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 "SkReadBuffer.h"
  11 #include "SkWriteBuffer.h"
  12 #include "SkRegion.h"
  13
  14 class SK_API SkAlphaThresholdFilterImpl : public SkImageFilter {
  15 public:
  16     SkAlphaThresholdFilterImpl(const SkRegion& region, SkScalar innerThreshold,
  17                                SkScalar outerThreshold, SkImageFilter* input);
  18
  19     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkAlphaThresholdFilterImpl)
  20
  21 protected:
  22     explicit SkAlphaThresholdFilterImpl(SkReadBuffer& buffer);
  23     virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE;
  24
  25     virtual bool onFilterImage(Proxy*, const SkBitmap& src, const Context&,
  26                                SkBitmap* result, SkIPoint* offset) const SK_OVERRIDE;
  27 #if SK_SUPPORT_GPU
  28     virtual bool asNewEffect(GrEffect** effect, GrTexture* texture,
  29                              const SkMatrix& matrix, const SkIRect& bounds) const SK_OVERRIDE;
  30 #endif
  31
  32 private:
  33     SkRegion fRegion;
  34     SkScalar fInnerThreshold;
  35     SkScalar fOuterThreshold;
  36     typedef SkImageFilter INHERITED;
  37 };
  38
  39 SkImageFilter* SkAlphaThresholdFilter::Create(const SkRegion& region,
  40                                               SkScalar innerThreshold,
  41                                               SkScalar outerThreshold,
  42                                               SkImageFilter* input) {
  43     return SkNEW_ARGS(SkAlphaThresholdFilterImpl, (region, innerThreshold, outerThreshold, input));
  44 }
  45
  46 #if SK_SUPPORT_GPU
  47 #include "GrContext.h"
  48 #include "GrCoordTransform.h"
  49 #include "GrEffect.h"
  50 #include "gl/GrGLEffect.h"
  51 #include "gl/GrGLShaderBuilder.h"
  52 #include "GrTBackendEffectFactory.h"
  53 #include "GrTextureAccess.h"
  54
  55 #include "SkGr.h"
  56
  57 class GrGLAlphaThresholdEffect;
  58
  59 class AlphaThresholdEffect : public GrEffect {
  60
  61 public:
  62     static GrEffect* Create(GrTexture* texture,
  63                             GrTexture* maskTexture,
  64                             float innerThreshold,
  65                             float outerThreshold) {
  66         return SkNEW_ARGS(AlphaThresholdEffect, (texture,
  67                                                  maskTexture,
  68                                                  innerThreshold,
  69                                                  outerThreshold));
  70     }
  71
  72     virtual ~AlphaThresholdEffect() {};
  73
  74     static const char* Name() { return "Alpha Threshold"; }
  75
  76     virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE;
  77     virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const SK_OVERRIDE;
  78
  79     float innerThreshold() const { return fInnerThreshold; }
  80     float outerThreshold() const { return fOuterThreshold; }
  81
  82     typedef GrGLAlphaThresholdEffect GLEffect;
  83
  84 private:
  85     AlphaThresholdEffect(GrTexture* texture,
  86                          GrTexture* maskTexture,
  87                          float innerThreshold,
  88                          float outerThreshold)
  89         : fInnerThreshold(innerThreshold)
  90         , fOuterThreshold(outerThreshold)
  91         , fImageCoordTransform(kLocal_GrCoordSet, MakeDivByTextureWHMatrix(texture), texture)
  92         , fImageTextureAccess(texture)
  93         , fMaskCoordTransform(kLocal_GrCoordSet, MakeDivByTextureWHMatrix(maskTexture), maskTexture)
  94         , fMaskTextureAccess(maskTexture) {
  95         this->addCoordTransform(&fImageCoordTransform);
  96         this->addTextureAccess(&fImageTextureAccess);
  97         this->addCoordTransform(&fMaskCoordTransform);
  98         this->addTextureAccess(&fMaskTextureAccess);
  99     }
 100
 101     virtual bool onIsEqual(const GrEffect&) const SK_OVERRIDE;
 102
