gecko/layout/base/FrameLayerBuilder.h
Chris Lord 15c3324aa3 Bug 772079 - Fix ThebesLayerInvalidRegion being destroyed too soon. r=roc
A comment in ApplyThebesLayerInvalidation says that it preserves the content
of ThebesLayerInvalidRegion, in case there are multiple container layers for
the same frame. SetHasContainerLayer, however, immediately clears said property.

This was causing invalidations to be lost since Bug 758620 on fixed-position
elements, as they were being separated out onto their own layers but were still
merged in the root scroll layer. This is tracked in Bug 769541.

This fixes the problem by storing the new invalid region in DisplayItemDataEntry
and clearing/setting the ThebesLayerInvalidRegion property in the
UpdateDisplayItemData callback from FrameLayerBuilder::WillEndTransaction.
2012-07-14 08:49:05 +01:00

608 lines
23 KiB
C++

/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef FRAMELAYERBUILDER_H_
#define FRAMELAYERBUILDER_H_
#include "nsTHashtable.h"
#include "nsHashKeys.h"
#include "nsTArray.h"
#include "nsRegion.h"
#include "nsIFrame.h"
#include "Layers.h"
class nsDisplayListBuilder;
class nsDisplayList;
class nsDisplayItem;
class gfxContext;
class nsRootPresContext;
namespace mozilla {
enum LayerState {
LAYER_NONE,
LAYER_INACTIVE,
LAYER_ACTIVE,
// Force an active layer even if it causes incorrect rendering, e.g.
// when the layer has rounded rect clips.
LAYER_ACTIVE_FORCE,
// Special layer that is metadata only.
LAYER_ACTIVE_EMPTY
};
class RefCountedRegion : public RefCounted<RefCountedRegion> {
public:
nsRegion mRegion;
};
/**
* The FrameLayerBuilder belongs to an nsDisplayListBuilder and is
* responsible for converting display lists into layer trees.
*
* The most important API in this class is BuildContainerLayerFor. This
* method takes a display list as input and constructs a ContainerLayer
* with child layers that render the contents of the display list. It
* also updates userdata for the retained layer manager, and
* DisplayItemDataProperty data for frames, to record the relationship
* between frames and layers.
*
* That data enables us to retain layer trees. When constructing a
* ContainerLayer, we first check to see if there's an existing
* ContainerLayer for the same frame that can be recycled. If we recycle
* it, we also try to reuse its existing ThebesLayer children to render
* the display items without layers of their own. The idea is that by
* recycling layers deterministically, we can ensure that when nothing
* changes in a display list, we will reuse the existing layers without
* changes.
*
* We expose a GetLeafLayerFor method that can be called by display items
* that make their own layers (e.g. canvas and video); this method
* locates the last layer used to render the display item, if any, and
* return it as a candidate for recycling.
*
* FrameLayerBuilder sets up ThebesLayers so that 0,0 in the Thebes layer
* corresponds to the (pixel-snapped) top-left of the aActiveScrolledRoot.
* It sets up ContainerLayers so that 0,0 in the container layer
* corresponds to the snapped top-left of the display list reference frame.
*
* When we construct a container layer, we know the transform that will be
* applied to the layer. If the transform scales the content, we can get
* better results when intermediate buffers are used by pushing some scale
* from the container's transform down to the children. For ThebesLayer
* children, the scaling can be achieved by changing the size of the layer
* and drawing into it with increased or decreased resolution. By convention,
* integer types (nsIntPoint/nsIntSize/nsIntRect/nsIntRegion) are all in layer
* coordinates, post-scaling, whereas appunit types are all pre-scaling.
*/
class FrameLayerBuilder {
public:
typedef layers::ContainerLayer ContainerLayer;
typedef layers::Layer Layer;
typedef layers::ThebesLayer ThebesLayer;
typedef layers::LayerManager LayerManager;
FrameLayerBuilder() :
mRetainingManager(nsnull),
mDetectedDOMModification(false),
mInvalidateAllLayers(false)
{
mNewDisplayItemData.Init();
mThebesLayerItems.Init();
}
static void Shutdown();
void Init(nsDisplayListBuilder* aBuilder);
/**
* Call this to notify that we have just started a transaction on the
* retained layer manager aManager.
*/
void DidBeginRetainedLayerTransaction(LayerManager* aManager);
/**
* Call this just before we end a transaction on aManager. If aManager
* is not the retained layer manager then it must be a temporary layer
* manager that will not be used again.
*/
void WillEndTransaction(LayerManager* aManager);
/**
* Call this after we end a transaction on aManager. If aManager
* is not the retained layer manager then it must be a temporary layer
* manager that will not be used again.
