gecko/layout/generic/nsCanvasFrame.cpp
Robert O'Callahan d0dd680745 Bug 733607. Restructure logic to compute snapped bounds of display items in layer coordinates. Moves responsibility for computing snapped bounds from within the display items to callers of GetBounds/GetOpaqueRegion. r=tnikkel
Previously we snapped the results of nsDisplayItem::GetBounds and
nsDisplayItem::GetOpaqueRegion internally. By tracking which display items were
inside transforms, we disabled snapping quite conservatively whenever an ancestor
had a transform, which is undesirable.

With this patch, we don't snap inside GetBounds or GetOpaqueRegion, but just return
a boolean flag indicating whether the item will draw with snapping or not. This flag
is conservative so that "true" means we will snap (if the graphics context has a transform
that allows snapping), but "false" means we might or might not snap (so it's always safe
to return false).

FrameLayerBuilder takes over responsibility for snapping item bounds. When it converts
display item bounds to layer pixel coordinates, it checks the snap flag returned from
the display item and checks whether the transform when we draw into the layer will be
a known scale (the ContainerParameters scale factors) plus integer translation. If both
are true, we snap the item bounds when converting to layer pixel coordinates. With
this approach, we can snap item bounds even when the items have ancestors with active
transforms.
2012-04-10 23:24:18 +12:00

605 lines
21 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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*
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*
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*
* The Initial Developer of the Original Code is
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*
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/* rendering object that goes directly inside the document's scrollbars */
#include "nsCanvasFrame.h"
#include "nsIServiceManager.h"
#include "nsHTMLParts.h"
#include "nsContainerFrame.h"
#include "nsCSSRendering.h"
#include "nsPresContext.h"
#include "nsStyleContext.h"
#include "nsRenderingContext.h"
#include "nsGUIEvent.h"
#include "nsStyleConsts.h"
#include "nsGkAtoms.h"
#include "nsEventStateManager.h"
#include "nsIPresShell.h"
#include "nsIScrollPositionListener.h"
#include "nsDisplayList.h"
#include "nsCSSFrameConstructor.h"
#include "nsFrameManager.h"
// for focus
#include "nsIScrollableFrame.h"
#include "nsIDocShell.h"
#ifdef DEBUG_rods
//#define DEBUG_CANVAS_FOCUS
#endif
nsIFrame*
NS_NewCanvasFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
{
return new (aPresShell) nsCanvasFrame(aContext);
}
NS_IMPL_FRAMEARENA_HELPERS(nsCanvasFrame)
NS_QUERYFRAME_HEAD(nsCanvasFrame)
NS_QUERYFRAME_ENTRY(nsCanvasFrame)
NS_QUERYFRAME_TAIL_INHERITING(nsContainerFrame)
void
nsCanvasFrame::DestroyFrom(nsIFrame* aDestructRoot)
{
DestroyAbsoluteFrames(aDestructRoot);
nsIScrollableFrame* sf =
PresContext()->GetPresShell()->GetRootScrollFrameAsScrollable();
if (sf) {
sf->RemoveScrollPositionListener(this);
}
nsContainerFrame::DestroyFrom(aDestructRoot);
}
void
nsCanvasFrame::ScrollPositionWillChange(nscoord aX, nscoord aY)
{
if (mDoPaintFocus) {
mDoPaintFocus = false;
PresContext()->FrameManager()->GetRootFrame()->InvalidateFrameSubtree();
}
}
NS_IMETHODIMP
nsCanvasFrame::SetHasFocus(bool aHasFocus)
{
if (mDoPaintFocus != aHasFocus) {
mDoPaintFocus = aHasFocus;
PresContext()->FrameManager()->GetRootFrame()->InvalidateFrameSubtree();
if (!mAddedScrollPositionListener) {
nsIScrollableFrame* sf =
PresContext()->GetPresShell()->GetRootScrollFrameAsScrollable();
if (sf) {
sf->AddScrollPositionListener(this);
mAddedScrollPositionListener = true;
}
}
}
return NS_OK;
}
NS_IMETHODIMP
nsCanvasFrame::SetInitialChildList(ChildListID aListID,
nsFrameList& aChildList)
{
NS_ASSERTION(aListID != kPrincipalList ||
aChildList.IsEmpty() || aChildList.OnlyChild(),
"Primary child list can have at most one frame in it");
return nsContainerFrame::SetInitialChildList(aListID, aChildList);
}
NS_IMETHODIMP
nsCanvasFrame::AppendFrames(ChildListID aListID,
nsFrameList& aFrameList)
{
NS_ASSERTION(aListID == kPrincipalList ||
aListID == kAbsoluteList, "unexpected child list ID");
NS_PRECONDITION(aListID != kAbsoluteList ||
mFrames.IsEmpty(), "already have a child frame");
if (aListID != kPrincipalList) {
// We only support the Principal and Absolute child lists.
