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/GrGLSL.h"
  18 #include "gl/GrGLTexture.h"
  19 #include "GrTBackendEffectFactory.h"
  20
  21 class GrGLMagnifierEffect;
  22
  23 class GrMagnifierEffect : public GrSingleTextureEffect {
  24
  25 public:
  26     static GrEffectRef* Create(GrTexture* texture,
  27                                float xOffset,
  28                                float yOffset,
  29                                float xZoom,
  30                                float yZoom,
  31                                float xInset,
  32                                float yInset) {
  33         AutoEffectUnref effect(SkNEW_ARGS(GrMagnifierEffect, (texture,
  34                                                               xOffset,
  35                                                               yOffset,
  36                                                               xZoom,
  37                                                               yZoom,
  38                                                               xInset,
  39                                                               yInset)));
  40         return CreateEffectRef(effect);
  41     }
  42
  43     virtual ~GrMagnifierEffect() {};
  44
  45     static const char* Name() { return "Magnifier"; }
  46
  47     virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE;
  48     virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const SK_OVERRIDE;
  49
  50     float x_offset() const { return fXOffset; }
  51     float y_offset() const { return fYOffset; }
  52     float x_zoom() const { return fXZoom; }
  53     float y_zoom() const { return fYZoom; }
  54     float x_inset() const { return fXInset; }
  55     float y_inset() const { return fYInset; }
  56
  57     typedef GrGLMagnifierEffect GLEffect;
  58
  59 private:
  60     GrMagnifierEffect(GrTexture* texture,
  61                       float xOffset,
  62                       float yOffset,
  63                       float xZoom,
  64                       float yZoom,
  65                       float xInset,
  66                       float yInset)
  67         : GrSingleTextureEffect(texture, MakeDivByTextureWHMatrix(texture))
  68         , fXOffset(xOffset)
  69         , fYOffset(yOffset)
  70         , fXZoom(xZoom)
  71         , fYZoom(yZoom)
  72         , fXInset(xInset)
  73         , fYInset(yInset) {}
  74
  75     virtual bool onIsEqual(const GrEffect&) const SK_OVERRIDE;
  76
  77     GR_DECLARE_EFFECT_TEST;
  78
  79     float fXOffset;
  80     float fYOffset;
  81     float fXZoom;
  82     float fYZoom;
  83     float fXInset;
  84     float fYInset;
  85
  86     typedef GrSingleTextureEffect INHERITED;
  87 };
  88
  89 // For brevity
  90 typedef GrGLUniformManager::UniformHandle UniformHandle;
  91
  92 class GrGLMagnifierEffect : public GrGLEffect {
  93 public:
  94     GrGLMagnifierEffect(const GrBackendEffectFactory&, const GrDrawEffect&);
  95
  96     virtual void emitCode(GrGLShaderBuilder*,
  97                           const GrDrawEffect&,
  98                           EffectKey,
  99                           const char* outputColor,
 100                           const char* inputColor,
 101                           const TransformedCoordsArray&,
 102                           const TextureSamplerArray&) SK_OVERRIDE;
 103
 104     virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE;
 105
 106 private:
 107     UniformHandle       fOffsetVar;
 108     UniformHandle       fZoomVar;
 109     UniformHandle       fInsetVar;
 110
 111     typedef GrGLEffect INHERITED;
 112 };
 113
 114 GrGLMagnifierEffect::GrGLMagnifierEffect(const GrBackendEffectFactory& factory, const GrDrawEffect&)
 115     : INHERITED(factory) {
 116 }
 117
 118 void GrGLMagnifierEffect::emitCode(GrGLShaderBuilder* builder,
 119                                    const GrDrawEffect&,
 120                                    EffectKey key,
 121                                    const char* outputColor,
 122                                    const char* inputColor,
 123                                    const TransformedCoordsArray& coords,
 124                                    const TextureSamplerArray& samplers) {
 125     SkString coords2D = builder->ensureFSCoords2D(coords, 0);
 126     fOffsetVar = builder->addUniform(
 127         GrGLShaderBuilder::kFragment_Visibility |
 128         GrGLShaderBuilder::kVertex_Visibility,
 129         kVec2f_GrSLType, "uOffset");
 130     fZoomVar = builder->addUniform(
 131         GrGLShaderBuilder::kFragment_Visibility |
 132         GrGLShaderBuilder::kVertex_Visibility,
 133         kVec2f_GrSLType, "uZoom");
 134     fInsetVar = builder->addUniform(
