src/third_party/skia/src/effects/SkAlphaThresholdFilter.cpp

   1 /*
   2  * Copyright 2013 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 "SkAlphaThresholdFilter.h"
   9 #include "SkBitmap.h"
  10 #include "SkFlattenableBuffers.h"
  11 #include "SkRegion.h"
  12
  13 class SK_API SkAlphaThresholdFilterImpl : public SkImageFilter {
  14 public:
  15     SkAlphaThresholdFilterImpl(const SkRegion& region, SkScalar innerThreshold, SkScalar outerThreshold);
  16
  17     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkAlphaThresholdFilterImpl)
  18
  19 protected:
  20     explicit SkAlphaThresholdFilterImpl(SkFlattenableReadBuffer& buffer);
  21     virtual void flatten(SkFlattenableWriteBuffer&) const SK_OVERRIDE;
  22
  23     virtual bool onFilterImage(Proxy*, const SkBitmap& src, const SkMatrix&,
  24                                SkBitmap* result, SkIPoint* offset) SK_OVERRIDE;
  25 #if SK_SUPPORT_GPU
  26     virtual bool asNewEffect(GrEffectRef** effect, GrTexture* texture,
  27                              const SkMatrix& matrix, const SkIRect& bounds) const SK_OVERRIDE;
  28 #endif
  29
  30 private:
  31     SkRegion fRegion;
  32     SkScalar fInnerThreshold;
  33     SkScalar fOuterThreshold;
  34     typedef SkImageFilter INHERITED;
  35 };
  36
  37 SkImageFilter* SkAlphaThresholdFilter::Create(const SkRegion& region,
  38                                               SkScalar innerThreshold,
  39                                               SkScalar outerThreshold) {
  40     return SkNEW_ARGS(SkAlphaThresholdFilterImpl, (region, innerThreshold, outerThreshold));
  41 }
  42
  43 #if SK_SUPPORT_GPU
  44 #include "GrContext.h"
  45 #include "GrCoordTransform.h"
  46 #include "GrEffect.h"
  47 #include "gl/GrGLEffect.h"
  48 #include "GrTBackendEffectFactory.h"
  49 #include "GrTextureAccess.h"
  50
  51 #include "SkGr.h"
  52
  53 class GrGLAlphaThresholdEffect;
  54
  55 class AlphaThresholdEffect : public GrEffect {
  56
  57 public:
  58     static GrEffectRef* Create(GrTexture* texture,
  59                                GrTexture* maskTexture,
  60                                float innerThreshold,
  61                                float outerThreshold) {
  62         AutoEffectUnref effect(SkNEW_ARGS(AlphaThresholdEffect, (texture,
  63                                                                  maskTexture,
  64                                                                  innerThreshold,
  65                                                                  outerThreshold)));
  66         return CreateEffectRef(effect);
  67     }
  68
  69     virtual ~AlphaThresholdEffect() {};
  70
  71     static const char* Name() { return "Alpha Threshold"; }
  72
  73     virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE;
  74     virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const SK_OVERRIDE;
  75
  76     float innerThreshold() const { return fInnerThreshold; }
  77     float outerThreshold() const { return fOuterThreshold; }
  78
  79     typedef GrGLAlphaThresholdEffect GLEffect;
  80
  81 private:
  82     AlphaThresholdEffect(GrTexture* texture,
  83                          GrTexture* maskTexture,
  84                          float innerThreshold,
  85                          float outerThreshold)
  86         : fInnerThreshold(innerThreshold)
  87         , fOuterThreshold(outerThreshold)
  88         , fImageCoordTransform(kLocal_GrCoordSet, MakeDivByTextureWHMatrix(texture), texture)
  89         , fImageTextureAccess(texture)
  90         , fMaskCoordTransform(kLocal_GrCoordSet, MakeDivByTextureWHMatrix(maskTexture), maskTexture)
  91         , fMaskTextureAccess(maskTexture) {
  92         this->addCoordTransform(&fImageCoordTransform);
  93         this->addTextureAccess(&fImageTextureAccess);
  94         this->addCoordTransform(&fMaskCoordTransform);
  95         this->addTextureAccess(&fMaskTextureAccess);
