Line data Source code
1 : /*
2 : * Copyright 2015 Google Inc.
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 Sk4pxXfermode_DEFINED
9 : #define Sk4pxXfermode_DEFINED
10 :
11 : #include "Sk4px.h"
12 : #include "SkMSAN.h"
13 : #include "SkNx.h"
14 : #include "SkXfermode_proccoeff.h"
15 :
16 : namespace {
17 :
18 : // Most xfermodes can be done most efficiently 4 pixels at a time in 8 or 16-bit fixed point.
19 : #define XFERMODE(Xfermode) \
20 : struct Xfermode { Sk4px operator()(const Sk4px&, const Sk4px&) const; }; \
21 : inline Sk4px Xfermode::operator()(const Sk4px& d, const Sk4px& s) const
22 :
23 0 : XFERMODE(Clear) { return Sk4px::DupPMColor(0); }
24 0 : XFERMODE(Src) { return s; }
25 0 : XFERMODE(Dst) { return d; }
26 0 : XFERMODE(SrcIn) { return s.approxMulDiv255(d.alphas() ); }
27 0 : XFERMODE(SrcOut) { return s.approxMulDiv255(d.alphas().inv()); }
28 0 : XFERMODE(SrcOver) { return s + d.approxMulDiv255(s.alphas().inv()); }
29 0 : XFERMODE(DstIn) { return SrcIn ()(s,d); }
30 0 : XFERMODE(DstOut) { return SrcOut ()(s,d); }
31 0 : XFERMODE(DstOver) { return SrcOver()(s,d); }
32 :
33 : // [ S * Da + (1 - Sa) * D]
34 0 : XFERMODE(SrcATop) { return (s * d.alphas() + d * s.alphas().inv()).div255(); }
35 0 : XFERMODE(DstATop) { return SrcATop()(s,d); }
36 : //[ S * (1 - Da) + (1 - Sa) * D ]
37 0 : XFERMODE(Xor) { return (s * d.alphas().inv() + d * s.alphas().inv()).div255(); }
38 : // [S + D ]
39 0 : XFERMODE(Plus) { return s.saturatedAdd(d); }
40 : // [S * D ]
41 0 : XFERMODE(Modulate) { return s.approxMulDiv255(d); }
42 : // [S + D - S * D]
43 0 : XFERMODE(Screen) {
44 : // Doing the math as S + (1-S)*D or S + (D - S*D) means the add and subtract can be done
45 : // in 8-bit space without overflow. S + (1-S)*D is a touch faster because inv() is cheap.
46 0 : return s + d.approxMulDiv255(s.inv());
47 : }
48 0 : XFERMODE(Multiply) { return (s * d.alphas().inv() + d * s.alphas().inv() + s*d).div255(); }
49 : // [ Sa + Da - Sa*Da, Sc + Dc - 2*min(Sc*Da, Dc*Sa) ] (And notice Sa*Da == min(Sa*Da, Da*Sa).)
50 0 : XFERMODE(Difference) {
51 0 : auto m = Sk4px::Wide::Min(s * d.alphas(), d * s.alphas()).div255();
52 : // There's no chance of underflow, and if we subtract m before adding s+d, no overflow.
53 0 : return (s - m) + (d - m.zeroAlphas());
54 : }
55 : // [ Sa + Da - Sa*Da, Sc + Dc - 2*Sc*Dc ]
56 0 : XFERMODE(Exclusion) {
57 0 : auto p = s.approxMulDiv255(d);
58 : // There's no chance of underflow, and if we subtract p before adding src+dst, no overflow.
59 0 : return (s - p) + (d - p.zeroAlphas());
60 : }
61 :
62 : // We take care to use exact math for these next few modes where alphas
63 : // and colors are calculated using significantly different math. We need
64 : // to preserve premul invariants, and exact math makes this easier.
65 : //
66 : // TODO: Some of these implementations might be able to be sped up a bit
67 : // while maintaining exact math, but let's follow up with that.