 135         GrGLShaderBuilder::kFragment_Visibility |
 136         GrGLShaderBuilder::kVertex_Visibility,
 137         kVec2f_GrSLType, "uInset");
 138
 139     builder->fsCodeAppendf("\t\tvec2 coord = %s;\n", coords2D.c_str());
 140     builder->fsCodeAppendf("\t\tvec2 zoom_coord = %s + %s / %s;\n",
 141                            builder->getUniformCStr(fOffsetVar),
 142                            coords2D.c_str(),
 143                            builder->getUniformCStr(fZoomVar));
 144
 145     builder->fsCodeAppend("\t\tvec2 delta = min(coord, vec2(1.0, 1.0) - coord);\n");
 146
 147     builder->fsCodeAppendf("\t\tdelta = delta / %s;\n", builder->getUniformCStr(fInsetVar));
 148
 149     builder->fsCodeAppend("\t\tfloat weight = 0.0;\n");
 150     builder->fsCodeAppend("\t\tif (delta.s < 2.0 && delta.t < 2.0) {\n");
 151     builder->fsCodeAppend("\t\t\tdelta = vec2(2.0, 2.0) - delta;\n");
 152     builder->fsCodeAppend("\t\t\tfloat dist = length(delta);\n");
 153     builder->fsCodeAppend("\t\t\tdist = max(2.0 - dist, 0.0);\n");
 154     builder->fsCodeAppend("\t\t\tweight = min(dist * dist, 1.0);\n");
 155     builder->fsCodeAppend("\t\t} else {\n");
 156     builder->fsCodeAppend("\t\t\tvec2 delta_squared = delta * delta;\n");
 157     builder->fsCodeAppend("\t\t\tweight = min(min(delta_squared.s, delta_squared.y), 1.0);\n");
 158     builder->fsCodeAppend("\t\t}\n");
 159
 160     builder->fsCodeAppend("\t\tvec2 mix_coord = mix(coord, zoom_coord, weight);\n");
 161     builder->fsCodeAppend("\t\tvec4 output_color = ");
 162     builder->fsAppendTextureLookup(samplers[0], "mix_coord");
 163     builder->fsCodeAppend(";\n");
 164
 165     builder->fsCodeAppendf("\t\t%s = output_color;", outputColor);
 166     SkString modulate;
 167     GrGLSLMulVarBy4f(&modulate, 2, outputColor, inputColor);
 168     builder->fsCodeAppend(modulate.c_str());
 169 }
 170
 171 void GrGLMagnifierEffect::setData(const GrGLUniformManager& uman,
 172                                   const GrDrawEffect& drawEffect) {
 173     const GrMagnifierEffect& zoom = drawEffect.castEffect<GrMagnifierEffect>();
 174     uman.set2f(fOffsetVar, zoom.x_offset(), zoom.y_offset());
 175     uman.set2f(fZoomVar, zoom.x_zoom(), zoom.y_zoom());
 176     uman.set2f(fInsetVar, zoom.x_inset(), zoom.y_inset());
 177 }
 178
 179 /////////////////////////////////////////////////////////////////////
 180
 181 GR_DEFINE_EFFECT_TEST(GrMagnifierEffect);
 182
 183 GrEffectRef* GrMagnifierEffect::TestCreate(SkRandom* random,
 184                                            GrContext* context,
 185                                            const GrDrawTargetCaps&,
 186                                            GrTexture** textures) {
 187     GrTexture* texture = textures[0];
 188     const int kMaxWidth = 200;
 189     const int kMaxHeight = 200;
 190     const int kMaxInset = 20;
 191     uint32_t width = random->nextULessThan(kMaxWidth);
 192     uint32_t height = random->nextULessThan(kMaxHeight);
 193     uint32_t x = random->nextULessThan(kMaxWidth - width);
 194     uint32_t y = random->nextULessThan(kMaxHeight - height);
 195     uint32_t inset = random->nextULessThan(kMaxInset);
 196
 197     GrEffectRef* effect = GrMagnifierEffect::Create(
 198         texture,
 199         (float) width / texture->width(),
 200         (float) height / texture->height(),
 201         texture->width() / (float) x,
 202         texture->height() / (float) y,
 203         (float) inset / texture->width(),
 204         (float) inset / texture->height());
 205     SkASSERT(NULL != effect);
 206     return effect;
 207 }
 208
 209 ///////////////////////////////////////////////////////////////////////////////
 210
 211 const GrBackendEffectFactory& GrMagnifierEffect::getFactory() const {
 212     return GrTBackendEffectFactory<GrMagnifierEffect>::getInstance();
 213 }
 214
 215 bool GrMagnifierEffect::onIsEqual(const GrEffect& sBase) const {
 216     const GrMagnifierEffect& s = CastEffect<GrMagnifierEffect>(sBase);
 217     return (this->texture(0) == s.texture(0) &&
 218             this->fXOffset == s.fXOffset &&
 219             this->fYOffset == s.fYOffset &&
 220             this->fXZoom == s.fXZoom &&
 221             this->fYZoom == s.fYZoom &&
 222             this->fXInset == s.fXInset &&
 223             this->fYInset == s.fYInset);
 224 }
 225
 226 void GrMagnifierEffect::getConstantColorComponents(GrColor* color, uint32_t* validFlags) const {
 227     this->updateConstantColorComponentsForModulation(color, validFlags);
 228 }
 229
 230 #endif
 231
 232 ////////////////////////////////////////////////////////////////////////////////
