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1 /* | 1 /* |
2 * Copyright 2006 The Android Open Source Project | 2 * Copyright 2006 The Android Open Source Project |
3 * | 3 * |
4 * Use of this source code is governed by a BSD-style license that can be | 4 * Use of this source code is governed by a BSD-style license that can be |
5 * found in the LICENSE file. | 5 * found in the LICENSE file. |
6 */ | 6 */ |
7 | 7 |
8 | 8 |
9 #ifndef SkShader_DEFINED | 9 #ifndef SkShader_DEFINED |
10 #define SkShader_DEFINED | 10 #define SkShader_DEFINED |
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31 * to be modified. | 31 * to be modified. |
32 */ | 32 */ |
33 class SK_API SkShader : public SkFlattenable { | 33 class SK_API SkShader : public SkFlattenable { |
34 public: | 34 public: |
35 SK_DECLARE_INST_COUNT(SkShader) | 35 SK_DECLARE_INST_COUNT(SkShader) |
36 | 36 |
37 SkShader(); | 37 SkShader(); |
38 virtual ~SkShader(); | 38 virtual ~SkShader(); |
39 | 39 |
40 /** | 40 /** |
41 * Returns true if the local matrix is not an identity matrix. | 41 * Returns true if the local matrix is not an identity matrix. |
42 */ | 42 */ |
43 bool hasLocalMatrix() const { return !fLocalMatrix.isIdentity(); } | 43 bool hasLocalMatrix() const { return !fLocalMatrix.isIdentity(); } |
44 | 44 |
45 /** | 45 /** |
46 * Returns the local matrix. | 46 * Returns the local matrix. |
47 */ | 47 */ |
48 const SkMatrix& getLocalMatrix() const { return fLocalMatrix; } | 48 const SkMatrix& getLocalMatrix() const { return fLocalMatrix; } |
49 | 49 |
50 /** | 50 /** |
51 * Set the shader's local matrix. | 51 * Set the shader's local matrix. |
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89 //! set if this shader's shadeSpan16() method can be called | 89 //! set if this shader's shadeSpan16() method can be called |
90 kHasSpan16_Flag = 0x02, | 90 kHasSpan16_Flag = 0x02, |
91 | 91 |
92 /** Set this bit if the shader's native data type is instrinsically 16 | 92 /** Set this bit if the shader's native data type is instrinsically 16 |
93 bit, meaning that calling the 32bit shadeSpan() entry point will | 93 bit, meaning that calling the 32bit shadeSpan() entry point will |
94 mean the the impl has to up-sample 16bit data into 32bit. Used as a | 94 mean the the impl has to up-sample 16bit data into 32bit. Used as a |
95 a means of clearing a dither request if the it will have no effect | 95 a means of clearing a dither request if the it will have no effect |
96 */ | 96 */ |
97 kIntrinsicly16_Flag = 0x04, | 97 kIntrinsicly16_Flag = 0x04, |
98 | 98 |
99 /** set (after setContext) if the spans only vary in X (const in Y). | 99 /** set if the spans only vary in X (const in Y). |
100 e.g. an Nx1 bitmap that is being tiled in Y, or a linear-gradient | 100 e.g. an Nx1 bitmap that is being tiled in Y, or a linear-gradient |
101 that varies from left-to-right. This flag specifies this for | 101 that varies from left-to-right. This flag specifies this for |
102 shadeSpan(). | 102 shadeSpan(). |
103 */ | 103 */ |
104 kConstInY32_Flag = 0x08, | 104 kConstInY32_Flag = 0x08, |
105 | 105 |
106 /** same as kConstInY32_Flag, but is set if this is true for shadeSpan16 | 106 /** same as kConstInY32_Flag, but is set if this is true for shadeSpan16 |
107 which may not always be the case, since shadeSpan16 may be | 107 which may not always be the case, since shadeSpan16 may be |
108 predithered, which would mean it was not const in Y, even though | 108 predithered, which would mean it was not const in Y, even though |
109 the 32bit shadeSpan() would be const. | 109 the 32bit shadeSpan() would be const. |
110 */ | 110 */ |
111 kConstInY16_Flag = 0x10 | 111 kConstInY16_Flag = 0x10 |
112 }; | 112 }; |
113 | 113 |
114 /** | 114 /** |
115 * Called sometimes before drawing with this shader. Return the type of | |
116 * alpha your shader will return. The default implementation returns 0. | |
117 * Your subclass should override if it can (even sometimes) report a | |
118 * non-zero value, since that will enable various blitters to perform | |
119 * faster. | |
120 */ | |