return NS_ERROR_INVALID_ARG;
}
if (!mFrames.IsEmpty()) {
// We only allow a single principal child frame.
return NS_ERROR_INVALID_ARG;
}
// Insert the new frames
NS_ASSERTION(aFrameList.FirstChild() == aFrameList.LastChild(),
"Only one principal child frame allowed");
#ifdef NS_DEBUG
nsFrame::VerifyDirtyBitSet(aFrameList);
#endif
mFrames.AppendFrames(nsnull, aFrameList);
PresContext()->PresShell()->
FrameNeedsReflow(this, nsIPresShell::eTreeChange,
NS_FRAME_HAS_DIRTY_CHILDREN);
return NS_OK;
}
NS_IMETHODIMP
nsCanvasFrame::InsertFrames(ChildListID aListID,
nsIFrame* aPrevFrame,
nsFrameList& aFrameList)
{
// Because we only support a single child frame inserting is the same
// as appending
NS_PRECONDITION(!aPrevFrame, "unexpected previous sibling frame");
if (aPrevFrame)
return NS_ERROR_UNEXPECTED;
return AppendFrames(aListID, aFrameList);
}
NS_IMETHODIMP
nsCanvasFrame::RemoveFrame(ChildListID aListID,
nsIFrame* aOldFrame)
{
NS_ASSERTION(aListID == kPrincipalList ||
aListID == kAbsoluteList, "unexpected child list ID");
if (aListID != kPrincipalList || aListID != kAbsoluteList) {
// We only support the Principal and Absolute child lists.
return NS_ERROR_INVALID_ARG;
}
if (aOldFrame != mFrames.FirstChild())
return NS_ERROR_FAILURE;
// It's our one and only child frame
// Damage the area occupied by the deleted frame
// The child of the canvas probably can't have an outline, but why bother
// thinking about that?
Invalidate(aOldFrame->GetVisualOverflowRect() + aOldFrame->GetPosition());
// Remove the frame and destroy it
mFrames.DestroyFrame(aOldFrame);
PresContext()->PresShell()->
FrameNeedsReflow(this, nsIPresShell::eTreeChange,
NS_FRAME_HAS_DIRTY_CHILDREN);
return NS_OK;
}
nsRect nsCanvasFrame::CanvasArea() const
{
// Not clear which overflow rect we want here, but it probably doesn't
// matter.
nsRect result(GetVisualOverflowRect());
nsIScrollableFrame *scrollableFrame = do_QueryFrame(GetParent());
if (scrollableFrame) {
nsRect portRect = scrollableFrame->GetScrollPortRect();
result.UnionRect(result, nsRect(nsPoint(0, 0), portRect.Size()));
}
return result;
}
void
nsDisplayCanvasBackground::Paint(nsDisplayListBuilder* aBuilder,
nsRenderingContext* aCtx)
{
nsCanvasFrame* frame = static_cast<nsCanvasFrame*>(mFrame);
nsPoint offset = ToReferenceFrame();
nsRect bgClipRect = frame->CanvasArea() + offset;
if (NS_GET_A(mExtraBackgroundColor) > 0) {
aCtx->SetColor(mExtraBackgroundColor);
aCtx->FillRect(bgClipRect);
}
nsCSSRendering::PaintBackground(mFrame->PresContext(), *aCtx, mFrame,
mVisibleRect,
nsRect(offset, mFrame->GetSize()),
aBuilder->GetBackgroundPaintFlags(),
&bgClipRect);
}
/**
* A display item to paint the focus ring for the document.
*
* The only reason this can't use nsDisplayGeneric is overriding GetBounds.
