michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: /* rendering object for the HTML <canvas> element */
michael@0: 
michael@0: #include "nsHTMLCanvasFrame.h"
michael@0: 
michael@0: #include "nsGkAtoms.h"
michael@0: #include "mozilla/dom/HTMLCanvasElement.h"
michael@0: #include "nsDisplayList.h"
michael@0: #include "nsLayoutUtils.h"
michael@0: #include "Layers.h"
michael@0: #include "ActiveLayerTracker.h"
michael@0: 
michael@0: #include <algorithm>
michael@0: 
michael@0: using namespace mozilla;
michael@0: using namespace mozilla::dom;
michael@0: using namespace mozilla::layers;
michael@0: 
michael@0: class nsDisplayCanvas : public nsDisplayItem {
michael@0: public:
michael@0:   nsDisplayCanvas(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame)
michael@0:     : nsDisplayItem(aBuilder, aFrame)
michael@0:   {
michael@0:     MOZ_COUNT_CTOR(nsDisplayCanvas);
michael@0:   }
michael@0: #ifdef NS_BUILD_REFCNT_LOGGING
michael@0:   virtual ~nsDisplayCanvas() {
michael@0:     MOZ_COUNT_DTOR(nsDisplayCanvas);
michael@0:   }
michael@0: #endif
michael@0: 
michael@0:   NS_DISPLAY_DECL_NAME("nsDisplayCanvas", TYPE_CANVAS)
michael@0: 
michael@0:   virtual nsRegion GetOpaqueRegion(nsDisplayListBuilder* aBuilder,
michael@0:                                    bool* aSnap) MOZ_OVERRIDE {
michael@0:     *aSnap = false;
michael@0:     nsIFrame* f = Frame();
michael@0:     HTMLCanvasElement *canvas =
michael@0:       HTMLCanvasElement::FromContent(f->GetContent());
michael@0:     nsRegion result;
michael@0:     if (canvas->GetIsOpaque()) {
michael@0:       result = GetBounds(aBuilder, aSnap);
michael@0:     }
michael@0:     return result;
michael@0:   }
michael@0: 
michael@0:   virtual nsRect GetBounds(nsDisplayListBuilder* aBuilder,
michael@0:                            bool* aSnap) MOZ_OVERRIDE {
michael@0:     *aSnap = true;
michael@0:     nsHTMLCanvasFrame* f = static_cast<nsHTMLCanvasFrame*>(Frame());
michael@0:     return f->GetInnerArea() + ToReferenceFrame();
michael@0:   }
michael@0: 
michael@0:   virtual already_AddRefed<Layer> BuildLayer(nsDisplayListBuilder* aBuilder,
michael@0:                                              LayerManager* aManager,
michael@0:                                              const ContainerLayerParameters& aContainerParameters) MOZ_OVERRIDE
michael@0:   {
michael@0:     return static_cast<nsHTMLCanvasFrame*>(mFrame)->
michael@0:       BuildLayer(aBuilder, aManager, this, aContainerParameters);
michael@0:   }
michael@0:   virtual LayerState GetLayerState(nsDisplayListBuilder* aBuilder,
michael@0:                                    LayerManager* aManager,
michael@0:                                    const ContainerLayerParameters& aParameters) MOZ_OVERRIDE
michael@0:   {
michael@0:     if (HTMLCanvasElement::FromContent(mFrame->GetContent())->ShouldForceInactiveLayer(aManager))
michael@0:       return LAYER_INACTIVE;
michael@0: 
michael@0:     // If compositing is cheap, just do that
michael@0:     if (aManager->IsCompositingCheap() ||
michael@0:         ActiveLayerTracker::IsContentActive(mFrame))
michael@0:       return mozilla::LAYER_ACTIVE;
michael@0: 
michael@0:     return LAYER_INACTIVE;
michael@0:   }
michael@0: };
michael@0: 
michael@0: 
michael@0: nsIFrame*
michael@0: NS_NewHTMLCanvasFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
michael@0: {
michael@0:   return new (aPresShell) nsHTMLCanvasFrame(aContext);
michael@0: }
michael@0: 
michael@0: NS_QUERYFRAME_HEAD(nsHTMLCanvasFrame)
michael@0:   NS_QUERYFRAME_ENTRY(nsHTMLCanvasFrame)
michael@0: NS_QUERYFRAME_TAIL_INHERITING(nsContainerFrame)
michael@0: 
michael@0: NS_IMPL_FRAMEARENA_HELPERS(nsHTMLCanvasFrame)
michael@0: 
michael@0: void
michael@0: nsHTMLCanvasFrame::Init(nsIContent* aContent,
michael@0:                         nsIFrame*   aParent,
michael@0:                         nsIFrame*   aPrevInFlow)
michael@0: {
michael@0:   nsContainerFrame::Init(aContent, aParent, aPrevInFlow);
michael@0: 
michael@0:   // We can fill in the canvas before the canvas frame is created, in
michael@0:   // which case we never get around to marking the content as active. Therefore,
michael@0:   // we mark it active here when we create the frame.
