| /* |
| * 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 "SkFlattenable.h" |
| #include "SkMask.h" |
| #include "SkMatrix.h" |
| #include "SkPaint.h" |
| #include "../gpu/GrColor.h" |
| |
| class SkPath; |
| class SkPicture; |
| class SkXfermode; |
| class GrContext; |
| class GrEffectRef; |
| |
| /** \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: |
| SK_DECLARE_INST_COUNT(SkShader) |
| |
| SkShader(const SkMatrix* localMatrix = NULL); |
| virtual ~SkShader(); |
| |
| /** |
| * Returns the local matrix. |
| */ |
| const SkMatrix& getLocalMatrix() const { return fLocalMatrix; } |
| |
| /** |
| * Returns true if the local matrix is not an identity matrix. |
| */ |
| bool hasLocalMatrix() const { return !fLocalMatrix.isIdentity(); } |
| |
| #ifdef SK_SUPPORT_LEGACY_SHADER_LOCALMATRIX |
| /** |
| * Set the shader's local matrix. |
| * @param localM The shader's new local matrix. |
| */ |
| void setLocalMatrix(const SkMatrix& localM) { fLocalMatrix = localM; } |
| |
| /** |
| * Reset the shader's local matrix to identity. |
| */ |
| void resetLocalMatrix() { fLocalMatrix.reset(); } |
| #endif |
| |
| 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 |
| |
| kTileModeCount |
| }; |
| |
| // override these in your subclass |
| |
| enum Flags { |
| //!< set if all of the colors will be opaque |
| kOpaqueAlpha_Flag = 0x01, |
| |
| //! set if this shader's shadeSpan16() method can be called |
| kHasSpan16_Flag = 0x02, |
| |
| /** Set this bit if the shader's native data type is instrinsically 16 |
| bit, meaning that calling the 32bit shadeSpan() entry point will |
| mean the the impl has to up-sample 16bit data into 32bit. Used as a |
| a means of clearing a dither request if the it will have no effect |
| */ |
| kIntrinsicly16_Flag = 0x04, |
| |
| /** set if the spans only vary in X (const in Y). |
| e.g. an Nx1 bitmap that is being tiled in Y, or a linear-gradient |
| that varies from left-to-right. This flag specifies this for |
| shadeSpan(). |
| */ |
| kConstInY32_Flag = 0x08, |
| |
| /** same as kConstInY32_Flag, but is set if this is true for shadeSpan16 |
| which may not always be the case, since shadeSpan16 may be |
| predithered, which would mean it was not const in Y, even though |
| the 32bit shadeSpan() would be const. |
| */ |
| kConstInY16_Flag = 0x10 |
| }; |
| |
| /** |
| * 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; } |
| |
| /** |
| * ContextRec acts as a parameter bundle for creating Contexts. |
| */ |
| struct ContextRec { |
| ContextRec() : fDevice(NULL), fPaint(NULL), fMatrix(NULL), fLocalMatrix(NULL) {} |
| ContextRec(const SkBitmap& device, const SkPaint& paint, const SkMatrix& matrix) |
| : fDevice(&device) |
| , fPaint(&paint) |
| , fMatrix(&matrix) |
| , fLocalMatrix(NULL) {} |
| |
| const SkBitmap* fDevice; // the bitmap we are drawing into |
| const SkPaint* fPaint; // the current paint associated with the draw |
| const SkMatrix* fMatrix; // the current matrix in the canvas |
| const SkMatrix* fLocalMatrix; // optional local matrix |
| }; |
| |
| class Context : public ::SkNoncopyable { |
| public: |
| Context(const SkShader& shader, const ContextRec&); |
| |
| virtual ~Context(); |
| |
| /** |
| * Called sometimes before drawing with this shader. Return the type of |
| * alpha your shader will return. The default implementation returns 0. |
| * Your subclass should override if it can (even sometimes) report a |
| * non-zero value, since that will enable various blitters to perform |
| * faster. |
| */ |
| virtual uint32_t getFlags() const { return 0; } |
| |
| /** |
| * Return the alpha associated with the data returned by shadeSpan16(). If |
| * kHasSpan16_Flag is not set, this value is meaningless. |
| */ |
| virtual uint8_t getSpan16Alpha() const { return fPaintAlpha; } |
| |
| /** |
| * Called for each span of the object being drawn. Your subclass should |
| * set the appropriate colors (with premultiplied alpha) that correspond |
| * to the specified device coordinates. |
| */ |
| virtual void shadeSpan(int x, int y, SkPMColor[], int count) = 0; |
| |
| typedef void (*ShadeProc)(void* ctx, int x, int y, SkPMColor[], int count); |
| virtual ShadeProc asAShadeProc(void** ctx); |
| |
| /** |
| * Called only for 16bit devices when getFlags() returns |
| * kOpaqueAlphaFlag | kHasSpan16_Flag |
| */ |
