gecko-dev/layout/base/nsDisplayListInvalidation.h

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/*-*- Mode: C++; tab-width: 2; 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 NSDISPLAYLISTINVALIDATION_H_
#define NSDISPLAYLISTINVALIDATION_H_
#include "mozilla/Attributes.h"
#include "FrameLayerBuilder.h"
#include "imgIContainer.h"
#include "nsRect.h"
#include "nsColor.h"
#include "gfxRect.h"
class nsDisplayBackgroundImage;
class nsCharClipDisplayItem;
class nsDisplayItem;
class nsDisplayListBuilder;
class nsDisplaySVGEffects;
class nsDisplayTableItem;
class nsDisplayThemedBackground;
/**
* This stores the geometry of an nsDisplayItem, and the area
* that will be affected when painting the item.
*
* It is used to retain information about display items so they
* can be compared against new display items in the next paint.
*/
class nsDisplayItemGeometry
{
public:
nsDisplayItemGeometry(nsDisplayItem* aItem, nsDisplayListBuilder* aBuilder);
virtual ~nsDisplayItemGeometry();
/**
* Compute the area required to be invalidated if this
* display item is removed.
*/
const nsRect& ComputeInvalidationRegion() { return mBounds; }
/**
* Shifts all retained areas of the nsDisplayItemGeometry by the given offset.
*
* This is used to compensate for scrolling, since the destination buffer
* can scroll without requiring a full repaint.
*
* @param aOffset Offset to shift by.
*/
virtual void MoveBy(const nsPoint& aOffset)
{
mBounds.MoveBy(aOffset);
}
/**
* Bounds of the display item
*/
nsRect mBounds;
};
/**
* A default geometry implementation, used by nsDisplayItem. Retains
* and compares the bounds, and border rect.
*
* This should be sufficient for the majority of display items.
*/
class nsDisplayItemGenericGeometry : public nsDisplayItemGeometry
{
public:
nsDisplayItemGenericGeometry(nsDisplayItem* aItem, nsDisplayListBuilder* aBuilder);
virtual void MoveBy(const nsPoint& aOffset) override;
nsRect mBorderRect;
};
bool ShouldSyncDecodeImages(nsDisplayListBuilder* aBuilder);
/**
* nsImageGeometryMixin is a mixin for geometry items that draw images. Geometry
* items that include this mixin can track drawing results and use that
* information to inform invalidation decisions.
*
* This mixin uses CRTP; its template parameter should be the type of the class
* that is inheriting from it. See nsDisplayItemGenericImageGeometry for an
* example.
*/
template <typename T>
class nsImageGeometryMixin
{
public:
nsImageGeometryMixin(nsDisplayItem* aItem, nsDisplayListBuilder* aBuilder)
: mLastDrawResult(mozilla::image::DrawResult::NOT_READY)
, mWaitingForPaint(false)
{
// Transfer state from the previous version of this geometry item.
auto lastGeometry =
static_cast<T*>(mozilla::FrameLayerBuilder::GetMostRecentGeometry(aItem));
if (lastGeometry) {
mLastDrawResult = lastGeometry->mLastDrawResult;
mWaitingForPaint = lastGeometry->mWaitingForPaint;
}
// If our display item is going to invalidate to trigger sync decoding of
// images, mark ourselves as waiting for a paint. If we actually get
// painted, UpdateDrawResult will get called, and we'll clear the flag.
if (ShouldSyncDecodeImages(aBuilder) &&
ShouldInvalidateToSyncDecodeImages()) {
mWaitingForPaint = true;
}
}
static void UpdateDrawResult(nsDisplayItem* aItem,
mozilla::image::DrawResult aResult)
{
auto lastGeometry =
static_cast<T*>(mozilla::FrameLayerBuilder::GetMostRecentGeometry(aItem));
if (lastGeometry) {
lastGeometry->mLastDrawResult = aResult;
lastGeometry->mWaitingForPaint = false;
}
}
bool ShouldInvalidateToSyncDecodeImages() const
{
if (mWaitingForPaint) {
// We previously invalidated for sync decoding and haven't gotten painted
// since them. This suggests that our display item is completely occluded
// and there's no point in invalidating again - and because the reftest
// harness takes a new snapshot every time we invalidate, doing so might
// lead to an invalidation loop if we're in a reftest.
return false;
}
if (mLastDrawResult == mozilla::image::DrawResult::SUCCESS ||
mLastDrawResult == mozilla::image::DrawResult::BAD_IMAGE) {
return false;
}
return true;
}
private:
mozilla::image::DrawResult mLastDrawResult;
bool mWaitingForPaint;
};
/**
* nsDisplayItemGenericImageGeometry is a generic geometry item class that
* includes nsImageGeometryMixin.