michael@0:   ActiveLayerTracker::NotifyContentChange(this);
michael@0: }
michael@0: 
michael@0: nsHTMLCanvasFrame::~nsHTMLCanvasFrame()
michael@0: {
michael@0: }
michael@0: 
michael@0: nsIntSize
michael@0: nsHTMLCanvasFrame::GetCanvasSize()
michael@0: {
michael@0:   nsIntSize size(0,0);
michael@0:   HTMLCanvasElement *canvas =
michael@0:     HTMLCanvasElement::FromContentOrNull(GetContent());
michael@0:   if (canvas) {
michael@0:     size = canvas->GetSize();
michael@0:   } else {
michael@0:     NS_NOTREACHED("couldn't get canvas size");
michael@0:   }
michael@0: 
michael@0:   return size;
michael@0: }
michael@0: 
michael@0: /* virtual */ nscoord
michael@0: nsHTMLCanvasFrame::GetMinWidth(nsRenderingContext *aRenderingContext)
michael@0: {
michael@0:   // XXX The caller doesn't account for constraints of the height,
michael@0:   // min-height, and max-height properties.
michael@0:   nscoord result = nsPresContext::CSSPixelsToAppUnits(GetCanvasSize().width);
michael@0:   DISPLAY_MIN_WIDTH(this, result);
michael@0:   return result;
michael@0: }
michael@0: 
michael@0: /* virtual */ nscoord
michael@0: nsHTMLCanvasFrame::GetPrefWidth(nsRenderingContext *aRenderingContext)
michael@0: {
michael@0:   // XXX The caller doesn't account for constraints of the height,
michael@0:   // min-height, and max-height properties.
michael@0:   nscoord result = nsPresContext::CSSPixelsToAppUnits(GetCanvasSize().width);
michael@0:   DISPLAY_PREF_WIDTH(this, result);
michael@0:   return result;
michael@0: }
michael@0: 
michael@0: /* virtual */ nsSize
michael@0: nsHTMLCanvasFrame::GetIntrinsicRatio()
michael@0: {
michael@0:   nsIntSize size(GetCanvasSize());
michael@0:   return nsSize(nsPresContext::CSSPixelsToAppUnits(size.width),
michael@0:                 nsPresContext::CSSPixelsToAppUnits(size.height));
michael@0: }
michael@0: 
michael@0: /* virtual */ nsSize
michael@0: nsHTMLCanvasFrame::ComputeSize(nsRenderingContext *aRenderingContext,
michael@0:                                nsSize aCBSize, nscoord aAvailableWidth,
michael@0:                                nsSize aMargin, nsSize aBorder, nsSize aPadding,
michael@0:                                uint32_t aFlags)
michael@0: {
michael@0:   nsIntSize size = GetCanvasSize();
michael@0: 
michael@0:   IntrinsicSize intrinsicSize;
michael@0:   intrinsicSize.width.SetCoordValue(nsPresContext::CSSPixelsToAppUnits(size.width));
michael@0:   intrinsicSize.height.SetCoordValue(nsPresContext::CSSPixelsToAppUnits(size.height));
michael@0: 
michael@0:   nsSize intrinsicRatio = GetIntrinsicRatio(); // won't actually be used
michael@0: 
michael@0:   return nsLayoutUtils::ComputeSizeWithIntrinsicDimensions(
michael@0:                             aRenderingContext, this,
michael@0:                             intrinsicSize, intrinsicRatio, aCBSize,
michael@0:                             aMargin, aBorder, aPadding);
michael@0: }
michael@0: 
michael@0: nsresult
michael@0: nsHTMLCanvasFrame::Reflow(nsPresContext*           aPresContext,
michael@0:                           nsHTMLReflowMetrics&     aMetrics,
michael@0:                           const nsHTMLReflowState& aReflowState,
michael@0:                           nsReflowStatus&          aStatus)
michael@0: {
michael@0:   DO_GLOBAL_REFLOW_COUNT("nsHTMLCanvasFrame");
michael@0:   DISPLAY_REFLOW(aPresContext, this, aReflowState, aMetrics, aStatus);
michael@0:   NS_FRAME_TRACE(NS_FRAME_TRACE_CALLS,
michael@0:                   ("enter nsHTMLCanvasFrame::Reflow: availSize=%d,%d",
michael@0:                   aReflowState.AvailableWidth(), aReflowState.AvailableHeight()));