68 :
69 0 : XFERMODE(HardLight) {
70 0 : auto sa = s.alphas(),
71 0 : da = d.alphas();
72 :
73 0 : auto srcover = s + (d * sa.inv()).div255();
74 :
75 0 : auto isLite = ((sa-s) < s).widenLoHi();
76 :
77 0 : auto lite = sa*da - ((da-d)*(sa-s) << 1),
78 0 : dark = s*d << 1,
79 0 : both = s*da.inv() + d*sa.inv();
80 :
81 0 : auto alphas = srcover;
82 0 : auto colors = (both + isLite.thenElse(lite, dark)).div255();
83 0 : return alphas.zeroColors() + colors.zeroAlphas();
84 : }
85 0 : XFERMODE(Overlay) { return HardLight()(s,d); }
86 :
87 0 : XFERMODE(Darken) {
88 0 : auto sa = s.alphas(),
89 0 : da = d.alphas();
90 :
91 0 : auto sda = (s*da).div255(),
92 0 : dsa = (d*sa).div255();
93 :
94 0 : auto srcover = s + (d * sa.inv()).div255(),
95 0 : dstover = d + (s * da.inv()).div255();
96 0 : auto alphas = srcover,
97 0 : colors = (sda < dsa).thenElse(srcover, dstover);
98 0 : return alphas.zeroColors() + colors.zeroAlphas();
99 : }
100 0 : XFERMODE(Lighten) {
101 0 : auto sa = s.alphas(),
102 0 : da = d.alphas();
103 :
104 0 : auto sda = (s*da).div255(),
105 0 : dsa = (d*sa).div255();
106 :
107 0 : auto srcover = s + (d * sa.inv()).div255(),
108 0 : dstover = d + (s * da.inv()).div255();
109 0 : auto alphas = srcover,
110 0 : colors = (dsa < sda).thenElse(srcover, dstover);
111 0 : return alphas.zeroColors() + colors.zeroAlphas();
112 : }
113 : #undef XFERMODE
114 :
115 : // Some xfermodes use math like divide or sqrt that's best done in floats 1 pixel at a time.
116 : #define XFERMODE(Xfermode) \
117 : struct Xfermode { Sk4f operator()(const Sk4f&, const Sk4f&) const; }; \
118 : inline Sk4f Xfermode::operator()(const Sk4f& d, const Sk4f& s) const
119 :
120 0 : static inline Sk4f a_rgb(const Sk4f& a, const Sk4f& rgb) {
121 : static_assert(SK_A32_SHIFT == 24, "");
122 0 : return a * Sk4f(0,0,0,1) + rgb * Sk4f(1,1,1,0);
123 : }
124 0 : static inline Sk4f alphas(const Sk4f& f) {
125 0 : return f[SK_A32_SHIFT/8];
126 : }
127 :
128 0 : XFERMODE(ColorDodge) {
129 0 : auto sa = alphas(s),
130 0 : da = alphas(d),
131 0 : isa = Sk4f(1)-sa,
132 0 : ida = Sk4f(1)-da;
133 :
134 0 : auto srcover = s + d*isa,
135 0 : dstover = d + s*ida,
136 0 : otherwise = sa * Sk4f::Min(da, (d*sa)*(sa-s).invert()) + s*ida + d*isa;
137 :
138 : // Order matters here, preferring d==0 over s==sa.
139 0 : auto colors = (d == Sk4f(0)).thenElse(dstover,
140 0 : (s == sa).thenElse(srcover,
141 0 : otherwise));
142 0 : return a_rgb(srcover, colors);
143 : }
144 0 : XFERMODE(ColorBurn) {
145 0 : auto sa = alphas(s),
146 0 : da = alphas(d),
147 0 : isa = Sk4f(1)-sa,
148 0 : ida = Sk4f(1)-da;
149 :
150 0 : auto srcover = s + d*isa,
151 0 : dstover = d + s*ida,
152 0 : otherwise = sa*(da-Sk4f::Min(da, (da-d)*sa*s.invert())) + s*ida + d*isa;
153 :
154 : // Order matters here, preferring d==da over s==0.
155 0 : auto colors = (d == da).thenElse(dstover,
156 0 : (s == Sk4f(0)).thenElse(srcover,
157 0 : otherwise));
158 0 : return a_rgb(srcover, colors);
159 : }
160 0 : XFERMODE(SoftLight) {
161 0 : auto sa = alphas(s),
162 0 : da = alphas(d),
163 0 : isa = Sk4f(1)-sa,
164 0 : ida = Sk4f(1)-da;
165 :
166 : // Some common terms.
167 0 : auto m = (da > Sk4f(0)).thenElse(d / da, Sk4f(0)),
168 0 : s2 = Sk4f(2)*s,
169 0 : m4 = Sk4f(4)*m;
170 :
171 : // The logic forks three ways:
172 : // 1. dark src?
173 : // 2. light src, dark dst?
174 : // 3. light src, light dst?
175 0 : auto darkSrc = d*(sa + (s2 - sa)*(Sk4f(1) - m)), // Used in case 1.
