gecko-dev/image/ClippedImage.cpp

497 lines
16 KiB
C++

/* -*- 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/. */
#include <new> // Workaround for bug in VS10; see bug 981264.
#include <cmath>
#include <utility>
#include "gfxDrawable.h"
#include "gfxPlatform.h"
#include "gfxUtils.h"
#include "mozilla/gfx/2D.h"
#include "mozilla/RefPtr.h"
#include "ImageRegion.h"
#include "Orientation.h"
#include "SVGImageContext.h"
#include "ClippedImage.h"
namespace mozilla {
using namespace gfx;
using layers::LayerManager;
using layers::ImageContainer;
using std::make_pair;
using std::modf;
using std::pair;
namespace image {
class ClippedImageCachedSurface
{
public:
ClippedImageCachedSurface(already_AddRefed<SourceSurface> aSurface,
const nsIntSize& aSize,
const Maybe<SVGImageContext>& aSVGContext,
float aFrame,
uint32_t aFlags)
: mSurface(aSurface)
, mSize(aSize)
, mFrame(aFrame)
, mFlags(aFlags)
{
MOZ_ASSERT(mSurface, "Must have a valid surface");
if (aSVGContext) {
mSVGContext.emplace(*aSVGContext);
}
}
bool Matches(const nsIntSize& aSize,
const Maybe<SVGImageContext>& aSVGContext,
float aFrame,
uint32_t aFlags)
{
return mSize == aSize &&
mSVGContext == aSVGContext &&
mFrame == aFrame &&
mFlags == aFlags;
}
already_AddRefed<SourceSurface> Surface() {
RefPtr<SourceSurface> surf(mSurface);
return surf.forget();
}
private:
RefPtr<SourceSurface> mSurface;
const nsIntSize mSize;
Maybe<SVGImageContext> mSVGContext;
const float mFrame;
const uint32_t mFlags;
};
class DrawSingleTileCallback : public gfxDrawingCallback
{
public:
DrawSingleTileCallback(ClippedImage* aImage,
const nsIntSize& aSize,
const Maybe<SVGImageContext>& aSVGContext,
uint32_t aWhichFrame,
uint32_t aFlags)
: mImage(aImage)
, mSize(aSize)
, mSVGContext(aSVGContext)
, mWhichFrame(aWhichFrame)
, mFlags(aFlags)
{
MOZ_ASSERT(mImage, "Must have an image to clip");
}
virtual bool operator()(gfxContext* aContext,
const gfxRect& aFillRect,
const GraphicsFilter& aFilter,
const gfxMatrix& aTransform)
{
MOZ_ASSERT(aTransform.IsIdentity(),
"Caller is probably CreateSamplingRestrictedDrawable, "
"which should not happen");
// Draw the image. |gfxCallbackDrawable| always calls this function with
// arguments that guarantee we never tile.
mImage->DrawSingleTile(aContext, mSize, ImageRegion::Create(aFillRect),
mWhichFrame, aFilter, mSVGContext, mFlags);
return true;
}
private:
nsRefPtr<ClippedImage> mImage;
const nsIntSize mSize;
const Maybe<SVGImageContext>& mSVGContext;
const uint32_t mWhichFrame;
const uint32_t mFlags;
};
ClippedImage::ClippedImage(Image* aImage,
nsIntRect aClip)
: ImageWrapper(aImage)
, mClip(aClip)
{
MOZ_ASSERT(aImage != nullptr, "ClippedImage requires an existing Image");
}
ClippedImage::~ClippedImage()
{ }
bool
ClippedImage::ShouldClip()
{
// We need to evaluate the clipping region against the image's width and
// height once they're available to determine if it's valid and whether we
// actually need to do any work. We may fail if the image's width and height
// aren't available yet, in which case we'll try again later.
if (mShouldClip.isNothing()) {
int32_t width, height;
nsRefPtr<ProgressTracker> progressTracker =
InnerImage()->GetProgressTracker();
if (InnerImage()->HasError()) {
// If there's a problem with the inner image we'll let it handle
// everything.
mShouldClip.emplace(false);
} else if (NS_SUCCEEDED(InnerImage()->GetWidth(&width)) && width > 0 &&
NS_SUCCEEDED(InnerImage()->GetHeight(&height)) && height > 0) {
// Clamp the clipping region to the size of the underlying image.
