid = line->mFirstChild;
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if (kid == aClearanceFrame) {
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line->SetHasClearance();
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line->MarkDirty();
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dirtiedLine = true;
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if (!setBlockIsEmpty && aBlockIsEmpty) {
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setBlockIsEmpty = true;
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*aBlockIsEmpty = false;
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}
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goto done;
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}
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// Here is where we recur. Now that we have determined that a
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// generational collapse is required we need to compute the
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// child blocks margin and so in so that we can look into
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// it. For its margins to be computed we need to have a reflow
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// input for it.
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// We may have to construct an extra reflow input here if
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// we drilled down through a block wrapper. At the moment
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// we can only drill down one level so we only have to support
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// one extra reflow input.
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const ReflowInput* outerReflowInput = &aRI;
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if (frame != aRI.mFrame) {
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NS_ASSERTION(frame->GetParent() == aRI.mFrame,
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"Can only drill through one level of block wrapper");
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LogicalSize availSpace = aRI.ComputedSize(frame->GetWritingMode());
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outerReflowInput =
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new ReflowInput(prescontext, aRI, frame, availSpace);
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}
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{
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LogicalSize availSpace =
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outerReflowInput->ComputedSize(kid->GetWritingMode());
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ReflowInput innerReflowInput(prescontext, *outerReflowInput, kid,
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availSpace);
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// Record that we're being optimistic by assuming the kid
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// has no clearance
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if (kid->StyleDisplay()->mClear != StyleClear::None ||
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!nsBlockFrame::BlockCanIntersectFloats(kid)) {
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*aMayNeedRetry = true;
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}
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if (ComputeCollapsedBStartMargin(innerReflowInput, aMargin,
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aClearanceFrame, aMayNeedRetry,
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&isEmpty)) {
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line->MarkDirty();
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dirtiedLine = true;
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}
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if (isEmpty) {
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LogicalMargin innerMargin =
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innerReflowInput.ComputedLogicalMargin(parentWM);
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aMargin->Include(innerMargin.BEnd(parentWM));
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}
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}
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if (outerReflowInput != &aRI) {
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delete const_cast<ReflowInput*>(outerReflowInput);
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}
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}
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if (!isEmpty) {
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if (!setBlockIsEmpty && aBlockIsEmpty) {
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setBlockIsEmpty = true;
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*aBlockIsEmpty = false;
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}
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goto done;
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}
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}
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if (!setBlockIsEmpty && aBlockIsEmpty) {
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// The first time we reach here is when this is the first block
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// and we have processed all its normal lines.
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setBlockIsEmpty = true;
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// All lines are empty, or we wouldn't be here!
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*aBlockIsEmpty = aRI.mFrame->IsSelfEmpty();
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}
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}
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}
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done:
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if (!setBlockIsEmpty && aBlockIsEmpty) {
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*aBlockIsEmpty = aRI.mFrame->IsEmpty();
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}
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#ifdef NOISY_BLOCK_DIR_MARGINS
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aRI.mFrame->ListTag(stdout);
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printf(": => %d\n", aMargin->get());
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#endif
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return dirtiedLine;
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}
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void nsBlockReflowContext::ReflowBlock(const LogicalRect& aSpace,
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bool aApplyBStartMargin,
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nsCollapsingMargin& aPrevMargin,
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nscoord aClearance, nsLineBox* aLine,
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ReflowInput& aFrameRI,
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nsReflowStatus& aFrameReflowStatus,
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BlockReflowState& aState) {
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mFrame = aFrameRI.mFrame;
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mWritingMode = aState.mReflowInput.GetWritingMode();
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mContainerSize = aState.ContainerSize();
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mSpace = aSpace;
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if (!aState.IsAdjacentWithBStart()) {
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aFrameRI.mFlags.mIsTopOfPage = false; // make sure this is cleared
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}
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if (aApplyBStartMargin) {
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mBStartMargin = aPrevMargin;
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#ifdef NOISY_BLOCK_DIR_MARGINS
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mOuterReflowInput.mFrame->ListTag(stdout);
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printf(": reflowing ");
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mFrame->ListTag(stdout);
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printf(" margin => %d, clearance => %d\n", mBStartMargin.get(), aClearance);
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#endif
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// Adjust the available size if it's constrained so that the
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// child frame doesn't think it can reflow into its margin area.
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if (mWritingMode.IsOrthogonalTo(mFrame->GetWritingMode())) {
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if (NS_UNCONSTRAINEDSIZE != aFrameRI.AvailableISize()) {
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aFrameRI.SetAvailableISize(std::max(
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0, aFrameRI.AvailableISize() - mBStartMargin.get() - aClearance));
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}
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} else {
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if (NS_UNCONSTRAINEDSIZE != aFrameRI.AvailableBSize()) {
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aFrameRI.SetAvailableBSize(std::max(
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0, aFrameRI.AvailableBSize() - mBStartMargin.get() - aClearance));
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}
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}
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} else {
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// nsBlockFrame::ReflowBlock might call us multiple times with
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// *different* values of aApplyBStartMargin.
