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 "SkReadBuffer.h"
  12 #include "SkWriteBuffer.h"
  13 #include "SkValidationUtils.h"
  14
  15 ////////////////////////////////////////////////////////////////////////////////
  16 #if SK_SUPPORT_GPU
  17 #include "effects/GrSingleTextureEffect.h"
  18 #include "gl/GrGLProcessor.h"
  19 #include "gl/builders/GrGLProgramBuilder.h"
  20 #include "gl/GrGLSL.h"
  21 #include "gl/GrGLTexture.h"
  22 #include "GrInvariantOutput.h"
  23 #include "GrTBackendProcessorFactory.h"
  24
  25 class GrGLMagnifierEffect;
  26
  27 class GrMagnifierEffect : public GrSingleTextureEffect {
  28
  29 public:
  30     static GrFragmentProcessor* Create(GrTexture* texture,
  31                                        float xOffset,
  32                                        float yOffset,
  33                                        float xInvZoom,
  34                                        float yInvZoom,
  35                                        float xInvInset,
  36                                        float yInvInset) {
  37         return SkNEW_ARGS(GrMagnifierEffect, (texture,
  38                                               xOffset,
  39                                               yOffset,
  40                                               xInvZoom,
  41                                               yInvZoom,
  42                                               xInvInset,
  43                                               yInvInset));
  44     }
  45
  46     virtual ~GrMagnifierEffect() {};
  47
  48     static const char* Name() { return "Magnifier"; }
  49
  50     virtual const GrBackendFragmentProcessorFactory& getFactory() const SK_OVERRIDE;
  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 GLProcessor;
  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, GrCoordTransform::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 GrFragmentProcessor&) const SK_OVERRIDE;
  77
  78     virtual void onComputeInvariantOutput(GrInvariantOutput* inout) const SK_OVERRIDE;
  79
  80     GR_DECLARE_FRAGMENT_PROCESSOR_TEST;
  81
  82     float fXOffset;
  83     float fYOffset;
  84     float fXInvZoom;
  85     float fYInvZoom;
  86     float fXInvInset;
  87     float fYInvInset;
  88
  89     typedef GrSingleTextureEffect INHERITED;
  90 };
  91
  92 // For brevity
  93 typedef GrGLProgramDataManager::UniformHandle UniformHandle;
  94
  95 class GrGLMagnifierEffect : public GrGLFragmentProcessor {
  96 public:
  97     GrGLMagnifierEffect(const GrBackendProcessorFactory&, const GrProcessor&);
  98
  99     virtual void emitCode(GrGLFPBuilder*,
 100                           const GrFragmentProcessor&,
 101                           const char* outputColor,
 102                           const char* inputColor,
 103                           const TransformedCoordsArray&,
 104                           const TextureSamplerArray&) SK_OVERRIDE;
 105
 106     virtual void setData(const GrGLProgramDataManager&, const GrProcessor&) SK_OVERRIDE;
 107
 108 private:
 109     UniformHandle       fOffsetVar;
 110     UniformHandle       fInvZoomVar;
 111     UniformHandle       fInvInsetVar;
 112
 113     typedef GrGLFragmentProcessor INHERITED;
 114 };
 115
 116 GrGLMagnifierEffect::GrGLMagnifierEffect(const GrBackendProcessorFactory& factory,
 117                                          const GrProcessor&)
 118     : INHERITED(factory) {
 119 }
 120
 121 void GrGLMagnifierEffect::emitCode(GrGLFPBuilder* builder,
 122                                    const GrFragmentProcessor&,
 123                                    const char* outputColor,