 233 SkMagnifierImageFilter::SkMagnifierImageFilter(SkFlattenableReadBuffer& buffer)
 234   : INHERITED(buffer) {
 235     float x = buffer.readScalar();
 236     float y = buffer.readScalar();
 237     float width = buffer.readScalar();
 238     float height = buffer.readScalar();
 239     fSrcRect = SkRect::MakeXYWH(x, y, width, height);
 240     fInset = buffer.readScalar();
 241 }
 242
 243 // FIXME:  implement single-input semantics
 244 SkMagnifierImageFilter::SkMagnifierImageFilter(SkRect srcRect, SkScalar inset)
 245     : INHERITED(0), fSrcRect(srcRect), fInset(inset) {
 246     SkASSERT(srcRect.x() >= 0 && srcRect.y() >= 0 && inset >= 0);
 247 }
 248
 249 #if SK_SUPPORT_GPU
 250 bool SkMagnifierImageFilter::asNewEffect(GrEffectRef** effect, GrTexture* texture, const SkMatrix&, const SkIRect&) const {
 251     if (effect) {
 252         *effect = GrMagnifierEffect::Create(texture,
 253                                             fSrcRect.x() / texture->width(),
 254                                             fSrcRect.y() / texture->height(),
 255                                             texture->width() / fSrcRect.width(),
 256                                             texture->height() / fSrcRect.height(),
 257                                             fInset / texture->width(),
 258                                             fInset / texture->height());
 259     }
 260     return true;
 261 }
 262 #endif
 263
 264 void SkMagnifierImageFilter::flatten(SkFlattenableWriteBuffer& buffer) const {
 265     this->INHERITED::flatten(buffer);
 266     buffer.writeScalar(fSrcRect.x());
 267     buffer.writeScalar(fSrcRect.y());
 268     buffer.writeScalar(fSrcRect.width());
 269     buffer.writeScalar(fSrcRect.height());
 270     buffer.writeScalar(fInset);
 271 }
 272
 273 bool SkMagnifierImageFilter::onFilterImage(Proxy*, const SkBitmap& src,
 274                                            const SkMatrix&, SkBitmap* dst,
 275                                            SkIPoint* offset) {
 276     SkASSERT(src.config() == SkBitmap::kARGB_8888_Config);
 277     SkASSERT(fSrcRect.width() < src.width());
 278     SkASSERT(fSrcRect.height() < src.height());
 279
 280     if (src.config() != SkBitmap::kARGB_8888_Config) {
 281       return false;
 282     }
 283
 284     SkAutoLockPixels alp(src);
 285     SkASSERT(src.getPixels());
 286     if (!src.getPixels() || src.width() <= 0 || src.height() <= 0) {
 287       return false;
 288     }
 289
 290     SkScalar inv_inset = fInset > 0 ? SkScalarInvert(fInset) : SK_Scalar1;
 291
 292     SkScalar inv_x_zoom = fSrcRect.width() / src.width();
 293     SkScalar inv_y_zoom = fSrcRect.height() / src.height();
 294
 295     dst->setConfig(src.config(), src.width(), src.height());
 296     dst->allocPixels();
 297     SkColor* sptr = src.getAddr32(0, 0);
 298     SkColor* dptr = dst->getAddr32(0, 0);
 299     int width = src.width(), height = src.height();
 300     for (int y = 0; y < height; ++y) {
 301         for (int x = 0; x < width; ++x) {
 302             SkScalar x_dist = SkMin32(x, width - x - 1) * inv_inset;
 303             SkScalar y_dist = SkMin32(y, height - y - 1) * inv_inset;
 304             SkScalar weight = 0;
 305
 306             static const SkScalar kScalar2 = SkScalar(2);
 307
 308             // To create a smooth curve at the corners, we need to work on
 309             // a square twice the size of the inset.
 310             if (x_dist < kScalar2 && y_dist < kScalar2) {
 311                 x_dist = kScalar2 - x_dist;
 312                 y_dist = kScalar2 - y_dist;
 313
 314                 SkScalar dist = SkScalarSqrt(SkScalarSquare(x_dist) +
 315                                              SkScalarSquare(y_dist));
 316                 dist = SkMaxScalar(kScalar2 - dist, 0);
 317                 weight = SkMinScalar(SkScalarSquare(dist), SK_Scalar1);
 318             } else {
 319                 SkScalar sqDist = SkMinScalar(SkScalarSquare(x_dist),
 320                                               SkScalarSquare(y_dist));
 321                 weight = SkMinScalar(sqDist, SK_Scalar1);
 322             }
 323
 324             SkScalar x_interp = SkScalarMul(weight, (fSrcRect.x() + x * inv_x_zoom)) +
 325                            (SK_Scalar1 - weight) * x;
 326             SkScalar y_interp = SkScalarMul(weight, (fSrcRect.y() + y * inv_y_zoom)) +
 327                            (SK_Scalar1 - weight) * y;
 328
 329             int x_val = SkMin32(SkScalarFloorToInt(x_interp), width - 1);
 330             int y_val = SkMin32(SkScalarFloorToInt(y_interp), height - 1);
 331
 332             *dptr = sptr[y_val * width + x_val];
 333             dptr++;
 334         }
 335     }
 336     return true;
 337 }