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mBStartMargin.Zero();
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}
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nscoord tI = 0, tB = 0;
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// The values of x and y do not matter for floats, so don't bother
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// calculating them. Floats are guaranteed to have their own float
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// manager, so tI and tB don't matter. mICoord and mBCoord don't
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// matter becacuse they are only used in PlaceBlock, which is not used
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// for floats.
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if (aLine) {
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// Compute inline/block coordinate where reflow will begin. Use the
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// rules from 10.3.3 to determine what to apply. At this point in the
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// reflow auto inline-start/end margins will have a zero value.
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LogicalMargin usedMargin = aFrameRI.ComputedLogicalMargin(mWritingMode);
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mICoord = mSpace.IStart(mWritingMode) + usedMargin.IStart(mWritingMode);
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mBCoord = mSpace.BStart(mWritingMode) + mBStartMargin.get() + aClearance;
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LogicalRect space(
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mWritingMode, mICoord, mBCoord,
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mSpace.ISize(mWritingMode) - usedMargin.IStartEnd(mWritingMode),
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mSpace.BSize(mWritingMode) - usedMargin.BStartEnd(mWritingMode));
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tI = space.LineLeft(mWritingMode, mContainerSize);
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tB = mBCoord;
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if (!mFrame->HasAnyStateBits(NS_BLOCK_BFC_STATE_BITS)) {
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aFrameRI.mBlockDelta =
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mOuterReflowInput.mBlockDelta + mBCoord - aLine->BStart();
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}
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}
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#ifdef DEBUG
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mMetrics.ISize(mWritingMode) = nscoord(0xdeadbeef);
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mMetrics.BSize(mWritingMode) = nscoord(0xdeadbeef);
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#endif
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mOuterReflowInput.mFloatManager->Translate(tI, tB);
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mFrame->Reflow(mPresContext, mMetrics, aFrameRI, aFrameReflowStatus);
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mOuterReflowInput.mFloatManager->Translate(-tI, -tB);
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#ifdef DEBUG
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if (!aFrameReflowStatus.IsInlineBreakBefore()) {
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if ((ABSURD_SIZE(mMetrics.ISize(mWritingMode)) ||
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ABSURD_SIZE(mMetrics.BSize(mWritingMode))) &&
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!mFrame->GetParent()->IsAbsurdSizeAssertSuppressed()) {
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printf("nsBlockReflowContext: ");
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mFrame->ListTag(stdout);
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printf(" metrics=%d,%d!\n", mMetrics.ISize(mWritingMode),
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mMetrics.BSize(mWritingMode));
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}
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if ((mMetrics.ISize(mWritingMode) == nscoord(0xdeadbeef)) ||
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(mMetrics.BSize(mWritingMode) == nscoord(0xdeadbeef))) {
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printf("nsBlockReflowContext: ");
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mFrame->ListTag(stdout);
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printf(" didn't set i/b %d,%d!\n", mMetrics.ISize(mWritingMode),
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mMetrics.BSize(mWritingMode));
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}
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}
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#endif
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if (!mFrame->HasOverflowAreas()) {
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mMetrics.SetOverflowAreasToDesiredBounds();
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}
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if (!aFrameReflowStatus.IsInlineBreakBefore() &&
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!aFrameRI.WillReflowAgainForClearance() &&
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aFrameReflowStatus.IsFullyComplete()) {
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// If mFrame is fully-complete and has a next-in-flow, we need to delete
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// them now. Do not do this when a break-before is signaled or when a
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// clearance frame is discovered in mFrame's subtree because mFrame is going
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// to get reflowed again (whether the frame is (in)complete is undefined in
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// that case anyway).
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if (nsIFrame* kidNextInFlow = mFrame->GetNextInFlow()) {
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// Remove all of the childs next-in-flows. Make sure that we ask
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// the right parent to do the removal (it's possible that the
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// parent is not this because we are executing pullup code).
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// Floats will eventually be removed via nsBlockFrame::RemoveFloat
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// which detaches the placeholder from the float.
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nsOverflowContinuationTracker::AutoFinish fini(aState.mOverflowTracker,
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mFrame);
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nsIFrame::DestroyContext context(mPresContext->PresShell());
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kidNextInFlow->GetParent()->DeleteNextInFlowChild(context, kidNextInFlow,
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true);
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}
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}
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}
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/**
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* Attempt to place the block frame within the available space. If
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* it fits, apply inline-dir ("horizontal") positioning (CSS 10.3.3),
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* collapse margins (CSS2 8.3.1). Also apply relative positioning.
