src/effects/SkMagnifierImageFilter.cpp

   1 /*
   2  * Copyright 2012 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 #include "SkBitmap.h"
   9 #include "SkMagnifierImageFilter.h"
  10 #include "SkColorPriv.h"
  11 #include "SkFlattenableBuffers.h"
  12
  13 ////////////////////////////////////////////////////////////////////////////////
  14 #if SK_SUPPORT_GPU
  15 #include "effects/GrSingleTextureEffect.h"
  16 #include "gl/GrGLEffect.h"
  17 #include "gl/GrGLEffectMatrix.h"
  18 #include "gl/GrGLSL.h"
  19 #include "gl/GrGLTexture.h"
  20 #include "GrTBackendEffectFactory.h"
  21
  22 class GrGLMagnifierEffect;
  23
  24 class GrMagnifierEffect : public GrSingleTextureEffect {
  25
  26 public:
  27     static GrEffectRef* Create(GrTexture* texture,
  28                                float xOffset,
  29                                float yOffset,
  30                                float xZoom,
  31                                float yZoom,
  32                                float xInset,
  33                                float yInset) {
  34         AutoEffectUnref effect(SkNEW_ARGS(GrMagnifierEffect, (texture,
  35                                                               xOffset,
  36                                                               yOffset,
  37                                                               xZoom,
  38                                                               yZoom,
  39                                                               xInset,
  40                                                               yInset)));
  41         return CreateEffectRef(effect);
  42     }
  43
  44     virtual ~GrMagnifierEffect() {};
  45
  46     static const char* Name() { return "Magnifier"; }
  47
  48     virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE;
  49     virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const SK_OVERRIDE;
  50
  51     float x_offset() const { return fXOffset; }
  52     float y_offset() const { return fYOffset; }
  53     float x_zoom() const { return fXZoom; }
  54     float y_zoom() const { return fYZoom; }
  55     float x_inset() const { return fXInset; }
  56     float y_inset() const { return fYInset; }
  57
  58     typedef GrGLMagnifierEffect GLEffect;
  59
  60 private:
  61     GrMagnifierEffect(GrTexture* texture,
  62                       float xOffset,
  63                       float yOffset,
  64                       float xZoom,
  65                       float yZoom,
  66                       float xInset,
  67                       float yInset)
  68         : GrSingleTextureEffect(texture, MakeDivByTextureWHMatrix(texture))
  69         , fXOffset(xOffset)
  70         , fYOffset(yOffset)
  71         , fXZoom(xZoom)
  72         , fYZoom(yZoom)
  73         , fXInset(xInset)
  74         , fYInset(yInset) {}
  75
  76     virtual bool onIsEqual(const GrEffect&) const SK_OVERRIDE;
  77
  78     GR_DECLARE_EFFECT_TEST;
  79
  80     float fXOffset;
  81     float fYOffset;
  82     float fXZoom;
  83     float fYZoom;
  84     float fXInset;
  85     float fYInset;
  86
  87     typedef GrSingleTextureEffect INHERITED;
  88 };
  89
  90 // For brevity
  91 typedef GrGLUniformManager::UniformHandle UniformHandle;
  92
  93 class GrGLMagnifierEffect : public GrGLEffect {
  94 public:
  95     GrGLMagnifierEffect(const GrBackendEffectFactory&, const GrDrawEffect&);
  96
  97     virtual void emitCode(GrGLShaderBuilder*,
  98                           const GrDrawEffect&,
  99                           EffectKey,
 100                           const char* outputColor,
 101                           const char* inputColor,
 102                           const TextureSamplerArray&) SK_OVERRIDE;
 103
 104     virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE;