121 virtual uint32_t getFlags() { return 0; } | |
122 | |
123 /** | |
124 * Returns true if the shader is guaranteed to produce only opaque | 115 * Returns true if the shader is guaranteed to produce only opaque |
125 * colors, subject to the SkPaint using the shader to apply an opaque | 116 * colors, subject to the SkPaint using the shader to apply an opaque |
126 * alpha value. Subclasses should override this to allow some | 117 * alpha value. Subclasses should override this to allow some |
127 * optimizations. isOpaque() can be called at any time, unlike getFlags, | 118 * optimizations. |
128 * which only works properly when the context is set. | |
129 */ | 119 */ |
130 virtual bool isOpaque() const { return false; } | 120 virtual bool isOpaque() const { return false; } |
131 | 121 |
132 /** | 122 class Context : public ::SkNoncopyable { |
133 * Return the alpha associated with the data returned by shadeSpan16(). If | 123 public: |
134 * kHasSpan16_Flag is not set, this value is meaningless. | 124 Context(const SkShader& shader, const SkBitmap& device, |
135 */ | 125 const SkPaint& paint, const SkMatrix& matrix); |
136 virtual uint8_t getSpan16Alpha() const { return fPaintAlpha; } | 126 |
| 127 virtual ~Context(); |
| 128 |
| 129 /** |
| 130 * Called sometimes before drawing with this shader. Return the type of |
| 131 * alpha your shader will return. The default implementation returns 0. |
| 132 * Your subclass should override if it can (even sometimes) report a |
| 133 * non-zero value, since that will enable various blitters to perform |
| 134 * faster. |
| 135 */ |
| 136 virtual uint32_t getFlags() const { return 0; } |
| 137 |
| 138 /** |
| 139 * Return the alpha associated with the data returned by shadeSpan16().
If |
| 140 * kHasSpan16_Flag is not set, this value is meaningless. |
| 141 */ |
| 142 virtual uint8_t getSpan16Alpha() const { return fPaintAlpha; } |
| 143 |
| 144 /** |
| 145 * Called for each span of the object being drawn. Your subclass should |
| 146 * set the appropriate colors (with premultiplied alpha) that correspon
d |
| 147 * to the specified device coordinates. |
| 148 */ |
| 149 virtual void shadeSpan(int x, int y, SkPMColor[], int count) = 0; |
| 150 |
| 151 typedef void (*ShadeProc)(void* ctx, int x, int y, SkPMColor[], int coun
t); |
| 152 virtual ShadeProc asAShadeProc(void** ctx); |
| 153 |
| 154 /** |
| 155 * Called only for 16bit devices when getFlags() returns |
| 156 * kOpaqueAlphaFlag | kHasSpan16_Flag |
| 157 */ |
| 158 virtual void shadeSpan16(int x, int y, uint16_t[], int count); |
| 159 |
| 160 /** |
| 161 * Similar to shadeSpan, but only returns the alpha-channel for a span. |
| 162 * The default implementation calls shadeSpan() and then extracts the a
lpha |
| 163 * values from the returned colors. |
| 164 */ |
| 165 virtual void shadeSpanAlpha(int x, int y, uint8_t alpha[], int count); |
| 166 |
| 167 /** |
| 168 * Helper function that returns true if this shader's shadeSpan16() met
hod |
| 169 * can be called. |
| 170 */ |
| 171 bool canCallShadeSpan16() { |
| 172 return SkShader::CanCallShadeSpan16(this->getFlags()); |
| 173 } |
| 174 |
| 175 protected: |
| 176 // Reference to shader, so we don't have to dupe information. |
| 177 const SkShader& fShader; |
| 178 |
| 179 enum MatrixClass { |
| 180 kLinear_MatrixClass, // no perspective |
| 181 kFixedStepInX_MatrixClass, // fast perspective, need to call fi
xedStepInX() each |
| 182 // scanline |
| 183 kPerspective_MatrixClass // slow perspective, need to mappoin
ts each pixel |
| 184 }; |
| 185 static MatrixClass ComputeMatrixClass(const SkMatrix&); |
| 186 |
| 187 uint8_t getPaintAlpha() const { return fPaintAlpha; } |
| 188 const SkMatrix& getTotalInverse() const { return fTotalInverse; } |
| 189 MatrixClass getInverseClass() const { return (MatrixClass)fTotal
InverseClass; } |
| 190 |
| 191 private: |
| 192 SkMatrix fTotalInverse; |
| 193 uint8_t fPaintAlpha; |
| 194 uint8_t fTotalInverseClass; |
| 195 |
| 196 typedef SkNoncopyable INHERITED; |
| 197 }; |
137 | 198 |
138 /** | 199 /** |