176 0 : darkDst = (m4*m4 + m4)*(m - Sk4f(1)) + Sk4f(7)*m, // Used in case 2.
177 0 : liteDst = m.sqrt() - m, // Used in case 3.
178 0 : liteSrc = d*sa + da*(s2-sa)*(Sk4f(4)*d <= da).thenElse(darkDst, liteDst); // Case 2 or 3?
179 :
180 0 : auto alpha = s + d*isa;
181 0 : auto colors = s*ida + d*isa + (s2 <= sa).thenElse(darkSrc, liteSrc); // Case 1 or 2/3?
182 :
183 0 : return a_rgb(alpha, colors);
184 : }
185 : #undef XFERMODE
186 :
187 : // A reasonable fallback mode for doing AA is to simply apply the transfermode first,
188 : // then linearly interpolate the AA.
189 : template <typename Xfermode>
190 0 : static Sk4px xfer_aa(const Sk4px& d, const Sk4px& s, const Sk4px& aa) {
191 0 : Sk4px bw = Xfermode()(d, s);
192 0 : return (bw * aa + d * aa.inv()).div255();
193 : }
194 :
195 : // For some transfermodes we specialize AA, either for correctness or performance.
196 : #define XFERMODE_AA(Xfermode) \
197 : template <> Sk4px xfer_aa<Xfermode>(const Sk4px& d, const Sk4px& s, const Sk4px& aa)
198 :
199 : // Plus' clamp needs to happen after AA. skia:3852
200 0 : XFERMODE_AA(Plus) { // [ clamp( (1-AA)D + (AA)(S+D) ) == clamp(D + AA*S) ]
201 0 : return d.saturatedAdd(s.approxMulDiv255(aa));
202 : }
203 :
204 : #undef XFERMODE_AA
205 :
206 : // Src and Clear modes are safe to use with unitialized dst buffers,
207 : // even if the implementation branches based on bytes from dst (e.g. asserts in Debug mode).
208 : // For those modes, just lie to MSAN that dst is always intialized.
209 0 : template <typename Xfermode> static void mark_dst_initialized_if_safe(void*, void*) {}
210 0 : template <> void mark_dst_initialized_if_safe<Src>(void* dst, void* end) {
211 0 : sk_msan_mark_initialized(dst, end, "Src doesn't read dst.");
212 0 : }
213 0 : template <> void mark_dst_initialized_if_safe<Clear>(void* dst, void* end) {
214 0 : sk_msan_mark_initialized(dst, end, "Clear doesn't read dst.");
215 0 : }
216 :
217 : template <typename Xfermode>
218 0 : class Sk4pxXfermode : public SkProcCoeffXfermode {
219 : public:
220 0 : Sk4pxXfermode(const ProcCoeff& rec, SkBlendMode mode)
221 0 : : INHERITED(rec, mode) {}
222 :
223 0 : void xfer32(SkPMColor dst[], const SkPMColor src[], int n, const SkAlpha aa[]) const override {
224 0 : mark_dst_initialized_if_safe<Xfermode>(dst, dst+n);
225 0 : if (nullptr == aa) {
226 0 : Sk4px::MapDstSrc(n, dst, src, Xfermode());
227 : } else {
228 0 : Sk4px::MapDstSrcAlpha(n, dst, src, aa, xfer_aa<Xfermode>);
229 : }
230 0 : }
231 :
232 0 : void xfer16(uint16_t dst[], const SkPMColor src[], int n, const SkAlpha aa[]) const override {
233 0 : mark_dst_initialized_if_safe<Xfermode>(dst, dst+n);
234 : SkPMColor dst32[4];
235 0 : while (n >= 4) {
236 0 : dst32[0] = SkPixel16ToPixel32(dst[0]);
237 0 : dst32[1] = SkPixel16ToPixel32(dst[1]);
238 0 : dst32[2] = SkPixel16ToPixel32(dst[2]);
239 0 : dst32[3] = SkPixel16ToPixel32(dst[3]);
240 :
241 0 : this->xfer32(dst32, src, 4, aa);
242 :
243 0 : dst[0] = SkPixel32ToPixel16(dst32[0]);
244 0 : dst[1] = SkPixel32ToPixel16(dst32[1]);
245 0 : dst[2] = SkPixel32ToPixel16(dst32[2]);
