NS_IMETHODIMP
nsCanvasFrame::Reflow(nsPresContext* aPresContext,
nsHTMLReflowMetrics& aDesiredSize,
const nsHTMLReflowState& aReflowState,
nsReflowStatus& aStatus)
{
DO_GLOBAL_REFLOW_COUNT("nsCanvasFrame");
DISPLAY_REFLOW(aPresContext, this, aReflowState, aDesiredSize, aStatus);
NS_FRAME_TRACE_REFLOW_IN("nsCanvasFrame::Reflow");
// Initialize OUT parameter
aStatus = NS_FRAME_COMPLETE;
nsCanvasFrame* prevCanvasFrame = static_cast<nsCanvasFrame*>
(GetPrevInFlow());
if (prevCanvasFrame) {
nsAutoPtr<nsFrameList> overflow(prevCanvasFrame->StealOverflowFrames());
if (overflow) {
NS_ASSERTION(overflow->OnlyChild(),
"must have doc root as canvas frame's only child");
nsContainerFrame::ReparentFrameViewList(aPresContext, *overflow,
prevCanvasFrame, this);
// Prepend overflow to the our child list. There may already be
// children placeholders for fixed-pos elements, which don't get
// reflowed but must not be lost until the canvas frame is destroyed.
mFrames.InsertFrames(this, nullptr, *overflow);
}
}
// Set our size up front, since some parts of reflow depend on it
// being already set. Note that the computed height may be
// unconstrained; that's ok. Consumers should watch out for that.
SetSize(nsSize(aReflowState.ComputedWidth(), aReflowState.ComputedHeight()));
// Reflow our one and only normal child frame. It's either the root
// element's frame or a placeholder for that frame, if the root element
// is abs-pos or fixed-pos. We may have additional children which
// are placeholders for continuations of fixed-pos content, but those
// don't need to be reflowed. The normal child is always comes before
// the fixed-pos placeholders, because we insert it at the start
// of the child list, above.
nsHTMLReflowMetrics kidDesiredSize;
if (mFrames.IsEmpty()) {
// We have no child frame, so return an empty size
aDesiredSize.width = aDesiredSize.height = 0;
} else {
nsIFrame* kidFrame = mFrames.FirstChild();
bool kidDirty = (kidFrame->GetStateBits() & NS_FRAME_IS_DIRTY) != 0;
nsHTMLReflowState kidReflowState(aPresContext, aReflowState, kidFrame,
nsSize(aReflowState.availableWidth,
aReflowState.availableHeight));
if (aReflowState.mFlags.mVResize &&
(kidFrame->GetStateBits() & NS_FRAME_CONTAINS_RELATIVE_HEIGHT)) {
// Tell our kid it's being vertically resized too. Bit of a
// hack for framesets.
kidReflowState.mFlags.mVResize = true;
}
nsPoint kidPt(kidReflowState.mComputedMargin.left,
kidReflowState.mComputedMargin.top);
// Apply CSS relative positioning
const nsStyleDisplay* styleDisp = kidFrame->GetStyleDisplay();
if (NS_STYLE_POSITION_RELATIVE == styleDisp->mPosition) {
kidPt += nsPoint(kidReflowState.mComputedOffsets.left,
kidReflowState.mComputedOffsets.top);
}
// Reflow the frame
ReflowChild(kidFrame, aPresContext, kidDesiredSize, kidReflowState,
kidPt.x, kidPt.y, 0, aStatus);
// Complete the reflow and position and size the child frame
FinishReflowChild(kidFrame, aPresContext, &kidReflowState, kidDesiredSize,
kidPt.x, kidPt.y, 0);
if (!NS_FRAME_IS_FULLY_COMPLETE(aStatus)) {
nsIFrame* nextFrame = kidFrame->GetNextInFlow();
NS_ASSERTION(nextFrame || aStatus & NS_FRAME_REFLOW_NEXTINFLOW,
"If it's incomplete and has no nif yet, it must flag a nif reflow.");
if (!nextFrame) {
nsresult rv = aPresContext->PresShell()->FrameConstructor()->
CreateContinuingFrame(aPresContext, kidFrame, this, &nextFrame);
NS_ENSURE_SUCCESS(rv, rv);
SetOverflowFrames(aPresContext, nsFrameList(nextFrame, nextFrame));
// Root overflow containers will be normal children of
// the canvas frame, but that's ok because there
// aren't any other frames we need to isolate them from
// during reflow.
}
if (NS_FRAME_OVERFLOW_IS_INCOMPLETE(aStatus)) {
nextFrame->AddStateBits(NS_FRAME_IS_OVERFLOW_CONTAINER);
}
}
// If the child frame was just inserted, then we're responsible for making sure
// it repaints
if (kidDirty) {
// But we have a new child, which will affect our background, so
// invalidate our whole rect.
// Note: Even though we request to be sized to our child's size, our
// scroll frame ensures that we are always the size of the viewport.
