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 "GrInvariantOutput.h"
  18 #include "effects/GrSingleTextureEffect.h"
  19 #include "gl/GrGLProcessor.h"
  20 #include "gl/GrGLSL.h"
  21 #include "gl/GrGLTexture.h"
  22 #include "gl/builders/GrGLProgramBuilder.h"
  23
  24 class GrMagnifierEffect : public GrSingleTextureEffect {
  25
  26 public:
  27     static GrFragmentProcessor* Create(GrTexture* texture,
  28                                        float xOffset,
  29                                        float yOffset,
  30                                        float xInvZoom,
  31                                        float yInvZoom,
  32                                        float xInvInset,
  33                                        float yInvInset) {
  34         return SkNEW_ARGS(GrMagnifierEffect, (texture,
  35                                               xOffset,
  36                                               yOffset,
  37                                               xInvZoom,
  38                                               yInvZoom,
  39                                               xInvInset,
  40                                               yInvInset));
  41     }
  42
  43     virtual ~GrMagnifierEffect() {};
  44
  45     const char* name() const override { return "Magnifier"; }
  46
  47     void getGLProcessorKey(const GrGLCaps&, GrProcessorKeyBuilder*) const override;
  48
  49     GrGLFragmentProcessor* createGLInstance() const 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 private:
  59     GrMagnifierEffect(GrTexture* texture,
  60                       float xOffset,
  61                       float yOffset,
  62                       float xInvZoom,
  63                       float yInvZoom,
  64                       float xInvInset,
  65                       float yInvInset)
  66         : GrSingleTextureEffect(texture, GrCoordTransform::MakeDivByTextureWHMatrix(texture))
  67         , fXOffset(xOffset)
  68         , fYOffset(yOffset)
  69         , fXInvZoom(xInvZoom)
  70         , fYInvZoom(yInvZoom)
  71         , fXInvInset(xInvInset)
  72         , fYInvInset(yInvInset) {
  73         this->initClassID<GrMagnifierEffect>();
  74     }
  75
  76     bool onIsEqual(const GrFragmentProcessor&) const override;
  77
  78     void onComputeInvariantOutput(GrInvariantOutput* inout) const 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 GrProcessor&);
  98
  99     virtual void emitCode(GrGLFPBuilder*,
 100                           const GrFragmentProcessor&,
 101                           const char* outputColor,
 102                           const char* inputColor,
 103                           const TransformedCoordsArray&,
 104                           const TextureSamplerArray&) override;
 105
 106     void setData(const GrGLProgramDataManager&, const GrProcessor&) override;
 107
 108 private:
 109     UniformHandle       fOffsetVar;
 110     UniformHandle       fInvZoomVar;
 111     UniformHandle       fInvInsetVar;
 112
 113     typedef GrGLFragmentProcessor INHERITED;
 114 };
 115
 116 GrGLMagnifierEffect::GrGLMagnifierEffect(const GrProcessor&) {
 117 }
 118
 119 void GrGLMagnifierEffect::emitCode(GrGLFPBuilder* builder,
 120                                    const GrFragmentProcessor&,
 121                                    const char* outputColor,
 122                                    const char* inputColor,
 123                                    const TransformedCoordsArray& coords,
 124                                    const TextureSamplerArray& samplers) {
 125     fOffsetVar = builder->addUniform(
 126         GrGLProgramBuilder::kFragment_Visibility |
 127         GrGLProgramBuilder::kVertex_Visibility,
 128         kVec2f_GrSLType, kDefault_GrSLPrecision, "Offset");
 129     fInvZoomVar = builder->addUniform(
 130         GrGLProgramBuilder::kFragment_Visibility |
 131         GrGLProgramBuilder::kVertex_Visibility,
 132         kVec2f_GrSLType, kDefault_GrSLPrecision, "InvZoom");
 133     fInvInsetVar = builder->addUniform(
 134         GrGLProgramBuilder::kFragment_Visibility |
 135         GrGLProgramBuilder::kVertex_Visibility,
 136         kVec2f_GrSLType, kDefault_GrSLPrecision, "InvInset");
 137
 138     GrGLFPFragmentBuilder* fsBuilder = builder->getFragmentShaderBuilder();
 139     SkString coords2D = fsBuilder->ensureFSCoords2D(coords, 0);
 140     fsBuilder->codeAppendf("\t\tvec2 coord = %s;\n", coords2D.c_str());
 141     fsBuilder->codeAppendf("\t\tvec2 zoom_coord = %s + %s * %s;\n",
 142                            builder->getUniformCStr(fOffsetVar),
 143                            coords2D.c_str(),
