1 /*
2 * Copyright 2017 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 #include "SkHighContrastFilter.h"
9 #include "SkArenaAlloc.h"
10 #include "SkColorData.h"
11 #include "SkRasterPipeline.h"
12 #include "SkReadBuffer.h"
13 #include "SkString.h"
14 #include "SkWriteBuffer.h"
15
16 #if SK_SUPPORT_GPU
17 #include "GrColorSpaceInfo.h"
18 #include "GrContext.h"
19 #include "glsl/GrGLSLFragmentProcessor.h"
20 #include "glsl/GrGLSLFragmentShaderBuilder.h"
21 #endif
22
23 using InvertStyle = SkHighContrastConfig::InvertStyle;
24
25 class SkHighContrast_Filter : public SkColorFilter {
26 public:
SkHighContrast_Filter(const SkHighContrastConfig & config)27 SkHighContrast_Filter(const SkHighContrastConfig& config) {
28 fConfig = config;
29 // Clamp contrast to just inside -1 to 1 to avoid division by zero.
30 fConfig.fContrast = SkScalarPin(fConfig.fContrast,
31 -1.0f + FLT_EPSILON,
32 1.0f - FLT_EPSILON);
33 }
34
~SkHighContrast_Filter()35 ~SkHighContrast_Filter() override {}
36
37 #if SK_SUPPORT_GPU
38 std::unique_ptr<GrFragmentProcessor> asFragmentProcessor(
39 GrContext*, const GrColorSpaceInfo&) const override;
40 #endif
41
42 void onAppendStages(SkRasterPipeline* p,
43 SkColorSpace* dst,
44 SkArenaAlloc* scratch,
45 bool shaderIsOpaque) const override;
46
47 protected:
48 void flatten(SkWriteBuffer&) const override;
49
50 private:
51 SK_FLATTENABLE_HOOKS(SkHighContrast_Filter)
52
53 SkHighContrastConfig fConfig;
54
55 friend class SkHighContrastFilter;
56
57 typedef SkColorFilter INHERITED;
58 };
59
onAppendStages(SkRasterPipeline * p,SkColorSpace * dstCS,SkArenaAlloc * alloc,bool shaderIsOpaque) const60 void SkHighContrast_Filter::onAppendStages(SkRasterPipeline* p,
61 SkColorSpace* dstCS,
62 SkArenaAlloc* alloc,
63 bool shaderIsOpaque) const {
64 if (!shaderIsOpaque) {
65 p->append(SkRasterPipeline::unpremul);
66 }
67
68 if (!dstCS) {
69 // In legacy draws this effect approximately linearizes by squaring.
70 // When non-legacy, we're already (better) linearized.
71 auto square = alloc->make<skcms_TransferFunction>();
72 square->g = 2.0f; square->a = 1.0f;
73 square->b = square->c = square->d = square->e = square->f = 0;
74
75 p->append(SkRasterPipeline::parametric, square);
76 }
77
78 if (fConfig.fGrayscale) {
79 float r = SK_LUM_COEFF_R;
80 float g = SK_LUM_COEFF_G;
81 float b = SK_LUM_COEFF_B;
82 float* matrix = alloc->makeArray<float>(12);
83 matrix[0] = matrix[1] = matrix[2] = r;
84 matrix[3] = matrix[4] = matrix[5] = g;
85 matrix[6] = matrix[7] = matrix[8] = b;
86 p->append(SkRasterPipeline::matrix_3x4, matrix);
87 }
88
89 if (fConfig.fInvertStyle == InvertStyle::kInvertBrightness) {
90 float* matrix = alloc->makeArray<float>(12);
91 matrix[0] = matrix[4] = matrix[8] = -1;
92 matrix[9] = matrix[10] = matrix[11] = 1;
93 p->append(SkRasterPipeline::matrix_3x4, matrix);
94 } else if (fConfig.fInvertStyle == InvertStyle::kInvertLightness) {
95 p->append(SkRasterPipeline::rgb_to_hsl);
96 float* matrix = alloc->makeArray<float>(12);
97 matrix[0] = matrix[4] = matrix[11] = 1;
98 matrix[8] = -1;
99 p->append(SkRasterPipeline::matrix_3x4, matrix);
100 p->append(SkRasterPipeline::hsl_to_rgb);
101 }
102
103 if (fConfig.fContrast != 0.0) {
104 float* matrix = alloc->makeArray<float>(12);
105 float c = fConfig.fContrast;
106 float m = (1 + c) / (1 - c);
107 float b = (-0.5f * m + 0.5f);
108 matrix[0] = matrix[4] = matrix[8] = m;
109 matrix[9] = matrix[10] = matrix[11] = b;
110 p->append(SkRasterPipeline::matrix_3x4, matrix);
111 }
112
113 p->append(SkRasterPipeline::clamp_0);
114 p->append(SkRasterPipeline::clamp_1);
