/**
* Attempt to place the block frame within the available space. If
* it fits, apply horizontal positioning (CSS 10.3.3), collapse
* margins (CSS2 8.3.1). Also apply relative positioning.
*/
bool
nsBlockReflowContext::PlaceBlock(const nsHTMLReflowState& aReflowState,
bool aForceFit,
nsLineBox* aLine,
nsCollapsingMargin& aBottomMarginResult,
nsRect& aInFlowBounds,
nsOverflowAreas& aOverflowAreas,
nsReflowStatus aReflowStatus)
{
// Compute collapsed bottom margin value.
if (NS_FRAME_IS_COMPLETE(aReflowStatus)) {
aBottomMarginResult = mMetrics.mCarriedOutBottomMargin;
aBottomMarginResult.Include(aReflowState.ComputedPhysicalMargin().bottom);
} else {
// The used bottom-margin is set to zero above a break.
aBottomMarginResult.Zero();
}
nsPoint position(mX, mY);
nscoord backupContainingBlockAdvance = 0;
// Check whether the block's bottom margin collapses with its top
// margin. See CSS 2.1 section 8.3.1; those rules seem to match
// nsBlockFrame::IsEmpty(). Any such block must have zero height so
// check that first. Note that a block can have clearance and still
// have adjoining top/bottom margins, because the clearance goes
// above the top margin.
// Mark the frame as non-dirty; it has been reflowed (or we wouldn't
// be here), and we don't want to assert in CachedIsEmpty()
mFrame->RemoveStateBits(NS_FRAME_IS_DIRTY);
bool empty = 0 == mMetrics.Height() && aLine->CachedIsEmpty();
if (empty) {
// Collapse the bottom margin with the top margin that was already
// applied.
aBottomMarginResult.Include(mTopMargin);
#ifdef NOISY_VERTICAL_MARGINS
printf(" ");
nsFrame::ListTag(stdout, mOuterReflowState.frame);
printf(": ");
nsFrame::ListTag(stdout, mFrame);
printf(" -- collapsing top & bottom margin together; y=%d spaceY=%d\n",
position.y, mSpace.y);
#endif
// Section 8.3.1 of CSS 2.1 says that blocks with adjoining
// top/bottom margins whose top margin collapses with their
// parent's top margin should have their top border-edge at the
// top border-edge of their parent. We actually don't have to do
// anything special to make this happen. In that situation,
// nsBlockFrame::ShouldApplyTopMargin will have returned false,
// and mTopMargin and aClearance will have been zero in
// ReflowBlock.
// If we did apply our top margin, but now we're collapsing it
// into the bottom margin, we need to back up the containing
// block's y-advance by our top margin so that it doesn't get
// counted twice. Note that here we're allowing the line's bounds
// to become different from the block's position; we do this
// because the containing block will place the next line at the
// line's YMost, and it must place the next line at a different
// point from where this empty block will be.
backupContainingBlockAdvance = mTopMargin.get();
}
// See if the frame fit. If it's the first frame or empty then it
// always fits. If the height is unconstrained then it always fits,
// even if there's some sort of integer overflow that makes y +
// mMetrics.Height() appear to go beyond the available height.
if (!empty && !aForceFit && mSpace.height != NS_UNCONSTRAINEDSIZE) {
nscoord yMost = position.y - backupContainingBlockAdvance + mMetrics.Height();
if (yMost > mSpace.YMost()) {
// didn't fit, we must acquit.
mFrame->DidReflow(mPresContext, &aReflowState, nsDidReflowStatus::FINISHED);
return false;
}
}
aInFlowBounds = nsRect(position.x, position.y - backupContainingBlockAdvance,
mMetrics.Width(), mMetrics.Height());
aReflowState.ApplyRelativePositioning(&position);
// Now place the frame and complete the reflow process
nsContainerFrame::FinishReflowChild(mFrame, mPresContext, mMetrics,
&aReflowState, position.x, position.y, 0);
aOverflowAreas = mMetrics.mOverflowAreas + position;
return true;
}
bool
nsBlockReflowContext::ComputeCollapsedTopMargin(const nsHTMLReflowState& aRS,
nsCollapsingMargin* aMargin, nsIFrame* aClearanceFrame,
bool* aMayNeedRetry, bool* aBlockIsEmpty)
{
// Include frame's top margin
aMargin->Include(aRS.ComputedPhysicalMargin().top);
// The inclusion of the bottom margin when empty is done by the caller
// since it doesn't need to be done by the top-level (non-recursive)
// caller.