246 0 : dst[3] = SkPixel32ToPixel16(dst32[3]);
247 :
248 0 : dst += 4;
249 0 : src += 4;
250 0 : aa += aa ? 4 : 0;
251 0 : n -= 4;
252 : }
253 0 : while (n) {
254 0 : SkPMColor dst32 = SkPixel16ToPixel32(*dst);
255 0 : this->xfer32(&dst32, src, 1, aa);
256 0 : *dst = SkPixel32ToPixel16(dst32);
257 :
258 0 : dst += 1;
259 0 : src += 1;
260 0 : aa += aa ? 1 : 0;
261 0 : n -= 1;
262 : }
263 0 : }
264 :
265 : private:
266 : typedef SkProcCoeffXfermode INHERITED;
267 : };
268 :
269 : template <typename Xfermode>
270 0 : class Sk4fXfermode : public SkProcCoeffXfermode {
271 : public:
272 0 : Sk4fXfermode(const ProcCoeff& rec, SkBlendMode mode)
273 0 : : INHERITED(rec, mode) {}
274 :
275 0 : void xfer32(SkPMColor dst[], const SkPMColor src[], int n, const SkAlpha aa[]) const override {
276 0 : for (int i = 0; i < n; i++) {
277 0 : dst[i] = Xfer32_1(dst[i], src[i], aa ? aa+i : nullptr);
278 : }
279 0 : }
280 :
281 0 : void xfer16(uint16_t dst[], const SkPMColor src[], int n, const SkAlpha aa[]) const override {
282 0 : for (int i = 0; i < n; i++) {
283 0 : SkPMColor dst32 = SkPixel16ToPixel32(dst[i]);
284 0 : dst32 = Xfer32_1(dst32, src[i], aa ? aa+i : nullptr);
285 0 : dst[i] = SkPixel32ToPixel16(dst32);
286 : }
287 0 : }
288 :
289 : private:
290 0 : static SkPMColor Xfer32_1(SkPMColor dst, const SkPMColor src, const SkAlpha* aa) {
291 0 : Sk4f d = Load(dst),
292 0 : s = Load(src),
293 0 : b = Xfermode()(d, s);
294 0 : if (aa) {
295 0 : Sk4f a = Sk4f(*aa) * Sk4f(1.0f/255);
296 0 : b = b*a + d*(Sk4f(1)-a);
297 : }
298 0 : return Round(b);
299 : }
300 :
301 0 : static Sk4f Load(SkPMColor c) {
302 0 : return SkNx_cast<float>(Sk4b::Load(&c)) * Sk4f(1.0f/255);
303 : }
304 :
305 0 : static SkPMColor Round(const Sk4f& f) {
306 : SkPMColor c;
307 0 : SkNx_cast<uint8_t>(f * Sk4f(255) + Sk4f(0.5f)).store(&c);
308 0 : return c;
309 : }
310 :
311 : typedef SkProcCoeffXfermode INHERITED;
312 : };
313 :
314 : } // namespace
315 :
316 : namespace SK_OPTS_NS {
317 :
318 0 : static SkXfermode* create_xfermode(const ProcCoeff& rec, SkBlendMode mode) {
319 0 : switch (mode) {
320 : #define CASE(Xfermode) \
321 : case SkBlendMode::k##Xfermode: return new Sk4pxXfermode<Xfermode>(rec, mode)
322 0 : CASE(Clear);
323 0 : CASE(Src);
324 0 : CASE(Dst);
325 0 : CASE(SrcOver);
326 0 : CASE(DstOver);
327 0 : CASE(SrcIn);
328 0 : CASE(DstIn);
329 0 : CASE(SrcOut);
330 0 : CASE(DstOut);
331 0 : CASE(SrcATop);
332 0 : CASE(DstATop);
333 0 : CASE(Xor);
334 0 : CASE(Plus);
335 0 : CASE(Modulate);
336 0 : CASE(Screen);
337 0 : CASE(Multiply);
338 0 : CASE(Difference);
339 0 : CASE(Exclusion);
340 0 : CASE(HardLight);
341 0 : CASE(Overlay);
342 0 : CASE(Darken);
343 0 : CASE(Lighten);
344 : #undef CASE
345 :
346 : #define CASE(Xfermode) \
347 : case SkBlendMode::k##Xfermode: return new Sk4fXfermode<Xfermode>(rec, mode)
348 0 : CASE(ColorDodge);
349 0 : CASE(ColorBurn);
350 0 : CASE(SoftLight);
351 : #undef CASE
352 :
353 0 : default: break;
354 : }
355 0 : return nullptr;
356 : }
357 :
358 : } // namespace SK_OPTS_NS
359 :
360 : #endif//Sk4pxXfermode_DEFINED
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