*/
class nsDisplayCanvasFocus : public nsDisplayItem {
public:
nsDisplayCanvasFocus(nsDisplayListBuilder* aBuilder, nsCanvasFrame *aFrame)
: nsDisplayItem(aBuilder, aFrame)
{
MOZ_COUNT_CTOR(nsDisplayCanvasFocus);
}
virtual ~nsDisplayCanvasFocus() {
MOZ_COUNT_DTOR(nsDisplayCanvasFocus);
}
virtual nsRect GetBounds(nsDisplayListBuilder* aBuilder, bool* aSnap)
{
*aSnap = false;
// This is an overestimate, but that's not a problem.
nsCanvasFrame* frame = static_cast<nsCanvasFrame*>(mFrame);
return frame->CanvasArea() + ToReferenceFrame();
}
virtual void Paint(nsDisplayListBuilder* aBuilder,
nsRenderingContext* aCtx)
{
nsCanvasFrame* frame = static_cast<nsCanvasFrame*>(mFrame);
frame->PaintFocus(*aCtx, ToReferenceFrame());
}
NS_DISPLAY_DECL_NAME("CanvasFocus", TYPE_CANVAS_FOCUS)
};
NS_IMETHODIMP
nsCanvasFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder,
const nsRect& aDirtyRect,
const nsDisplayListSet& aLists)
{
nsresult rv;
if (GetPrevInFlow()) {
DisplayOverflowContainers(aBuilder, aDirtyRect, aLists);
}
// Force a background to be shown. We may have a background propagated to us,
// in which case GetStyleBackground wouldn't have the right background
// and the code in nsFrame::DisplayBorderBackgroundOutline might not give us
// a background.
// We don't have any border or outline, and our background draws over
// the overflow area, so just add nsDisplayCanvasBackground instead of
// calling DisplayBorderBackgroundOutline.
if (IsVisibleForPainting(aBuilder)) {
rv = aLists.BorderBackground()->AppendNewToTop(new (aBuilder)
nsDisplayCanvasBackground(aBuilder, this));
NS_ENSURE_SUCCESS(rv, rv);
}
nsIFrame* kid;
for (kid = GetFirstPrincipalChild(); kid; kid = kid->GetNextSibling()) {
// Put our child into its own pseudo-stack.
rv = BuildDisplayListForChild(aBuilder, kid, aDirtyRect, aLists);
NS_ENSURE_SUCCESS(rv, rv);
}
#ifdef DEBUG_CANVAS_FOCUS
nsCOMPtr<nsIContent> focusContent;
aPresContext->EventStateManager()->
GetFocusedContent(getter_AddRefs(focusContent));
bool hasFocus = false;
nsCOMPtr<nsISupports> container;
aPresContext->GetContainer(getter_AddRefs(container));
nsCOMPtr<nsIDocShell> docShell(do_QueryInterface(container));
if (docShell) {
docShell->GetHasFocus(&hasFocus);
printf("%p - nsCanvasFrame::Paint R:%d,%d,%d,%d DR: %d,%d,%d,%d\n", this,
mRect.x, mRect.y, mRect.width, mRect.height,
aDirtyRect.x, aDirtyRect.y, aDirtyRect.width, aDirtyRect.height);
}
printf("%p - Focus: %s c: %p DoPaint:%s\n", docShell.get(), hasFocus?"Y":"N",
focusContent.get(), mDoPaintFocus?"Y":"N");
#endif
if (!mDoPaintFocus)
return NS_OK;
// Only paint the focus if we're visible
if (!GetStyleVisibility()->IsVisible())
return NS_OK;
return aLists.Outlines()->AppendNewToTop(new (aBuilder)
nsDisplayCanvasFocus(aBuilder, this));
}
void
nsCanvasFrame::PaintFocus(nsRenderingContext& aRenderingContext, nsPoint aPt)
{
nsRect focusRect(aPt, GetSize());
nsIScrollableFrame *scrollableFrame = do_QueryFrame(GetParent());
if (scrollableFrame) {
nsRect portRect = scrollableFrame->GetScrollPortRect();
focusRect.width = portRect.width;
focusRect.height = portRect.height;
focusRect.MoveBy(scrollableFrame->GetScrollPosition());
}
// XXX use the root frame foreground color, but should we find BODY frame
// for HTML documents?