#ifdef NOISY_VERTICAL_MARGINS
nsFrame::ListTag(stdout, aRS.frame);
printf(": %d => %d\n", aRS.ComputedPhysicalMargin().top, aMargin->get());
#endif
bool dirtiedLine = false;
bool setBlockIsEmpty = false;
// Calculate the frame's generational top-margin from its child
// blocks. Note that if the frame has a non-zero top-border or
// top-padding then this step is skipped because it will be a margin
// root. It is also skipped if the frame is a margin root for other
// reasons.
nsIFrame* frame = DescendIntoBlockLevelFrame(aRS.frame);
nsPresContext* prescontext = frame->PresContext();
nsBlockFrame* block = nullptr;
if (0 == aRS.ComputedPhysicalBorderPadding().top) {
block = nsLayoutUtils::GetAsBlock(frame);
if (block) {
bool topMarginRoot, unused;
block->IsMarginRoot(&topMarginRoot, &unused);
if (topMarginRoot) {
block = nullptr;
}
}
}
// iterate not just through the lines of 'block' but also its
// overflow lines and the normal and overflow lines of its next in
// flows. Note that this will traverse some frames more than once:
// for example, if A contains B and A->nextinflow contains
// B->nextinflow, we'll traverse B->nextinflow twice. But this is
// OK because our traversal is idempotent.
for ( ;block; block = static_cast<nsBlockFrame*>(block->GetNextInFlow())) {
for (int overflowLines = 0; overflowLines <= 1; ++overflowLines) {
nsBlockFrame::line_iterator line;
nsBlockFrame::line_iterator line_end;
bool anyLines = true;
if (overflowLines) {
nsBlockFrame::FrameLines* frames = block->GetOverflowLines();
nsLineList* lines = frames ? &frames->mLines : nullptr;
if (!lines) {
anyLines = false;
} else {
line = lines->begin();
line_end = lines->end();
}
} else {
line = block->begin_lines();
line_end = block->end_lines();
}
for (; anyLines && line != line_end; ++line) {
if (!aClearanceFrame && line->HasClearance()) {
// If we don't have a clearance frame, then we're computing
// the collapsed margin in the first pass, assuming that all
// lines have no clearance. So clear their clearance flags.
line->ClearHasClearance();
line->MarkDirty();
dirtiedLine = true;
}
bool isEmpty;
if (line->IsInline()) {
isEmpty = line->IsEmpty();
} else {
nsIFrame* kid = line->mFirstChild;
if (kid == aClearanceFrame) {
line->SetHasClearance();
line->MarkDirty();
dirtiedLine = true;
goto done;
}
// Here is where we recur. Now that we have determined that a
// generational collapse is required we need to compute the
// child blocks margin and so in so that we can look into
// it. For its margins to be computed we need to have a reflow
// state for it.
// We may have to construct an extra reflow state here if
// we drilled down through a block wrapper. At the moment
// we can only drill down one level so we only have to support
// one extra reflow state.
const nsHTMLReflowState* outerReflowState = &aRS;
if (frame != aRS.frame) {
NS_ASSERTION(frame->GetParent() == aRS.frame,
"Can only drill through one level of block wrapper");
nsSize availSpace(aRS.ComputedWidth(), aRS.ComputedHeight());
outerReflowState = new nsHTMLReflowState(prescontext,
aRS, frame, availSpace);
}
{
nsSize availSpace(outerReflowState->ComputedWidth(),
outerReflowState->ComputedHeight());
nsHTMLReflowState innerReflowState(prescontext,
*outerReflowState, kid,
availSpace);
// Record that we're being optimistic by assuming the kid
// has no clearance
if (kid->StyleDisplay()->mBreakType != NS_STYLE_CLEAR_NONE) {
*aMayNeedRetry = true;
}
if (ComputeCollapsedTopMargin(innerReflowState, aMargin, aClearanceFrame, aMayNeedRetry, &isEmpty)) {
line->MarkDirty();
dirtiedLine = true;
}
if (isEmpty)
aMargin->Include(innerReflowState.ComputedPhysicalMargin().bottom);
}
if (outerReflowState != &aRS) {
delete const_cast<nsHTMLReflowState*>(outerReflowState);
}
}
if (!isEmpty) {
if (!setBlockIsEmpty && aBlockIsEmpty) {
setBlockIsEmpty = true;
*aBlockIsEmpty = false;
}
goto done;
}
}
if (!setBlockIsEmpty && aBlockIsEmpty) {
// The first time we reach here is when this is the first block
// and we have processed all its normal lines.
setBlockIsEmpty = true;
// All lines are empty, or we wouldn't be here!
