1 /*
2 * Copyright 2006 The Android Open Source Project
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8 #ifndef SkColorData_DEFINED
9 #define SkColorData_DEFINED
10
11 #include "include/core/SkColor.h"
12 #include "include/core/SkColorPriv.h"
13 #include "include/private/base/SkTo.h"
14
15 ////////////////////////////////////////////////////////////////////////////////////////////
16 // Convert a 16bit pixel to a 32bit pixel
17
18 #define SK_R16_BITS 5
19 #define SK_G16_BITS 6
20 #define SK_B16_BITS 5
21
22 #define SK_R16_SHIFT (SK_B16_BITS + SK_G16_BITS)
23 #define SK_G16_SHIFT (SK_B16_BITS)
24 #define SK_B16_SHIFT 0
25
26 #define SK_R16_MASK ((1 << SK_R16_BITS) - 1)
27 #define SK_G16_MASK ((1 << SK_G16_BITS) - 1)
28 #define SK_B16_MASK ((1 << SK_B16_BITS) - 1)
29
30 #define SkGetPackedR16(color) (((unsigned)(color) >> SK_R16_SHIFT) & SK_R16_MASK)
31 #define SkGetPackedG16(color) (((unsigned)(color) >> SK_G16_SHIFT) & SK_G16_MASK)
32 #define SkGetPackedB16(color) (((unsigned)(color) >> SK_B16_SHIFT) & SK_B16_MASK)
33
SkR16ToR32(unsigned r)34 static inline unsigned SkR16ToR32(unsigned r) {
35 return (r << (8 - SK_R16_BITS)) | (r >> (2 * SK_R16_BITS - 8));
36 }
37
SkG16ToG32(unsigned g)38 static inline unsigned SkG16ToG32(unsigned g) {
39 return (g << (8 - SK_G16_BITS)) | (g >> (2 * SK_G16_BITS - 8));
40 }
41
SkB16ToB32(unsigned b)42 static inline unsigned SkB16ToB32(unsigned b) {
43 return (b << (8 - SK_B16_BITS)) | (b >> (2 * SK_B16_BITS - 8));
44 }
45
46 #define SkPacked16ToR32(c) SkR16ToR32(SkGetPackedR16(c))
47 #define SkPacked16ToG32(c) SkG16ToG32(SkGetPackedG16(c))
48 #define SkPacked16ToB32(c) SkB16ToB32(SkGetPackedB16(c))
49
50 //////////////////////////////////////////////////////////////////////////////
51
52 #define SkASSERT_IS_BYTE(x) SkASSERT(0 == ((x) & ~0xFFu))
53
54 // Reverse the bytes coorsponding to RED and BLUE in a packed pixels. Note the
55 // pair of them are in the same 2 slots in both RGBA and BGRA, thus there is
56 // no need to pass in the colortype to this function.
SkSwizzle_RB(uint32_t c)57 static inline uint32_t SkSwizzle_RB(uint32_t c) {
58 static const uint32_t kRBMask = (0xFF << SK_R32_SHIFT) | (0xFF << SK_B32_SHIFT);
59
60 unsigned c0 = (c >> SK_R32_SHIFT) & 0xFF;
61 unsigned c1 = (c >> SK_B32_SHIFT) & 0xFF;
62 return (c & ~kRBMask) | (c0 << SK_B32_SHIFT) | (c1 << SK_R32_SHIFT);
63 }
64
SkPackARGB_as_RGBA(U8CPU a,U8CPU r,U8CPU g,U8CPU b)65 static inline uint32_t SkPackARGB_as_RGBA(U8CPU a, U8CPU r, U8CPU g, U8CPU b) {
66 SkASSERT_IS_BYTE(a);
67 SkASSERT_IS_BYTE(r);
68 SkASSERT_IS_BYTE(g);
69 SkASSERT_IS_BYTE(b);
70 return (a << SK_RGBA_A32_SHIFT) | (r << SK_RGBA_R32_SHIFT) |
71 (g << SK_RGBA_G32_SHIFT) | (b << SK_RGBA_B32_SHIFT);
72 }
73
SkPackARGB_as_BGRA(U8CPU a,U8CPU r,U8CPU g,U8CPU b)74 static inline uint32_t SkPackARGB_as_BGRA(U8CPU a, U8CPU r, U8CPU g, U8CPU b) {
75 SkASSERT_IS_BYTE(a);
76 SkASSERT_IS_BYTE(r);
77 SkASSERT_IS_BYTE(g);
78 SkASSERT_IS_BYTE(b);
79 return (a << SK_BGRA_A32_SHIFT) | (r << SK_BGRA_R32_SHIFT) |
80 (g << SK_BGRA_G32_SHIFT) | (b << SK_BGRA_B32_SHIFT);
81 }
82
SkSwizzle_RGBA_to_PMColor(uint32_t c)83 static inline SkPMColor SkSwizzle_RGBA_to_PMColor(uint32_t c) {