139 * Called once before drawing, with the current paint and device matrix. | 200 * Subclasses should be sure to call their INHERITED::validContext() if |
140 * Return true if your shader supports these parameters, or false if not. | 201 * they override this method. |
141 * If false is returned, nothing will be drawn. If true is returned, then | |
142 * a balancing call to endContext() will be made before the next call to | |
143 * setContext. | |
144 * | |
145 * Subclasses should be sure to call their INHERITED::setContext() if they | |
146 * override this method. | |
147 */ | 202 */ |
148 virtual bool setContext(const SkBitmap& device, const SkPaint& paint, | 203 virtual bool validContext(const SkBitmap& device, const SkPaint& paint, |
149 const SkMatrix& matrix); | 204 const SkMatrix& matrix, SkMatrix* totalInverse = N
ULL) const; |
150 | 205 |
151 /** | 206 /** |
152 * Assuming setContext returned true, endContext() will be called when | 207 * Create the actual object that does the shading. |
153 * the draw using the shader has completed. It is an error for setContext | 208 * Returns NULL if validContext() returns false. |
154 * to be called twice w/o an intervening call to endContext(). | 209 * Size of storage must be >= contextSize. |
155 * | |
156 * Subclasses should be sure to call their INHERITED::endContext() if they | |
157 * override this method. | |
158 */ | 210 */ |
159 virtual void endContext(); | 211 virtual Context* createContext(const SkBitmap& device, |
160 | 212 const SkPaint& paint, |
161 SkDEBUGCODE(bool setContextHasBeenCalled() const { return SkToBool(fInSetCon
text); }) | 213 const SkMatrix& matrix, |
| 214 void* storage) const = 0; |
162 | 215 |
163 /** | 216 /** |
164 * Called for each span of the object being drawn. Your subclass should | 217 * Return the size of a Context returned by createContext. |
165 * set the appropriate colors (with premultiplied alpha) that correspond | |
166 * to the specified device coordinates. | |
167 */ | 218 */ |
168 virtual void shadeSpan(int x, int y, SkPMColor[], int count) = 0; | 219 virtual size_t contextSize() const = 0; |
169 | |
170 typedef void (*ShadeProc)(void* ctx, int x, int y, SkPMColor[], int count); | |
171 virtual ShadeProc asAShadeProc(void** ctx); | |
172 | |
173 /** | |
174 * Called only for 16bit devices when getFlags() returns | |
175 * kOpaqueAlphaFlag | kHasSpan16_Flag | |
176 */ | |
177 virtual void shadeSpan16(int x, int y, uint16_t[], int count); | |
178 | |
179 /** | |
180 * Similar to shadeSpan, but only returns the alpha-channel for a span. | |
181 * The default implementation calls shadeSpan() and then extracts the alpha | |
182 * values from the returned colors. | |
183 */ | |
184 virtual void shadeSpanAlpha(int x, int y, uint8_t alpha[], int count); | |
185 | |
186 /** | |
187 * Helper function that returns true if this shader's shadeSpan16() method | |
188 * can be called. | |
189 */ | |
190 bool canCallShadeSpan16() { | |
191 return SkShader::CanCallShadeSpan16(this->getFlags()); | |
192 } | |
193 | 220 |
194 /** | 221 /** |
195 * Helper to check the flags to know if it is legal to call shadeSpan16() | 222 * Helper to check the flags to know if it is legal to call shadeSpan16() |
196 */ | 223 */ |
197 static bool CanCallShadeSpan16(uint32_t flags) { | 224 static bool CanCallShadeSpan16(uint32_t flags) { |
198 return (flags & kHasSpan16_Flag) != 0; | 225 return (flags & kHasSpan16_Flag) != 0; |
199 } | 226 } |
200 | 227 |
201 /** | 228 /** |
202 Gives method bitmap should be read to implement a shader. | 229 Gives method bitmap should be read to implement a shader. |
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315 uint32_t fGradientFlags; //!< see SkGradientShader::Flags | 342 uint32_t fGradientFlags; //!< see SkGradientShader::Flags |
316 }; | 343 }; |
317 | 344 |
318 virtual GradientType asAGradient(GradientInfo* info) const; | 345 virtual GradientType asAGradient(GradientInfo* info) const; |
319 | 346 |
320 /** | 347 /** |
321 * If the shader subclass has a GrEffect implementation, this resturns the
effect to install. | 348 * If the shader subclass has a GrEffect implementation, this resturns the