*/
void DidEndTransaction(LayerManager* aManager);
struct ContainerParameters {
ContainerParameters() :
mXScale(1), mYScale(1),
mInTransformedSubtree(false), mInActiveTransformedSubtree(false),
mDisableSubpixelAntialiasingInDescendants(false)
{}
ContainerParameters(float aXScale, float aYScale) :
mXScale(aXScale), mYScale(aYScale),
mInTransformedSubtree(false), mInActiveTransformedSubtree(false),
mDisableSubpixelAntialiasingInDescendants(false)
{}
ContainerParameters(float aXScale, float aYScale,
const ContainerParameters& aParent) :
mXScale(aXScale), mYScale(aYScale),
mInTransformedSubtree(aParent.mInTransformedSubtree),
mInActiveTransformedSubtree(aParent.mInActiveTransformedSubtree),
mDisableSubpixelAntialiasingInDescendants(aParent.mDisableSubpixelAntialiasingInDescendants)
{}
float mXScale, mYScale;
bool mInTransformedSubtree;
bool mInActiveTransformedSubtree;
bool mDisableSubpixelAntialiasingInDescendants;
/**
* When this is false, ThebesLayer coordinates are drawn to with an integer
* translation and the scale in mXScale/mYScale.
*/
bool AllowResidualTranslation()
{
// If we're in a transformed subtree, but no ancestor transform is actively
// changing, we'll use the residual translation when drawing into the
// ThebesLayer to ensure that snapping exactly matches the ideal transform.
return mInTransformedSubtree && !mInActiveTransformedSubtree;
}
};
/**
* Build a container layer for a display item that contains a child
* list, either reusing an existing one or creating a new one. It
* sets the container layer children to layers which together render
* the contents of the display list. It reuses existing layers from
* the retained layer manager if possible.
* aContainer may be null, in which case we construct a root layer.
* This gets called by display list code. It calls BuildLayer on the
* items in the display list, making items with their own layers
* children of the new container, and assigning all other items to
* ThebesLayer children created and managed by the FrameLayerBuilder.
* Returns a layer with clip rect cleared; it is the
* caller's responsibility to add any clip rect. The visible region
* is set based on what's in the layer.
* The container layer is transformed by aTransform (if non-null), and
* the result is transformed by the scale factors in aContainerParameters.
*/
already_AddRefed<ContainerLayer>
BuildContainerLayerFor(nsDisplayListBuilder* aBuilder,
LayerManager* aManager,
nsIFrame* aContainerFrame,
nsDisplayItem* aContainerItem,
const nsDisplayList& aChildren,
const ContainerParameters& aContainerParameters,
const gfx3DMatrix* aTransform);
/**
* Get a retained layer for a display item that needs to create its own
* layer for rendering (i.e. under nsDisplayItem::BuildLayer). Returns
* null if no retained layer is available, which usually means that this
* display item didn't have a layer before so the caller will
* need to create one.
* Returns a layer with clip rect cleared; it is the
* caller's responsibility to add any clip rect and set the visible
* region.
*/
Layer* GetLeafLayerFor(nsDisplayListBuilder* aBuilder,
LayerManager* aManager,
nsDisplayItem* aItem);
/**
* Call this during invalidation if aFrame has
* the NS_FRAME_HAS_CONTAINER_LAYER state bit. Only the nearest
* ancestor frame of the damaged frame that has
* NS_FRAME_HAS_CONTAINER_LAYER needs to be invalidated this way.
*/
static void InvalidateThebesLayerContents(nsIFrame* aFrame,
const nsRect& aRect);
/**
* For any descendant frame of aFrame (including across documents) that
* has an associated container layer, invalidate all the contents of
* all ThebesLayer children of the container. Useful when aFrame is
* being moved and we need to invalidate everything in aFrame's subtree.
*/
static void InvalidateThebesLayersInSubtree(nsIFrame* aFrame);
/**
* Call this to force all retained layers to be discarded and recreated at
* the next paint.
*/
static void InvalidateAllLayers(LayerManager* aManager);
/**
* Call this to determine if a frame has a dedicated (non-Thebes) layer
* for the given display item key. If there isn't one, we return null,
* otherwise we return the layer.
*/
static Layer* GetDedicatedLayer(nsIFrame* aFrame, PRUint32 aDisplayItemKey);
/**
* This callback must be provided to EndTransaction. The callback data
* must be the nsDisplayListBuilder containing this FrameLayerBuilder.
* This function can be called multiple times in a row to draw
* different regions.
