| /* |
| * 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 SkShader_DEFINED |
| #define SkShader_DEFINED |
| |
| #include "SkBitmap.h" |
| #include "SkFilterQuality.h" |
| #include "SkFlattenable.h" |
| #include "SkImageInfo.h" |
| #include "SkMask.h" |
| #include "SkMatrix.h" |
| #include "SkPaint.h" |
| #include "../gpu/GrColor.h" |
| |
| class SkArenaAlloc; |
| class SkColorFilter; |
| class SkColorSpace; |
| class SkColorSpaceXformer; |
| class SkImage; |
| class SkPath; |
| class SkPicture; |
| class SkRasterPipeline; |
| class GrContext; |
| class GrFragmentProcessor; |
| |
| /** \class SkShader |
| * |
| * Shaders specify the source color(s) for what is being drawn. If a paint |
| * has no shader, then the paint's color is used. If the paint has a |
| * shader, then the shader's color(s) are use instead, but they are |
| * modulated by the paint's alpha. This makes it easy to create a shader |
| * once (e.g. bitmap tiling or gradient) and then change its transparency |
| * w/o having to modify the original shader... only the paint's alpha needs |
| * to be modified. |
| */ |
| class SK_API SkShader : public SkFlattenable { |
| public: |
| enum TileMode { |
| /** replicate the edge color if the shader draws outside of its |
| * original bounds |
| */ |
| kClamp_TileMode, |
| |
| /** repeat the shader's image horizontally and vertically */ |
| kRepeat_TileMode, |
| |
| /** repeat the shader's image horizontally and vertically, alternating |
| * mirror images so that adjacent images always seam |
| */ |
| kMirror_TileMode, |
| |
| #if 0 |
| /** only draw within the original domain, return 0 everywhere else */ |
| kDecal_TileMode, |
| #endif |
| }; |
| |
| enum { |
| kTileModeCount = kMirror_TileMode + 1 |
| }; |
| |
| /** |
| * Returns the local matrix. |
| * |
| * FIXME: This can be incorrect for a Shader with its own local matrix |
| * that is also wrapped via CreateLocalMatrixShader. |
| */ |
| const SkMatrix& getLocalMatrix() const; |
| |
| /** |
| * Returns true if the shader is guaranteed to produce only opaque |
| * colors, subject to the SkPaint using the shader to apply an opaque |
| * alpha value. Subclasses should override this to allow some |
| * optimizations. |
| */ |
| virtual bool isOpaque() const { return false; } |
| |
| #ifdef SK_SUPPORT_LEGACY_SHADER_ISABITMAP |
| /** |
| * Returns true if this shader is just a bitmap, and if not null, returns the bitmap, |
| * localMatrix, and tilemodes. If this is not a bitmap, returns false and ignores the |
| * out-parameters. |
| */ |
| bool isABitmap(SkBitmap* outTexture, SkMatrix* outMatrix, TileMode xy[2]) const; |
| |
| bool isABitmap() const { |
| return this->isABitmap(nullptr, nullptr, nullptr); |
| } |
| #endif |
| |
| /** |
| * Iff this shader is backed by a single SkImage, return its ptr (the caller must ref this |
| * if they want to keep it longer than the lifetime of the shader). If not, return nullptr. |
| */ |
| SkImage* isAImage(SkMatrix* localMatrix, TileMode xy[2]) const; |
| |
| bool isAImage() const { |
| return this->isAImage(nullptr, nullptr) != nullptr; |
| } |
| |
| /** |
| * If the shader subclass can be represented as a gradient, asAGradient |
| * returns the matching GradientType enum (or kNone_GradientType if it |
| * cannot). Also, if info is not null, asAGradient populates info with |
| * the relevant (see below) parameters for the gradient. fColorCount |
| * is both an input and output parameter. On input, it indicates how |
| * many entries in fColors and fColorOffsets can be used, if they are |
| * non-NULL. After asAGradient has run, fColorCount indicates how |
| * many color-offset pairs there are in the gradient. If there is |
| * insufficient space to store all of the color-offset pairs, fColors |
| * and fColorOffsets will not be altered. fColorOffsets specifies |
| * where on the range of 0 to 1 to transition to the given color. |
| * The meaning of fPoint and fRadius is dependant on the type of gradient. |
| * |
| * None: |
| * info is ignored. |
| * Color: |
| * fColorOffsets[0] is meaningless. |
| * Linear: |
| * fPoint[0] and fPoint[1] are the end-points of the gradient |
| * Radial: |
| * fPoint[0] and fRadius[0] are the center and radius |
| * Conical: |
| * fPoint[0] and fRadius[0] are the center and radius of the 1st circle |
| * fPoint[1] and fRadius[1] are the center and radius of the 2nd circle |
| * Sweep: |
| * fPoint[0] is the center of the sweep. |
| */ |
| |
| enum GradientType { |
| kNone_GradientType, |
| kColor_GradientType, |
| kLinear_GradientType, |
| kRadial_GradientType, |
| kSweep_GradientType, |
| kConical_GradientType, |
| kLast_GradientType = kConical_GradientType |
| }; |
| |
| struct GradientInfo { |
| int fColorCount; //!< In-out parameter, specifies passed size |
| // of fColors/fColorOffsets on input, and |
| // actual number of colors/offsets on |
| // output. |
| SkColor* fColors; //!< The colors in the gradient. |
| SkScalar* fColorOffsets; //!< The unit offset for color transitions. |
| SkPoint fPoint[2]; //!< Type specific, see above. |
| SkScalar fRadius[2]; //!< Type specific, see above. |
| TileMode fTileMode; //!< The tile mode used. |
| uint32_t fGradientFlags; //!< see SkGradientShader::Flags |
| }; |
| |
| virtual GradientType asAGradient(GradientInfo* info) const; |
| |
| #ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK |
| struct ComposeRec { |
| const SkShader* fShaderA; |
| const SkShader* fShaderB; |
| SkBlendMode fBlendMode; |
| }; |
| virtual bool asACompose(ComposeRec*) const { return false; } |
| #endif |
| |
| ////////////////////////////////////////////////////////////////////////// |
| // Methods to create combinations or variants of shaders |
| |
| /** |
| * Return a shader that will apply the specified localMatrix to this shader. |
| * The specified matrix will be applied before any matrix associated with this shader. |
| */ |
| sk_sp<SkShader> makeWithLocalMatrix(const SkMatrix&) const; |
| |
| /** |
| * Create a new shader that produces the same colors as invoking this shader and then applying |
| * the colorfilter. |
| */ |
| sk_sp<SkShader> makeWithColorFilter(sk_sp<SkColorFilter>) const; |
| |
| ////////////////////////////////////////////////////////////////////////// |
| // Factory methods for stock shaders |
| |
| /** |
| * Call this to create a new "empty" shader, that will not draw anything. |
| */ |
| static sk_sp<SkShader> MakeEmptyShader(); |
| |
| /** |
| * Call this to create a new shader that just draws the specified color. This should always |
| * draw the same as a paint with this color (and no shader). |
| */ |
| static sk_sp<SkShader> MakeColorShader(SkColor); |
| |
| /** |
| * Create a shader that draws the specified color (in the specified colorspace). |
| * |
| * This works around the limitation that SkPaint::setColor() only takes byte values, and does |
| * not support specific colorspaces. |
| */ |
| static sk_sp<SkShader> MakeColorShader(const SkColor4f&, sk_sp<SkColorSpace>); |
| |
| /** |
| * Compose two shaders together, using two operators: mode and lerp. The resulting colors |
| * are computed by first combining the src and dst shaders using mode, and then linearly |
| * interpolating between the dst and result colors using lerp. |
| * |
| * result = dst * (1 - lerp) + (src (mode) dst) * lerp |
| * |
| * If either shader is nullptr, then this returns nullptr. |
| * If lerp is NaN then this returns nullptr, otherwise lerp is clamped to [0..1]. |
| */ |
| static sk_sp<SkShader> MakeCompose(sk_sp<SkShader> dst, sk_sp<SkShader> src, |
| SkBlendMode mode, float lerp = 1); |
| |
| /* |
| * DEPRECATED: call MakeCompose. |
| */ |
| static sk_sp<SkShader> MakeComposeShader(sk_sp<SkShader> dst, sk_sp<SkShader> src, |
| SkBlendMode mode) { |
| return MakeCompose(std::move(dst), std::move(src), mode, 1); |
| } |
| |
| /** |
| * Compose two shaders together using a weighted average. |
| * |
| * result = dst * (1 - lerp) + src * lerp |
| * |
| * If either shader is nullptr, then this returns nullptr. |
| * If lerp is NaN then this returns nullptr, otherwise lerp is clamped to [0..1]. |
| */ |
| static sk_sp<SkShader> MakeMixer(sk_sp<SkShader> dst, sk_sp<SkShader> src, float lerp) { |
| return MakeCompose(std::move(dst), std::move(src), SkBlendMode::kSrc, lerp); |
| } |
| |
| /** Call this to create a new shader that will draw with the specified bitmap. |
| * |
| * If the bitmap cannot be used (e.g. has no pixels, or its dimensions |
| * exceed implementation limits (currently at 64K - 1)) then SkEmptyShader |
| * may be returned. |
| * |
| * If the src is kA8_Config then that mask will be colorized using the color on |
| * the paint. |
| * |
| * @param src The bitmap to use inside the shader |
| * @param tmx The tiling mode to use when sampling the bitmap in the x-direction. |
| * @param tmy The tiling mode to use when sampling the bitmap in the y-direction. |
| * @return Returns a new shader object. Note: this function never returns null. |
| */ |
| static sk_sp<SkShader> MakeBitmapShader(const SkBitmap& src, TileMode tmx, TileMode tmy, |
| const SkMatrix* localMatrix = nullptr); |
| |
| // NOTE: You can create an SkImage Shader with SkImage::newShader(). |
| |
| /** Call this to create a new shader that will draw with the specified picture. |
| * |
| * @param src The picture to use inside the shader (if not NULL, its ref count |
| * is incremented). The SkPicture must not be changed after |
| * successfully creating a picture shader. |
| * @param tmx The tiling mode to use when sampling the bitmap in the x-direction. |
| * @param tmy The tiling mode to use when sampling the bitmap in the y-direction. |
| * @param tile The tile rectangle in picture coordinates: this represents the subset |
| * (or superset) of the picture used when building a tile. It is not |
| * affected by localMatrix and does not imply scaling (only translation |
| * and cropping). If null, the tile rect is considered equal to the picture |
| * bounds. |
| * @return Returns a new shader object. Note: this function never returns null. |
| */ |
| static sk_sp<SkShader> MakePictureShader(sk_sp<SkPicture> src, TileMode tmx, TileMode tmy, |
| const SkMatrix* localMatrix, const SkRect* tile); |
| |
| /** |
| * If this shader can be represented by another shader + a localMatrix, return that shader and |
| * the localMatrix. If not, return nullptr and ignore the localMatrix parameter. |
| */ |
| // TODO: clean up clients, move to SkShaderBase. |
| virtual sk_sp<SkShader> makeAsALocalMatrixShader(SkMatrix* localMatrix) const; |
| |
| private: |
| SkShader() = default; |
| friend class SkShaderBase; |
| |
| typedef SkFlattenable INHERITED; |
| }; |
| |
| #endif |