115
116 if (!dstCS) {
117 // See the previous if(!dstCS) { ... }
118 auto sqrt = alloc->make<skcms_TransferFunction>();
119 sqrt->g = 0.5f; sqrt->a = 1.0f;
120 sqrt->b = sqrt->c = sqrt->d = sqrt->e = sqrt->f = 0;
121
122 p->append(SkRasterPipeline::parametric, sqrt);
123 }
124
125 if (!shaderIsOpaque) {
126 p->append(SkRasterPipeline::premul);
127 }
128 }
129
flatten(SkWriteBuffer & buffer) const130 void SkHighContrast_Filter::flatten(SkWriteBuffer& buffer) const {
131 buffer.writeBool(fConfig.fGrayscale);
132 buffer.writeInt(static_cast<int>(fConfig.fInvertStyle));
133 buffer.writeScalar(fConfig.fContrast);
134 }
135
CreateProc(SkReadBuffer & buffer)136 sk_sp<SkFlattenable> SkHighContrast_Filter::CreateProc(SkReadBuffer& buffer) {
137 SkHighContrastConfig config;
138 config.fGrayscale = buffer.readBool();
139 config.fInvertStyle = buffer.read32LE(InvertStyle::kLast);
140 config.fContrast = buffer.readScalar();
141
142 return SkHighContrastFilter::Make(config);
143 }
144
Make(const SkHighContrastConfig & config)145 sk_sp<SkColorFilter> SkHighContrastFilter::Make(
146 const SkHighContrastConfig& config) {
147 if (!config.isValid()) {
148 return nullptr;
149 }
150 return sk_make_sp<SkHighContrast_Filter>(config);
151 }
152
RegisterFlattenables()153 void SkHighContrastFilter::RegisterFlattenables() {
154 SK_REGISTER_FLATTENABLE(SkHighContrast_Filter);
155 }
156
157 #if SK_SUPPORT_GPU
158 class HighContrastFilterEffect : public GrFragmentProcessor {
159 public:
Make(const SkHighContrastConfig & config,bool linearize)160 static std::unique_ptr<GrFragmentProcessor> Make(const SkHighContrastConfig& config,
161 bool linearize) {
162 return std::unique_ptr<GrFragmentProcessor>(new HighContrastFilterEffect(config,
163 linearize));
164 }
165
name() const166 const char* name() const override { return "HighContrastFilter"; }
167
config() const168 const SkHighContrastConfig& config() const { return fConfig; }
linearize() const169 bool linearize() const { return fLinearize; }
170
clone() const171 std::unique_ptr<GrFragmentProcessor> clone() const override {
172 return Make(fConfig, fLinearize);
173 }
174
175 private:
HighContrastFilterEffect(const SkHighContrastConfig & config,bool linearize)176 HighContrastFilterEffect(const SkHighContrastConfig& config, bool linearize)
177 : INHERITED(kHighContrastFilterEffect_ClassID, kNone_OptimizationFlags)
178 , fConfig(config)
179 , fLinearize(linearize) {}
180
181 GrGLSLFragmentProcessor* onCreateGLSLInstance() const override;
182
183 virtual void onGetGLSLProcessorKey(const GrShaderCaps& caps,
184 GrProcessorKeyBuilder* b) const override;
185
onIsEqual(const GrFragmentProcessor & other) const186 bool onIsEqual(const GrFragmentProcessor& other) const override {
187 const HighContrastFilterEffect& that = other.cast<HighContrastFilterEffect>();
188 return fConfig.fGrayscale == that.fConfig.fGrayscale &&
189 fConfig.fInvertStyle == that.fConfig.fInvertStyle &&
190 fConfig.fContrast == that.fConfig.fContrast &&
191 fLinearize == that.fLinearize;
192 }
193
194 SkHighContrastConfig fConfig;
195 bool fLinearize;
196
197 typedef GrFragmentProcessor INHERITED;
198 };
199
200 class GLHighContrastFilterEffect : public GrGLSLFragmentProcessor {
201 public:
202 static void GenKey(const GrProcessor&, const GrShaderCaps&, GrProcessorKeyBuilder*);
203
204 protected:
205 void onSetData(const GrGLSLProgramDataManager&, const GrFragmentProcessor&) override;
206 void emitCode(EmitArgs& args) override;
207
208 private:
209 UniformHandle fContrastUni;
210
211 typedef GrGLSLFragmentProcessor INHERITED;
212 };
