| /* |
| * 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 "SkBlendMode.h" |
| #include "SkColor.h" |
| #include "SkFlattenable.h" |
| #include "SkRefCnt.h" |
| |
| class GrContext; |
| class GrColorSpaceInfo; |
| class GrFragmentProcessor; |
| class SkArenaAlloc; |
| class SkBitmap; |
| class SkColorSpace; |
| class SkColorSpaceXformer; |
| class SkRasterPipeline; |
| |
| /** |
| * 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: |
| /** |
| * 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, SkBlendMode* bmode) 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; |
| |
| void appendStages(SkRasterPipeline*, SkColorSpace*, SkArenaAlloc*, bool shaderIsOpaque) const; |
| |
| enum Flags { |
| /** If set the filter methods will not change the alpha channel of the colors. |
| */ |
| kAlphaUnchanged_Flag = 1 << 0, |
| }; |
| |
| /** Returns the flags for this filter. Override in subclasses to return custom flags. |
| */ |
| virtual uint32_t getFlags() const { return 0; } |
| |
| SkColor filterColor(SkColor) const; |
| SkColor4f filterColor4f(const SkColor4f&) 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 blend 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 sk_sp<SkColorFilter> MakeModeFilter(SkColor c, SkBlendMode mode); |
| |
| /** Construct a colorfilter whose effect is to first apply the inner filter and then apply |
| * this filter, applied to the output of the inner filter. |
| * |
| * result = this(inner(...)) |
| * |
| * Due to internal limits, it is possible that this will return NULL, so the caller must |
| * always check. |
| */ |
| sk_sp<SkColorFilter> makeComposed(sk_sp<SkColorFilter> inner) const; |
| |
| // DEPRECATED, call makeComposed instead |
| static sk_sp<SkColorFilter> MakeComposeFilter(sk_sp<SkColorFilter> outer, |
| sk_sp<SkColorFilter> inner) { |
| return outer ? outer->makeComposed(inner) : inner; |
| } |
| |
| /** Construct a color filter that transforms a color by a 4x5 matrix. The matrix is in row- |
| * major order and the translation column is specified in unnormalized, 0...255, space. |
| */ |
| static sk_sp<SkColorFilter> MakeMatrixFilterRowMajor255(const SkScalar array[20]); |
| |
| /** Construct a colorfilter that applies the srgb gamma curve to the RGB channels */ |
| static sk_sp<SkColorFilter> MakeLinearToSRGBGamma(); |
| |
| /** Construct a colorfilter that applies the inverse of the srgb gamma curve to the |
| * RGB channels |
| */ |
| static sk_sp<SkColorFilter> MakeSRGBToLinearGamma(); |
| |
| #if SK_SUPPORT_GPU |
| /** |
| * A subclass may implement this factory function to work with the GPU backend. It returns |
| * a GrFragmentProcessor that implemets the color filter in GPU shader code. |
| * |
| * The fragment processor receives a premultiplied input color and produces a premultiplied |
| * output color. |
| * |
| * A null return indicates that the color filter isn't implemented for the GPU backend. |
| */ |
| virtual std::unique_ptr<GrFragmentProcessor> asFragmentProcessor( |
| GrContext*, const GrColorSpaceInfo& dstColorSpaceInfo) const; |
| #endif |
| |
| bool affectsTransparentBlack() const { |
| return this->filterColor(0) != 0; |
| } |
| |
| SK_TO_STRING_PUREVIRT() |
| |
| SK_DECLARE_FLATTENABLE_REGISTRAR_GROUP() |
| SK_DEFINE_FLATTENABLE_TYPE(SkColorFilter) |
| |
| protected: |
| SkColorFilter() {} |
| |
| sk_sp<SkColorFilter> makeColorSpace(SkColorSpaceXformer* xformer) const { |
| return this->onMakeColorSpace(xformer); |
| } |
| virtual sk_sp<SkColorFilter> onMakeColorSpace(SkColorSpaceXformer*) const { |
| return sk_ref_sp(const_cast<SkColorFilter*>(this)); |
| } |
| |
| /** |
| * If this subclass can optimally createa composition with the inner filter, return it as |
| * a new filter (which the caller must unref() when it is done). If no such optimization |
| * is known, return NULL. |
| * |
| * e.g. result(color) == this_filter(inner(color)) |
| */ |
| virtual sk_sp<SkColorFilter> onMakeComposed(sk_sp<SkColorFilter>) const { return nullptr; } |
| |
| private: |
| /* |
| * Returns 1 if this is a single filter (not a composition of other filters), otherwise it |
| * reutrns the number of leaf-node filters in a composition. This should be the same value |
| * as the number of GrFragmentProcessors returned by asFragmentProcessors's array parameter. |
| * |
| * e.g. compose(filter, compose(compose(filter, filter), filter)) --> 4 |
| */ |
| virtual int privateComposedFilterCount() const { return 1; } |
| |
| virtual void onAppendStages(SkRasterPipeline*, SkColorSpace*, SkArenaAlloc*, |
| bool shaderIsOpaque) const = 0; |
| |
| friend class SkColorSpaceXformer; |
| friend class SkComposeColorFilter; |
| |
| typedef SkFlattenable INHERITED; |
| }; |
| |
| #endif |