effect to install. |
322 * The incoming color to the effect has r=g=b=a all extracted from the SkPa
int's alpha. | 349 * The incoming color to the effect has r=g=b=a all extracted from the SkPa
int's alpha. |
323 * The output color should be the computed SkShader premul color modulated
by the incoming | 350 * The output color should be the computed SkShader premul color modulated
by the incoming |
324 * color. The GrContext may be used by the effect to create textures. The G
PU device does not | 351 * color. The GrContext may be used by the effect to create textures. The G
PU device does not |
325 * call setContext. Instead we pass the SkPaint here in case the shader nee
ds paint info. | 352 * call createContext. Instead we pass the SkPaint here in case the shader
needs paint info. |
326 */ | 353 */ |
327 virtual GrEffectRef* asNewEffect(GrContext* context, const SkPaint& paint) c
onst; | 354 virtual GrEffectRef* asNewEffect(GrContext* context, const SkPaint& paint) c
onst; |
328 | 355 |
329 ////////////////////////////////////////////////////////////////////////// | 356 ////////////////////////////////////////////////////////////////////////// |
330 // Factory methods for stock shaders | 357 // Factory methods for stock shaders |
331 | 358 |
332 /** Call this to create a new shader that will draw with the specified bitma
p. | 359 /** Call this to create a new shader that will draw with the specified bitma
p. |
333 * | 360 * |
334 * If the bitmap cannot be used (e.g. has no pixels, or its dimensions | 361 * If the bitmap cannot be used (e.g. has no pixels, or its dimensions |
335 * exceed implementation limits (currently at 64K - 1)) then SkEmptyShader | 362 * exceed implementation limits (currently at 64K - 1)) then SkEmptyShader |
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355 * @param tmx The tiling mode to use when sampling the bitmap in the x-dir
ection. | 382 * @param tmx The tiling mode to use when sampling the bitmap in the x-dir
ection. |
356 * @param tmy The tiling mode to use when sampling the bitmap in the y-dir
ection. | 383 * @param tmy The tiling mode to use when sampling the bitmap in the y-dir
ection. |
357 * @return Returns a new shader object. Note: this function never retur
ns null. | 384 * @return Returns a new shader object. Note: this function never retur
ns null. |
358 */ | 385 */ |
359 static SkShader* CreatePictureShader(SkPicture* src, TileMode tmx, TileMode
tmy); | 386 static SkShader* CreatePictureShader(SkPicture* src, TileMode tmx, TileMode
tmy); |
360 | 387 |
361 SK_TO_STRING_VIRT() | 388 SK_TO_STRING_VIRT() |
362 SK_DEFINE_FLATTENABLE_TYPE(SkShader) | 389 SK_DEFINE_FLATTENABLE_TYPE(SkShader) |
363 | 390 |
364 protected: | 391 protected: |
365 enum MatrixClass { | |
366 kLinear_MatrixClass, // no perspective | |
367 kFixedStepInX_MatrixClass, // fast perspective, need to call fixedS
tepInX() each scanline | |
368 kPerspective_MatrixClass // slow perspective, need to mappoints e
ach pixel | |
369 }; | |
370 static MatrixClass ComputeMatrixClass(const SkMatrix&); | |
371 | |
372 // These can be called by your subclass after setContext() has been called | |
373 uint8_t getPaintAlpha() const { return fPaintAlpha; } | |
374 const SkMatrix& getTotalInverse() const { return fTotalInverse; } | |
375 MatrixClass getInverseClass() const { return (MatrixClass)fTotalInve
rseClass; } | |
376 | 392 |
377 SkShader(SkReadBuffer& ); | 393 SkShader(SkReadBuffer& ); |
378 virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE; | 394 virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE; |
| 395 |
379 private: | 396 private: |
380 SkMatrix fLocalMatrix; | 397 SkMatrix fLocalMatrix; |
381 SkMatrix fTotalInverse; | 398 |
382 uint8_t fPaintAlpha; | 399 bool computeTotalInverse(const SkMatrix& matrix, SkMatrix* totalInverse) con
st; |
383 uint8_t fTotalInverseClass; | |
384 SkDEBUGCODE(SkBool8 fInSetContext;) | |
385 | 400 |
386 typedef SkFlattenable INHERITED; | 401 typedef SkFlattenable INHERITED; |
387 }; | 402 }; |
388 | 403 |
389 #endif | 404 #endif |
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