213
onCreateGLSLInstance() const214 GrGLSLFragmentProcessor* HighContrastFilterEffect::onCreateGLSLInstance() const {
215 return new GLHighContrastFilterEffect();
216 }
217
onGetGLSLProcessorKey(const GrShaderCaps & caps,GrProcessorKeyBuilder * b) const218 void HighContrastFilterEffect::onGetGLSLProcessorKey(const GrShaderCaps& caps,
219 GrProcessorKeyBuilder* b) const {
220 GLHighContrastFilterEffect::GenKey(*this, caps, b);
221 }
222
onSetData(const GrGLSLProgramDataManager & pdm,const GrFragmentProcessor & proc)223 void GLHighContrastFilterEffect::onSetData(const GrGLSLProgramDataManager& pdm,
224 const GrFragmentProcessor& proc) {
225 const HighContrastFilterEffect& hcfe = proc.cast<HighContrastFilterEffect>();
226 pdm.set1f(fContrastUni, hcfe.config().fContrast);
227 }
228
GenKey(const GrProcessor & proc,const GrShaderCaps &,GrProcessorKeyBuilder * b)229 void GLHighContrastFilterEffect::GenKey(
230 const GrProcessor& proc, const GrShaderCaps&, GrProcessorKeyBuilder* b) {
231 const HighContrastFilterEffect& hcfe = proc.cast<HighContrastFilterEffect>();
232 b->add32(static_cast<uint32_t>(hcfe.config().fGrayscale));
233 b->add32(static_cast<uint32_t>(hcfe.config().fInvertStyle));
234 b->add32(hcfe.linearize() ? 1 : 0);
235 }
236
emitCode(EmitArgs & args)237 void GLHighContrastFilterEffect::emitCode(EmitArgs& args) {
238 const HighContrastFilterEffect& hcfe = args.fFp.cast<HighContrastFilterEffect>();
239 const SkHighContrastConfig& config = hcfe.config();
240
241 const char* contrast;
242 fContrastUni = args.fUniformHandler->addUniform(kFragment_GrShaderFlag, kHalf_GrSLType,
243 "contrast", &contrast);
244
245 GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
246
247 fragBuilder->codeAppendf("half4 color = %s;", args.fInputColor);
248
249 // Unpremultiply. The max() is to guard against 0 / 0.
250 fragBuilder->codeAppendf("half nonZeroAlpha = max(color.a, 0.00001);");
251 fragBuilder->codeAppendf("color = half4(color.rgb / nonZeroAlpha, nonZeroAlpha);");
252
253 if (hcfe.linearize()) {
254 fragBuilder->codeAppend("color.rgb = color.rgb * color.rgb;");
255 }
256
257 // Grayscale.
258 if (config.fGrayscale) {
259 fragBuilder->codeAppendf("half luma = dot(color, half4(%f, %f, %f, 0));",
260 SK_LUM_COEFF_R, SK_LUM_COEFF_G, SK_LUM_COEFF_B);
261 fragBuilder->codeAppendf("color = half4(luma, luma, luma, 0);");
262 }
263
264 if (config.fInvertStyle == InvertStyle::kInvertBrightness) {
265 fragBuilder->codeAppendf("color = half4(1, 1, 1, 1) - color;");
266 }
267
268 if (config.fInvertStyle == InvertStyle::kInvertLightness) {
269 // Convert from RGB to HSL.
270 fragBuilder->codeAppendf("half fmax = max(color.r, max(color.g, color.b));");
271 fragBuilder->codeAppendf("half fmin = min(color.r, min(color.g, color.b));");
272 fragBuilder->codeAppendf("half l = (fmax + fmin) / 2;");
273
274 fragBuilder->codeAppendf("half h;");
275 fragBuilder->codeAppendf("half s;");
276
277 fragBuilder->codeAppendf("if (fmax == fmin) {");
278 fragBuilder->codeAppendf(" h = 0;");
279 fragBuilder->codeAppendf(" s = 0;");
280 fragBuilder->codeAppendf("} else {");
281 fragBuilder->codeAppendf(" half d = fmax - fmin;");
282 fragBuilder->codeAppendf(" s = l > 0.5 ?");
283 fragBuilder->codeAppendf(" d / (2 - fmax - fmin) :");
284 fragBuilder->codeAppendf(" d / (fmax + fmin);");
285 // We'd like to just write "if (color.r == fmax) { ... }". On many GPUs, running the
286 // angle_d3d9_es2 config, that failed. It seems that max(x, y) is not necessarily equal
287 // to either x or y. Tried several ways to fix it, but this was the only reasonable fix.
