| /* |
| * Copyright 2011 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #ifndef SkImageFilter_DEFINED |
| #define SkImageFilter_DEFINED |
| |
| #include "SkFlattenable.h" |
| |
| class SkBitmap; |
| class SkColorFilter; |
| class SkDevice; |
| class SkMatrix; |
| struct SkIPoint; |
| struct SkIRect; |
| struct SkRect; |
| class GrCustomStage; |
| class GrTexture; |
| |
| /** |
| * Experimental. |
| * |
| * Base class for image filters. If one is installed in the paint, then |
| * all drawing occurs as usual, but it is as if the drawing happened into an |
| * offscreen (before the xfermode is applied). This offscreen bitmap will |
| * then be handed to the imagefilter, who in turn creates a new bitmap which |
| * is what will finally be drawn to the device (using the original xfermode). |
| * |
| * THIS SIGNATURE IS TEMPORARY |
| * |
| * There are several weaknesses in this function signature: |
| * 1. Does not expose the destination/target device, so filters that can draw |
| * directly to it are unable to take advantage of that optimization. |
| * 2. Does not expose a way to create a "compabitible" image (i.e. gpu -> gpu) |
| * 3. As with #1, the filter is unable to "read" the dest (which would be slow) |
| * |
| * Therefore, we should not create any real dependencies on this API yet -- it |
| * is being checked in as a check-point so we can explore these and other |
| * considerations. |
| */ |
| class SK_API SkImageFilter : public SkFlattenable { |
| public: |
| SK_DECLARE_INST_COUNT(SkImageFilter) |
| |
| class Proxy { |
| public: |
| virtual ~Proxy() {}; |
| |
| virtual SkDevice* createDevice(int width, int height) = 0; |
| // returns true if the proxy can handle this filter natively |
| virtual bool canHandleImageFilter(SkImageFilter*) = 0; |
| // returns true if the proxy handled the filter itself. if this returns |
| // false then the filter's code will be called. |
| virtual bool filterImage(SkImageFilter*, const SkBitmap& src, |
| const SkMatrix& ctm, |
| SkBitmap* result, SkIPoint* offset) = 0; |
| }; |
| |
| /** |
| * Request a new (result) image to be created from the src image. |
| * If the src has no pixels (isNull()) then the request just wants to |
| * receive the config and width/height of the result. |
| * |
| * The matrix is the current matrix on the canvas. |
| * |
| * Offset is the amount to translate the resulting image relative to the |
| * src when it is drawn. |
| * |
| * If the result image cannot be created, return false, in which case both |
| * the result and offset parameters will be ignored by the caller. |
| */ |
| bool filterImage(Proxy*, const SkBitmap& src, const SkMatrix& ctm, |
| SkBitmap* result, SkIPoint* offset); |
| |
| /** |
| * Given the src bounds of an image, this returns the bounds of the result |
| * image after the filter has been applied. |
| */ |
| bool filterBounds(const SkIRect& src, const SkMatrix& ctm, SkIRect* dst); |
| |
| /** |
| * Returns true if the filter can be expressed a single-pass |
| * GrCustomStage, used to process this filter on the GPU, or false if |
| * not. |
| * |
| * If stage is non-NULL, a new GrCustomStage instance is stored |
| * in it. The caller assumes ownership of the stage, and it is up to the |
| * caller to unref it. |
| */ |
| virtual bool asNewCustomStage(GrCustomStage** stage, GrTexture*) const; |
| |
| /** |
| * Returns true if the filter can be processed on the GPU. This is most |
| * often used for multi-pass effects, where intermediate results must be |
| * rendered to textures. For single-pass effects, use asNewCustomStage(). |
| * The default implementation returns false. |
| */ |
| virtual bool canFilterImageGPU() const; |
| |
| /** |
| * Process this image filter on the GPU. texture is the source texture |
| * for processing, and rect is the effect region to process. The |
| * function must allocate a new texture of at least rect width/height |
| * size, and return it to the caller. The default implementation returns |
| * NULL. |
| */ |
| virtual GrTexture* onFilterImageGPU(Proxy*, GrTexture* texture, const SkRect& rect); |
| |
| /** |
| * Returns this image filter as a color filter if possible, |
| * NULL otherwise. |
| */ |
| virtual SkColorFilter* asColorFilter() const; |
| |
| /** |
| * Returns the number of inputs this filter will accept (some inputs can |
| * be NULL). |
| */ |
| int countInputs() const { return fInputCount; } |
| |
| /** |
| * Returns the input filter at a given index, or NULL if no input is |
| * connected. The indices used are filter-specific. |
| */ |
| SkImageFilter* getInput(int i) const { |
| SkASSERT(i < fInputCount); |
| return fInputs[i]; |
| } |
| |
| protected: |
| SkImageFilter(int inputCount, SkImageFilter** inputs); |
| |
| // The ... represents inputCount SkImageFilter pointers, upon which this |
| // constructor will call SkSafeRef(). This is the same behaviour as |
| // the SkImageFilter(int, SkImageFilter**) constructor above. |
| explicit SkImageFilter(int inputCount, ...); |
| |
| virtual ~SkImageFilter(); |
| |
| explicit SkImageFilter(SkFlattenableReadBuffer& rb); |
| |
| virtual void flatten(SkFlattenableWriteBuffer& wb) const SK_OVERRIDE; |
| |
| // Default impl returns false |
| virtual bool onFilterImage(Proxy*, const SkBitmap& src, const SkMatrix&, |
| SkBitmap* result, SkIPoint* offset); |
| // Default impl copies src into dst and returns true |
| virtual bool onFilterBounds(const SkIRect&, const SkMatrix&, SkIRect*); |
| |
| // Return the result of processing the given input, or the source bitmap |
| // if we have no connected input at that index. |
| SkBitmap getInputResult(int index, Proxy*, const SkBitmap& src, const SkMatrix&, |
| SkIPoint*); |
| |
| private: |
| typedef SkFlattenable INHERITED; |
| int fInputCount; |
| SkImageFilter** fInputs; |
| }; |
| |
| #endif |