84 #ifdef SK_PMCOLOR_IS_RGBA
85 return c;
86 #else
87 return SkSwizzle_RB(c);
88 #endif
89 }
90
SkSwizzle_BGRA_to_PMColor(uint32_t c)91 static inline SkPMColor SkSwizzle_BGRA_to_PMColor(uint32_t c) {
92 #ifdef SK_PMCOLOR_IS_BGRA
93 return c;
94 #else
95 return SkSwizzle_RB(c);
96 #endif
97 }
98
99 //////////////////////////////////////////////////////////////////////////////
100
101 ///@{
102 /** See ITU-R Recommendation BT.709 at http://www.itu.int/rec/R-REC-BT.709/ .*/
103 #define SK_ITU_BT709_LUM_COEFF_R (0.2126f)
104 #define SK_ITU_BT709_LUM_COEFF_G (0.7152f)
105 #define SK_ITU_BT709_LUM_COEFF_B (0.0722f)
106 ///@}
107
108 ///@{
109 /** A float value which specifies this channel's contribution to luminance. */
110 #define SK_LUM_COEFF_R SK_ITU_BT709_LUM_COEFF_R
111 #define SK_LUM_COEFF_G SK_ITU_BT709_LUM_COEFF_G
112 #define SK_LUM_COEFF_B SK_ITU_BT709_LUM_COEFF_B
113 ///@}
114
115 /** Computes the luminance from the given r, g, and b in accordance with
116 SK_LUM_COEFF_X. For correct results, r, g, and b should be in linear space.
117 */
SkComputeLuminance(U8CPU r,U8CPU g,U8CPU b)118 static inline U8CPU SkComputeLuminance(U8CPU r, U8CPU g, U8CPU b) {
119 //The following is
120 //r * SK_LUM_COEFF_R + g * SK_LUM_COEFF_G + b * SK_LUM_COEFF_B
121 //with SK_LUM_COEFF_X in 1.8 fixed point (rounding adjusted to sum to 256).
122 return (r * 54 + g * 183 + b * 19) >> 8;
123 }
124
125 /** Calculates 256 - (value * alpha256) / 255 in range [0,256],
126 * for [0,255] value and [0,256] alpha256.
127 */
SkAlphaMulInv256(U16CPU value,U16CPU alpha256)128 static inline U16CPU SkAlphaMulInv256(U16CPU value, U16CPU alpha256) {
129 unsigned prod = 0xFFFF - value * alpha256;
130 return (prod + (prod >> 8)) >> 8;
131 }
132
133 // The caller may want negative values, so keep all params signed (int)
134 // so we don't accidentally slip into unsigned math and lose the sign
135 // extension when we shift (in SkAlphaMul)
SkAlphaBlend(int src,int dst,int scale256)136 static inline int SkAlphaBlend(int src, int dst, int scale256) {
137 SkASSERT((unsigned)scale256 <= 256);
138 return dst + SkAlphaMul(src - dst, scale256);
139 }
140
SkPackRGB16(unsigned r,unsigned g,unsigned b)141 static inline uint16_t SkPackRGB16(unsigned r, unsigned g, unsigned b) {
142 SkASSERT(r <= SK_R16_MASK);
143 SkASSERT(g <= SK_G16_MASK);
144 SkASSERT(b <= SK_B16_MASK);
145
146 return SkToU16((r << SK_R16_SHIFT) | (g << SK_G16_SHIFT) | (b << SK_B16_SHIFT));
147 }
148
149 #define SK_R16_MASK_IN_PLACE (SK_R16_MASK << SK_R16_SHIFT)
150 #define SK_G16_MASK_IN_PLACE (SK_G16_MASK << SK_G16_SHIFT)
151 #define SK_B16_MASK_IN_PLACE (SK_B16_MASK << SK_B16_SHIFT)
152
153 ///////////////////////////////////////////////////////////////////////////////
154
155 /**
156 * Abstract 4-byte interpolation, implemented on top of SkPMColor
157 * utility functions. Third parameter controls blending of the first two:
158 * (src, dst, 0) returns dst
159 * (src, dst, 0xFF) returns src
160 * scale is [0..256], unlike SkFourByteInterp which takes [0..255]
161 */
