void
nsCanvasFrame::Reflow(nsPresContext* aPresContext,
nsHTMLReflowMetrics& aDesiredSize,
const nsHTMLReflowState& aReflowState,
nsReflowStatus& aStatus)
{
MarkInReflow();
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) {
AutoFrameListPtr overflow(aPresContext,
prevCanvasFrame->StealOverflowFrames());
if (overflow) {
NS_ASSERTION(overflow->OnlyChild(),
"must have doc root as canvas frame's only child");
nsContainerFrame::ReparentFrameViewList(*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(aReflowState);
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,
aReflowState.AvailableSize(kidFrame->GetWritingMode()));
if (aReflowState.IsBResize() &&
(kidFrame->GetStateBits() & NS_FRAME_CONTAINS_RELATIVE_BSIZE)) {
// Tell our kid it's being block-dir resized too. Bit of a
// hack for framesets.
kidReflowState.SetBResize(true);
}
WritingMode wm = aReflowState.GetWritingMode();
WritingMode kidWM = kidReflowState.GetWritingMode();
nsSize containerSize = aReflowState.ComputedPhysicalSize();
LogicalMargin margin = kidReflowState.ComputedLogicalMargin();
LogicalPoint kidPt(kidWM, margin.IStart(kidWM), margin.BStart(kidWM));
kidReflowState.ApplyRelativePositioning(&kidPt, containerSize);
// Reflow the frame
ReflowChild(kidFrame, aPresContext, kidDesiredSize, kidReflowState,
kidWM, kidPt, containerSize, 0, aStatus);
// Complete the reflow and position and size the child frame
FinishReflowChild(kidFrame, aPresContext, kidDesiredSize, &kidReflowState,
kidWM, kidPt, containerSize, 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) {
nextFrame = aPresContext->PresShell()->FrameConstructor()->
CreateContinuingFrame(aPresContext, kidFrame, this);
SetOverflowFrames(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.
LogicalSize finalSize(wm);
finalSize.ISize(wm) = aReflowState.ComputedISize();
if (aReflowState.ComputedBSize() == NS_UNCONSTRAINEDSIZE) {
finalSize.BSize(wm) = kidFrame->GetLogicalSize(wm).BSize(wm) +
kidReflowState.ComputedLogicalMargin().BStartEnd(wm);
} else {
finalSize.BSize(wm) = aReflowState.ComputedBSize();
}
aDesiredSize.SetSize(wm, finalSize);
aDesiredSize.SetOverflowAreasToDesiredBounds();
aDesiredSize.mOverflowAreas.UnionWith(
kidDesiredSize.mOverflowAreas + kidFrame->GetPosition());
}
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);
}
