| /* |
| * 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 SkDevice; |
| class SkMatrix; |
| struct SkPoint; |
| |
| /** |
| * 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: |
| 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); |
| |
| /** |
| * Experimental. |
| * |
| * If the filter can be expressed as a gaussian-blur, return true and |
| * set the sigma to the values for horizontal and vertical. |
| */ |
| virtual bool asABlur(SkSize* sigma) const; |
| |
| /** |
| * Experimental. |
| * |
| * If the filter can be expressed as an erode, return true and |
| * set the radius in X and Y. |
| */ |
| virtual bool asAnErode(SkISize* radius) const; |
| |
| /** |
| * Experimental. |
| * |
| * If the filter can be expressed as a dilation, return true and |
| * set the radius in X and Y. |
| */ |
| virtual bool asADilate(SkISize* radius) const; |
| |
| protected: |
| SkImageFilter() {} |
| explicit SkImageFilter(SkFlattenableReadBuffer& rb) : INHERITED(rb) {} |
| |
| // 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*); |
| |
| private: |
| typedef SkFlattenable INHERITED; |
| }; |
| |
| #endif |