 124                                    const char* inputColor,
 125                                    const TransformedCoordsArray& coords,
 126                                    const TextureSamplerArray& samplers) {
 127     fOffsetVar = builder->addUniform(
 128         GrGLProgramBuilder::kFragment_Visibility |
 129         GrGLProgramBuilder::kVertex_Visibility,
 130         kVec2f_GrSLType, "Offset");
 131     fInvZoomVar = builder->addUniform(
 132         GrGLProgramBuilder::kFragment_Visibility |
 133         GrGLProgramBuilder::kVertex_Visibility,
 134         kVec2f_GrSLType, "InvZoom");
 135     fInvInsetVar = builder->addUniform(
 136         GrGLProgramBuilder::kFragment_Visibility |
 137         GrGLProgramBuilder::kVertex_Visibility,
 138         kVec2f_GrSLType, "InvInset");
 139
 140     GrGLFPFragmentBuilder* fsBuilder = builder->getFragmentShaderBuilder();
 141     SkString coords2D = fsBuilder->ensureFSCoords2D(coords, 0);
 142     fsBuilder->codeAppendf("\t\tvec2 coord = %s;\n", coords2D.c_str());
 143     fsBuilder->codeAppendf("\t\tvec2 zoom_coord = %s + %s * %s;\n",
 144                            builder->getUniformCStr(fOffsetVar),
 145                            coords2D.c_str(),
 146                            builder->getUniformCStr(fInvZoomVar));
 147
 148     fsBuilder->codeAppend("\t\tvec2 delta = min(coord, vec2(1.0, 1.0) - coord);\n");
 149
 150     fsBuilder->codeAppendf("\t\tdelta = delta * %s;\n", builder->getUniformCStr(fInvInsetVar));
 151
 152     fsBuilder->codeAppend("\t\tfloat weight = 0.0;\n");
 153     fsBuilder->codeAppend("\t\tif (delta.s < 2.0 && delta.t < 2.0) {\n");
 154     fsBuilder->codeAppend("\t\t\tdelta = vec2(2.0, 2.0) - delta;\n");
 155     fsBuilder->codeAppend("\t\t\tfloat dist = length(delta);\n");
 156     fsBuilder->codeAppend("\t\t\tdist = max(2.0 - dist, 0.0);\n");
 157     fsBuilder->codeAppend("\t\t\tweight = min(dist * dist, 1.0);\n");
 158     fsBuilder->codeAppend("\t\t} else {\n");
 159     fsBuilder->codeAppend("\t\t\tvec2 delta_squared = delta * delta;\n");
 160     fsBuilder->codeAppend("\t\t\tweight = min(min(delta_squared.x, delta_squared.y), 1.0);\n");
 161     fsBuilder->codeAppend("\t\t}\n");
 162
 163     fsBuilder->codeAppend("\t\tvec2 mix_coord = mix(coord, zoom_coord, weight);\n");
 164     fsBuilder->codeAppend("\t\tvec4 output_color = ");
 165     fsBuilder->appendTextureLookup(samplers[0], "mix_coord");
 166     fsBuilder->codeAppend(";\n");
 167
 168     fsBuilder->codeAppendf("\t\t%s = output_color;", outputColor);
 169     SkString modulate;
 170     GrGLSLMulVarBy4f(&modulate, outputColor, inputColor);
 171     fsBuilder->codeAppend(modulate.c_str());
 172 }
 173
 174 void GrGLMagnifierEffect::setData(const GrGLProgramDataManager& pdman,
 175                                   const GrProcessor& effect) {
 176     const GrMagnifierEffect& zoom = effect.cast<GrMagnifierEffect>();
 177     pdman.set2f(fOffsetVar, zoom.x_offset(), zoom.y_offset());
 178     pdman.set2f(fInvZoomVar, zoom.x_inv_zoom(), zoom.y_inv_zoom());
 179     pdman.set2f(fInvInsetVar, zoom.x_inv_inset(), zoom.y_inv_inset());
 180 }
 181
 182 /////////////////////////////////////////////////////////////////////
 183
 184 GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrMagnifierEffect);
 185
 186 GrFragmentProcessor* GrMagnifierEffect::TestCreate(SkRandom* random,
 187                                                    GrContext* context,
 188                                                    const GrDrawTargetCaps&,
 189                                                    GrTexture** textures) {
 190     GrTexture* texture = textures[0];