SkFourByteInterp256(SkPMColor src,SkPMColor dst,int scale)162 static inline SkPMColor SkFourByteInterp256(SkPMColor src, SkPMColor dst, int scale) {
163 unsigned a = SkTo<uint8_t>(SkAlphaBlend(SkGetPackedA32(src), SkGetPackedA32(dst), scale));
164 unsigned r = SkTo<uint8_t>(SkAlphaBlend(SkGetPackedR32(src), SkGetPackedR32(dst), scale));
165 unsigned g = SkTo<uint8_t>(SkAlphaBlend(SkGetPackedG32(src), SkGetPackedG32(dst), scale));
166 unsigned b = SkTo<uint8_t>(SkAlphaBlend(SkGetPackedB32(src), SkGetPackedB32(dst), scale));
167
168 return SkPackARGB32(a, r, g, b);
169 }
170
171 /**
172 * Abstract 4-byte interpolation, implemented on top of SkPMColor
173 * utility functions. Third parameter controls blending of the first two:
174 * (src, dst, 0) returns dst
175 * (src, dst, 0xFF) returns src
176 */
SkFourByteInterp(SkPMColor src,SkPMColor dst,U8CPU srcWeight)177 static inline SkPMColor SkFourByteInterp(SkPMColor src, SkPMColor dst, U8CPU srcWeight) {
178 int scale = (int)SkAlpha255To256(srcWeight);
179 return SkFourByteInterp256(src, dst, scale);
180 }
181
182 /**
183 * 0xAARRGGBB -> 0x00AA00GG, 0x00RR00BB
184 */
SkSplay(uint32_t color,uint32_t * ag,uint32_t * rb)185 static inline void SkSplay(uint32_t color, uint32_t* ag, uint32_t* rb) {
186 const uint32_t mask = 0x00FF00FF;
187 *ag = (color >> 8) & mask;
188 *rb = color & mask;
189 }
190
191 /**
192 * 0xAARRGGBB -> 0x00AA00GG00RR00BB
193 * (note, ARGB -> AGRB)
194 */
SkSplay(uint32_t color)195 static inline uint64_t SkSplay(uint32_t color) {
196 const uint32_t mask = 0x00FF00FF;
197 uint64_t agrb = (color >> 8) & mask; // 0x0000000000AA00GG
198 agrb <<= 32; // 0x00AA00GG00000000
199 agrb |= color & mask; // 0x00AA00GG00RR00BB
200 return agrb;
201 }
202
203 /**
204 * 0xAAxxGGxx, 0xRRxxBBxx-> 0xAARRGGBB
205 */
SkUnsplay(uint32_t ag,uint32_t rb)206 static inline uint32_t SkUnsplay(uint32_t ag, uint32_t rb) {
207 const uint32_t mask = 0xFF00FF00;
208 return (ag & mask) | ((rb & mask) >> 8);
209 }
210
211 /**
212 * 0xAAxxGGxxRRxxBBxx -> 0xAARRGGBB
213 * (note, AGRB -> ARGB)
214 */
SkUnsplay(uint64_t agrb)215 static inline uint32_t SkUnsplay(uint64_t agrb) {
216 const uint32_t mask = 0xFF00FF00;
217 return SkPMColor(
218 ((agrb & mask) >> 8) | // 0x00RR00BB
219 ((agrb >> 32) & mask)); // 0xAARRGGBB
220 }
221
SkFastFourByteInterp256_32(SkPMColor src,SkPMColor dst,unsigned scale)222 static inline SkPMColor SkFastFourByteInterp256_32(SkPMColor src, SkPMColor dst, unsigned scale) {
223 SkASSERT(scale <= 256);
224
225 // Two 8-bit blends per two 32-bit registers, with space to make sure the math doesn't collide.
226 uint32_t src_ag, src_rb, dst_ag, dst_rb;
227 SkSplay(src, &src_ag, &src_rb);
228 SkSplay(dst, &dst_ag, &dst_rb);
229
230 const uint32_t ret_ag = src_ag * scale + (256 - scale) * dst_ag;
231 const uint32_t ret_rb = src_rb * scale + (256 - scale) * dst_rb;
232
233 return SkUnsplay(ret_ag, ret_rb);
234 }
235
SkFastFourByteInterp256_64(SkPMColor src,SkPMColor dst,unsigned scale)236 static inline SkPMColor SkFastFourByteInterp256_64(SkPMColor src, SkPMColor dst, unsigned scale) {
237 SkASSERT(scale <= 256);
238 // Four 8-bit blends in one 64-bit register, with space to make sure the math doesn't collide.