// Also note: GetPosition() on a CanvasFrame is always going to return
// (0, 0). We only want to invalidate GetRect() since Get*OverflowRect()
// could also include overflow to our top and left (out of the viewport)
// which doesn't need to be painted.
nsIFrame* viewport = PresContext()->GetPresShell()->GetRootFrame();
viewport->InvalidateFrame();
}
// Return our desired size. Normally it's what we're told, but
// sometimes we can be given an unconstrained height (when a window
// is sizing-to-content), and we should compute our desired height.
aDesiredSize.width = aReflowState.ComputedWidth();
if (aReflowState.ComputedHeight() == NS_UNCONSTRAINEDSIZE) {
aDesiredSize.height = kidFrame->GetRect().height +
kidReflowState.mComputedMargin.TopBottom();
} else {
aDesiredSize.height = aReflowState.ComputedHeight();
}
aDesiredSize.SetOverflowAreasToDesiredBounds();
aDesiredSize.mOverflowAreas.UnionWith(
kidDesiredSize.mOverflowAreas + kidPt);
}
if (prevCanvasFrame) {
ReflowOverflowContainerChildren(aPresContext, aReflowState,
aDesiredSize.mOverflowAreas, 0,
aStatus);
}
FinishReflowWithAbsoluteFrames(aPresContext, aDesiredSize, aReflowState, aStatus);
NS_FRAME_TRACE_REFLOW_OUT("nsCanvasFrame::Reflow", aStatus);
NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aDesiredSize);
return NS_OK;
}
NS_IMETHODIMP
nsColumnSetFrame::Reflow(nsPresContext* aPresContext,
nsHTMLReflowMetrics& aDesiredSize,
const nsHTMLReflowState& aReflowState,
nsReflowStatus& aStatus)
{
// Don't support interruption in columns
nsPresContext::InterruptPreventer noInterrupts(aPresContext);
DO_GLOBAL_REFLOW_COUNT("nsColumnSetFrame");
DISPLAY_REFLOW(aPresContext, this, aReflowState, aDesiredSize, aStatus);
// Initialize OUT parameter
aStatus = NS_FRAME_COMPLETE;
// Our children depend on our height if we have a fixed height.
if (aReflowState.ComputedHeight() != NS_AUTOHEIGHT) {
NS_ASSERTION(aReflowState.ComputedHeight() != NS_INTRINSICSIZE,
"Unexpected mComputedHeight");
AddStateBits(NS_FRAME_CONTAINS_RELATIVE_HEIGHT);
}
else {
RemoveStateBits(NS_FRAME_CONTAINS_RELATIVE_HEIGHT);
}
//------------ Handle Incremental Reflow -----------------
ReflowConfig config = ChooseColumnStrategy(aReflowState);
bool isBalancing = config.mBalanceColCount < PR_INT32_MAX;
// If balancing, then we allow the last column to grow to unbounded
// height during the first reflow. This gives us a way to estimate
// what the average column height should be, because we can measure
// the heights of all the columns and sum them up. But don't do this
// if we have a next in flow because we don't want to suck all its
// content back here and then have to push it out again!
nsIFrame* nextInFlow = GetNextInFlow();
bool unboundedLastColumn = isBalancing && !nextInFlow;
nsCollapsingMargin carriedOutBottomMargin;
ColumnBalanceData colData;
bool feasible = ReflowChildren(aDesiredSize, aReflowState,
aStatus, config, unboundedLastColumn, &carriedOutBottomMargin, colData);
if (isBalancing && !aPresContext->HasPendingInterrupt()) {
nscoord availableContentHeight = GetAvailableContentHeight(aReflowState);
// Termination of the algorithm below is guaranteed because
// knownFeasibleHeight - knownInfeasibleHeight decreases in every
// iteration.
nscoord knownFeasibleHeight = NS_INTRINSICSIZE;
nscoord knownInfeasibleHeight = 0;
// We set this flag when we detect that we may contain a frame
// that can break anywhere (thus foiling the linear decrease-by-one
// search)
bool maybeContinuousBreakingDetected = false;
while (!aPresContext->HasPendingInterrupt()) {
nscoord lastKnownFeasibleHeight = knownFeasibleHeight;
// Record what we learned from the last reflow
if (feasible) {
// maxHeight is feasible. Also, mLastBalanceHeight is feasible.
knownFeasibleHeight = NS_MIN(knownFeasibleHeight, colData.mMaxHeight);
knownFeasibleHeight = NS_MIN(knownFeasibleHeight, mLastBalanceHeight);
// Furthermore, no height less than the height of the last
// column can ever be feasible. (We might be able to reduce the
// height of a non-last column by moving content to a later column,
// but we can't do that with the last column.)
