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 #include "SkValidationUtils.h"
  13
  14 ////////////////////////////////////////////////////////////////////////////////
  15 #if SK_SUPPORT_GPU
  16 #include "effects/GrSingleTextureEffect.h"
  17 #include "gl/GrGLEffect.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 xInvZoom,
  31                                float yInvZoom,
  32                                float xInvInset,
  33                                float yInvInset) {
  34         AutoEffectUnref effect(SkNEW_ARGS(GrMagnifierEffect, (texture,
  35                                                               xOffset,
  36                                                               yOffset,
  37                                                               xInvZoom,
  38                                                               yInvZoom,
  39                                                               xInvInset,
  40                                                               yInvInset)));
  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_inv_zoom() const { return fXInvZoom; }
  54     float y_inv_zoom() const { return fYInvZoom; }
  55     float x_inv_inset() const { return fXInvInset; }
  56     float y_inv_inset() const { return fYInvInset; }
  57
  58     typedef GrGLMagnifierEffect GLEffect;
  59
  60 private:
  61     GrMagnifierEffect(GrTexture* texture,
  62                       float xOffset,
  63                       float yOffset,
  64                       float xInvZoom,
  65                       float yInvZoom,
  66                       float xInvInset,
  67                       float yInvInset)
  68         : GrSingleTextureEffect(texture, MakeDivByTextureWHMatrix(texture))
  69         , fXOffset(xOffset)
  70         , fYOffset(yOffset)
  71         , fXInvZoom(xInvZoom)
  72         , fYInvZoom(yInvZoom)
  73         , fXInvInset(xInvInset)
  74         , fYInvInset(yInvInset) {}
  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 fXInvZoom;
  83     float fYInvZoom;
  84     float fXInvInset;
  85     float fYInvInset;
  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 TransformedCoordsArray&,
 103                           const TextureSamplerArray&) SK_OVERRIDE;
 104
 105     virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE;
 106
 107 private:
 108     UniformHandle       fOffsetVar;
 109     UniformHandle       fInvZoomVar;
 110     UniformHandle       fInvInsetVar;
 111
 112     typedef GrGLEffect INHERITED;
 113 };
 114
 115 GrGLMagnifierEffect::GrGLMagnifierEffect(const GrBackendEffectFactory& factory, const GrDrawEffect&)
 116     : INHERITED(factory) {
 117 }
 118
 119 void GrGLMagnifierEffect::emitCode(GrGLShaderBuilder* builder,
 120                                    const GrDrawEffect&,
 121                                    EffectKey key,
 122                                    const char* outputColor,
 123                                    const char* inputColor,
 124                                    const TransformedCoordsArray& coords,
 125                                    const TextureSamplerArray& samplers) {
 126     SkString coords2D = builder->ensureFSCoords2D(coords, 0);
 127     fOffsetVar = builder->addUniform(
 128         GrGLShaderBuilder::kFragment_Visibility |
 129         GrGLShaderBuilder::kVertex_Visibility,
 130         kVec2f_GrSLType, "Offset");
 131     fInvZoomVar = builder->addUniform(
 132         GrGLShaderBuilder::kFragment_Visibility |
 133         GrGLShaderBuilder::kVertex_Visibility,
 134         kVec2f_GrSLType, "InvZoom");
 135     fInvInsetVar = builder->addUniform(
 136         GrGLShaderBuilder::kFragment_Visibility |
 137         GrGLShaderBuilder::kVertex_Visibility,
 138         kVec2f_GrSLType, "InvInset");
 139
 140     builder->fsCodeAppendf("\t\tvec2 coord = %s;\n", coords2D.c_str());
 141     builder->fsCodeAppendf("\t\tvec2 zoom_coord = %s + %s * %s;\n",
 142                            builder->getUniformCStr(fOffsetVar),
 143                            coords2D.c_str(),
 144                            builder->getUniformCStr(fInvZoomVar));
 145
 146     builder->fsCodeAppend("\t\tvec2 delta = min(coord, vec2(1.0, 1.0) - coord);\n");
 147
 148     builder->fsCodeAppendf("\t\tdelta = delta * %s;\n", builder->getUniformCStr(fInvInsetVar));
 149
 150     builder->fsCodeAppend("\t\tfloat weight = 0.0;\n");
 151     builder->fsCodeAppend("\t\tif (delta.s < 2.0 && delta.t < 2.0) {\n");
