skia2/include/core/SkImage.h
brianosman 69c166d2ce Add alphaType() to SkImage
Keep isOpaque as a convenience method -- many places really only need to
know that for optimization purposes (SrcOver -> Src, etc...).

In all the places where we pull data back out or convert to another
object and need to supply an SkImageInfo, we can avoid losing information
about premulness.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2250663002

Review-Url: https://codereview.chromium.org/2250663002
2016-08-17 14:01:05 -07:00

483 lines
22 KiB
C++

/*
* Copyright 2012 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkImage_DEFINED
#define SkImage_DEFINED
#include "SkFilterQuality.h"
#include "SkImageInfo.h"
#include "SkImageEncoder.h"
#include "SkRefCnt.h"
#include "SkScalar.h"
#include "SkShader.h"
class SkData;
class SkCanvas;
class SkColorTable;
class SkImageGenerator;
class SkPaint;
class SkPicture;
class SkPixelSerializer;
class SkString;
class SkSurface;
class GrContext;
class GrContextThreadSafeProxy;
class GrTexture;
/**
* SkImage is an abstraction for drawing a rectagle of pixels, though the
* particular type of image could be actually storing its data on the GPU, or
* as drawing commands (picture or PDF or otherwise), ready to be played back
* into another canvas.
*
* The content of SkImage is always immutable, though the actual storage may
* change, if for example that image can be re-created via encoded data or
* other means.
*
* SkImage always has a non-zero dimensions. If there is a request to create a new image, either
* directly or via SkSurface, and either of the requested dimensions are zero, then NULL will be
* returned.
*/
class SK_API SkImage : public SkRefCnt {
public:
typedef SkImageInfo Info;
typedef void* ReleaseContext;
static sk_sp<SkImage> MakeRasterCopy(const SkPixmap&);
static sk_sp<SkImage> MakeRasterData(const Info&, sk_sp<SkData> pixels, size_t rowBytes);
typedef void (*RasterReleaseProc)(const void* pixels, ReleaseContext);
/**
* Return a new Image referencing the specified pixels. These must remain valid and unchanged
* until the specified release-proc is called, indicating that Skia no longer has a reference
* to the pixels.
*
* Returns NULL if the requested pixmap info is unsupported.
*/
static sk_sp<SkImage> MakeFromRaster(const SkPixmap&, RasterReleaseProc, ReleaseContext);
/**
* Construct a new image from the specified bitmap. If the bitmap is marked immutable, and
* its pixel memory is shareable, it may be shared instead of copied.
*/
static sk_sp<SkImage> MakeFromBitmap(const SkBitmap&);
/**
* Construct a new SkImage based on the given ImageGenerator. Returns NULL on error.
* This function will always take ownership of the passed generator.
*
* If a subset is specified, it must be contained within the generator's bounds.
*/
static sk_sp<SkImage> MakeFromGenerator(SkImageGenerator*, const SkIRect* subset = nullptr);
/**
* Construct a new SkImage based on the specified encoded data. Returns NULL on failure,
* which can mean that the format of the encoded data was not recognized/supported.
*
* If a subset is specified, it must be contained within the encoded data's bounds.
*/
static sk_sp<SkImage> MakeFromEncoded(sk_sp<SkData> encoded, const SkIRect* subset = nullptr);
/**
* Create a new image from the specified descriptor. Note - the caller is responsible for
* managing the lifetime of the underlying platform texture.
*
* Will return NULL if the specified descriptor is unsupported.
*/
static sk_sp<SkImage> MakeFromTexture(GrContext* ctx, const GrBackendTextureDesc& desc) {
return MakeFromTexture(ctx, desc, kPremul_SkAlphaType, nullptr, nullptr, nullptr);
}
static sk_sp<SkImage> MakeFromTexture(GrContext* ctx, const GrBackendTextureDesc& de,
SkAlphaType at) {
return MakeFromTexture(ctx, de, at, nullptr, nullptr, nullptr);
}
typedef void (*TextureReleaseProc)(ReleaseContext);
/**
* Create a new image from the specified descriptor. The underlying platform texture must stay
* valid and unaltered until the specified release-proc is invoked, indicating that Skia
* no longer is holding a reference to it.