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*/
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bool nsBlockReflowContext::PlaceBlock(const ReflowInput& aReflowInput,
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bool aForceFit, nsLineBox* aLine,
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nsCollapsingMargin& aBEndMarginResult,
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OverflowAreas& aOverflowAreas,
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const nsReflowStatus& aReflowStatus) {
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// Compute collapsed block-end margin value.
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WritingMode parentWM = mMetrics.GetWritingMode();
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// Don't apply the block-end margin if the block has a *later* sibling across
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// column-span split.
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if (aReflowStatus.IsComplete() && !mFrame->HasColumnSpanSiblings()) {
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aBEndMarginResult = mMetrics.mCarriedOutBEndMargin;
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aBEndMarginResult.Include(
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aReflowInput.ComputedLogicalMargin(parentWM).BEnd(parentWM));
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} else {
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// The used block-end-margin is set to zero before a break.
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aBEndMarginResult.Zero();
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}
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nscoord backupContainingBlockAdvance = 0;
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// Check whether the block's block-end margin collapses with its block-start
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// margin. See CSS 2.1 section 8.3.1; those rules seem to match
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// nsBlockFrame::IsEmpty(). Any such block must have zero block-size so
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// check that first. Note that a block can have clearance and still
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// have adjoining block-start/end margins, because the clearance goes
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// above the block-start margin.
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// Mark the frame as non-dirty; it has been reflowed (or we wouldn't
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// be here), and we don't want to assert in CachedIsEmpty()
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mFrame->RemoveStateBits(NS_FRAME_IS_DIRTY);
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bool empty = 0 == mMetrics.BSize(parentWM) && aLine->CachedIsEmpty();
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if (empty) {
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// Collapse the block-end margin with the block-start margin that was
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// already applied.
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aBEndMarginResult.Include(mBStartMargin);
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#ifdef NOISY_BLOCK_DIR_MARGINS
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printf(" ");
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mOuterReflowInput.mFrame->ListTag(stdout);
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printf(": ");
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mFrame->ListTag(stdout);
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printf(
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" -- collapsing block start & end margin together; BStart=%d "
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"spaceBStart=%d\n",
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mBCoord, mSpace.BStart(mWritingMode));
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#endif
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// Section 8.3.1 of CSS 2.1 says that blocks with adjoining
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// "top/bottom" (i.e. block-start/end) margins whose top margin collapses
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// with their parent's top margin should have their top border-edge at the
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// top border-edge of their parent. We actually don't have to do
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// anything special to make this happen. In that situation,
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// nsBlockFrame::ShouldApplyBStartMargin will have returned false,
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// and mBStartMargin and aClearance will have been zero in
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// ReflowBlock.
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// If we did apply our block-start margin, but now we're collapsing it
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// into the block-end margin, we need to back up the containing
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// block's bCoord-advance by our block-start margin so that it doesn't get
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// counted twice. Note that here we're allowing the line's bounds
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// to become different from the block's position; we do this
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// because the containing block will place the next line at the
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// line's BEnd, and it must place the next line at a different
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// point from where this empty block will be.
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backupContainingBlockAdvance = mBStartMargin.get();
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}
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// See if the frame fit. If it's the first frame or empty then it
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// always fits. If the block-size is unconstrained then it always fits,
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// even if there's some sort of integer overflow that makes bCoord +
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// mMetrics.BSize() appear to go beyond the available block size.
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if (!empty && !aForceFit &&
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mSpace.BSize(mWritingMode) != NS_UNCONSTRAINEDSIZE) {
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nscoord bEnd =
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mBCoord - backupContainingBlockAdvance + mMetrics.BSize(mWritingMode);
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if (bEnd > mSpace.BEnd(mWritingMode)) {
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// didn't fit, we must acquit.
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mFrame->DidReflow(mPresContext, &aReflowInput);
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return false;
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}
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}
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aLine->SetBounds(mWritingMode, mICoord,
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mBCoord - backupContainingBlockAdvance,
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mMetrics.ISize(mWritingMode), mMetrics.BSize(mWritingMode),
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mContainerSize);
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// Now place the frame and complete the reflow process
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nsContainerFrame::FinishReflowChild(
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mFrame, mPresContext, mMetrics, &aReflowInput, mWritingMode,
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LogicalPoint(mWritingMode, mICoord, mBCoord), mContainerSize,
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nsIFrame::ReflowChildFlags::ApplyRelativePositioning);
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aOverflowAreas = mMetrics.mOverflowAreas + mFrame->GetPosition();
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return true;
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}
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