 152     builder->fsCodeAppend("\t\t\tdelta = vec2(2.0, 2.0) - delta;\n");
 153     builder->fsCodeAppend("\t\t\tfloat dist = length(delta);\n");
 154     builder->fsCodeAppend("\t\t\tdist = max(2.0 - dist, 0.0);\n");
 155     builder->fsCodeAppend("\t\t\tweight = min(dist * dist, 1.0);\n");
 156     builder->fsCodeAppend("\t\t} else {\n");
 157     builder->fsCodeAppend("\t\t\tvec2 delta_squared = delta * delta;\n");
 158     builder->fsCodeAppend("\t\t\tweight = min(min(delta_squared.x, delta_squared.y), 1.0);\n");
 159     builder->fsCodeAppend("\t\t}\n");
 160
 161     builder->fsCodeAppend("\t\tvec2 mix_coord = mix(coord, zoom_coord, weight);\n");
 162     builder->fsCodeAppend("\t\tvec4 output_color = ");
 163     builder->fsAppendTextureLookup(samplers[0], "mix_coord");
 164     builder->fsCodeAppend(";\n");
 165
 166     builder->fsCodeAppendf("\t\t%s = output_color;", outputColor);
 167     SkString modulate;
 168     GrGLSLMulVarBy4f(&modulate, 2, outputColor, inputColor);
 169     builder->fsCodeAppend(modulate.c_str());
 170 }
 171
 172 void GrGLMagnifierEffect::setData(const GrGLUniformManager& uman,
 173                                   const GrDrawEffect& drawEffect) {
 174     const GrMagnifierEffect& zoom = drawEffect.castEffect<GrMagnifierEffect>();
 175     uman.set2f(fOffsetVar, zoom.x_offset(), zoom.y_offset());
 176     uman.set2f(fInvZoomVar, zoom.x_inv_zoom(), zoom.y_inv_zoom());
 177     uman.set2f(fInvInsetVar, zoom.x_inv_inset(), zoom.y_inv_inset());
 178 }
 179
 180 /////////////////////////////////////////////////////////////////////
 181
 182 GR_DEFINE_EFFECT_TEST(GrMagnifierEffect);
 183
 184 GrEffectRef* GrMagnifierEffect::TestCreate(SkRandom* random,
 185                                            GrContext* context,
 186                                            const GrDrawTargetCaps&,
 187                                            GrTexture** textures) {
 188     GrTexture* texture = textures[0];
 189     const int kMaxWidth = 200;
 190     const int kMaxHeight = 200;
 191     const int kMaxInset = 20;
 192     uint32_t width = random->nextULessThan(kMaxWidth);
 193     uint32_t height = random->nextULessThan(kMaxHeight);
 194     uint32_t x = random->nextULessThan(kMaxWidth - width);
 195     uint32_t y = random->nextULessThan(kMaxHeight - height);
 196     uint32_t inset = random->nextULessThan(kMaxInset);
 197
 198     GrEffectRef* effect = GrMagnifierEffect::Create(
 199         texture,
 200         (float) width / texture->width(),
 201         (float) height / texture->height(),
 202         texture->width() / (float) x,
 203         texture->height() / (float) y,
 204         (float) inset / texture->width(),
 205         (float) inset / texture->height());
 206     SkASSERT(NULL != effect);
 207     return effect;
 208 }
 209
 210 ///////////////////////////////////////////////////////////////////////////////
 211
 212 const GrBackendEffectFactory& GrMagnifierEffect::getFactory() const {
 213     return GrTBackendEffectFactory<GrMagnifierEffect>::getInstance();
 214 }
 215
 216 bool GrMagnifierEffect::onIsEqual(const GrEffect& sBase) const {
 217     const GrMagnifierEffect& s = CastEffect<GrMagnifierEffect>(sBase);
 218     return (this->texture(0) == s.texture(0) &&
 219             this->fXOffset == s.fXOffset &&
 220             this->fYOffset == s.fYOffset &&
 221             this->fXInvZoom == s.fXInvZoom &&
 222             this->fYInvZoom == s.fYInvZoom &&
 223             this->fXInvInset == s.fXInvInset &&
 224             this->fYInvInset == s.fYInvInset);
 225 }
 226
 227 void GrMagnifierEffect::getConstantColorComponents(GrColor* color, uint32_t* validFlags) const {
 228     this->updateConstantColorComponentsForModulation(color, validFlags);
 229 }
 230
 231 #endif
 232
 233 ////////////////////////////////////////////////////////////////////////////////
 234 SkMagnifierImageFilter::SkMagnifierImageFilter(SkFlattenableReadBuffer& buffer)
 235   : INHERITED(buffer) {
 236     float x = buffer.readScalar();
 237     float y = buffer.readScalar();
 238     float width = buffer.readScalar();
 239     float height = buffer.readScalar();
 240     fSrcRect = SkRect::MakeXYWH(x, y, width, height);
 241     fInset = buffer.readScalar();
 242
 243     buffer.validate(SkIsValidRect(fSrcRect) && SkScalarIsFinite(fInset));
 244 }
 245
 246 // FIXME:  implement single-input semantics
 247 SkMagnifierImageFilter::SkMagnifierImageFilter(SkRect srcRect, SkScalar inset)