 105
 106     static inline EffectKey GenKey(const GrDrawEffect&, const GrGLCaps&);
 107
 108 private:
 109     UniformHandle       fOffsetVar;
 110     UniformHandle       fZoomVar;
 111     UniformHandle       fInsetVar;
 112
 113     GrGLEffectMatrix    fEffectMatrix;
 114
 115     typedef GrGLEffect INHERITED;
 116 };
 117
 118 GrGLMagnifierEffect::GrGLMagnifierEffect(const GrBackendEffectFactory& factory,
 119                                          const GrDrawEffect& drawEffect)
 120     : INHERITED(factory)
 121     , fEffectMatrix(drawEffect.castEffect<GrMagnifierEffect>().coordsType()) {
 122 }
 123
 124 void GrGLMagnifierEffect::emitCode(GrGLShaderBuilder* builder,
 125                                    const GrDrawEffect&,
 126                                    EffectKey key,
 127                                    const char* outputColor,
 128                                    const char* inputColor,
 129                                    const TextureSamplerArray& samplers) {
 130     SkString coords;
 131     fEffectMatrix.emitCodeMakeFSCoords2D(builder, key, &coords);
 132     fOffsetVar = builder->addUniform(
 133         GrGLShaderBuilder::kFragment_Visibility |
 134         GrGLShaderBuilder::kVertex_Visibility,
 135         kVec2f_GrSLType, "uOffset");
 136     fZoomVar = builder->addUniform(
 137         GrGLShaderBuilder::kFragment_Visibility |
 138         GrGLShaderBuilder::kVertex_Visibility,
 139         kVec2f_GrSLType, "uZoom");
 140     fInsetVar = builder->addUniform(
 141         GrGLShaderBuilder::kFragment_Visibility |
 142         GrGLShaderBuilder::kVertex_Visibility,
 143         kVec2f_GrSLType, "uInset");
 144
 145     builder->fsCodeAppendf("\t\tvec2 coord = %s;\n", coords.c_str());
 146     builder->fsCodeAppendf("\t\tvec2 zoom_coord = %s + %s / %s;\n",
 147                            builder->getUniformCStr(fOffsetVar),
 148                            coords.c_str(),
 149                            builder->getUniformCStr(fZoomVar));
 150
 151     builder->fsCodeAppend("\t\tvec2 delta = min(coord, vec2(1.0, 1.0) - coord);\n");
 152
 153     builder->fsCodeAppendf("\t\tdelta = delta / %s;\n", builder->getUniformCStr(fInsetVar));
 154
 155     builder->fsCodeAppend("\t\tfloat weight = 0.0;\n");
 156     builder->fsCodeAppend("\t\tif (delta.s < 2.0 && delta.t < 2.0) {\n");
 157     builder->fsCodeAppend("\t\t\tdelta = vec2(2.0, 2.0) - delta;\n");
 158     builder->fsCodeAppend("\t\t\tfloat dist = length(delta);\n");
 159     builder->fsCodeAppend("\t\t\tdist = max(2.0 - dist, 0.0);\n");
 160     builder->fsCodeAppend("\t\t\tweight = min(dist * dist, 1.0);\n");
 161     builder->fsCodeAppend("\t\t} else {\n");
 162     builder->fsCodeAppend("\t\t\tvec2 delta_squared = delta * delta;\n");
 163     builder->fsCodeAppend("\t\t\tweight = min(min(delta_squared.s, delta_squared.y), 1.0);\n");
 164     builder->fsCodeAppend("\t\t}\n");
 165
 166     builder->fsCodeAppend("\t\tvec2 mix_coord = mix(coord, zoom_coord, weight);\n");
 167     builder->fsCodeAppend("\t\tvec4 output_color = ");
 168     builder->fsAppendTextureLookup(samplers[0], "mix_coord");
 169     builder->fsCodeAppend(";\n");
 170
 171     builder->fsCodeAppendf("\t\t%s = output_color;", outputColor);
 172     SkString modulate;
 173     GrGLSLMulVarBy4f(&modulate, 2, outputColor, inputColor);
 174     builder->fsCodeAppend(modulate.c_str());
 175 }
 176
 177 void GrGLMagnifierEffect::setData(const GrGLUniformManager& uman,
 178                                   const GrDrawEffect& drawEffect) {
 179     const GrMagnifierEffect& zoom = drawEffect.castEffect<GrMagnifierEffect>();
 180     uman.set2f(fOffsetVar, zoom.x_offset(), zoom.y_offset());
 181     uman.set2f(fZoomVar, zoom.x_zoom(), zoom.y_zoom());
 182     uman.set2f(fInsetVar, zoom.x_inset(), zoom.y_inset());