if (mFrames.GetLength() == config.mBalanceColCount) {
knownInfeasibleHeight = NS_MAX(knownInfeasibleHeight,
colData.mLastHeight - 1);
}
} else {
knownInfeasibleHeight = NS_MAX(knownInfeasibleHeight, mLastBalanceHeight);
// If a column didn't fit in its available height, then its current
// height must be the minimum height for unbreakable content in
// the column, and therefore no smaller height can be feasible.
knownInfeasibleHeight = NS_MAX(knownInfeasibleHeight,
colData.mMaxOverflowingHeight - 1);
if (unboundedLastColumn) {
// The last column is unbounded, so all content got reflowed, so the
// mColMaxHeight is feasible.
knownFeasibleHeight = NS_MIN(knownFeasibleHeight,
colData.mMaxHeight);
}
}
#ifdef DEBUG_roc
printf("*** nsColumnSetFrame::Reflow balancing knownInfeasible=%d knownFeasible=%d\n",
knownInfeasibleHeight, knownFeasibleHeight);
#endif
if (knownInfeasibleHeight >= knownFeasibleHeight - 1) {
// knownFeasibleHeight is where we want to be
break;
}
if (knownInfeasibleHeight >= availableContentHeight) {
break;
}
if (lastKnownFeasibleHeight - knownFeasibleHeight == 1) {
// We decreased the feasible height by one twip only. This could
// indicate that there is a continuously breakable child frame
// that we are crawling through.
maybeContinuousBreakingDetected = PR_TRUE;
}
nscoord nextGuess = (knownFeasibleHeight + knownInfeasibleHeight)/2;
// The constant of 600 twips is arbitrary. It's about two line-heights.
if (knownFeasibleHeight - nextGuess < 600 &&
!maybeContinuousBreakingDetected) {
// We're close to our target, so just try shrinking just the
// minimum amount that will cause one of our columns to break
// differently.
nextGuess = knownFeasibleHeight - 1;
} else if (unboundedLastColumn) {
// Make a guess by dividing that into N columns. Add some slop
// to try to make it on the feasible side. The constant of
// 600 twips is arbitrary. It's about two line-heights.
nextGuess = colData.mSumHeight/config.mBalanceColCount + 600;
// Sanitize it
nextGuess = NS_MIN(NS_MAX(nextGuess, knownInfeasibleHeight + 1),
knownFeasibleHeight - 1);
} else if (knownFeasibleHeight == NS_INTRINSICSIZE) {
// This can happen when we had a next-in-flow so we didn't
// want to do an unbounded height measuring step. Let's just increase
// from the infeasible height by some reasonable amount.
nextGuess = knownInfeasibleHeight*2 + 600;
}
// Don't bother guessing more than our height constraint.
nextGuess = NS_MIN(availableContentHeight, nextGuess);
#ifdef DEBUG_roc
printf("*** nsColumnSetFrame::Reflow balancing choosing next guess=%d\n", nextGuess);
#endif
config.mColMaxHeight = nextGuess;
unboundedLastColumn = PR_FALSE;
AddStateBits(NS_FRAME_IS_DIRTY);
feasible = ReflowChildren(aDesiredSize, aReflowState,
aStatus, config, PR_FALSE,
&carriedOutBottomMargin, colData);
}
if (!feasible && !aPresContext->HasPendingInterrupt()) {
// We may need to reflow one more time at the feasible height to
// get a valid layout.
bool skip = false;
if (knownInfeasibleHeight >= availableContentHeight) {
config.mColMaxHeight = availableContentHeight;
if (mLastBalanceHeight == availableContentHeight) {
skip = PR_TRUE;
}
} else {
config.mColMaxHeight = knownFeasibleHeight;
}
if (!skip) {
// If our height is unconstrained, make sure that the last column is
// allowed to have arbitrary height here, even though we were balancing.
// Otherwise we'd have to split, and it's not clear what we'd do with
// that.
AddStateBits(NS_FRAME_IS_DIRTY);
ReflowChildren(aDesiredSize, aReflowState, aStatus, config,
availableContentHeight == NS_UNCONSTRAINEDSIZE,
&carriedOutBottomMargin, colData);
}
}
}
if (aPresContext->HasPendingInterrupt() &&
aReflowState.availableHeight == NS_UNCONSTRAINEDSIZE) {
// In this situation, we might be lying about our reflow status, because
// our last kid (the one that got interrupted) was incomplete. Fix that.
aStatus = NS_FRAME_COMPLETE;
}
CheckInvalidateSizeChange(aDesiredSize);
FinishReflowWithAbsoluteFrames(aPresContext, aDesiredSize, aReflowState, aStatus);
aDesiredSize.mCarriedOutBottomMargin = carriedOutBottomMargin;
NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aDesiredSize);
NS_ASSERTION(NS_FRAME_IS_FULLY_COMPLETE(aStatus) ||
aReflowState.availableHeight != NS_UNCONSTRAINEDSIZE,
"Column set should be complete if the available height is unconstrained");
return NS_OK;
}