 191     const int kMaxWidth = 200;
 192     const int kMaxHeight = 200;
 193     const int kMaxInset = 20;
 194     uint32_t width = random->nextULessThan(kMaxWidth);
 195     uint32_t height = random->nextULessThan(kMaxHeight);
 196     uint32_t x = random->nextULessThan(kMaxWidth - width);
 197     uint32_t y = random->nextULessThan(kMaxHeight - height);
 198     uint32_t inset = random->nextULessThan(kMaxInset);
 199
 200     GrFragmentProcessor* effect = GrMagnifierEffect::Create(
 201         texture,
 202         (float) width / texture->width(),
 203         (float) height / texture->height(),
 204         texture->width() / (float) x,
 205         texture->height() / (float) y,
 206         (float) inset / texture->width(),
 207         (float) inset / texture->height());
 208     SkASSERT(effect);
 209     return effect;
 210 }
 211
 212 ///////////////////////////////////////////////////////////////////////////////
 213
 214 const GrBackendFragmentProcessorFactory& GrMagnifierEffect::getFactory() const {
 215     return GrTBackendFragmentProcessorFactory<GrMagnifierEffect>::getInstance();
 216 }
 217
 218 bool GrMagnifierEffect::onIsEqual(const GrFragmentProcessor& sBase) const {
 219     const GrMagnifierEffect& s = sBase.cast<GrMagnifierEffect>();
 220     return (this->fXOffset == s.fXOffset &&
 221             this->fYOffset == s.fYOffset &&
 222             this->fXInvZoom == s.fXInvZoom &&
 223             this->fYInvZoom == s.fYInvZoom &&
 224             this->fXInvInset == s.fXInvInset &&
 225             this->fYInvInset == s.fYInvInset);
 226 }
 227
 228 void GrMagnifierEffect::onComputeInvariantOutput(GrInvariantOutput* inout) const {
 229     this->updateInvariantOutputForModulation(inout);
 230 }
 231
 232 #endif
 233
 234 ////////////////////////////////////////////////////////////////////////////////
 235
 236 SkImageFilter* SkMagnifierImageFilter::Create(const SkRect& srcRect, SkScalar inset,
 237                                               SkImageFilter* input) {
 238
 239     if (!SkScalarIsFinite(inset) || !SkIsValidRect(srcRect)) {
 240         return NULL;
 241     }
 242     // Negative numbers in src rect are not supported
 243     if (srcRect.fLeft < 0 || srcRect.fTop < 0) {
 244         return NULL;
 245     }
 246     return SkNEW_ARGS(SkMagnifierImageFilter, (srcRect, inset, input));
 247 }
 248
 249
 250 SkMagnifierImageFilter::SkMagnifierImageFilter(const SkRect& srcRect, SkScalar inset,
 251                                                SkImageFilter* input)
 252     : INHERITED(1, &input), fSrcRect(srcRect), fInset(inset) {
 253     SkASSERT(srcRect.x() >= 0 && srcRect.y() >= 0 && inset >= 0);
 254 }
 255
 256 #if SK_SUPPORT_GPU
 257 bool SkMagnifierImageFilter::asFragmentProcessor(GrFragmentProcessor** fp, GrTexture* texture,
 258                                                  const SkMatrix&, const SkIRect&) const {
 259     if (fp) {
 260         SkScalar yOffset = (texture->origin() == kTopLeft_GrSurfaceOrigin) ? fSrcRect.y() :
 261                            (texture->height() - (fSrcRect.y() + fSrcRect.height()));
 262         SkScalar invInset = fInset > 0 ? SkScalarInvert(fInset) : SK_Scalar1;
 263         *fp = GrMagnifierEffect::Create(texture,
 264                                         fSrcRect.x() / texture->width(),
 265                                         yOffset / texture->height(),
 266                                         fSrcRect.width() / texture->width(),
 267                                         fSrcRect.height() / texture->height(),
 268                                         texture->width() * invInset,