239 return SkUnsplay(SkSplay(src) * scale + (256-scale) * SkSplay(dst));
240 }
241
242 // TODO(mtklein): Replace slow versions with fast versions, using scale + (scale>>7) everywhere.
243
244 /**
245 * Same as SkFourByteInterp256, but faster.
246 */
SkFastFourByteInterp256(SkPMColor src,SkPMColor dst,unsigned scale)247 static inline SkPMColor SkFastFourByteInterp256(SkPMColor src, SkPMColor dst, unsigned scale) {
248 // On a 64-bit machine, _64 is about 10% faster than _32, but ~40% slower on a 32-bit machine.
249 if (sizeof(void*) == 4) {
250 return SkFastFourByteInterp256_32(src, dst, scale);
251 } else {
252 return SkFastFourByteInterp256_64(src, dst, scale);
253 }
254 }
255
256 /**
257 * Nearly the same as SkFourByteInterp, but faster and a touch more accurate, due to better
258 * srcWeight scaling to [0, 256].
259 */
SkFastFourByteInterp(SkPMColor src,SkPMColor dst,U8CPU srcWeight)260 static inline SkPMColor SkFastFourByteInterp(SkPMColor src, SkPMColor dst, U8CPU srcWeight) {
261 SkASSERT(srcWeight <= 255);
262 // scale = srcWeight + (srcWeight >> 7) is more accurate than
263 // scale = srcWeight + 1, but 7% slower
264 return SkFastFourByteInterp256(src, dst, srcWeight + (srcWeight >> 7));
265 }
266
267 /**
268 * Interpolates between colors src and dst using [0,256] scale.
269 */
SkPMLerp(SkPMColor src,SkPMColor dst,unsigned scale)270 static inline SkPMColor SkPMLerp(SkPMColor src, SkPMColor dst, unsigned scale) {
271 return SkFastFourByteInterp256(src, dst, scale);
272 }
273
SkBlendARGB32(SkPMColor src,SkPMColor dst,U8CPU aa)274 static inline SkPMColor SkBlendARGB32(SkPMColor src, SkPMColor dst, U8CPU aa) {
275 SkASSERT((unsigned)aa <= 255);
276
277 unsigned src_scale = SkAlpha255To256(aa);
278 unsigned dst_scale = SkAlphaMulInv256(SkGetPackedA32(src), src_scale);
279
280 const uint32_t mask = 0xFF00FF;
281
282 uint32_t src_rb = (src & mask) * src_scale;
283 uint32_t src_ag = ((src >> 8) & mask) * src_scale;
284
285 uint32_t dst_rb = (dst & mask) * dst_scale;
286 uint32_t dst_ag = ((dst >> 8) & mask) * dst_scale;
287
288 return (((src_rb + dst_rb) >> 8) & mask) | ((src_ag + dst_ag) & ~mask);
289 }
290
291 ////////////////////////////////////////////////////////////////////////////////////////////
292 // Convert a 32bit pixel to a 16bit pixel (no dither)
293
294 #define SkR32ToR16_MACRO(r) ((unsigned)(r) >> (SK_R32_BITS - SK_R16_BITS))
295 #define SkG32ToG16_MACRO(g) ((unsigned)(g) >> (SK_G32_BITS - SK_G16_BITS))
296 #define SkB32ToB16_MACRO(b) ((unsigned)(b) >> (SK_B32_BITS - SK_B16_BITS))
297
298 #ifdef SK_DEBUG
SkR32ToR16(unsigned r)299 static inline unsigned SkR32ToR16(unsigned r) {
300 SkR32Assert(r);
301 return SkR32ToR16_MACRO(r);
302 }
SkG32ToG16(unsigned g)303 static inline unsigned SkG32ToG16(unsigned g) {
304 SkG32Assert(g);
305 return SkG32ToG16_MACRO(g);
306 }
SkB32ToB16(unsigned b)307 static inline unsigned SkB32ToB16(unsigned b) {
308 SkB32Assert(b);
309 return SkB32ToB16_MACRO(b);
310 }