*
* Will return NULL if the specified descriptor is unsupported.
*/
static sk_sp<SkImage> MakeFromTexture(GrContext* ctx, const GrBackendTextureDesc& desc,
SkAlphaType at, TextureReleaseProc trp,
ReleaseContext rc) {
return MakeFromTexture(ctx, desc, at, nullptr, trp, rc);
}
/**
* Create a new image from the specified descriptor. The underlying platform texture must stay
* valid and unaltered until the specified release-proc is invoked, indicating that Skia
* no longer is holding a reference to it.
*
* Will return NULL if the specified descriptor is unsupported.
*/
static sk_sp<SkImage> MakeFromTexture(GrContext*, const GrBackendTextureDesc&, SkAlphaType,
sk_sp<SkColorSpace>, TextureReleaseProc, ReleaseContext);
/**
* Create a new image from the specified descriptor. Note - Skia will delete or recycle the
* texture when the image is released.
*
* Will return NULL if the specified descriptor is unsupported.
*/
static sk_sp<SkImage> MakeFromAdoptedTexture(GrContext*, const GrBackendTextureDesc&,
SkAlphaType = kPremul_SkAlphaType,
sk_sp<SkColorSpace> = nullptr);
/**
* Create a new image by copying the pixels from the specified y, u, v textures. The data
* from the textures is immediately ingested into the image and the textures can be modified or
* deleted after the function returns. The image will have the dimensions of the y texture.
*/
static sk_sp<SkImage> MakeFromYUVTexturesCopy(GrContext*, SkYUVColorSpace,
const GrBackendObject yuvTextureHandles[3],
const SkISize yuvSizes[3],
GrSurfaceOrigin,
sk_sp<SkColorSpace> = nullptr);
/**
* Create a new image by copying the pixels from the specified y and uv textures. The data
* from the textures is immediately ingested into the image and the textures can be modified or
* deleted after the function returns. The image will have the dimensions of the y texture.
*/
static sk_sp<SkImage> MakeFromNV12TexturesCopy(GrContext*, SkYUVColorSpace,
const GrBackendObject nv12TextureHandles[2],
const SkISize nv12Sizes[2], GrSurfaceOrigin,
sk_sp<SkColorSpace> = nullptr);
static sk_sp<SkImage> MakeFromPicture(sk_sp<SkPicture>, const SkISize& dimensions,
const SkMatrix*, const SkPaint*);
static sk_sp<SkImage> MakeTextureFromPixmap(GrContext*, const SkPixmap&, SkBudgeted budgeted);
///////////////////////////////////////////////////////////////////////////////////////////////
int width() const { return fWidth; }
int height() const { return fHeight; }
SkISize dimensions() const { return SkISize::Make(fWidth, fHeight); }
SkIRect bounds() const { return SkIRect::MakeWH(fWidth, fHeight); }
uint32_t uniqueID() const { return fUniqueID; }
SkAlphaType alphaType() const;
bool isOpaque() const { return SkAlphaTypeIsOpaque(this->alphaType()); }
/**
* Extracts YUV planes from the SkImage and stores them in client-provided memory. The sizes
* planes and rowBytes arrays are ordered [y, u, v].
*/
bool readYUV8Planes(const SkISize[3], void* const planes[3], const size_t rowBytes[3],
SkYUVColorSpace) const;
#ifdef SK_SUPPORT_LEGACY_CREATESHADER_PTR
SkShader* newShader(SkShader::TileMode, SkShader::TileMode,
const SkMatrix* localMatrix = nullptr) const;
#endif
sk_sp<SkShader> makeShader(SkShader::TileMode, SkShader::TileMode,
const SkMatrix* localMatrix = nullptr) const;
/**
* If the image has direct access to its pixels (i.e. they are in local RAM)
* return true, and if not null, return in the pixmap parameter the info about the
* images pixels.
*
* On failure, return false and ignore the pixmap parameter.
*/
bool peekPixels(SkPixmap* pixmap) const;
#ifdef SK_SUPPORT_LEGACY_PEEKPIXELS_PARMS
/**
* If the image has direct access to its pixels (i.e. they are in local
* RAM) return the (const) address of those pixels, and if not null, return
* the ImageInfo and rowBytes. The returned address is only valid while
* the image object is in scope.
*
* On failure, returns NULL and the info and rowBytes parameters are
* ignored.
*
* DEPRECATED -- use the SkPixmap variant instead
*/
const void* peekPixels(SkImageInfo* info, size_t* rowBytes) const;
#endif
/**
* Some images have to perform preliminary work in preparation for drawing. This can be
* decoding, uploading to a GPU, or other tasks. These happen automatically when an image
* is drawn, and often they are cached so that the cost is only paid the first time.
*
* Preroll() can be called before drawing to try to perform this prepatory work ahead of time.
* For images that have no such work, this returns instantly. Others may do some thing to
* prepare their cache and then return.
*
* If the image will drawn to a GPU-backed canvas or surface, pass the associated GrContext.
* If the image will be drawn to any other type of canvas or surface, pass null.
*/
void preroll(GrContext* = nullptr) const;
// DEPRECATED - currently used by Canvas2DLayerBridge in Chromium.
GrTexture* getTexture() const;
/**
* Returns true if the image is texture backed.
*/
bool isTextureBacked() const;
/**
* Retrieves the backend API handle of the texture. If flushPendingGrContextIO then the
* GrContext will issue to the backend API any deferred IO operations on the texture before
* returning.
*/
GrBackendObject getTextureHandle(bool flushPendingGrContextIO) const;
/**
* Hints to image calls where the system might cache computed intermediates (e.g. the results
* of decoding or a read-back from the GPU. Passing kAllow signals that the system's default
* behavior is fine. Passing kDisallow signals that caching should be avoided.
*/
enum CachingHint {
kAllow_CachingHint,
kDisallow_CachingHint,
};
/**
* Copy the pixels from the image into the specified buffer (pixels + rowBytes),
* converting them into the requested format (dstInfo). The image pixels are read
* starting at the specified (srcX,srcY) location.
*
* The specified ImageInfo and (srcX,srcY) offset specifies a source rectangle
*
* srcR.setXYWH(srcX, srcY, dstInfo.width(), dstInfo.height());
*
* srcR is intersected with the bounds of the image. If this intersection is not empty,
* then we have two sets of pixels (of equal size). Replace the dst pixels with the
* corresponding src pixels, performing any colortype/alphatype transformations needed
* (in the case where the src and dst have different colortypes or alphatypes).
*
* This call can fail, returning false, for several reasons:
* - If srcR does not intersect the image bounds.
* - If the requested colortype/alphatype cannot be converted from the image's types.
*/
bool readPixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRowBytes,
int srcX, int srcY, CachingHint = kAllow_CachingHint) const;
bool readPixels(const SkPixmap& dst, int srcX, int srcY,
CachingHint = kAllow_CachingHint) const;
/**
* Copy the pixels from this image into the dst pixmap, converting as needed into dst's
* colortype/alphatype. If the conversion cannot be performed, false is returned.
*
* If dst's dimensions differ from the src dimension, the image will be scaled, applying the
* specified filter-quality.
*/
bool scalePixels(const SkPixmap& dst, SkFilterQuality, CachingHint = kAllow_CachingHint) const;
/**
* Encode the image's pixels and return the result as a new SkData, which
* the caller must manage (i.e. call unref() when they are done).
*
* If the image type cannot be encoded, or the requested encoder type is
* not supported, this will return NULL.
*
* Note: this will attempt to encode the image's pixels in the specified format,
* even if the image returns a data from refEncoded(). That data will be ignored.
*/
SkData* encode(SkImageEncoder::Type, int quality) const;
/**
* Encode the image and return the result as a caller-managed SkData. This will
* attempt to reuse existing encoded data (as returned by refEncoded).
*
* We defer to the SkPixelSerializer both for vetting existing encoded data
* (useEncodedData) and for encoding the image (encode) when no such data is
* present or is rejected by the serializer.
*
* If not specified, we use a default serializer which 1) always accepts existing data
* (in any format) and 2) encodes to PNG.
*
* If no compatible encoded data exists and encoding fails, this method will also
* fail (return NULL).
*/
SkData* encode(SkPixelSerializer* = nullptr) const;
/**
* If the image already has its contents in encoded form (e.g. PNG or JPEG), return a ref
* to that data (which the caller must call unref() on). The caller is responsible for calling
* unref on the data when they are done.
*
* If the image does not already has its contents in encoded form, return NULL.
*
* Note: to force the image to return its contents as encoded data, try calling encode(...).
*/
SkData* refEncoded() const;
const char* toString(SkString*) const;
/**
* Return a new image that is a subset of this image. The underlying implementation may
* share the pixels, or it may make a copy.
*
* If subset does not intersect the bounds of this image, or the copy/share cannot be made,
* NULL will be returned.
*/
sk_sp<SkImage> makeSubset(const SkIRect& subset) const;
/**
* Ensures that an image is backed by a texture (when GrContext is non-null). If no
* transformation is required, the returned image may be the same as this image. If the this
* image is from a different GrContext, this will fail.
*/
sk_sp<SkImage> makeTextureImage(GrContext*) const;
/**
* If the image is texture-backed this will make a raster copy of it (or nullptr if reading back
* the pixels fails). Otherwise, it returns the original image.
*/
sk_sp<SkImage> makeNonTextureImage() const;
/**
* Apply a given image filter to this image, and return the filtered result.
*
* The subset represents the active portion of this image. The return value is similarly an
* SkImage, with an active subset (outSubset). This is usually used with texture-backed
* images, where the texture may be approx-match and thus larger than the required size.
*
* clipBounds constrains the device-space extent of the image which may be produced to the
* given rect.
*
* offset is the amount to translate the resulting image relative to the src when it is drawn.
* This is an out-param.
*
* If the result image cannot be created, or the result would be transparent black, null
* is returned, in which case the offset and outSubset parameters should be ignored by the
* caller.
*/
sk_sp<SkImage> makeWithFilter(const SkImageFilter* filter, const SkIRect& subset,
const SkIRect& clipBounds, SkIRect* outSubset,
SkIPoint* offset) const;
/** Drawing params for which a deferred texture image data should be optimized. */
struct DeferredTextureImageUsageParams {
DeferredTextureImageUsageParams() : fPreScaleMipLevel(0) {}
DeferredTextureImageUsageParams(const SkMatrix matrix, const SkFilterQuality quality,
int preScaleMipLevel)
: fMatrix(matrix), fQuality(quality), fPreScaleMipLevel(preScaleMipLevel) {}
SkMatrix fMatrix;
SkFilterQuality fQuality;
int fPreScaleMipLevel;
};
/**
* This method allows clients to capture the data necessary to turn a SkImage into a texture-
* backed image. If the original image is codec-backed this will decode into a format optimized
* for the context represented by the proxy. This method is thread safe with respect to the
* GrContext whence the proxy came. Clients allocate and manage the storage of the deferred
* texture data and control its lifetime. No cleanup is required, thus it is safe to simply free
* the memory out from under the data.
*
* The same method is used both for getting the size necessary for pre-uploaded texture data
* and for retrieving the data. The params array represents the set of draws over which to
* optimize the pre-upload data.
*
* When called with a null buffer this returns the size that the client must allocate in order
* to create deferred texture data for this image (or zero if this is an inappropriate
* candidate). The buffer allocated by the client should be 8 byte aligned.
*
* When buffer is not null this fills in the deferred texture data for this image in the
* provided buffer (assuming this is an appropriate candidate image and the buffer is
* appropriately aligned). Upon success the size written is returned, otherwise 0.
*/
size_t getDeferredTextureImageData(const GrContextThreadSafeProxy&,
const DeferredTextureImageUsageParams[],
int paramCnt,
void* buffer) const;
/**
* Returns a texture-backed image from data produced in SkImage::getDeferredTextureImageData.
* The context must be the context that provided the proxy passed to
* getDeferredTextureImageData.
*/
static sk_sp<SkImage> MakeFromDeferredTextureImageData(GrContext*, const void*, SkBudgeted);
// Helper functions to convert to SkBitmap
enum LegacyBitmapMode {
kRO_LegacyBitmapMode,
kRW_LegacyBitmapMode,
};
/**
* Attempt to create a bitmap with the same pixels as the image. The result will always be
* a raster-backed bitmap (texture-backed bitmaps are DEPRECATED, and not supported here).
*
* If the mode is kRO (read-only), the resulting bitmap will be marked as immutable.
*
* On succcess, returns true. On failure, returns false and the bitmap parameter will be reset
* to empty.
*/
bool asLegacyBitmap(SkBitmap*, LegacyBitmapMode) const;
/**
* Returns true if the image is backed by an image-generator or other src that creates
* (and caches) its pixels / texture on-demand.
*/
bool isLazyGenerated() const;
#ifdef SK_SUPPORT_LEGACY_IMAGEFACTORY
static SkImage* NewRasterCopy(const Info&, const void* pixels, size_t rowBytes,
SkColorTable* ctable = nullptr);
static SkImage* NewRasterData(const Info&, SkData* pixels, size_t rowBytes);
static SkImage* NewFromRaster(const Info&, const void* pixels, size_t rowBytes,
RasterReleaseProc, ReleaseContext);
static SkImage* NewFromBitmap(const SkBitmap&);
static SkImage* NewFromGenerator(SkImageGenerator*, const SkIRect* subset = nullptr);
static SkImage* NewFromEncoded(SkData* encoded, const SkIRect* subset = nullptr);
static SkImage* NewFromTexture(GrContext* ctx, const GrBackendTextureDesc& desc) {
return NewFromTexture(ctx, desc, kPremul_SkAlphaType, nullptr, nullptr);
}
static SkImage* NewFromTexture(GrContext* ctx, const GrBackendTextureDesc& de, SkAlphaType at) {
return NewFromTexture(ctx, de, at, nullptr, nullptr);
}
static SkImage* NewFromTexture(GrContext*, const GrBackendTextureDesc&, SkAlphaType,
TextureReleaseProc, ReleaseContext);
static SkImage* NewFromAdoptedTexture(GrContext*, const GrBackendTextureDesc&,
SkAlphaType = kPremul_SkAlphaType);
static SkImage* NewFromYUVTexturesCopy(GrContext*, SkYUVColorSpace,
const GrBackendObject yuvTextureHandles[3],
const SkISize yuvSizes[3],
GrSurfaceOrigin);
static SkImage* NewFromPicture(const SkPicture*, const SkISize& dimensions,
const SkMatrix*, const SkPaint*);
static SkImage* NewTextureFromPixmap(GrContext*, const SkPixmap&, SkBudgeted budgeted);
static SkImage* NewFromDeferredTextureImageData(GrContext*, const void*, SkBudgeted);
SkImage* newSubset(const SkIRect& subset) const { return this->makeSubset(subset).release(); }
SkImage* newTextureImage(GrContext* ctx) const { return this->makeTextureImage(ctx).release(); }
#endif
protected:
SkImage(int width, int height, uint32_t uniqueID);
private:
static sk_sp<SkImage> MakeTextureFromMipMap(GrContext*, const SkImageInfo&,
const GrMipLevel* texels, int mipLevelCount,
SkBudgeted);
const int fWidth;
const int fHeight;
const uint32_t fUniqueID;
typedef SkRefCnt INHERITED;
};
#endif