| /* |
| * 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" |
| #include "SkRect.h" |
| |
| class SkBitmap; |
| class SkColorFilter; |
| class SkDevice; |
| class SkMatrix; |
| struct SkIPoint; |
| class SkShader; |
| class GrEffectRef; |
| class GrTexture; |
| |
| /** |
| * 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). |
| */ |
| 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 |
| * GrEffect, used to process this filter on the GPU, or false if |
| * not. |
| * |
| * If effect is non-NULL, a new GrEffect instance is stored |
| * in it. The caller assumes ownership of the stage, and it is up to the |
| * caller to unref it. |
| * |
| * The effect can assume its vertexCoords space maps 1-to-1 with texels |
| * in the texture. "offset" is the delta between the source and |
| * destination rect's origins, when cropped processing is being performed. |
| */ |
| virtual bool asNewEffect(GrEffectRef** effect, GrTexture*, const SkIPoint& offset) 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 asNewEffect(). |
| * The default implementation returns asNewEffect(NULL, NULL). |
| */ |
| virtual bool canFilterImageGPU() const; |
| |
| /** |
| * Process this image filter 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 asNewEffect(). src is the |
| * source image for processing, as a texture-backed bitmap. result is |
| * the destination bitmap, which should contain a texture-backed pixelref |
| * on success. offset is the amount to translate the resulting image |
| * relative to the src when it is drawn. The default implementation does |
| * single-pass processing using asNewEffect(). |
| */ |
| virtual bool filterImageGPU(Proxy*, const SkBitmap& src, const SkMatrix& ctm, |
| SkBitmap* result, SkIPoint* offset); |
| |
| /** |
| * Returns whether this image filter is a color filter and puts the color filter into the |
| * "filterPtr" parameter if it can. Does nothing otherwise. |
| * If this returns false, then the filterPtr is unchanged. |
| * If this returns true, then if filterPtr is not null, it must be set to a ref'd colorfitler |
| * (i.e. it may not be set to NULL). |
| */ |
| virtual bool asColorFilter(SkColorFilter** filterPtr) 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]; |
| } |
| |
| /** |
| * Returns the crop rectangle of this filter. This is set at construction |
| * time, and determines which pixels from the input image will |
| * be processed. The size of this rectangle should be used as the size |
| * of the destination image. The origin of this rect should be used to |
| * offset access to the input images, and should also be added to the |
| * "offset" parameter in onFilterImage and filterImageGPU(). (The latter |
| * ensures that the resulting buffer is drawn in the correct location.) |
| */ |
| const SkIRect& cropRect() const { return fCropRect; } |
| |
| protected: |
| SkImageFilter(int inputCount, SkImageFilter** inputs, const SkIRect* cropRect = NULL); |
| |
| // Convenience constructor for 1-input filters. |
| explicit SkImageFilter(SkImageFilter* input, const SkIRect* cropRect = NULL); |
| |
| // Convenience constructor for 2-input filters. |
| SkImageFilter(SkImageFilter* input1, SkImageFilter* input2, const SkIRect* cropRect = NULL); |
| |
| 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*); |
| |
| // Sets rect to the intersection of rect and the crop rect. If there |
| // is no overlap, returns false and leaves rect unchanged. |
| bool applyCropRect(SkIRect* rect) const; |
| |
| private: |
| typedef SkFlattenable INHERITED; |
| int fInputCount; |
| SkImageFilter** fInputs; |
| SkIRect fCropRect; |
| }; |
| |
| #endif |