311 #else
312 #define SkR32ToR16(r) SkR32ToR16_MACRO(r)
313 #define SkG32ToG16(g) SkG32ToG16_MACRO(g)
314 #define SkB32ToB16(b) SkB32ToB16_MACRO(b)
315 #endif
316
SkPixel32ToPixel16(SkPMColor c)317 static inline U16CPU SkPixel32ToPixel16(SkPMColor c) {
318 unsigned r = ((c >> (SK_R32_SHIFT + (8 - SK_R16_BITS))) & SK_R16_MASK) << SK_R16_SHIFT;
319 unsigned g = ((c >> (SK_G32_SHIFT + (8 - SK_G16_BITS))) & SK_G16_MASK) << SK_G16_SHIFT;
320 unsigned b = ((c >> (SK_B32_SHIFT + (8 - SK_B16_BITS))) & SK_B16_MASK) << SK_B16_SHIFT;
321 return r | g | b;
322 }
323
SkPack888ToRGB16(U8CPU r,U8CPU g,U8CPU b)324 static inline U16CPU SkPack888ToRGB16(U8CPU r, U8CPU g, U8CPU b) {
325 return (SkR32ToR16(r) << SK_R16_SHIFT) |
326 (SkG32ToG16(g) << SK_G16_SHIFT) |
327 (SkB32ToB16(b) << SK_B16_SHIFT);
328 }
329
330 /////////////////////////////////////////////////////////////////////////////////////////
331
SkPixel16ToColor(U16CPU src)332 static inline SkColor SkPixel16ToColor(U16CPU src) {
333 SkASSERT(src == SkToU16(src));
334
335 unsigned r = SkPacked16ToR32(src);
336 unsigned g = SkPacked16ToG32(src);
337 unsigned b = SkPacked16ToB32(src);
338
339 SkASSERT((r >> (8 - SK_R16_BITS)) == SkGetPackedR16(src));
340 SkASSERT((g >> (8 - SK_G16_BITS)) == SkGetPackedG16(src));
341 SkASSERT((b >> (8 - SK_B16_BITS)) == SkGetPackedB16(src));
342
343 return SkColorSetRGB(r, g, b);
344 }
345
346 ///////////////////////////////////////////////////////////////////////////////
347
348 typedef uint16_t SkPMColor16;
349
350 // Put in OpenGL order (r g b a)
351 #define SK_A4444_SHIFT 0
352 #define SK_R4444_SHIFT 12
353 #define SK_G4444_SHIFT 8
354 #define SK_B4444_SHIFT 4
355
SkReplicateNibble(unsigned nib)356 static inline U8CPU SkReplicateNibble(unsigned nib) {
357 SkASSERT(nib <= 0xF);
358 return (nib << 4) | nib;
359 }
360
361 #define SkGetPackedA4444(c) (((unsigned)(c) >> SK_A4444_SHIFT) & 0xF)
362 #define SkGetPackedR4444(c) (((unsigned)(c) >> SK_R4444_SHIFT) & 0xF)
363 #define SkGetPackedG4444(c) (((unsigned)(c) >> SK_G4444_SHIFT) & 0xF)
364 #define SkGetPackedB4444(c) (((unsigned)(c) >> SK_B4444_SHIFT) & 0xF)
365
366 #define SkPacked4444ToA32(c) SkReplicateNibble(SkGetPackedA4444(c))
367
SkPixel4444ToPixel32(U16CPU c)368 static inline SkPMColor SkPixel4444ToPixel32(U16CPU c) {
369 uint32_t d = (SkGetPackedA4444(c) << SK_A32_SHIFT) |
370 (SkGetPackedR4444(c) << SK_R32_SHIFT) |
371 (SkGetPackedG4444(c) << SK_G32_SHIFT) |
372 (SkGetPackedB4444(c) << SK_B32_SHIFT);
373 return d | (d << 4);
374 }
375
376 using SkPMColor4f = SkRGBA4f<kPremul_SkAlphaType>;
377
378 constexpr SkPMColor4f SK_PMColor4fTRANSPARENT = { 0, 0, 0, 0 };
379 constexpr SkPMColor4f SK_PMColor4fBLACK = { 0, 0, 0, 1 };
380 constexpr SkPMColor4f SK_PMColor4fWHITE = { 1, 1, 1, 1 };
381 constexpr SkPMColor4f SK_PMColor4fILLEGAL = { SK_FloatNegativeInfinity,
382 SK_FloatNegativeInfinity,
383 SK_FloatNegativeInfinity,
384 SK_FloatNegativeInfinity };
385 #endif // SkColorData_DEFINED
386