  96     }
  97
  98     virtual bool onIsEqual(const GrEffect&) const SK_OVERRIDE;
  99
 100     GR_DECLARE_EFFECT_TEST;
 101
 102     float fInnerThreshold;
 103     float fOuterThreshold;
 104     GrCoordTransform fImageCoordTransform;
 105     GrTextureAccess  fImageTextureAccess;
 106     GrCoordTransform fMaskCoordTransform;
 107     GrTextureAccess  fMaskTextureAccess;
 108
 109     typedef GrEffect INHERITED;
 110 };
 111
 112 class GrGLAlphaThresholdEffect : public GrGLEffect {
 113 public:
 114     GrGLAlphaThresholdEffect(const GrBackendEffectFactory&, const GrDrawEffect&);
 115
 116     virtual void emitCode(GrGLShaderBuilder*,
 117                           const GrDrawEffect&,
 118                           EffectKey,
 119                           const char* outputColor,
 120                           const char* inputColor,
 121                           const TransformedCoordsArray&,
 122                           const TextureSamplerArray&) SK_OVERRIDE;
 123
 124     virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE;
 125
 126 private:
 127
 128     GrGLUniformManager::UniformHandle       fInnerThresholdVar;
 129     GrGLUniformManager::UniformHandle       fOuterThresholdVar;
 130
 131     typedef GrGLEffect INHERITED;
 132 };
 133
 134 GrGLAlphaThresholdEffect::GrGLAlphaThresholdEffect(const GrBackendEffectFactory& factory, const GrDrawEffect&)
 135     : INHERITED(factory) {
 136 }
 137
 138 void GrGLAlphaThresholdEffect::emitCode(GrGLShaderBuilder* builder,
 139                                         const GrDrawEffect&,
 140                                         EffectKey key,
 141                                         const char* outputColor,
 142                                         const char* inputColor,
 143                                         const TransformedCoordsArray& coords,
 144                                         const TextureSamplerArray& samplers) {
 145     SkString coords2D = builder->ensureFSCoords2D(coords, 0);
 146     SkString maskCoords2D = builder->ensureFSCoords2D(coords, 1);
 147     fInnerThresholdVar = builder->addUniform(
 148         GrGLShaderBuilder::kFragment_Visibility,
 149         kFloat_GrSLType, "inner_threshold");
 150     fOuterThresholdVar = builder->addUniform(
 151         GrGLShaderBuilder::kFragment_Visibility,
 152         kFloat_GrSLType, "outer_threshold");
 153
 154     builder->fsCodeAppendf("\t\tvec2 coord = %s;\n", coords2D.c_str());
 155     builder->fsCodeAppendf("\t\tvec2 mask_coord = %s;\n", maskCoords2D.c_str());
 156     builder->fsCodeAppend("\t\tvec4 input_color = ");
 157     builder->fsAppendTextureLookup(samplers[0], "coord");
 158     builder->fsCodeAppend(";\n");
 159     builder->fsCodeAppend("\t\tvec4 mask_color = ");
 160     builder->fsAppendTextureLookup(samplers[1], "mask_coord");
 161     builder->fsCodeAppend(";\n");
 162
 163     builder->fsCodeAppendf("\t\tfloat inner_thresh = %s;\n",
 164                            builder->getUniformCStr(fInnerThresholdVar));
 165     builder->fsCodeAppendf("\t\tfloat outer_thresh = %s;\n",
 166                            builder->getUniformCStr(fOuterThresholdVar));
 167     builder->fsCodeAppend("\t\tfloat mask = mask_color.a;\n");
 168
 169     builder->fsCodeAppend("vec4 color = input_color;\n");
 170     builder->fsCodeAppend("\t\tif (mask < 0.5) {\n"
 171                           "\t\t\tif (color.a > outer_thresh) {\n"
 172                           "\t\t\t\tfloat scale = outer_thresh / color.a;\n"
 173                           "\t\t\t\tcolor.rgb *= scale;\n"
 174                           "\t\t\t\tcolor.a = outer_thresh;\n"
 175                           "\t\t\t}\n"
 176                           "\t\t} else if (color.a < inner_thresh) {\n"
 177                           "\t\t\tfloat scale = inner_thresh / max(0.001, color.a);\n"
 178                           "\t\t\tcolor.rgb *= scale;\n"