*
* This should be sufficient for most display items that draw images.
*/
class nsDisplayItemGenericImageGeometry
: public nsDisplayItemGenericGeometry
, public nsImageGeometryMixin<nsDisplayItemGenericImageGeometry>
{
public:
nsDisplayItemGenericImageGeometry(nsDisplayItem* aItem,
nsDisplayListBuilder* aBuilder)
: nsDisplayItemGenericGeometry(aItem, aBuilder)
, nsImageGeometryMixin(aItem, aBuilder)
{ }
};
class nsDisplayItemBoundsGeometry : public nsDisplayItemGeometry
{
public:
nsDisplayItemBoundsGeometry(nsDisplayItem* aItem, nsDisplayListBuilder* aBuilder);
bool mHasRoundedCorners;
};
class nsDisplayBorderGeometry : public nsDisplayItemGeometry
{
public:
nsDisplayBorderGeometry(nsDisplayItem* aItem, nsDisplayListBuilder* aBuilder);
virtual void MoveBy(const nsPoint& aOffset) override;
nsRect mContentRect;
};
class nsDisplayBackgroundGeometry
: public nsDisplayItemGeometry
, public nsImageGeometryMixin<nsDisplayBackgroundGeometry>
{
public:
nsDisplayBackgroundGeometry(nsDisplayBackgroundImage* aItem, nsDisplayListBuilder* aBuilder);
virtual void MoveBy(const nsPoint& aOffset) override;
nsRect mPositioningArea;
};
class nsDisplayThemedBackgroundGeometry : public nsDisplayItemGeometry
{
public:
nsDisplayThemedBackgroundGeometry(nsDisplayThemedBackground* aItem, nsDisplayListBuilder* aBuilder);
virtual void MoveBy(const nsPoint& aOffset) override;
nsRect mPositioningArea;
bool mWindowIsActive;
};
class nsDisplayBoxShadowInnerGeometry : public nsDisplayItemGeometry
{
public:
nsDisplayBoxShadowInnerGeometry(nsDisplayItem* aItem, nsDisplayListBuilder* aBuilder);
virtual void MoveBy(const nsPoint& aOffset) override;
nsRect mPaddingRect;
};
class nsDisplayBoxShadowOuterGeometry : public nsDisplayItemGenericGeometry
{
public:
nsDisplayBoxShadowOuterGeometry(nsDisplayItem* aItem,
nsDisplayListBuilder* aBuilder,
float aOpacity);
float mOpacity;
};
class nsDisplaySolidColorGeometry : public nsDisplayItemBoundsGeometry
{
public:
nsDisplaySolidColorGeometry(nsDisplayItem* aItem,
nsDisplayListBuilder* aBuilder,
nscolor aColor)
: nsDisplayItemBoundsGeometry(aItem, aBuilder)
, mColor(aColor)
{ }
nscolor mColor;
};
class nsDisplaySVGEffectsGeometry : public nsDisplayItemGeometry
{
public:
nsDisplaySVGEffectsGeometry(nsDisplaySVGEffects* aItem, nsDisplayListBuilder* aBuilder);
virtual void MoveBy(const nsPoint& aOffset) override;
gfxRect mBBox;
gfxPoint mUserSpaceOffset;
nsPoint mFrameOffsetToReferenceFrame;
};
class nsCharClipGeometry : public nsDisplayItemGenericGeometry
{
public:
nsCharClipGeometry(nsCharClipDisplayItem* aItem, nsDisplayListBuilder* aBuilder);
nscoord mVisIStartEdge;
nscoord mVisIEndEdge;
};
class nsDisplayTableItemGeometry
: public nsDisplayItemGenericGeometry
, public nsImageGeometryMixin<nsDisplayTableItemGeometry>
{
public:
nsDisplayTableItemGeometry(nsDisplayTableItem* aItem,
nsDisplayListBuilder* aBuilder,
const nsPoint& aFrameOffsetToViewport);
nsPoint mFrameOffsetToViewport;
};
#endif /*NSDISPLAYLISTINVALIDATION_H_*/