mClip = mClip.Intersect(nsIntRect(0, 0, width, height));
// If the clipping region is the same size as the underlying image we
// don't have to do anything.
mShouldClip.emplace(!mClip.IsEqualInterior(nsIntRect(0, 0, width,
height)));
} else if (progressTracker &&
!(progressTracker->GetProgress() & FLAG_LOAD_COMPLETE)) {
// The image just hasn't finished loading yet. We don't yet know whether
// clipping with be needed or not for now. Just return without memorizing
// anything.
return false;
} else {
// We have a fully loaded image without a clearly defined width and
// height. This can happen with SVG images.
mShouldClip.emplace(false);
}
}
MOZ_ASSERT(mShouldClip.isSome(), "Should have computed a result");
return *mShouldClip;
}
NS_IMPL_ISUPPORTS_INHERITED0(ClippedImage, ImageWrapper)
NS_IMETHODIMP
ClippedImage::GetWidth(int32_t* aWidth)
{
if (!ShouldClip()) {
return InnerImage()->GetWidth(aWidth);
}
*aWidth = mClip.width;
return NS_OK;
}
NS_IMETHODIMP
ClippedImage::GetHeight(int32_t* aHeight)
{
if (!ShouldClip()) {
return InnerImage()->GetHeight(aHeight);
}
*aHeight = mClip.height;
return NS_OK;
}
NS_IMETHODIMP
ClippedImage::GetIntrinsicSize(nsSize* aSize)
{
if (!ShouldClip()) {
return InnerImage()->GetIntrinsicSize(aSize);
}
*aSize = nsSize(mClip.width, mClip.height);
return NS_OK;
}
NS_IMETHODIMP
ClippedImage::GetIntrinsicRatio(nsSize* aRatio)
{
if (!ShouldClip()) {
return InnerImage()->GetIntrinsicRatio(aRatio);
}
*aRatio = nsSize(mClip.width, mClip.height);
return NS_OK;
}
NS_IMETHODIMP_(already_AddRefed<SourceSurface>)
ClippedImage::GetFrame(uint32_t aWhichFrame,
uint32_t aFlags)
{
return GetFrameInternal(mClip.Size(), Nothing(), aWhichFrame, aFlags);
}
NS_IMETHODIMP_(already_AddRefed<SourceSurface>)
ClippedImage::GetFrameAtSize(const IntSize& aSize,
uint32_t aWhichFrame,
uint32_t aFlags)
{
// XXX(seth): It'd be nice to support downscale-during-decode for this case,
// but right now we just fall back to the intrinsic size.
return GetFrame(aWhichFrame, aFlags);
}
already_AddRefed<SourceSurface>
ClippedImage::GetFrameInternal(const nsIntSize& aSize,
const Maybe<SVGImageContext>& aSVGContext,
uint32_t aWhichFrame,
uint32_t aFlags)
{
if (!ShouldClip()) {
return InnerImage()->GetFrame(aWhichFrame, aFlags);
}
float frameToDraw = InnerImage()->GetFrameIndex(aWhichFrame);
if (!mCachedSurface || !mCachedSurface->Matches(aSize,
aSVGContext,
frameToDraw,
aFlags)) {
// Create a surface to draw into.
RefPtr<DrawTarget> target = gfxPlatform::GetPlatform()->
CreateOffscreenContentDrawTarget(IntSize(aSize.width, aSize.height),
SurfaceFormat::B8G8R8A8);
if (!target) {
NS_ERROR("Could not create a DrawTarget");
return nullptr;
}
nsRefPtr<gfxContext> ctx = new gfxContext(target);
// Create our callback.
nsRefPtr<gfxDrawingCallback> drawTileCallback =
new DrawSingleTileCallback(this, aSize, aSVGContext, aWhichFrame, aFlags);
nsRefPtr<gfxDrawable> drawable =
new gfxCallbackDrawable(drawTileCallback, aSize);
// Actually draw. The callback will end up invoking DrawSingleTile.
gfxUtils::DrawPixelSnapped(ctx, drawable, aSize,
ImageRegion::Create(aSize),
SurfaceFormat::B8G8R8A8,
GraphicsFilter::FILTER_FAST,
imgIContainer::FLAG_CLAMP);
// Cache the resulting surface.