nsIFrame* root = mFrames.FirstChild();
const nsStyleColor* color =
root ? root->GetStyleContext()->GetStyleColor() :
mStyleContext->GetStyleColor();
if (!color) {
NS_ERROR("current color cannot be found");
return;
}
nsCSSRendering::PaintFocus(PresContext(), aRenderingContext,
focusRect, color->mColor);
}
/* virtual */ nscoord
nsCanvasFrame::GetMinWidth(nsRenderingContext *aRenderingContext)
{
nscoord result;
DISPLAY_MIN_WIDTH(this, result);
if (mFrames.IsEmpty())
result = 0;
else
result = mFrames.FirstChild()->GetMinWidth(aRenderingContext);
return result;
}
/* virtual */ nscoord
nsCanvasFrame::GetPrefWidth(nsRenderingContext *aRenderingContext)
{
nscoord result;
DISPLAY_PREF_WIDTH(this, result);
if (mFrames.IsEmpty())
result = 0;
else
result = mFrames.FirstChild()->GetPrefWidth(aRenderingContext);
return result;
}
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, nsnull, *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();
nsRect oldKidRect = kidFrame->GetRect();
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->Invalidate(nsRect(nsPoint(0, 0), viewport->GetSize()));
} else {
nsRect newKidRect = kidFrame->GetRect();
if (newKidRect.TopLeft() == oldKidRect.TopLeft()) {
InvalidateRectDifference(oldKidRect, kidFrame->GetRect());
} else {
Invalidate(oldKidRect);
Invalidate(newKidRect);
}
}
// 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);
// Handle invalidating fixed-attachment backgrounds propagated to the
// canvas when the canvas size (and therefore the background positioning
// area's size) changes. Such backgrounds are not invalidated in the
// normal manner because the size of the original frame for that background
// may not have changed.
//
// This isn't the right fix for this issue, taken more generally. In
// particular, this doesn't handle fixed-attachment backgrounds that are *not*
// propagated. If a layer with the characteristics tested for below exists
// in a non-propagated background, we should invalidate the "corresponding"
// frame (which subsumes this special case if defined broadly). For now,
// however, this addresses the most common case. Given that this behavior has
// long been broken (non-zero percent background-size may be a new instance,
// but non-zero percent background-position is longstanding), we defer a
// fully correct fix until later.
if (nsSize(aDesiredSize.width, aDesiredSize.height) != GetSize()) {
nsIFrame* rootElementFrame =
aPresContext->PresShell()->FrameConstructor()->GetRootElementStyleFrame();
nsStyleContext* bgSC =
nsCSSRendering::FindCanvasBackground(this, rootElementFrame);
const nsStyleBackground* bg = bgSC->GetStyleBackground();
if (!bg->IsTransparent()) {
NS_FOR_VISIBLE_BACKGROUND_LAYERS_BACK_TO_FRONT(i, bg) {
const nsStyleBackground::Layer& layer = bg->mLayers[i];
if (layer.mAttachment == NS_STYLE_BG_ATTACHMENT_FIXED &&
layer.RenderingMightDependOnFrameSize()) {
Invalidate(nsRect(nsPoint(0, 0), GetSize()));
break;
}
}
}
}
}
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;
}
PRIntn
nsCanvasFrame::GetSkipSides() const
{
return 0;
}
nsIAtom*
nsCanvasFrame::GetType() const
{
return nsGkAtoms::canvasFrame;
}
NS_IMETHODIMP
nsCanvasFrame::GetContentForEvent(nsEvent* aEvent,
nsIContent** aContent)
{
NS_ENSURE_ARG_POINTER(aContent);
nsresult rv = nsFrame::GetContentForEvent(aEvent,
aContent);
if (NS_FAILED(rv) || !*aContent) {
nsIFrame* kid = mFrames.FirstChild();
if (kid) {
rv = kid->GetContentForEvent(aEvent,
aContent);
}
}
return rv;
}
#ifdef DEBUG
NS_IMETHODIMP
nsCanvasFrame::GetFrameName(nsAString& aResult) const
{
return MakeFrameName(NS_LITERAL_STRING("Canvas"), aResult);
}
#endif