 183     fEffectMatrix.setData(uman, zoom.getMatrix(), drawEffect, zoom.texture(0));
 184 }
 185
 186 GrGLEffect::EffectKey GrGLMagnifierEffect::GenKey(const GrDrawEffect& drawEffect,
 187                                                   const GrGLCaps&) {
 188     const GrMagnifierEffect& zoom = drawEffect.castEffect<GrMagnifierEffect>();
 189     return GrGLEffectMatrix::GenKey(zoom.getMatrix(),
 190                                     drawEffect,
 191                                     zoom.coordsType(),
 192                                     zoom.texture(0));
 193 }
 194
 195 /////////////////////////////////////////////////////////////////////
 196
 197 GR_DEFINE_EFFECT_TEST(GrMagnifierEffect);
 198
 199 GrEffectRef* GrMagnifierEffect::TestCreate(SkRandom* random,
 200                                            GrContext* context,
 201                                            const GrDrawTargetCaps&,
 202                                            GrTexture** textures) {
 203     const int kMaxWidth = 200;
 204     const int kMaxHeight = 200;
 205     const int kMaxInset = 20;
 206     uint32_t width = random->nextULessThan(kMaxWidth);
 207     uint32_t height = random->nextULessThan(kMaxHeight);
 208     uint32_t x = random->nextULessThan(kMaxWidth - width);
 209     uint32_t y = random->nextULessThan(kMaxHeight - height);
 210     SkScalar inset = SkIntToScalar(random->nextULessThan(kMaxInset));
 211
 212     SkAutoTUnref<SkMagnifierImageFilter> filter(
 213             new SkMagnifierImageFilter(
 214                 SkRect::MakeXYWH(SkIntToScalar(x), SkIntToScalar(y),
 215                                  SkIntToScalar(width), SkIntToScalar(height)),
 216                 inset));
 217     GrEffectRef* effect;
 218     filter->asNewEffect(&effect, textures[0], SkMatrix::I());
 219     SkASSERT(NULL != effect);
 220     return effect;
 221 }
 222
 223 ///////////////////////////////////////////////////////////////////////////////
 224
 225 const GrBackendEffectFactory& GrMagnifierEffect::getFactory() const {
 226     return GrTBackendEffectFactory<GrMagnifierEffect>::getInstance();
 227 }
 228
 229 bool GrMagnifierEffect::onIsEqual(const GrEffect& sBase) const {
 230     const GrMagnifierEffect& s = CastEffect<GrMagnifierEffect>(sBase);
 231     return (this->texture(0) == s.texture(0) &&
 232             this->fXOffset == s.fXOffset &&
 233             this->fYOffset == s.fYOffset &&
 234             this->fXZoom == s.fXZoom &&
 235             this->fYZoom == s.fYZoom &&
 236             this->fXInset == s.fXInset &&
 237             this->fYInset == s.fYInset);
 238 }
 239
 240 void GrMagnifierEffect::getConstantColorComponents(GrColor* color, uint32_t* validFlags) const {
 241     this->updateConstantColorComponentsForModulation(color, validFlags);
 242 }
 243
 244 #endif
 245
 246 ////////////////////////////////////////////////////////////////////////////////
 247 SkMagnifierImageFilter::SkMagnifierImageFilter(SkFlattenableReadBuffer& buffer)
 248   : INHERITED(buffer) {
 249     float x = buffer.readScalar();
 250     float y = buffer.readScalar();
 251     float width = buffer.readScalar();
 252     float height = buffer.readScalar();
 253     fSrcRect = SkRect::MakeXYWH(x, y, width, height);
 254     fInset = buffer.readScalar();
 255 }
 256
 257 // FIXME:  implement single-input semantics
 258 SkMagnifierImageFilter::SkMagnifierImageFilter(SkRect srcRect, SkScalar inset)
 259     : INHERITED(0), fSrcRect(srcRect), fInset(inset) {
 260     SkASSERT(srcRect.x() >= 0 && srcRect.y() >= 0 && inset >= 0);
 261 }
 262
 263 #if SK_SUPPORT_GPU
 264 bool SkMagnifierImageFilter::asNewEffect(GrEffectRef** effect, GrTexture* texture, const SkMatrix&) const {
 265     if (effect) {
 266         *effect = GrMagnifierEffect::Create(texture,
