| |
| /* |
| * Copyright 2006 The Android Open Source Project |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| |
| #ifndef SkColorFilter_DEFINED |
| #define SkColorFilter_DEFINED |
| |
| #include "SkColor.h" |
| #include "SkFlattenable.h" |
| #include "SkXfermode.h" |
| |
| class SkBitmap; |
| class GrEffectRef; |
| class GrContext; |
| |
| /** |
| * ColorFilters are optional objects in the drawing pipeline. When present in |
| * a paint, they are called with the "src" colors, and return new colors, which |
| * are then passed onto the next stage (either ImageFilter or Xfermode). |
| * |
| * All subclasses are required to be reentrant-safe : it must be legal to share |
| * the same instance between several threads. |
| */ |
| class SK_API SkColorFilter : public SkFlattenable { |
| public: |
| SK_DECLARE_INST_COUNT(SkColorFilter) |
| |
| /** |
| * If the filter can be represented by a source color plus Mode, this |
| * returns true, and sets (if not NULL) the color and mode appropriately. |
| * If not, this returns false and ignores the parameters. |
| */ |
| virtual bool asColorMode(SkColor* color, SkXfermode::Mode* mode) const; |
| |
| /** |
| * If the filter can be represented by a 5x4 matrix, this |
| * returns true, and sets the matrix appropriately. |
| * If not, this returns false and ignores the parameter. |
| */ |
| virtual bool asColorMatrix(SkScalar matrix[20]) const; |
| |
| /** |
| * If the filter can be represented by per-component table, return true, |
| * and if table is not null, copy the bitmap containing the table into it. |
| * |
| * The table bitmap will be in SkBitmap::kA8_Config. Each row corresponding |
| * to each component in ARGB order. e.g. row[0] == alpha, row[1] == red, |
| * etc. To transform a color, you (logically) perform the following: |
| * |
| * a' = *table.getAddr8(a, 0); |
| * r' = *table.getAddr8(r, 1); |
| * g' = *table.getAddr8(g, 2); |
| * b' = *table.getAddr8(b, 3); |
| * |
| * The original component value is the horizontal index for a given row, |
| * and the stored value at that index is the new value for that component. |
| */ |
| virtual bool asComponentTable(SkBitmap* table) const; |
| |
| /** Called with a scanline of colors, as if there was a shader installed. |
| The implementation writes out its filtered version into result[]. |
| Note: shader and result may be the same buffer. |
| @param src array of colors, possibly generated by a shader |
| @param count the number of entries in the src[] and result[] arrays |
| @param result written by the filter |
| */ |
| virtual void filterSpan(const SkPMColor src[], int count, |
| SkPMColor result[]) const = 0; |
| /** Called with a scanline of colors, as if there was a shader installed. |
| The implementation writes out its filtered version into result[]. |
| Note: shader and result may be the same buffer. |
| @param src array of colors, possibly generated by a shader |
| @param count the number of entries in the src[] and result[] arrays |
| @param result written by the filter |
| */ |
| virtual void filterSpan16(const uint16_t shader[], int count, |
| uint16_t result[]) const; |
| |
| enum Flags { |
| /** If set the filter methods will not change the alpha channel of the |
| colors. |
| */ |
| kAlphaUnchanged_Flag = 0x01, |
| /** If set, this subclass implements filterSpan16(). If this flag is |
| set, then kAlphaUnchanged_Flag must also be set. |
| */ |
| kHasFilter16_Flag = 0x02 |
| }; |
| |
| /** Returns the flags for this filter. Override in subclasses to return |
| custom flags. |
| */ |
| virtual uint32_t getFlags() const { return 0; } |
| |
| /** |
| * Apply this colorfilter to the specified SkColor. This routine handles |
| * converting to SkPMColor, calling the filter, and then converting back |
| * to SkColor. This method is not virtual, but will call filterSpan() |
| * which is virtual. |
| */ |
| SkColor filterColor(SkColor) const; |
| |
| /** Create a colorfilter that uses the specified color and mode. |
| If the Mode is DST, this function will return NULL (since that |
| mode will have no effect on the result). |
| @param c The source color used with the specified mode |
| @param mode The xfermode mode that is applied to each color in |
| the colorfilter's filterSpan[16,32] methods |
| @return colorfilter object that applies the src color and mode, |
| or NULL if the mode will have no effect. |
| */ |
| static SkColorFilter* CreateModeFilter(SkColor c, SkXfermode::Mode mode); |
| |
| /** Create a colorfilter that multiplies the RGB channels by one color, and |
| then adds a second color, pinning the result for each component to |
| [0..255]. The alpha components of the mul and add arguments |
| are ignored. |
| */ |
| static SkColorFilter* CreateLightingFilter(SkColor mul, SkColor add); |
| |
| /** A subclass may implement this factory function to work with the GPU backend. If the return |
| is non-NULL then the caller owns a ref on the returned object. |
| */ |
| virtual GrEffectRef* asNewEffect(GrContext*) const; |
| |
| SK_TO_STRING_PUREVIRT() |
| |
| SK_DECLARE_FLATTENABLE_REGISTRAR_GROUP() |
| SK_DEFINE_FLATTENABLE_TYPE(SkColorFilter) |
| |
| protected: |
| SkColorFilter() {} |
| SkColorFilter(SkReadBuffer& rb) : INHERITED(rb) {} |
| |
| private: |
| typedef SkFlattenable INHERITED; |
| }; |
| |
| #endif |