*/
static void DrawThebesLayer(ThebesLayer* aLayer,
gfxContext* aContext,
const nsIntRegion& aRegionToDraw,
const nsIntRegion& aRegionToInvalidate,
void* aCallbackData);
#ifdef MOZ_DUMP_PAINTING
/**
* Dumps this FrameLayerBuilder's retained layer manager's retained
* layer tree to stderr.
*/
void DumpRetainedLayerTree(FILE* aFile = stdout);
#endif
/******* PRIVATE METHODS to FrameLayerBuilder.cpp ********/
/* These are only in the public section because they need
* to be called by file-scope helper functions in FrameLayerBuilder.cpp.
*/
/**
* Record aItem as a display item that is rendered by aLayer.
*/
void AddLayerDisplayItem(Layer* aLayer,
nsDisplayItem* aItem,
LayerState aLayerState);
/**
* Record aItem as a display item that is rendered by the ThebesLayer
* aLayer, with aClipRect, where aContainerLayerFrame is the frame
* for the container layer this ThebesItem belongs to.
* aItem must have an underlying frame.
*/
struct Clip;
void AddThebesDisplayItem(ThebesLayer* aLayer,
nsDisplayItem* aItem,
const Clip& aClip,
nsIFrame* aContainerLayerFrame,
LayerState aLayerState);
/**
* Given a frame and a display item key that uniquely identifies a
* display item for the frame, find the layer that was last used to
* render that display item. Returns null if there is no such layer.
* This could be a dedicated layer for the display item, or a ThebesLayer
* that renders many display items.
*/
Layer* GetOldLayerFor(nsIFrame* aFrame, PRUint32 aDisplayItemKey);
/**
* Try to determine whether the ThebesLayer aLayer paints an opaque
* single color everywhere it's visible in aRect.
* If successful, return that color, otherwise return NS_RGBA(0,0,0,0).
*/
nscolor FindOpaqueColorCovering(nsDisplayListBuilder* aBuilder,
ThebesLayer* aLayer, const nsRect& aRect);
/**
* Destroy any stored LayerManagerDataProperty and the associated data for
* aFrame.
*/
static void DestroyDisplayItemDataFor(nsIFrame* aFrame)
{
aFrame->Properties().Delete(LayerManagerDataProperty());
}
LayerManager* GetRetainingLayerManager() { return mRetainingManager; }
/**
* Returns true if the given item (which we assume here is
* background-attachment:fixed) needs to be repainted as we scroll in its
* document.
* Returns false if it doesn't need to be repainted because the layer system
* is ensuring its fixed-ness for us.
*/
static bool NeedToInvalidateFixedDisplayItem(nsDisplayListBuilder* aBuilder,
nsDisplayItem* aItem);
/**
* Returns true if the given display item was rendered directly
* into a retained layer.
* Returns false if it was rendered into a temporary layer manager and then
* into a retained layer.
*/
static bool HasRetainedLayerFor(nsIFrame* aFrame, PRUint32 aDisplayItemKey);
/**
* Save transform that was in aLayer when we last painted. It must be an integer
* translation.
*/
void SaveLastPaintOffset(ThebesLayer* aLayer);
/**
* Get the translation transform that was in aLayer when we last painted. It's either
* the transform saved by SaveLastPaintTransform, or else the transform
* that's currently in the layer (which must be an integer translation).
*/
nsIntPoint GetLastPaintOffset(ThebesLayer* aLayer);
/**
* Return resolution and scroll offset of ThebesLayer content associated
* with aFrame's subtree.
* Returns true if some ThebesLayer was found.
* This just looks for the first ThebesLayer and returns its data. There
* could be other ThebesLayers with different resolution and offsets.
*/
static bool GetThebesLayerResolutionForFrame(nsIFrame* aFrame,
double* aXRes, double* aYRes,
gfxPoint* aPoint);
/**
* Clip represents the intersection of an optional rectangle with a
* list of rounded rectangles.
*/
struct Clip {
struct RoundedRect {
nsRect mRect;
// Indices into mRadii are the NS_CORNER_* constants in nsStyleConsts.h
nscoord mRadii[8];
bool operator==(const RoundedRect& aOther) const {
if (!mRect.IsEqualInterior(aOther.mRect)) {
return false;
}
NS_FOR_CSS_HALF_CORNERS(corner) {
if (mRadii[corner] != aOther.mRadii[corner]) {
return false;
}
}
return true;
}
bool operator!=(const RoundedRect& aOther) const {
return !(*this == aOther);
}
};
nsRect mClipRect;
nsTArray<RoundedRect> mRoundedClipRects;
bool mHaveClipRect;
Clip() : mHaveClipRect(false) {}
// Construct as the intersection of aOther and aClipItem.