mCachedSurface = new ClippedImageCachedSurface(target->Snapshot(), aSize,
aSVGContext, frameToDraw,
aFlags);
}
MOZ_ASSERT(mCachedSurface, "Should have a cached surface now");
return mCachedSurface->Surface();
}
NS_IMETHODIMP_(bool)
ClippedImage::IsImageContainerAvailable(LayerManager* aManager, uint32_t aFlags)
{
if (!ShouldClip()) {
return InnerImage()->IsImageContainerAvailable(aManager, aFlags);
}
return false;
}
NS_IMETHODIMP_(already_AddRefed<ImageContainer>)
ClippedImage::GetImageContainer(LayerManager* aManager, uint32_t aFlags)
{
// XXX(seth): We currently don't have a way of clipping the result of
// GetImageContainer. We work around this by always returning null, but if it
// ever turns out that ClippedImage is widely used on codepaths that can
// actually benefit from GetImageContainer, it would be a good idea to fix
// that method for performance reasons.
if (!ShouldClip()) {
return InnerImage()->GetImageContainer(aManager, aFlags);
}
return nullptr;
}
static bool
MustCreateSurface(gfxContext* aContext,
const nsIntSize& aSize,
const ImageRegion& aRegion,
const uint32_t aFlags)
{
gfxRect imageRect(0, 0, aSize.width, aSize.height);
bool willTile = !imageRect.Contains(aRegion.Rect()) &&
!(aFlags & imgIContainer::FLAG_CLAMP);
bool willResample = aContext->CurrentMatrix().HasNonIntegerTranslation() &&
(willTile || !aRegion.RestrictionContains(imageRect));
return willTile || willResample;
}
NS_IMETHODIMP_(DrawResult)
ClippedImage::Draw(gfxContext* aContext,
const nsIntSize& aSize,
const ImageRegion& aRegion,
uint32_t aWhichFrame,
GraphicsFilter aFilter,
const Maybe<SVGImageContext>& aSVGContext,
uint32_t aFlags)
{
if (!ShouldClip()) {
return InnerImage()->Draw(aContext, aSize, aRegion, aWhichFrame,
aFilter, aSVGContext, aFlags);
}
// Check for tiling. If we need to tile then we need to create a
// gfxCallbackDrawable to handle drawing for us.
if (MustCreateSurface(aContext, aSize, aRegion, aFlags)) {
// Create a temporary surface containing a single tile of this image.
// GetFrame will call DrawSingleTile internally.
RefPtr<SourceSurface> surface =
GetFrameInternal(aSize, aSVGContext, aWhichFrame, aFlags);
if (!surface) {
return DrawResult::TEMPORARY_ERROR;
}
// Create a drawable from that surface.
nsRefPtr<gfxSurfaceDrawable> drawable =
new gfxSurfaceDrawable(surface, aSize);
// Draw.
gfxUtils::DrawPixelSnapped(aContext, drawable, aSize, aRegion,
SurfaceFormat::B8G8R8A8, aFilter);
return DrawResult::SUCCESS;
}
return DrawSingleTile(aContext, aSize, aRegion, aWhichFrame,
aFilter, aSVGContext, aFlags);
}
static SVGImageContext
UnclipViewport(const SVGImageContext& aOldContext,
const pair<nsIntSize, nsIntSize>& aInnerAndClipSize)
{
nsIntSize innerSize(aInnerAndClipSize.first);
nsIntSize clipSize(aInnerAndClipSize.second);
// Map the viewport to the inner image. (Note that we don't take the aSize
// parameter of Draw into account, just the clipping region.)