 248     : INHERITED(0), fSrcRect(srcRect), fInset(inset) {
 249     SkASSERT(srcRect.x() >= 0 && srcRect.y() >= 0 && inset >= 0);
 250 }
 251
 252 #if SK_SUPPORT_GPU
 253 bool SkMagnifierImageFilter::asNewEffect(GrEffectRef** effect, GrTexture* texture, const SkMatrix&, const SkIRect&) const {
 254     if (effect) {
 255         SkScalar yOffset = (texture->origin() == kTopLeft_GrSurfaceOrigin) ? fSrcRect.y() :
 256                            (texture->height() - (fSrcRect.y() + fSrcRect.height()));
 257         SkScalar invInset = fInset > 0 ? SkScalarInvert(fInset) : SK_Scalar1;
 258         *effect = GrMagnifierEffect::Create(texture,
 259                                             fSrcRect.x() / texture->width(),
 260                                             yOffset / texture->height(),
 261                                             fSrcRect.width() / texture->width(),
 262                                             fSrcRect.height() / texture->height(),
 263                                             texture->width() * invInset,
 264                                             texture->height() * invInset);
 265     }
 266     return true;
 267 }
 268 #endif
 269
 270 void SkMagnifierImageFilter::flatten(SkFlattenableWriteBuffer& buffer) const {
 271     this->INHERITED::flatten(buffer);
 272     buffer.writeScalar(fSrcRect.x());
 273     buffer.writeScalar(fSrcRect.y());
 274     buffer.writeScalar(fSrcRect.width());
 275     buffer.writeScalar(fSrcRect.height());
 276     buffer.writeScalar(fInset);
 277 }
 278
 279 bool SkMagnifierImageFilter::onFilterImage(Proxy*, const SkBitmap& src,
 280                                            const SkMatrix&, SkBitmap* dst,
 281                                            SkIPoint* offset) {
 282     SkASSERT(src.config() == SkBitmap::kARGB_8888_Config);
 283     SkASSERT(fSrcRect.width() < src.width());
 284     SkASSERT(fSrcRect.height() < src.height());
 285
 286     if (src.config() != SkBitmap::kARGB_8888_Config) {
 287       return false;
 288     }
 289
 290     SkAutoLockPixels alp(src);
 291     SkASSERT(src.getPixels());
 292     if (!src.getPixels() || src.width() <= 0 || src.height() <= 0) {
 293       return false;
 294     }
 295
 296     SkScalar inv_inset = fInset > 0 ? SkScalarInvert(fInset) : SK_Scalar1;
 297
 298     SkScalar inv_x_zoom = fSrcRect.width() / src.width();
 299     SkScalar inv_y_zoom = fSrcRect.height() / src.height();
 300
 301     dst->setConfig(src.config(), src.width(), src.height());
 302     dst->allocPixels();
 303     SkColor* sptr = src.getAddr32(0, 0);
 304     SkColor* dptr = dst->getAddr32(0, 0);
 305     int width = src.width(), height = src.height();
 306     for (int y = 0; y < height; ++y) {
 307         for (int x = 0; x < width; ++x) {
 308             SkScalar x_dist = SkMin32(x, width - x - 1) * inv_inset;
 309             SkScalar y_dist = SkMin32(y, height - y - 1) * inv_inset;
 310             SkScalar weight = 0;
 311
 312             static const SkScalar kScalar2 = SkScalar(2);
 313
 314             // To create a smooth curve at the corners, we need to work on
 315             // a square twice the size of the inset.
 316             if (x_dist < kScalar2 && y_dist < kScalar2) {
 317                 x_dist = kScalar2 - x_dist;
 318                 y_dist = kScalar2 - y_dist;
 319
 320                 SkScalar dist = SkScalarSqrt(SkScalarSquare(x_dist) +
 321                                              SkScalarSquare(y_dist));
 322                 dist = SkMaxScalar(kScalar2 - dist, 0);
 323                 weight = SkMinScalar(SkScalarSquare(dist), SK_Scalar1);
 324             } else {
 325                 SkScalar sqDist = SkMinScalar(SkScalarSquare(x_dist),
 326                                               SkScalarSquare(y_dist));
 327                 weight = SkMinScalar(sqDist, SK_Scalar1);
 328             }
 329
 330             SkScalar x_interp = SkScalarMul(weight, (fSrcRect.x() + x * inv_x_zoom)) +
 331                            (SK_Scalar1 - weight) * x;
 332             SkScalar y_interp = SkScalarMul(weight, (fSrcRect.y() + y * inv_y_zoom)) +
 333                            (SK_Scalar1 - weight) * y;
 334
 335             int x_val = SkMin32(SkScalarFloorToInt(x_interp), width - 1);
 336             int y_val = SkMin32(SkScalarFloorToInt(y_interp), height - 1);
 337
 338             *dptr = sptr[y_val * width + x_val];
 339             dptr++;
 340         }
 341     }
 342     return true;
 343 }