michael@0: 
michael@0:   NS_PRECONDITION(mState & NS_FRAME_IN_REFLOW, "frame is not in reflow");
michael@0: 
michael@0:   aStatus = NS_FRAME_COMPLETE;
michael@0: 
michael@0:   aMetrics.Width() = aReflowState.ComputedWidth();
michael@0:   aMetrics.Height() = aReflowState.ComputedHeight();
michael@0: 
michael@0:   // stash this away so we can compute our inner area later
michael@0:   mBorderPadding   = aReflowState.ComputedPhysicalBorderPadding();
michael@0: 
michael@0:   aMetrics.Width() += mBorderPadding.left + mBorderPadding.right;
michael@0:   aMetrics.Height() += mBorderPadding.top + mBorderPadding.bottom;
michael@0: 
michael@0:   if (GetPrevInFlow()) {
michael@0:     nscoord y = GetContinuationOffset(&aMetrics.Width());
michael@0:     aMetrics.Height() -= y + mBorderPadding.top;
michael@0:     aMetrics.Height() = std::max(0, aMetrics.Height());
michael@0:   }
michael@0: 
michael@0:   aMetrics.SetOverflowAreasToDesiredBounds();
michael@0:   FinishAndStoreOverflow(&aMetrics);
michael@0: 
michael@0:   // Reflow the single anon block child.
michael@0:   nsReflowStatus childStatus;
michael@0:   nsSize availSize(aReflowState.ComputedWidth(), NS_UNCONSTRAINEDSIZE);
michael@0:   nsIFrame* childFrame = mFrames.FirstChild();
michael@0:   NS_ASSERTION(!childFrame->GetNextSibling(), "HTML canvas should have 1 kid");
michael@0:   nsHTMLReflowMetrics childDesiredSize(aReflowState.GetWritingMode(), aMetrics.mFlags);
michael@0:   nsHTMLReflowState childReflowState(aPresContext, aReflowState, childFrame,
michael@0:                                      availSize);
michael@0:   ReflowChild(childFrame, aPresContext, childDesiredSize, childReflowState,
michael@0:               0, 0, 0, childStatus, nullptr);
michael@0:   FinishReflowChild(childFrame, aPresContext, childDesiredSize,
michael@0:                     &childReflowState, 0, 0, 0);
michael@0: 
michael@0:   NS_FRAME_TRACE(NS_FRAME_TRACE_CALLS,
michael@0:                   ("exit nsHTMLCanvasFrame::Reflow: size=%d,%d",
michael@0:                   aMetrics.Width(), aMetrics.Height()));
michael@0:   NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aMetrics);
michael@0: 
michael@0:   return NS_OK;
michael@0: }
michael@0: 
michael@0: // FIXME taken from nsImageFrame, but then had splittable frame stuff
michael@0: // removed.  That needs to be fixed.
michael@0: nsRect 
michael@0: nsHTMLCanvasFrame::GetInnerArea() const
michael@0: {
michael@0:   nsRect r;
michael@0:   r.x = mBorderPadding.left;
michael@0:   r.y = mBorderPadding.top;
michael@0:   r.width = mRect.width - mBorderPadding.left - mBorderPadding.right;
michael@0:   r.height = mRect.height - mBorderPadding.top - mBorderPadding.bottom;
michael@0:   return r;
michael@0: }
michael@0: 
michael@0: already_AddRefed<Layer>
michael@0: nsHTMLCanvasFrame::BuildLayer(nsDisplayListBuilder* aBuilder,
michael@0:                               LayerManager* aManager,
michael@0:                               nsDisplayItem* aItem,
michael@0:                               const ContainerLayerParameters& aContainerParameters)
michael@0: {
michael@0:   nsRect area = GetContentRect() - GetPosition() + aItem->ToReferenceFrame();
michael@0:   HTMLCanvasElement* element = static_cast<HTMLCanvasElement*>(GetContent());
michael@0:   nsIntSize canvasSize = GetCanvasSize();
michael@0: 
michael@0:   nsPresContext* presContext = PresContext();
michael@0:   element->HandlePrintCallback(presContext->Type());
michael@0: 
michael@0:   if (canvasSize.width <= 0 || canvasSize.height <= 0 || area.IsEmpty())
michael@0:     return nullptr;
michael@0: 
michael@0:   CanvasLayer* oldLayer = static_cast<CanvasLayer*>