| virtual void shadeSpan16(int x, int y, uint16_t[], int count); |
| |
| /** |
| * Similar to shadeSpan, but only returns the alpha-channel for a span. |
| * The default implementation calls shadeSpan() and then extracts the alpha |
| * values from the returned colors. |
| */ |
| virtual void shadeSpanAlpha(int x, int y, uint8_t alpha[], int count); |
| |
| /** |
| * Helper function that returns true if this shader's shadeSpan16() method |
| * can be called. |
| */ |
| bool canCallShadeSpan16() { |
| return SkShader::CanCallShadeSpan16(this->getFlags()); |
| } |
| |
| protected: |
| // Reference to shader, so we don't have to dupe information. |
| const SkShader& fShader; |
| |
| enum MatrixClass { |
| kLinear_MatrixClass, // no perspective |
| kFixedStepInX_MatrixClass, // fast perspective, need to call fixedStepInX() each |
| // scanline |
| kPerspective_MatrixClass // slow perspective, need to mappoints each pixel |
| }; |
| static MatrixClass ComputeMatrixClass(const SkMatrix&); |
| |
| uint8_t getPaintAlpha() const { return fPaintAlpha; } |
| const SkMatrix& getTotalInverse() const { return fTotalInverse; } |
| MatrixClass getInverseClass() const { return (MatrixClass)fTotalInverseClass; } |
| const SkMatrix& getCTM() const { return fCTM; } |
| private: |
| SkMatrix fCTM; |
| SkMatrix fTotalInverse; |
| uint8_t fPaintAlpha; |
| uint8_t fTotalInverseClass; |
| |
| typedef SkNoncopyable INHERITED; |
| }; |
| |
| /** |
| * Create the actual object that does the shading. |
| * Size of storage must be >= contextSize. |
| */ |
| Context* createContext(const ContextRec&, void* storage) const; |
| |
| /** |
| * Return the size of a Context returned by createContext. |
| * |
| * Override this if your subclass overrides createContext, to return the correct size of |
| * your subclass' context. |
| */ |
| virtual size_t contextSize() const; |
| |
| /** |
| * Helper to check the flags to know if it is legal to call shadeSpan16() |
| */ |
| static bool CanCallShadeSpan16(uint32_t flags) { |
| return (flags & kHasSpan16_Flag) != 0; |
| } |
| |
| /** |
| Gives method bitmap should be read to implement a shader. |
| Also determines number and interpretation of "extra" parameters returned |
| by asABitmap |
| */ |
| enum BitmapType { |
| kNone_BitmapType, //<! Shader is not represented as a bitmap |
| kDefault_BitmapType,//<! Access bitmap using local coords transformed |
| // by matrix. No extras |
| kRadial_BitmapType, //<! Access bitmap by transforming local coordinates |
| // by the matrix and taking the distance of result |
| // from (0,0) as bitmap column. Bitmap is 1 pixel |
| // tall. No extras |
| kSweep_BitmapType, //<! Access bitmap by transforming local coordinates |
| // by the matrix and taking the angle of result |
| // to (0,0) as bitmap x coord, where angle = 0 is |
| // bitmap left edge of bitmap = 2pi is the |
| // right edge. Bitmap is 1 pixel tall. No extras |
| kTwoPointRadial_BitmapType, |
| //<! Matrix transforms to space where (0,0) is |
| // the center of the starting circle. The second |
| // circle will be centered (x, 0) where x may be |
| // 0. The post-matrix space is normalized such |
| // that 1 is the second radius - first radius. |
| // Three extra parameters are returned: |
| // 0: x-offset of second circle center |
| // to first. |
| // 1: radius of first circle in post-matrix |
| // space |
| // 2: the second radius minus the first radius |
| // in pre-transformed space. |
| kTwoPointConical_BitmapType, |
| //<! Matrix transforms to space where (0,0) is |
| // the center of the starting circle. The second |
| // circle will be centered (x, 0) where x may be |
| // 0. |
| // Three extra parameters are returned: |
| // 0: x-offset of second circle center |
| // to first. |
| // 1: radius of first circle |
| // 2: the second radius minus the first radius |
| kLinear_BitmapType, //<! Access bitmap using local coords transformed |
| // by matrix. No extras |
| |
| kLast_BitmapType = kLinear_BitmapType |
| }; |
| /** Optional methods for shaders that can pretend to be a bitmap/texture |
| to play along with opengl. Default just returns kNone_BitmapType and |
| ignores the out parameters. |
| |
| @param outTexture if non-NULL will be the bitmap representing the shader |
| after return. |
| @param outMatrix if non-NULL will be the matrix to apply to vertices |
| to access the bitmap after return. |