 103     GR_DECLARE_EFFECT_TEST;
 104
 105     float fInnerThreshold;
 106     float fOuterThreshold;
 107     GrCoordTransform fImageCoordTransform;
 108     GrTextureAccess  fImageTextureAccess;
 109     GrCoordTransform fMaskCoordTransform;
 110     GrTextureAccess  fMaskTextureAccess;
 111
 112     typedef GrEffect INHERITED;
 113 };
 114
 115 class GrGLAlphaThresholdEffect : public GrGLEffect {
 116 public:
 117     GrGLAlphaThresholdEffect(const GrBackendEffectFactory&, const GrDrawEffect&);
 118
 119     virtual void emitCode(GrGLShaderBuilder*,
 120                           const GrDrawEffect&,
 121                           const GrEffectKey&,
 122                           const char* outputColor,
 123                           const char* inputColor,
 124                           const TransformedCoordsArray&,
 125                           const TextureSamplerArray&) SK_OVERRIDE;
 126
 127     virtual void setData(const GrGLProgramDataManager&, const GrDrawEffect&) SK_OVERRIDE;
 128
 129 private:
 130
 131     GrGLProgramDataManager::UniformHandle fInnerThresholdVar;
 132     GrGLProgramDataManager::UniformHandle fOuterThresholdVar;
 133
 134     typedef GrGLEffect INHERITED;
 135 };
 136
 137 GrGLAlphaThresholdEffect::GrGLAlphaThresholdEffect(const GrBackendEffectFactory& factory, const GrDrawEffect&)
 138     : INHERITED(factory) {
 139 }
 140
 141 void GrGLAlphaThresholdEffect::emitCode(GrGLShaderBuilder* builder,
 142                                         const GrDrawEffect&,
 143                                         const GrEffectKey& key,
 144                                         const char* outputColor,
 145                                         const char* inputColor,
 146                                         const TransformedCoordsArray& coords,
 147                                         const TextureSamplerArray& samplers) {
 148     SkString coords2D = builder->ensureFSCoords2D(coords, 0);
 149     SkString maskCoords2D = builder->ensureFSCoords2D(coords, 1);
 150     fInnerThresholdVar = builder->addUniform(
 151         GrGLShaderBuilder::kFragment_Visibility,
 152         kFloat_GrSLType, "inner_threshold");
 153     fOuterThresholdVar = builder->addUniform(
 154         GrGLShaderBuilder::kFragment_Visibility,
 155         kFloat_GrSLType, "outer_threshold");
 156
 157     builder->fsCodeAppendf("\t\tvec2 coord = %s;\n", coords2D.c_str());
 158     builder->fsCodeAppendf("\t\tvec2 mask_coord = %s;\n", maskCoords2D.c_str());
 159     builder->fsCodeAppend("\t\tvec4 input_color = ");
 160     builder->fsAppendTextureLookup(samplers[0], "coord");
 161     builder->fsCodeAppend(";\n");
 162     builder->fsCodeAppend("\t\tvec4 mask_color = ");
 163     builder->fsAppendTextureLookup(samplers[1], "mask_coord");
 164     builder->fsCodeAppend(";\n");
 165
 166     builder->fsCodeAppendf("\t\tfloat inner_thresh = %s;\n",
 167                            builder->getUniformCStr(fInnerThresholdVar));
 168     builder->fsCodeAppendf("\t\tfloat outer_thresh = %s;\n",
 169                            builder->getUniformCStr(fOuterThresholdVar));
 170     builder->fsCodeAppend("\t\tfloat mask = mask_color.a;\n");
 171
 172     builder->fsCodeAppend("vec4 color = input_color;\n");
 173     builder->fsCodeAppend("\t\tif (mask < 0.5) {\n"
 174                           "\t\t\tif (color.a > outer_thresh) {\n"
 175                           "\t\t\t\tfloat scale = outer_thresh / color.a;\n"
 176                           "\t\t\t\tcolor.rgb *= scale;\n"
 177                           "\t\t\t\tcolor.a = outer_thresh;\n"
 178                           "\t\t\t}\n"
 179                           "\t\t} else if (color.a < inner_thresh) {\n"
 180                           "\t\t\tfloat scale = inner_thresh / max(0.001, color.a);\n"
 181                           "\t\t\tcolor.rgb *= scale;\n"
 182                           "\t\t\tcolor.a = inner_thresh;\n"