 269                                         texture->height() * invInset);
 270     }
 271     return true;
 272 }
 273 #endif
 274
 275 SkFlattenable* SkMagnifierImageFilter::CreateProc(SkReadBuffer& buffer) {
 276     SK_IMAGEFILTER_UNFLATTEN_COMMON(common, 1);
 277     SkRect src;
 278     buffer.readRect(&src);
 279     return Create(src, buffer.readScalar(), common.getInput(0));
 280 }
 281
 282 void SkMagnifierImageFilter::flatten(SkWriteBuffer& buffer) const {
 283     this->INHERITED::flatten(buffer);
 284     buffer.writeRect(fSrcRect);
 285     buffer.writeScalar(fInset);
 286 }
 287
 288 bool SkMagnifierImageFilter::onFilterImage(Proxy*, const SkBitmap& src,
 289                                            const Context&, SkBitmap* dst,
 290                                            SkIPoint* offset) const {
 291     SkASSERT(src.colorType() == kN32_SkColorType);
 292     SkASSERT(fSrcRect.width() < src.width());
 293     SkASSERT(fSrcRect.height() < src.height());
 294
 295     if ((src.colorType() != kN32_SkColorType) ||
 296         (fSrcRect.width() >= src.width()) ||
 297         (fSrcRect.height() >= src.height())) {
 298       return false;
 299     }
 300
 301     SkAutoLockPixels alp(src);
 302     SkASSERT(src.getPixels());
 303     if (!src.getPixels() || src.width() <= 0 || src.height() <= 0) {
 304       return false;
 305     }
 306
 307     if (!dst->tryAllocPixels(src.info())) {
 308         return false;
 309     }
 310
 311     SkScalar inv_inset = fInset > 0 ? SkScalarInvert(fInset) : SK_Scalar1;
 312
 313     SkScalar inv_x_zoom = fSrcRect.width() / src.width();
 314     SkScalar inv_y_zoom = fSrcRect.height() / src.height();
 315
 316     SkColor* sptr = src.getAddr32(0, 0);
 317     SkColor* dptr = dst->getAddr32(0, 0);
 318     int width = src.width(), height = src.height();
 319     for (int y = 0; y < height; ++y) {
 320         for (int x = 0; x < width; ++x) {
 321             SkScalar x_dist = SkMin32(x, width - x - 1) * inv_inset;
 322             SkScalar y_dist = SkMin32(y, height - y - 1) * inv_inset;
 323             SkScalar weight = 0;
 324
 325             static const SkScalar kScalar2 = SkScalar(2);
 326
 327             // To create a smooth curve at the corners, we need to work on
 328             // a square twice the size of the inset.
 329             if (x_dist < kScalar2 && y_dist < kScalar2) {
 330                 x_dist = kScalar2 - x_dist;
 331                 y_dist = kScalar2 - y_dist;
 332
 333                 SkScalar dist = SkScalarSqrt(SkScalarSquare(x_dist) +
 334                                              SkScalarSquare(y_dist));
 335                 dist = SkMaxScalar(kScalar2 - dist, 0);
 336                 weight = SkMinScalar(SkScalarSquare(dist), SK_Scalar1);
 337             } else {
 338                 SkScalar sqDist = SkMinScalar(SkScalarSquare(x_dist),
 339                                               SkScalarSquare(y_dist));
 340                 weight = SkMinScalar(sqDist, SK_Scalar1);
 341             }
 342
 343             SkScalar x_interp = SkScalarMul(weight, (fSrcRect.x() + x * inv_x_zoom)) +
 344                            (SK_Scalar1 - weight) * x;
 345             SkScalar y_interp = SkScalarMul(weight, (fSrcRect.y() + y * inv_y_zoom)) +
 346                            (SK_Scalar1 - weight) * y;
 347
 348             int x_val = SkPin32(SkScalarFloorToInt(x_interp), 0, width - 1);
 349             int y_val = SkPin32(SkScalarFloorToInt(y_interp), 0, height - 1);
 350
 351             *dptr = sptr[y_val * width + x_val];
 352             dptr++;
 353         }
 354     }
 355     return true;
 356 }