| @param xy if non-NULL will be the tile modes that should be |
| used to access the bitmap after return. |
| @param twoPointRadialParams Two extra return values needed for two point |
| radial bitmaps. The first is the x-offset of |
| the second point and the second is the radius |
| about the first point. |
| */ |
| virtual BitmapType asABitmap(SkBitmap* outTexture, SkMatrix* outMatrix, |
| TileMode xy[2]) const; |
| |
| /** |
| * 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 |
| * Radial2: |
| * 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, |
| kRadial2_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; |
| |
| /** |
| * If the shader subclass is composed of two shaders, return true, and if rec is not NULL, |
| * fill it out with info about the shader. |
| * |
| * These are bare pointers; the ownership and reference count are unchanged. |
| */ |
| |
| struct ComposeRec { |
| const SkShader* fShaderA; |
| const SkShader* fShaderB; |
| const SkXfermode* fMode; |
| }; |
| |
| virtual bool asACompose(ComposeRec* rec) const { return false; } |
| |
| |
| /** |
| * Returns true if the shader subclass succeeds in setting the grEffect and the grColor output |
| * parameters to a value, returns false if it fails or if there is not an implementation of |
| * this method in the shader subclass. |
| * The incoming color to the effect has r=g=b=a all extracted from the SkPaint's alpha. |
| * The output color should be the computed SkShader premul color modulated by the incoming |
| * color. The GrContext may be used by the effect to create textures. The GPU device does not |
| * call createContext. Instead we pass the SkPaint here in case the shader needs paint info. |
| */ |
| virtual bool asNewEffect(GrContext* context, const SkPaint& paint, |
| const SkMatrix* localMatrixOrNull, GrColor* grColor, |
| GrEffectRef** grEffect) const; |
| |
| #ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK |
| /** |
| * If the shader is a custom shader which has data the caller might want, call this function |
| * to get that data. |
| */ |
| virtual bool asACustomShader(void** customData) const { return false; } |
| #endif |
| |
| ////////////////////////////////////////////////////////////////////////// |
| // Factory methods for stock shaders |
| |
| /** |
| * Call this to create a new "empty" shader, that will not draw anything. |
| */ |
| static SkShader* CreateEmptyShader(); |
| |
| /** 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 SkShader* CreateBitmapShader(const SkBitmap& src, |
| TileMode tmx, TileMode tmy, |
| const SkMatrix* localMatrix = NULL); |
| |
| /** 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. |
| * FIXME: src cannot be const due to SkCanvas::drawPicture |
| * @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 SkShader* CreatePictureShader(SkPicture* src, TileMode tmx, TileMode tmy, |
| const SkMatrix* localMatrix = NULL); |
| |
| /** |
| * Return a shader that will apply the specified localMatrix to the proxy shader. |
| * The specified matrix will be applied before any matrix associated with the proxy. |
| * |
| * Note: ownership of the proxy is not transferred (though a ref is taken). |
| */ |
| static SkShader* CreateLocalMatrixShader(SkShader* proxy, const SkMatrix& localMatrix); |
| |
| /** |
| * If this shader can be represented by another shader + a localMatrix, return that shader |
| * and, if not NULL, the localMatrix. If not, return NULL and ignore the localMatrix parameter. |
| * |
| * Note: the returned shader (if not NULL) will have been ref'd, and it is the responsibility |
| * of the caller to balance that with unref() when they are done. |
| */ |
| virtual SkShader* refAsALocalMatrixShader(SkMatrix* localMatrix) const; |
| |
| SK_TO_STRING_VIRT() |
| SK_DEFINE_FLATTENABLE_TYPE(SkShader) |
| |
| protected: |
| SkShader(SkReadBuffer& ); |
| virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE; |
| |
| bool computeTotalInverse(const ContextRec&, SkMatrix* totalInverse) const; |
| |
| /** |
| * Your subclass must also override contextSize() if it overrides onCreateContext(). |
| * Base class impl returns NULL. |
| */ |
| virtual Context* onCreateContext(const ContextRec&, void* storage) const; |
| |
| private: |
| SkMatrix fLocalMatrix; |
| |
| typedef SkFlattenable INHERITED; |
| }; |
| |
| #endif |