michael@0:     (aManager->GetLayerBuilder()->GetLeafLayerFor(aBuilder, aItem));
michael@0:   nsRefPtr<CanvasLayer> layer = element->GetCanvasLayer(aBuilder, oldLayer, aManager);
michael@0:   if (!layer)
michael@0:     return nullptr;
michael@0: 
michael@0:   gfxRect r = gfxRect(presContext->AppUnitsToGfxUnits(area.x),
michael@0:                       presContext->AppUnitsToGfxUnits(area.y),
michael@0:                       presContext->AppUnitsToGfxUnits(area.width),
michael@0:                       presContext->AppUnitsToGfxUnits(area.height));
michael@0: 
michael@0:   // Transform the canvas into the right place
michael@0:   gfx::Matrix transform;
michael@0:   gfxPoint p = r.TopLeft() + aContainerParameters.mOffset;
michael@0:   transform.Translate(p.x, p.y);
michael@0:   transform.Scale(r.Width()/canvasSize.width, r.Height()/canvasSize.height);
michael@0:   layer->SetBaseTransform(gfx::Matrix4x4::From2D(transform));
michael@0:   layer->SetFilter(nsLayoutUtils::GetGraphicsFilterForFrame(this));
michael@0:   layer->SetVisibleRegion(nsIntRect(0, 0, canvasSize.width, canvasSize.height));
michael@0: 
michael@0:   return layer.forget();
michael@0: }
michael@0: 
michael@0: void
michael@0: nsHTMLCanvasFrame::BuildDisplayList(nsDisplayListBuilder*   aBuilder,
michael@0:                                     const nsRect&           aDirtyRect,
michael@0:                                     const nsDisplayListSet& aLists)
michael@0: {
michael@0:   if (!IsVisibleForPainting(aBuilder))
michael@0:     return;
michael@0: 
michael@0:   DisplayBorderBackgroundOutline(aBuilder, aLists);
michael@0: 
michael@0:   DisplayListClipState::AutoClipContainingBlockDescendantsToContentBox
michael@0:     clip(aBuilder, this, DisplayListClipState::ASSUME_DRAWING_RESTRICTED_TO_CONTENT_RECT);
michael@0: 
michael@0:   aLists.Content()->AppendNewToTop(
michael@0:     new (aBuilder) nsDisplayCanvas(aBuilder, this));
michael@0: 
michael@0:   DisplaySelectionOverlay(aBuilder, aLists.Content(),
michael@0:                           nsISelectionDisplay::DISPLAY_IMAGES);
michael@0: }
michael@0: 
michael@0: nsIAtom*
michael@0: nsHTMLCanvasFrame::GetType() const
michael@0: {
michael@0:   return nsGkAtoms::HTMLCanvasFrame;
michael@0: }
michael@0: 
michael@0: // get the offset into the content area of the image where aImg starts if it is a continuation.
michael@0: // from nsImageFrame
michael@0: nscoord 
michael@0: nsHTMLCanvasFrame::GetContinuationOffset(nscoord* aWidth) const
michael@0: {
michael@0:   nscoord offset = 0;
michael@0:   if (aWidth) {
michael@0:     *aWidth = 0;
michael@0:   }
michael@0: 
michael@0:   if (GetPrevInFlow()) {
michael@0:     for (nsIFrame* prevInFlow = GetPrevInFlow() ; prevInFlow; prevInFlow = prevInFlow->GetPrevInFlow()) {
michael@0:       nsRect rect = prevInFlow->GetRect();
michael@0:       if (aWidth) {
michael@0:         *aWidth = rect.width;
michael@0:       }
michael@0:       offset += rect.height;
michael@0:     }
michael@0:     offset -= mBorderPadding.top;
michael@0:     offset = std::max(0, offset);
michael@0:   }
michael@0:   return offset;
michael@0: }
michael@0: 
michael@0: #ifdef ACCESSIBILITY
michael@0: a11y::AccType
michael@0: nsHTMLCanvasFrame::AccessibleType()
michael@0: {
michael@0:   return a11y::eHTMLCanvasType;
michael@0: }
michael@0: #endif
michael@0: 
michael@0: #ifdef DEBUG_FRAME_DUMP
michael@0: nsresult
michael@0: nsHTMLCanvasFrame::GetFrameName(nsAString& aResult) const
michael@0: {
michael@0:   return MakeFrameName(NS_LITERAL_STRING("HTMLCanvas"), aResult);
michael@0: }
michael@0: #endif
michael@0: