319 lines
13 KiB
C++
319 lines
13 KiB
C++
/*
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* Copyright 2012 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef SkImage_DEFINED
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#define SkImage_DEFINED
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#include "SkFilterQuality.h"
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#include "SkImageInfo.h"
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#include "SkImageEncoder.h"
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#include "SkRefCnt.h"
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#include "SkScalar.h"
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#include "SkShader.h"
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class SkData;
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class SkCanvas;
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class SkColorTable;
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class SkImageGenerator;
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class SkPaint;
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class SkPicture;
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class SkPixelSerializer;
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class SkString;
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class SkSurface;
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class GrContext;
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class GrTexture;
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/**
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* SkImage is an abstraction for drawing a rectagle of pixels, though the
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* particular type of image could be actually storing its data on the GPU, or
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* as drawing commands (picture or PDF or otherwise), ready to be played back
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* into another canvas.
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*
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* The content of SkImage is always immutable, though the actual storage may
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* change, if for example that image can be re-created via encoded data or
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* other means.
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*
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* SkImage always has a non-zero dimensions. If there is a request to create a new image, either
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* directly or via SkSurface, and either of the requested dimensions are zero, then NULL will be
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* returned.
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*/
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class SK_API SkImage : public SkRefCnt {
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public:
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typedef SkImageInfo Info;
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typedef void* ReleaseContext;
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static SkImage* NewRasterCopy(const Info&, const void* pixels, size_t rowBytes,
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SkColorTable* ctable = NULL);
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static SkImage* NewRasterData(const Info&, SkData* pixels, size_t rowBytes);
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typedef void (*RasterReleaseProc)(const void* pixels, ReleaseContext);
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/**
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* Return a new Image referencing the specified pixels. These must remain valid and unchanged
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* until the specified release-proc is called, indicating that Skia no longer has a reference
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* to the pixels.
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*
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* Returns NULL if the requested Info is unsupported.
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*/
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static SkImage* NewFromRaster(const Info&, const void* pixels, size_t rowBytes,
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RasterReleaseProc, ReleaseContext);
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/**
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* Construct a new image from the specified bitmap. If the bitmap is marked immutable, and
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* its pixel memory is shareable, it may be shared instead of copied.
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*/
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static SkImage* NewFromBitmap(const SkBitmap&);
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/**
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* Construct a new SkImage based on the given ImageGenerator.
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* This function will always take ownership of the passed
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* ImageGenerator. Returns NULL on error.
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*
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* If a subset is specified, it must be contained within the generator's bounds.
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*/
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static SkImage* NewFromGenerator(SkImageGenerator*, const SkIRect* subset = NULL);
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/**
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* Construct a new SkImage based on the specified encoded data. Returns NULL on failure,
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* which can mean that the format of the encoded data was not recognized/supported.
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*
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* If a subset is specified, it must be contained within the encoded data's bounds.
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*
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* Regardless of success or failure, the caller is responsible for managing their ownership
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* of the data.
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*/
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static SkImage* NewFromEncoded(SkData* encoded, const SkIRect* subset = NULL);
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/**
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* Create a new image from the specified descriptor. Note - the caller is responsible for
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* managing the lifetime of the underlying platform texture.
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*
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* Will return NULL if the specified descriptor is unsupported.
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*/
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static SkImage* NewFromTexture(GrContext* ctx, const GrBackendTextureDesc& desc) {
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return NewFromTexture(ctx, desc, kPremul_SkAlphaType, NULL, NULL);
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}
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static SkImage* NewFromTexture(GrContext* ctx, const GrBackendTextureDesc& de, SkAlphaType at) {
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return NewFromTexture(ctx, de, at, NULL, NULL);
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}
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typedef void (*TextureReleaseProc)(ReleaseContext);
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/**
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* Create a new image from the specified descriptor. The underlying platform texture must stay
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* valid and unaltered until the specified release-proc is invoked, indicating that Skia
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* no longer is holding a reference to it.
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*
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* Will return NULL if the specified descriptor is unsupported.
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*/
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static SkImage* NewFromTexture(GrContext*, const GrBackendTextureDesc&, SkAlphaType,
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TextureReleaseProc, ReleaseContext);
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/**
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* Create a new image from the specified descriptor. Note - Skia will delete or recycle the
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* texture when the image is released.
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*
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* Will return NULL if the specified descriptor is unsupported.
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*/
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static SkImage* NewFromAdoptedTexture(GrContext*, const GrBackendTextureDesc&,
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SkAlphaType = kPremul_SkAlphaType);
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/**
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* Create a new image by copying the pixels from the specified descriptor. No reference is
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* kept to the original platform texture.
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*
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* Will return NULL if the specified descriptor is unsupported.
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*/
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static SkImage* NewFromTextureCopy(GrContext*, const GrBackendTextureDesc&,
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SkAlphaType = kPremul_SkAlphaType);
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/**
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* Create a new image by copying the pixels from the specified y, u, v textures. The data
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* from the textures is immediately ingested into the image and the textures can be modified or
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* deleted after the function returns. The image will have the dimensions of the y texture.
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*/
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static SkImage* NewFromYUVTexturesCopy(GrContext*, SkYUVColorSpace,
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const GrBackendObject yuvTextureHandles[3],
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const SkISize yuvSizes[3],
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GrSurfaceOrigin);
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static SkImage* NewFromPicture(const SkPicture*, const SkISize& dimensions,
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const SkMatrix*, const SkPaint*);
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///////////////////////////////////////////////////////////////////////////////////////////////
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int width() const { return fWidth; }
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int height() const { return fHeight; }
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SkISize dimensions() const { return SkISize::Make(fWidth, fHeight); }
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SkIRect bounds() const { return SkIRect::MakeWH(fWidth, fHeight); }
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uint32_t uniqueID() const { return fUniqueID; }
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virtual bool isOpaque() const { return false; }
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virtual SkShader* newShader(SkShader::TileMode,
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SkShader::TileMode,
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const SkMatrix* localMatrix = NULL) const;
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/**
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* If the image has direct access to its pixels (i.e. they are in local
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* RAM) return the (const) address of those pixels, and if not null, return
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* the ImageInfo and rowBytes. The returned address is only valid while
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* the image object is in scope.
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*
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* On failure, returns NULL and the info and rowBytes parameters are
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* ignored.
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*/
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const void* peekPixels(SkImageInfo* info, size_t* rowBytes) const;
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/**
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* If the image has direct access to its pixels (i.e. they are in local
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* RAM) return the (const) address of those pixels, and if not null, return
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* true, and if pixmap is not NULL, set it to point into the image.
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*
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* On failure, return false and ignore the pixmap parameter.
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*/
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bool peekPixels(SkPixmap* pixmap) const;
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/**
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* Some images have to perform preliminary work in preparation for drawing. This can be
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* decoding, uploading to a GPU, or other tasks. These happen automatically when an image
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* is drawn, and often they are cached so that the cost is only paid the first time.
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*
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* Preroll() can be called before drawing to try to perform this prepatory work ahead of time.
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* For images that have no such work, this returns instantly. Others may do some thing to
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* prepare their cache and then return.
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*
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* If the image will drawn to a GPU-backed canvas or surface, pass the associated GrContext.
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* If the image will be drawn to any other type of canvas or surface, pass null.
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*/
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void preroll(GrContext* = nullptr) const;
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// DEPRECATED
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GrTexture* getTexture() const;
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/**
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* Returns true if the image is texture backed.
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*/
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bool isTextureBacked() const;
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/**
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* Retrieves the backend API handle of the texture. If flushPendingGrContextIO then the
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* GrContext will issue to the backend API any deferred IO operations on the texture before
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* returning.
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*/
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GrBackendObject getTextureHandle(bool flushPendingGrContextIO) const;
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/**
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* Copy the pixels from the image into the specified buffer (pixels + rowBytes),
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* converting them into the requested format (dstInfo). The image pixels are read
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* starting at the specified (srcX,srcY) location.
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*
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* The specified ImageInfo and (srcX,srcY) offset specifies a source rectangle
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*
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* srcR.setXYWH(srcX, srcY, dstInfo.width(), dstInfo.height());
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*
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* srcR is intersected with the bounds of the image. If this intersection is not empty,
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* then we have two sets of pixels (of equal size). Replace the dst pixels with the
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* corresponding src pixels, performing any colortype/alphatype transformations needed
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* (in the case where the src and dst have different colortypes or alphatypes).
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*
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* This call can fail, returning false, for several reasons:
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* - If srcR does not intersect the image bounds.
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* - If the requested colortype/alphatype cannot be converted from the image's types.
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*/
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bool readPixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRowBytes,
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int srcX, int srcY) const;
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bool readPixels(const SkPixmap& dst, int srcX, int srcY) const;
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/**
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* Encode the image's pixels and return the result as a new SkData, which
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* the caller must manage (i.e. call unref() when they are done).
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*
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* If the image type cannot be encoded, or the requested encoder type is
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* not supported, this will return NULL.
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*
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* Note: this will attempt to encode the image's pixels in the specified format,
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* even if the image returns a data from refEncoded(). That data will be ignored.
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*/
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SkData* encode(SkImageEncoder::Type, int quality) const;
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/**
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* Encode the image and return the result as a caller-managed SkData. This will
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* attempt to reuse existing encoded data (as returned by refEncoded).
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*
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* We defer to the SkPixelSerializer both for vetting existing encoded data
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* (useEncodedData) and for encoding the image (encodePixels) when no such data is
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* present or is rejected by the serializer.
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*
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* If not specified, we use a default serializer which 1) always accepts existing data
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* (in any format) and 2) encodes to PNG.
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*
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* If no compatible encoded data exists and encoding fails, this method will also
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* fail (return NULL).
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*/
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SkData* encode(SkPixelSerializer* = nullptr) const;
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/**
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* If the image already has its contents in encoded form (e.g. PNG or JPEG), return a ref
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* to that data (which the caller must call unref() on). The caller is responsible for calling
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* unref on the data when they are done.
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*
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* If the image does not already has its contents in encoded form, return NULL.
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*
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* Note: to force the image to return its contents as encoded data, try calling encode(...).
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*/
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SkData* refEncoded() const;
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const char* toString(SkString*) const;
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/**
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* Return a new image that is a subset of this image. The underlying implementation may
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* share the pixels, or it may make a copy.
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*
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* If subset does not intersect the bounds of this image, or the copy/share cannot be made,
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* NULL will be returned.
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*/
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SkImage* newSubset(const SkIRect& subset) const;
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// Helper functions to convert to SkBitmap
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enum LegacyBitmapMode {
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kRO_LegacyBitmapMode,
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kRW_LegacyBitmapMode,
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};
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/**
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* Attempt to create a bitmap with the same pixels as the image. The result will always be
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* a raster-backed bitmap (texture-backed bitmaps are DEPRECATED, and not supported here).
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*
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* If the mode is kRO (read-only), the resulting bitmap will be marked as immutable.
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*
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* On succcess, returns true. On failure, returns false and the bitmap parameter will be reset
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* to empty.
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*/
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bool asLegacyBitmap(SkBitmap*, LegacyBitmapMode) const;
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/**
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* Returns true if the image is backed by an image-generator or other src that creates
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* (and caches) its pixels / texture on-demand.
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*/
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bool isLazyGenerated() const;
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protected:
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SkImage(int width, int height, uint32_t uniqueID);
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private:
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const int fWidth;
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const int fHeight;
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const uint32_t fUniqueID;
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typedef SkRefCnt INHERITED;
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};
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#endif
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