 183                           "\t\t}\n");
 184
 185     builder->fsCodeAppendf("%s = %s;\n", outputColor,
 186                            (GrGLSLExpr4(inputColor) * GrGLSLExpr4("color")).c_str());
 187 }
 188
 189 void GrGLAlphaThresholdEffect::setData(const GrGLProgramDataManager& pdman,
 190                                   const GrDrawEffect& drawEffect) {
 191     const AlphaThresholdEffect& alpha_threshold =
 192         drawEffect.castEffect<AlphaThresholdEffect>();
 193     pdman.set1f(fInnerThresholdVar, alpha_threshold.innerThreshold());
 194     pdman.set1f(fOuterThresholdVar, alpha_threshold.outerThreshold());
 195 }
 196
 197 /////////////////////////////////////////////////////////////////////
 198
 199 GR_DEFINE_EFFECT_TEST(AlphaThresholdEffect);
 200
 201 GrEffect* AlphaThresholdEffect::TestCreate(SkRandom* random,
 202                                            GrContext* context,
 203                                            const GrDrawTargetCaps&,
 204                                            GrTexture** textures) {
 205     GrTexture* bmpTex = textures[GrEffectUnitTest::kSkiaPMTextureIdx];
 206     GrTexture* maskTex = textures[GrEffectUnitTest::kAlphaTextureIdx];
 207     float inner_thresh = random->nextUScalar1();
 208     float outer_thresh = random->nextUScalar1();
 209     return AlphaThresholdEffect::Create(bmpTex, maskTex, inner_thresh, outer_thresh);
 210 }
 211
 212 ///////////////////////////////////////////////////////////////////////////////
 213
 214 const GrBackendEffectFactory& AlphaThresholdEffect::getFactory() const {
 215     return GrTBackendEffectFactory<AlphaThresholdEffect>::getInstance();
 216 }
 217
 218 bool AlphaThresholdEffect::onIsEqual(const GrEffect& sBase) const {
 219     const AlphaThresholdEffect& s = CastEffect<AlphaThresholdEffect>(sBase);
 220     return (this->texture(0) == s.texture(0) &&
 221             this->fInnerThreshold == s.fInnerThreshold &&
 222             this->fOuterThreshold == s.fOuterThreshold);
 223 }
 224
 225 void AlphaThresholdEffect::getConstantColorComponents(GrColor* color, uint32_t* validFlags) const {
 226     if ((*validFlags & kA_GrColorComponentFlag) && 0xFF == GrColorUnpackA(*color) &&
 227         GrPixelConfigIsOpaque(this->texture(0)->config())) {
 228         *validFlags = kA_GrColorComponentFlag;
 229     } else {
 230         *validFlags = 0;
 231     }
 232 }
 233
 234 #endif
 235
 236 SkAlphaThresholdFilterImpl::SkAlphaThresholdFilterImpl(SkReadBuffer& buffer)
 237   : INHERITED(1, buffer) {
 238     fInnerThreshold = buffer.readScalar();
 239     fOuterThreshold = buffer.readScalar();
 240     buffer.readRegion(&fRegion);
 241 }
 242
 243 SkAlphaThresholdFilterImpl::SkAlphaThresholdFilterImpl(const SkRegion& region,
 244                                                        SkScalar innerThreshold,
 245                                                        SkScalar outerThreshold,
 246                                                        SkImageFilter* input)
 247     : INHERITED(1, &input)
 248     , fRegion(region)
 249     , fInnerThreshold(innerThreshold)
 250     , fOuterThreshold(outerThreshold) {
 251 }
 252
 253 #if SK_SUPPORT_GPU
 254 bool SkAlphaThresholdFilterImpl::asNewEffect(GrEffect** effect, GrTexture* texture,
 255                                              const SkMatrix& in_matrix, const SkIRect&) const {
 256     if (effect) {
 257         GrContext* context = texture->getContext();
 258         GrTextureDesc maskDesc;
 259         if (context->isConfigRenderable(kAlpha_8_GrPixelConfig, false)) {
 260             maskDesc.fConfig = kAlpha_8_GrPixelConfig;
 261         } else {
 262             maskDesc.fConfig = kRGBA_8888_GrPixelConfig;
 263         }
 264         maskDesc.fFlags = kRenderTarget_GrTextureFlagBit | kNoStencil_GrTextureFlagBit;
 265         // Add one pixel of border to ensure that clamp mode will be all zeros
 266         // the outside.