 179                           "\t\t\tcolor.a = inner_thresh;\n"
 180                           "\t\t}\n");
 181
 182     builder->fsCodeAppendf("%s = %s;\n", outputColor,
 183                            (GrGLSLExpr4(inputColor) * GrGLSLExpr4("color")).c_str());
 184 }
 185
 186 void GrGLAlphaThresholdEffect::setData(const GrGLUniformManager& uman,
 187                                   const GrDrawEffect& drawEffect) {
 188     const AlphaThresholdEffect& alpha_threshold =
 189         drawEffect.castEffect<AlphaThresholdEffect>();
 190     uman.set1f(fInnerThresholdVar, alpha_threshold.innerThreshold());
 191     uman.set1f(fOuterThresholdVar, alpha_threshold.outerThreshold());
 192 }
 193
 194 /////////////////////////////////////////////////////////////////////
 195
 196 GR_DEFINE_EFFECT_TEST(AlphaThresholdEffect);
 197
 198 GrEffectRef* AlphaThresholdEffect::TestCreate(SkRandom* random,
 199                                               GrContext* context,
 200                                               const GrDrawTargetCaps&,
 201                                               GrTexture** textures) {
 202     GrTexture* bmpTex = textures[GrEffectUnitTest::kSkiaPMTextureIdx];
 203     GrTexture* maskTex = textures[GrEffectUnitTest::kAlphaTextureIdx];
 204     float inner_thresh = random->nextUScalar1();
 205     float outer_thresh = random->nextUScalar1();
 206     return AlphaThresholdEffect::Create(bmpTex, maskTex, inner_thresh, outer_thresh);
 207 }
 208
 209 ///////////////////////////////////////////////////////////////////////////////
 210
 211 const GrBackendEffectFactory& AlphaThresholdEffect::getFactory() const {
 212     return GrTBackendEffectFactory<AlphaThresholdEffect>::getInstance();
 213 }
 214
 215 bool AlphaThresholdEffect::onIsEqual(const GrEffect& sBase) const {
 216     const AlphaThresholdEffect& s = CastEffect<AlphaThresholdEffect>(sBase);
 217     return (this->texture(0) == s.texture(0) &&
 218             this->fInnerThreshold == s.fInnerThreshold &&
 219             this->fOuterThreshold == s.fOuterThreshold);
 220 }
 221
 222 void AlphaThresholdEffect::getConstantColorComponents(GrColor* color, uint32_t* validFlags) const {
 223     if ((*validFlags & kA_GrColorComponentFlag) && 0xFF == GrColorUnpackA(*color) &&
 224         GrPixelConfigIsOpaque(this->texture(0)->config())) {
 225         *validFlags = kA_GrColorComponentFlag;
 226     } else {
 227         *validFlags = 0;
 228     }
 229 }
 230
 231 #endif
 232
 233 SkAlphaThresholdFilterImpl::SkAlphaThresholdFilterImpl(SkFlattenableReadBuffer& buffer)
 234   : INHERITED(1, buffer) {
 235     fInnerThreshold = buffer.readScalar();
 236     fOuterThreshold = buffer.readScalar();
 237     buffer.readRegion(&fRegion);
 238 }
 239
 240 SkAlphaThresholdFilterImpl::SkAlphaThresholdFilterImpl(const SkRegion& region,
 241                                                        SkScalar innerThreshold,
 242                                                        SkScalar outerThreshold)
 243     : INHERITED(0)
 244     , fRegion(region)
 245     , fInnerThreshold(innerThreshold)
 246     , fOuterThreshold(outerThreshold) {
 247 }
 248
 249 #if SK_SUPPORT_GPU
 250 bool SkAlphaThresholdFilterImpl::asNewEffect(GrEffectRef** effect, GrTexture* texture,
 251                                              const SkMatrix& in_matrix, const SkIRect&) const {
 252     if (effect) {
 253         GrContext* context = texture->getContext();
 254         GrTextureDesc maskDesc;
 255         if (context->isConfigRenderable(kAlpha_8_GrPixelConfig, false)) {
 256             maskDesc.fConfig = kAlpha_8_GrPixelConfig;
 257         } else {
 258             maskDesc.fConfig = kRGBA_8888_GrPixelConfig;
 259         }
 260         maskDesc.fFlags = kRenderTarget_GrTextureFlagBit | kNoStencil_GrTextureFlagBit;
 261         // Add one pixel of border to ensure that clamp mode will be all zeros
 262         // the outside.