CSSIntSize vSize(aOldContext.GetViewportSize());
vSize.width = ceil(vSize.width * double(innerSize.width) / clipSize.width);
vSize.height =
ceil(vSize.height * double(innerSize.height) / clipSize.height);
return SVGImageContext(vSize,
aOldContext.GetPreserveAspectRatio());
}
DrawResult
ClippedImage::DrawSingleTile(gfxContext* aContext,
const nsIntSize& aSize,
const ImageRegion& aRegion,
uint32_t aWhichFrame,
GraphicsFilter aFilter,
const Maybe<SVGImageContext>& aSVGContext,
uint32_t aFlags)
{
MOZ_ASSERT(!MustCreateSurface(aContext, aSize, aRegion, aFlags),
"Shouldn't need to create a surface");
gfxRect clip(mClip.x, mClip.y, mClip.width, mClip.height);
nsIntSize size(aSize), innerSize(aSize);
if (NS_SUCCEEDED(InnerImage()->GetWidth(&innerSize.width)) &&
NS_SUCCEEDED(InnerImage()->GetHeight(&innerSize.height))) {
double scaleX = aSize.width / clip.width;
double scaleY = aSize.height / clip.height;
// Map the clip and size to the scale requested by the caller.
clip.Scale(scaleX, scaleY);
size = innerSize;
size.Scale(scaleX, scaleY);
} else {
MOZ_ASSERT(false,
"If ShouldClip() led us to draw then we should never get here");
}
// We restrict our drawing to only the clipping region, and translate so that
// the clipping region is placed at the position the caller expects.
ImageRegion region(aRegion);
region.MoveBy(clip.x, clip.y);
region = region.Intersect(clip);
gfxContextMatrixAutoSaveRestore saveMatrix(aContext);
aContext->Multiply(gfxMatrix::Translation(-clip.x, -clip.y));
return InnerImage()->Draw(aContext, size, region,
aWhichFrame, aFilter,
aSVGContext.map(UnclipViewport,
make_pair(innerSize, mClip.Size())),
aFlags);
}
NS_IMETHODIMP
ClippedImage::RequestDiscard()
{
// We're very aggressive about discarding.
mCachedSurface = nullptr;
return InnerImage()->RequestDiscard();
}
NS_IMETHODIMP_(Orientation)
ClippedImage::GetOrientation()
{
// XXX(seth): This should not actually be here; this is just to work around a
// what appears to be a bug in MSVC's linker.
return InnerImage()->GetOrientation();
}
nsIntSize
ClippedImage::OptimalImageSizeForDest(const gfxSize& aDest,
uint32_t aWhichFrame,
GraphicsFilter aFilter, uint32_t aFlags)
{
if (!ShouldClip()) {
return InnerImage()->OptimalImageSizeForDest(aDest, aWhichFrame, aFilter,
aFlags);
}
int32_t imgWidth, imgHeight;
if (NS_SUCCEEDED(InnerImage()->GetWidth(&imgWidth)) &&
NS_SUCCEEDED(InnerImage()->GetHeight(&imgHeight))) {
// To avoid ugly sampling artifacts, ClippedImage needs the image size to
// be chosen such that the clipping region lies on pixel boundaries.
// First, we select a scale that's good for ClippedImage. An integer
// multiple of the size of the clipping region is always fine.
nsIntSize scale(ceil(aDest.width / mClip.width),
ceil(aDest.height / mClip.height));
// Determine the size we'd prefer to render the inner image at, and ask the
// inner image what size we should actually use.
gfxSize desiredSize(imgWidth * scale.width, imgHeight * scale.height);
nsIntSize innerDesiredSize =
InnerImage()->OptimalImageSizeForDest(desiredSize, aWhichFrame,
aFilter, aFlags);
// To get our final result, we take the inner image's desired size and
// determine how large the clipped region would be at that scale. (Again, we
// ensure an integer multiple of the size of the clipping region.)
nsIntSize finalScale(ceil(double(innerDesiredSize.width) / imgWidth),
ceil(double(innerDesiredSize.height) / imgHeight));
return mClip.Size() * finalScale;
} else {
MOZ_ASSERT(false,
"If ShouldClip() led us to draw then we should never get here");
return InnerImage()->OptimalImageSizeForDest(aDest, aWhichFrame, aFilter,
aFlags);
}
}
NS_IMETHODIMP_(nsIntRect)
ClippedImage::GetImageSpaceInvalidationRect(const nsIntRect& aRect)
{
if (!ShouldClip()) {
return InnerImage()->GetImageSpaceInvalidationRect(aRect);
}
nsIntRect rect(InnerImage()->GetImageSpaceInvalidationRect(aRect));
rect = rect.Intersect(mClip);
rect.MoveBy(-mClip.x, -mClip.y);
return rect;
}
} // namespace image
} // namespace mozilla