288 fragBuilder->codeAppendf(" if (color.r >= color.g && color.r >= color.b) {");
289 fragBuilder->codeAppendf(" h = (color.g - color.b) / d + ");
290 fragBuilder->codeAppendf(" (color.g < color.b ? 6 : 0);");
291 fragBuilder->codeAppendf(" } else if (color.g >= color.b) {");
292 fragBuilder->codeAppendf(" h = (color.b - color.r) / d + 2;");
293 fragBuilder->codeAppendf(" } else {");
294 fragBuilder->codeAppendf(" h = (color.r - color.g) / d + 4;");
295 fragBuilder->codeAppendf(" }");
296 fragBuilder->codeAppendf("}");
297 fragBuilder->codeAppendf("h /= 6;");
298 fragBuilder->codeAppendf("l = 1.0 - l;");
299 // Convert back from HSL to RGB.
300 SkString hue2rgbFuncName;
301 const GrShaderVar gHue2rgbArgs[] = {
302 GrShaderVar("p", kHalf_GrSLType),
303 GrShaderVar("q", kHalf_GrSLType),
304 GrShaderVar("t", kHalf_GrSLType),
305 };
306 fragBuilder->emitFunction(kHalf_GrSLType,
307 "hue2rgb",
308 SK_ARRAY_COUNT(gHue2rgbArgs),
309 gHue2rgbArgs,
310 "if (t < 0)"
311 " t += 1;"
312 "if (t > 1)"
313 " t -= 1;"
314 "if (t < 1/6.)"
315 " return p + (q - p) * 6 * t;"
316 "if (t < 1/2.)"
317 " return q;"
318 "if (t < 2/3.)"
319 " return p + (q - p) * (2/3. - t) * 6;"
320 "return p;",
321 &hue2rgbFuncName);
322 fragBuilder->codeAppendf("if (s == 0) {");
323 fragBuilder->codeAppendf(" color = half4(l, l, l, 0);");
324 fragBuilder->codeAppendf("} else {");
325 fragBuilder->codeAppendf(" half q = l < 0.5 ? l * (1 + s) : l + s - l * s;");
326 fragBuilder->codeAppendf(" half p = 2 * l - q;");
327 fragBuilder->codeAppendf(" color.r = %s(p, q, h + 1/3.);", hue2rgbFuncName.c_str());
328 fragBuilder->codeAppendf(" color.g = %s(p, q, h);", hue2rgbFuncName.c_str());
329 fragBuilder->codeAppendf(" color.b = %s(p, q, h - 1/3.);", hue2rgbFuncName.c_str());
330 fragBuilder->codeAppendf("}");
331 }
332
333 // Contrast.
334 fragBuilder->codeAppendf("if (%s != 0) {", contrast);
335 fragBuilder->codeAppendf(" half m = (1 + %s) / (1 - %s);", contrast, contrast);
336 fragBuilder->codeAppendf(" half off = (-0.5 * m + 0.5);");
337 fragBuilder->codeAppendf(" color = m * color + off;");
338 fragBuilder->codeAppendf("}");
339
340 // Clamp.
341 fragBuilder->codeAppendf("color = saturate(color);");
342
343 if (hcfe.linearize()) {
344 fragBuilder->codeAppend("color.rgb = sqrt(color.rgb);");
345 }
346
347 // Restore the original alpha and premultiply.
348 fragBuilder->codeAppendf("color.a = %s.a;", args.fInputColor);
349 fragBuilder->codeAppendf("color.rgb *= color.a;");
350
351 // Copy to the output color.
352 fragBuilder->codeAppendf("%s = color;", args.fOutputColor);
353 }
354
asFragmentProcessor(GrContext *,const GrColorSpaceInfo & csi) const355 std::unique_ptr<GrFragmentProcessor> SkHighContrast_Filter::asFragmentProcessor(
356 GrContext*, const GrColorSpaceInfo& csi) const {
357 bool linearize = !csi.isLinearlyBlended();
358 return HighContrastFilterEffect::Make(fConfig, linearize);
359 }
360 #endif
361