 267         maskDesc.fWidth = texture->width();
 268         maskDesc.fHeight = texture->height();
 269         GrAutoScratchTexture ast(context, maskDesc, GrContext::kApprox_ScratchTexMatch);
 270         GrTexture*  maskTexture = ast.texture();
 271         if (NULL == maskTexture) {
 272             return false;
 273         }
 274
 275         {
 276             GrContext::AutoRenderTarget art(context, ast.texture()->asRenderTarget());
 277             GrPaint grPaint;
 278             grPaint.setBlendFunc(kOne_GrBlendCoeff, kZero_GrBlendCoeff);
 279             SkRegion::Iterator iter(fRegion);
 280             context->clear(NULL, 0x0, true);
 281
 282             SkMatrix old_matrix = context->getMatrix();
 283             context->setMatrix(in_matrix);
 284
 285             while (!iter.done()) {
 286                 SkRect rect = SkRect::Make(iter.rect());
 287                 context->drawRect(grPaint, rect);
 288                 iter.next();
 289             }
 290             context->setMatrix(old_matrix);
 291         }
 292
 293         *effect = AlphaThresholdEffect::Create(texture,
 294                                                maskTexture,
 295                                                fInnerThreshold,
 296                                                fOuterThreshold);
 297     }
 298     return true;
 299 }
 300 #endif
 301
 302 void SkAlphaThresholdFilterImpl::flatten(SkWriteBuffer& buffer) const {
 303     this->INHERITED::flatten(buffer);
 304     buffer.writeScalar(fInnerThreshold);
 305     buffer.writeScalar(fOuterThreshold);
 306     buffer.writeRegion(fRegion);
 307 }
 308
 309 bool SkAlphaThresholdFilterImpl::onFilterImage(Proxy*, const SkBitmap& src,
 310                                                const Context& ctx, SkBitmap* dst,
 311                                                SkIPoint* offset) const {
 312     SkASSERT(src.colorType() == kN32_SkColorType);
 313
 314     if (src.colorType() != kN32_SkColorType) {
 315         return false;
 316     }
 317
 318     SkMatrix localInverse;
 319     if (!ctx.ctm().invert(&localInverse)) {
 320         return false;
 321     }
 322
 323     SkAutoLockPixels alp(src);
 324     SkASSERT(src.getPixels());
 325     if (!src.getPixels() || src.width() <= 0 || src.height() <= 0) {
 326         return false;
 327     }
 328
 329     if (!dst->allocPixels(src.info())) {
 330         return false;
 331     }
 332
 333     U8CPU innerThreshold = (U8CPU)(fInnerThreshold * 0xFF);
 334     U8CPU outerThreshold = (U8CPU)(fOuterThreshold * 0xFF);
 335     SkColor* sptr = src.getAddr32(0, 0);
 336     SkColor* dptr = dst->getAddr32(0, 0);
 337     int width = src.width(), height = src.height();
 338     for (int y = 0; y < height; ++y) {
 339         for (int x = 0; x < width; ++x) {
 340             const SkColor& source = sptr[y * width + x];
 341             SkColor output_color(source);
 342             SkPoint position;
 343             localInverse.mapXY((SkScalar)x, (SkScalar)y, &position);
 344             if (fRegion.contains((int32_t)position.x(), (int32_t)position.y())) {
 345                 if (SkColorGetA(source) < innerThreshold) {
 346                     U8CPU alpha = SkColorGetA(source);
 347                     if (alpha == 0)
 348                         alpha = 1;
 349                     float scale = (float)innerThreshold / alpha;
 350                     output_color = SkColorSetARGB(innerThreshold,
 351                                                   (U8CPU)(SkColorGetR(source) * scale),
 352                                                   (U8CPU)(SkColorGetG(source) * scale),
 353                                                   (U8CPU)(SkColorGetB(source) * scale));
 354                 }
 355             } else {
 356                 if (SkColorGetA(source) > outerThreshold) {
 357                     float scale = (float)outerThreshold / SkColorGetA(source);
 358                     output_color = SkColorSetARGB(outerThreshold,
 359                                                   (U8CPU)(SkColorGetR(source) * scale),
 360                                                   (U8CPU)(SkColorGetG(source) * scale),
 361                                                   (U8CPU)(SkColorGetB(source) * scale));
 362                 }
 363             }
 364             dptr[y * dst->width() + x] = output_color;
 365         }
 366     }
 367
 368     return true;
 369 }