*aBlockIsEmpty = aRS.frame->IsSelfEmpty();
}
}
}
done:
if (!setBlockIsEmpty && aBlockIsEmpty) {
*aBlockIsEmpty = aRS.frame->IsEmpty();
}
#ifdef NOISY_VERTICAL_MARGINS
nsFrame::ListTag(stdout, aRS.frame);
printf(": => %d\n", aMargin->get());
#endif
return dirtiedLine;
}
nsresult
nsBlockReflowContext::ReflowBlock(const nsRect& aSpace,
bool aApplyTopMargin,
nsCollapsingMargin& aPrevMargin,
nscoord aClearance,
bool aIsAdjacentWithTop,
nsLineBox* aLine,
nsHTMLReflowState& aFrameRS,
nsReflowStatus& aFrameReflowStatus,
nsBlockReflowState& aState)
{
nsresult rv = NS_OK;
mFrame = aFrameRS.frame;
mSpace = aSpace;
if (!aIsAdjacentWithTop) {
aFrameRS.mFlags.mIsTopOfPage = false; // make sure this is cleared
}
if (aApplyTopMargin) {
mTopMargin = aPrevMargin;
#ifdef NOISY_VERTICAL_MARGINS
nsFrame::ListTag(stdout, mOuterReflowState.frame);
printf(": reflowing ");
nsFrame::ListTag(stdout, mFrame);
printf(" margin => %d, clearance => %d\n", mTopMargin.get(), aClearance);
#endif
// Adjust the available height if its constrained so that the
// child frame doesn't think it can reflow into its margin area.
if (NS_UNCONSTRAINEDSIZE != aFrameRS.AvailableHeight()) {
aFrameRS.AvailableHeight() -= mTopMargin.get() + aClearance;
}
}
nscoord tx = 0, ty = 0;
// The values of x and y do not matter for floats, so don't bother calculating
// them. Floats are guaranteed to have their own float manager, so tx and ty
// don't matter. mX and mY don't matter becacuse they are only used in
// PlaceBlock, which is not used for floats.
if (aLine) {
// Compute x/y coordinate where reflow will begin. Use the rules
// from 10.3.3 to determine what to apply. At this point in the
// reflow auto left/right margins will have a zero value.
mX = tx = mSpace.x + aFrameRS.ComputedPhysicalMargin().left;
mY = ty = mSpace.y + mTopMargin.get() + aClearance;
if ((mFrame->GetStateBits() & NS_BLOCK_FLOAT_MGR) == 0)
aFrameRS.mBlockDelta = mOuterReflowState.mBlockDelta + ty - aLine->mBounds.y;
}
// Let frame know that we are reflowing it
mFrame->WillReflow(mPresContext);
#ifdef DEBUG
mMetrics.Width() = nscoord(0xdeadbeef);
mMetrics.Height() = nscoord(0xdeadbeef);
#endif
mOuterReflowState.mFloatManager->Translate(tx, ty);
rv = mFrame->Reflow(mPresContext, mMetrics, aFrameRS, aFrameReflowStatus);
mOuterReflowState.mFloatManager->Translate(-tx, -ty);
#ifdef DEBUG
if (!NS_INLINE_IS_BREAK_BEFORE(aFrameReflowStatus)) {
if (CRAZY_SIZE(mMetrics.Width()) || CRAZY_SIZE(mMetrics.Height())) {
printf("nsBlockReflowContext: ");
nsFrame::ListTag(stdout, mFrame);
printf(" metrics=%d,%d!\n", mMetrics.Width(), mMetrics.Height());
}
if ((mMetrics.Width() == nscoord(0xdeadbeef)) ||
(mMetrics.Height() == nscoord(0xdeadbeef))) {
printf("nsBlockReflowContext: ");
nsFrame::ListTag(stdout, mFrame);
printf(" didn't set w/h %d,%d!\n", mMetrics.Width(), mMetrics.Height());
}
}
#endif
if (!mFrame->HasOverflowAreas()) {
mMetrics.SetOverflowAreasToDesiredBounds();
}
if (!NS_INLINE_IS_BREAK_BEFORE(aFrameReflowStatus) ||
(mFrame->GetStateBits() & NS_FRAME_OUT_OF_FLOW)) {
// If frame is complete and has a next-in-flow, we need to delete
// them now. Do not do this when a break-before is signaled because
// the frame is going to get reflowed again (and may end up wanting
// a next-in-flow where it ends up), unless it is an out of flow frame.
if (NS_FRAME_IS_FULLY_COMPLETE(aFrameReflowStatus)) {
nsIFrame* kidNextInFlow = mFrame->GetNextInFlow();
if (nullptr != kidNextInFlow) {
// Remove all of the childs next-in-flows. Make sure that we ask
// the right parent to do the removal (it's possible that the
// parent is not this because we are executing pullup code).
// Floats will eventually be removed via nsBlockFrame::RemoveFloat
// which detaches the placeholder from the float.
nsOverflowContinuationTracker::AutoFinish fini(aState.mOverflowTracker, mFrame);
static_cast<nsContainerFrame*>(kidNextInFlow->GetParent())
->DeleteNextInFlowChild(kidNextInFlow, true);
}
}
}
return rv;
}