Clip(const Clip& aOther, nsDisplayItem* aClipItem);
// Apply this |Clip| to the given gfxContext. Any saving of state
// or clearing of other clips must be done by the caller.
// See aBegin/aEnd note on ApplyRoundedRectsTo.
void ApplyTo(gfxContext* aContext, nsPresContext* aPresContext,
PRUint32 aBegin = 0, PRUint32 aEnd = PR_UINT32_MAX);
void ApplyRectTo(gfxContext* aContext, PRInt32 A2D) const;
// Applies the rounded rects in this Clip to aContext
// Will only apply rounded rects from aBegin (inclusive) to aEnd
// (exclusive) or the number of rounded rects, whichever is smaller.
void ApplyRoundedRectsTo(gfxContext* aContext, PRInt32 A2DPRInt32,
PRUint32 aBegin, PRUint32 aEnd) const;
// Draw (fill) the rounded rects in this clip to aContext
void DrawRoundedRectsTo(gfxContext* aContext, PRInt32 A2D,
PRUint32 aBegin, PRUint32 aEnd) const;
// 'Draw' (create as a path, does not stroke or fill) aRoundRect to aContext
void AddRoundedRectPathTo(gfxContext* aContext, PRInt32 A2D,
const RoundedRect &aRoundRect) const;
// Return a rectangle contained in the intersection of aRect with this
// clip region. Tries to return the largest possible rectangle, but may
// not succeed.
nsRect ApproximateIntersect(const nsRect& aRect) const;
// Returns false if aRect is definitely not clipped by a rounded corner in
// this clip. Returns true if aRect is clipped by a rounded corner in this
// clip or it can not be quickly determined that it is not clipped by a
// rounded corner in this clip.
bool IsRectClippedByRoundedCorner(const nsRect& aRect) const;
// Intersection of all rects in this clip ignoring any rounded corners.
nsRect NonRoundedIntersection() const;
// Gets rid of any rounded corners in this clip.
void RemoveRoundedCorners();
bool operator==(const Clip& aOther) const {
return mHaveClipRect == aOther.mHaveClipRect &&
(!mHaveClipRect || mClipRect.IsEqualInterior(aOther.mClipRect)) &&
mRoundedClipRects == aOther.mRoundedClipRects;
}
bool operator!=(const Clip& aOther) const {
return !(*this == aOther);
}
};
protected:
/**
* We store an array of these for each frame that is associated with
* one or more retained layers. Each DisplayItemData records the layer
* used to render one of the frame's display items.
*/
class DisplayItemData {
public:
DisplayItemData(Layer* aLayer, PRUint32 aKey, LayerState aLayerState)
: mLayer(aLayer), mDisplayItemKey(aKey), mLayerState(aLayerState) {}
nsRefPtr<Layer> mLayer;
PRUint32 mDisplayItemKey;
LayerState mLayerState;
};
static void RemoveFrameFromLayerManager(nsIFrame* aFrame, void* aPropertyValue);
NS_DECLARE_FRAME_PROPERTY_WITH_FRAME_IN_DTOR(LayerManagerDataProperty,
RemoveFrameFromLayerManager)
/**
* We accumulate DisplayItemData elements in a hashtable during
* the paint process, and store them in the frame property only when
* paint is complete. This is the hashentry for that hashtable.
*/
class DisplayItemDataEntry : public nsPtrHashKey<nsIFrame> {
public:
DisplayItemDataEntry(const nsIFrame *key) : nsPtrHashKey<nsIFrame>(key), mIsSharingContainerLayer(false) {}
DisplayItemDataEntry(DisplayItemDataEntry &toCopy) :
nsPtrHashKey<nsIFrame>(toCopy.mKey), mIsSharingContainerLayer(toCopy.mIsSharingContainerLayer)
{
// This isn't actually a copy-constructor; notice that it steals toCopy's
// array and invalid region. Be careful.
mData.SwapElements(toCopy.mData);
mInvalidRegion.swap(toCopy.mInvalidRegion);
}
bool HasNonEmptyContainerLayer();
nsAutoTArray<DisplayItemData, 1> mData;
nsRefPtr<RefCountedRegion> mInvalidRegion;
bool mIsSharingContainerLayer;
enum { ALLOW_MEMMOVE = false };
};
// LayerManagerData needs to see DisplayItemDataEntry.
friend class LayerManagerData;
// Flash the area within the context clip if paint flashing is enabled.
static void FlashPaint(gfxContext *aContext);
/*
* Get the DisplayItemData array associated with this frame, or null if one
* doesn't exist.