 267                                             fSrcRect.x() / texture->width(),
 268                                             fSrcRect.y() / texture->height(),
 269                                             texture->width() / fSrcRect.width(),
 270                                             texture->height() / fSrcRect.height(),
 271                                             fInset / texture->width(),
 272                                             fInset / texture->height());
 273     }
 274     return true;
 275 }
 276 #endif
 277
 278 void SkMagnifierImageFilter::flatten(SkFlattenableWriteBuffer& buffer) const {
 279     this->INHERITED::flatten(buffer);
 280     buffer.writeScalar(fSrcRect.x());
 281     buffer.writeScalar(fSrcRect.y());
 282     buffer.writeScalar(fSrcRect.width());
 283     buffer.writeScalar(fSrcRect.height());
 284     buffer.writeScalar(fInset);
 285 }
 286
 287 bool SkMagnifierImageFilter::onFilterImage(Proxy*, const SkBitmap& src,
 288                                            const SkMatrix&, SkBitmap* dst,
 289                                            SkIPoint* offset) {
 290     SkASSERT(src.config() == SkBitmap::kARGB_8888_Config);
 291     SkASSERT(fSrcRect.width() < src.width());
 292     SkASSERT(fSrcRect.height() < src.height());
 293
 294     if (src.config() != SkBitmap::kARGB_8888_Config) {
 295       return false;
 296     }
 297
 298     SkAutoLockPixels alp(src);
 299     SkASSERT(src.getPixels());
 300     if (!src.getPixels() || src.width() <= 0 || src.height() <= 0) {
 301       return false;
 302     }
 303
 304     SkScalar inv_inset = fInset > 0 ? SkScalarInvert(fInset) : SK_Scalar1;
 305
 306     SkScalar inv_x_zoom = fSrcRect.width() / src.width();
 307     SkScalar inv_y_zoom = fSrcRect.height() / src.height();
 308
 309     dst->setConfig(src.config(), src.width(), src.height());
 310     dst->allocPixels();
 311     SkColor* sptr = src.getAddr32(0, 0);
 312     SkColor* dptr = dst->getAddr32(0, 0);
 313     int width = src.width(), height = src.height();
 314     for (int y = 0; y < height; ++y) {
 315         for (int x = 0; x < width; ++x) {
 316             SkScalar x_dist = SkMin32(x, width - x - 1) * inv_inset;
 317             SkScalar y_dist = SkMin32(y, height - y - 1) * inv_inset;
 318             SkScalar weight = 0;
 319
 320             static const SkScalar kScalar2 = SkScalar(2);
 321
 322             // To create a smooth curve at the corners, we need to work on
 323             // a square twice the size of the inset.
 324             if (x_dist < kScalar2 && y_dist < kScalar2) {
 325                 x_dist = kScalar2 - x_dist;
 326                 y_dist = kScalar2 - y_dist;
 327
 328                 SkScalar dist = SkScalarSqrt(SkScalarSquare(x_dist) +
 329                                              SkScalarSquare(y_dist));
 330                 dist = SkMaxScalar(kScalar2 - dist, 0);
 331                 weight = SkMinScalar(SkScalarSquare(dist), SK_Scalar1);
 332             } else {
 333                 SkScalar sqDist = SkMinScalar(SkScalarSquare(x_dist),
 334                                               SkScalarSquare(y_dist));
 335                 weight = SkMinScalar(sqDist, SK_Scalar1);
 336             }
 337
 338             SkScalar x_interp = SkScalarMul(weight, (fSrcRect.x() + x * inv_x_zoom)) +
 339                            (SK_Scalar1 - weight) * x;
 340             SkScalar y_interp = SkScalarMul(weight, (fSrcRect.y() + y * inv_y_zoom)) +
 341                            (SK_Scalar1 - weight) * y;
 342
 343             int x_val = SkMin32(SkScalarFloorToInt(x_interp), width - 1);
 344             int y_val = SkMin32(SkScalarFloorToInt(y_interp), height - 1);
 345
 346             *dptr = sptr[y_val * width + x_val];
 347             dptr++;
 348         }
 349     }
 350     return true;
 351 }