 263         maskDesc.fWidth = texture->width();
 264         maskDesc.fHeight = texture->height();
 265         GrAutoScratchTexture ast(context, maskDesc, GrContext::kApprox_ScratchTexMatch);
 266         GrTexture*  maskTexture = ast.texture();
 267         if (NULL == maskTexture) {
 268             return false;
 269         }
 270
 271         {
 272             GrContext::AutoRenderTarget art(context, ast.texture()->asRenderTarget());
 273             GrPaint grPaint;
 274             grPaint.setBlendFunc(kOne_GrBlendCoeff, kZero_GrBlendCoeff);
 275             SkRegion::Iterator iter(fRegion);
 276             context->clear(NULL, 0x0, true);
 277
 278             SkMatrix old_matrix = context->getMatrix();
 279             context->setMatrix(in_matrix);
 280
 281             while (!iter.done()) {
 282                 SkRect rect = SkRect::Make(iter.rect());
 283                 context->drawRect(grPaint, rect);
 284                 iter.next();
 285             }
 286             context->setMatrix(old_matrix);
 287         }
 288
 289         *effect = AlphaThresholdEffect::Create(texture,
 290                                                maskTexture,
 291                                                fInnerThreshold,
 292                                                fOuterThreshold);
 293     }
 294     return true;
 295 }
 296 #endif
 297
 298 void SkAlphaThresholdFilterImpl::flatten(SkFlattenableWriteBuffer& buffer) const {
 299     this->INHERITED::flatten(buffer);
 300     buffer.writeScalar(fInnerThreshold);
 301     buffer.writeScalar(fOuterThreshold);
 302     buffer.writeRegion(fRegion);
 303 }
 304
 305 bool SkAlphaThresholdFilterImpl::onFilterImage(Proxy*, const SkBitmap& src,
 306                                                const SkMatrix& matrix, SkBitmap* dst,
 307                                                SkIPoint* offset) {
 308     SkASSERT(src.config() == SkBitmap::kARGB_8888_Config);
 309
 310     if (src.config() != SkBitmap::kARGB_8888_Config) {
 311         return false;
 312     }
 313
 314     SkMatrix localInverse;
 315     if (!matrix.invert(&localInverse)) {
 316         return false;
 317     }
 318
 319     SkAutoLockPixels alp(src);
 320     SkASSERT(src.getPixels());
 321     if (!src.getPixels() || src.width() <= 0 || src.height() <= 0) {
 322         return false;
 323     }
 324
 325     dst->setConfig(src.config(), src.width(), src.height());
 326     if (!dst->allocPixels()) {
 327         return false;
 328     }
 329
 330     U8CPU innerThreshold = (U8CPU)(fInnerThreshold * 0xFF);
 331     U8CPU outerThreshold = (U8CPU)(fOuterThreshold * 0xFF);
 332     SkColor* sptr = src.getAddr32(0, 0);
 333     SkColor* dptr = dst->getAddr32(0, 0);
 334     int width = src.width(), height = src.height();
 335     for (int y = 0; y < height; ++y) {
 336         for (int x = 0; x < width; ++x) {
 337             const SkColor& source = sptr[y * width + x];
 338             SkColor output_color(source);
 339             SkPoint position;
 340             localInverse.mapXY((SkScalar)x, (SkScalar)y, &position);
 341             if (fRegion.contains((int32_t)position.x(), (int32_t)position.y())) {
 342                 if (SkColorGetA(source) < innerThreshold) {
 343                     U8CPU alpha = SkColorGetA(source);
 344                     if (alpha == 0)
 345                         alpha = 1;
 346                     float scale = (float)innerThreshold / alpha;
 347                     output_color = SkColorSetARGB(innerThreshold,
 348                                                   (U8CPU)(SkColorGetR(source) * scale),
 349                                                   (U8CPU)(SkColorGetG(source) * scale),
 350                                                   (U8CPU)(SkColorGetB(source) * scale));
 351                 }
 352             } else {
 353                 if (SkColorGetA(source) > outerThreshold) {
 354                     float scale = (float)outerThreshold / SkColorGetA(source);
 355                     output_color = SkColorSetARGB(outerThreshold,
 356                                                   (U8CPU)(SkColorGetR(source) * scale),
 357                                                   (U8CPU)(SkColorGetG(source) * scale),
 358                                                   (U8CPU)(SkColorGetB(source) * scale));
 359                 }
 360             }
 361             dptr[y * dst->width() + x] = output_color;
 362         }
 363     }
 364
 365     return true;
 366 }