*
* Note that the pointer returned here is only valid so long as you don't
* poke the LayerManagerData's mFramesWithLayers hashtable.
*/
static nsTArray<DisplayItemData>* GetDisplayItemDataArrayForFrame(nsIFrame *aFrame);
/**
* A useful hashtable iteration function that removes the
* DisplayItemData property for the frame, clears its
* NS_FRAME_HAS_CONTAINER_LAYER bit and returns PL_DHASH_REMOVE.
* aClosure is ignored.
*/
static PLDHashOperator RemoveDisplayItemDataForFrame(DisplayItemDataEntry* aEntry,
void* aClosure)
{
return UpdateDisplayItemDataForFrame(aEntry, nsnull);
}
/**
* We store one of these for each display item associated with a
* ThebesLayer, in a hashtable that maps each ThebesLayer to an array
* of ClippedDisplayItems. (ThebesLayerItemsEntry is the hash entry
* for that hashtable.)
* These are only stored during the paint process, so that the
* DrawThebesLayer callback can figure out which items to draw for the
* ThebesLayer.
* mItem always has an underlying frame.
*/
struct ClippedDisplayItem {
ClippedDisplayItem(nsDisplayItem* aItem, const Clip& aClip)
: mItem(aItem), mClip(aClip)
{
}
nsDisplayItem* mItem;
Clip mClip;
bool mInactiveLayer;
};
/**
* We accumulate ClippedDisplayItem elements in a hashtable during
* the paint process. This is the hashentry for that hashtable.
*/
public:
class ThebesLayerItemsEntry : public nsPtrHashKey<ThebesLayer> {
public:
ThebesLayerItemsEntry(const ThebesLayer *key) :
nsPtrHashKey<ThebesLayer>(key), mContainerLayerFrame(nsnull),
mHasExplicitLastPaintOffset(false), mCommonClipCount(0) {}
ThebesLayerItemsEntry(const ThebesLayerItemsEntry &toCopy) :
nsPtrHashKey<ThebesLayer>(toCopy.mKey), mItems(toCopy.mItems)
{
NS_ERROR("Should never be called, since we ALLOW_MEMMOVE");
}
nsTArray<ClippedDisplayItem> mItems;
nsIFrame* mContainerLayerFrame;
// The translation set on this ThebesLayer before we started updating the
// layer tree.
nsIntPoint mLastPaintOffset;
bool mHasExplicitLastPaintOffset;
/**
* The first mCommonClipCount rounded rectangle clips are identical for
* all items in the layer. Computed in ThebesLayerData.
*/
PRUint32 mCommonClipCount;
enum { ALLOW_MEMMOVE = true };
};
/**
* Get the ThebesLayerItemsEntry object associated with aLayer in this
* FrameLayerBuilder
*/
ThebesLayerItemsEntry* GetThebesLayerItemsEntry(ThebesLayer* aLayer)
{
return mThebesLayerItems.GetEntry(aLayer);
}
protected:
void RemoveThebesItemsForLayerSubtree(Layer* aLayer);
static void SetAndClearInvalidRegion(DisplayItemDataEntry* aEntry);
static PLDHashOperator UpdateDisplayItemDataForFrame(DisplayItemDataEntry* aEntry,
void* aUserArg);
static PLDHashOperator StoreNewDisplayItemData(DisplayItemDataEntry* aEntry,
void* aUserArg);
/**
* Returns true if the DOM has been modified since we started painting,
* in which case we should bail out and not paint anymore. This should
* never happen, but plugins can trigger it in some cases.
*/
bool CheckDOMModified();
/**
* The layer manager belonging to the widget that is being retained
* across paints.
*/
LayerManager* mRetainingManager;
/**
* The root prescontext for the display list builder reference frame
*/
nsRootPresContext* mRootPresContext;
/**
* A map from frames to a list of (display item key, layer) pairs that
* describes what layers various parts of the frame are assigned to.
*/
nsTHashtable<DisplayItemDataEntry> mNewDisplayItemData;
/**
* A map from ThebesLayers to the list of display items (plus
* clipping data) to be rendered in the layer.
*/
nsTHashtable<ThebesLayerItemsEntry> mThebesLayerItems;
/**
* Saved generation counter so we can detect DOM changes.
*/
PRUint32 mInitialDOMGeneration;
/**
* Set to true if we have detected and reported DOM modification during
* the current paint.
*/
bool mDetectedDOMModification;
/**
* Indicates that the entire layer tree should be rerendered
* during this paint.
*/
bool mInvalidateAllLayers;
};
}
#endif /* FRAMELAYERBUILDER_H_ */