 144                            builder->getUniformCStr(fInvZoomVar));
 145
 146     fsBuilder->codeAppend("\t\tvec2 delta = min(coord, vec2(1.0, 1.0) - coord);\n");
 147
 148     fsBuilder->codeAppendf("\t\tdelta = delta * %s;\n", builder->getUniformCStr(fInvInsetVar));
 149
 150     fsBuilder->codeAppend("\t\tfloat weight = 0.0;\n");
 151     fsBuilder->codeAppend("\t\tif (delta.s < 2.0 && delta.t < 2.0) {\n");
 152     fsBuilder->codeAppend("\t\t\tdelta = vec2(2.0, 2.0) - delta;\n");
 153     fsBuilder->codeAppend("\t\t\tfloat dist = length(delta);\n");
 154     fsBuilder->codeAppend("\t\t\tdist = max(2.0 - dist, 0.0);\n");
 155     fsBuilder->codeAppend("\t\t\tweight = min(dist * dist, 1.0);\n");
 156     fsBuilder->codeAppend("\t\t} else {\n");
 157     fsBuilder->codeAppend("\t\t\tvec2 delta_squared = delta * delta;\n");
 158     fsBuilder->codeAppend("\t\t\tweight = min(min(delta_squared.x, delta_squared.y), 1.0);\n");
 159     fsBuilder->codeAppend("\t\t}\n");
 160
 161     fsBuilder->codeAppend("\t\tvec2 mix_coord = mix(coord, zoom_coord, weight);\n");
 162     fsBuilder->codeAppend("\t\tvec4 output_color = ");
 163     fsBuilder->appendTextureLookup(samplers[0], "mix_coord");
 164     fsBuilder->codeAppend(";\n");
 165
 166     fsBuilder->codeAppendf("\t\t%s = output_color;", outputColor);
 167     SkString modulate;
 168     GrGLSLMulVarBy4f(&modulate, outputColor, inputColor);
 169     fsBuilder->codeAppend(modulate.c_str());
 170 }
 171
 172 void GrGLMagnifierEffect::setData(const GrGLProgramDataManager& pdman,
 173                                   const GrProcessor& effect) {
 174     const GrMagnifierEffect& zoom = effect.cast<GrMagnifierEffect>();
 175     pdman.set2f(fOffsetVar, zoom.x_offset(), zoom.y_offset());
 176     pdman.set2f(fInvZoomVar, zoom.x_inv_zoom(), zoom.y_inv_zoom());
 177     pdman.set2f(fInvInsetVar, zoom.x_inv_inset(), zoom.y_inv_inset());
 178 }
 179
 180 /////////////////////////////////////////////////////////////////////
 181
 182 void GrMagnifierEffect::getGLProcessorKey(const GrGLCaps& caps,
 183                                           GrProcessorKeyBuilder* b) const {
 184     GrGLMagnifierEffect::GenKey(*this, caps, b);
 185 }
 186
 187 GrGLFragmentProcessor* GrMagnifierEffect::createGLInstance() const {
 188     return SkNEW_ARGS(GrGLMagnifierEffect, (*this));
 189 }
 190
 191 GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrMagnifierEffect);
 192
 193 GrFragmentProcessor* GrMagnifierEffect::TestCreate(SkRandom* random,
 194                                                    GrContext* context,
 195                                                    const GrDrawTargetCaps&,
 196                                                    GrTexture** textures) {
 197     GrTexture* texture = textures[0];
 198     const int kMaxWidth = 200;
 199     const int kMaxHeight = 200;
 200     const int kMaxInset = 20;
 201     uint32_t width = random->nextULessThan(kMaxWidth);
 202     uint32_t height = random->nextULessThan(kMaxHeight);
 203     uint32_t x = random->nextULessThan(kMaxWidth - width);
 204     uint32_t y = random->nextULessThan(kMaxHeight - height);
 205     uint32_t inset = random->nextULessThan(kMaxInset);
 206
 207     GrFragmentProcessor* effect = GrMagnifierEffect::Create(
 208         texture,
 209         (float) width / texture->width(),
 210         (float) height / texture->height(),
 211         texture->width() / (float) x,
 212         texture->height() / (float) y,
 213         (float) inset / texture->width(),
 214         (float) inset / texture->height());
 215     SkASSERT(effect);
 216     return effect;
 217 }
 218
 219 ///////////////////////////////////////////////////////////////////////////////
 220
 221 bool GrMagnifierEffect::onIsEqual(const GrFragmentProcessor& sBase) const {
 222     const GrMagnifierEffect& s = sBase.cast<GrMagnifierEffect>();
 223     return (this->fXOffset == s.fXOffset &&
 224             this->fYOffset == s.fYOffset &&
 225             this->fXInvZoom == s.fXInvZoom &&
 226             this->fYInvZoom == s.fYInvZoom &&
 227             this->fXInvInset == s.fXInvInset &&
 228             this->fYInvInset == s.fYInvInset);
 229 }
 230
 231 void GrMagnifierEffect::onComputeInvariantOutput(GrInvariantOutput* inout) const {
 232     this->updateInvariantOutputForModulation(inout);
 233 }
 234
 235 #endif
 236
 237 ////////////////////////////////////////////////////////////////////////////////
 238
 239 SkImageFilter* SkMagnifierImageFilter::Create(const SkRect& srcRect, SkScalar inset,
 240                                               SkImageFilter* input) {
 241
 242     if (!SkScalarIsFinite(inset) || !SkIsValidRect(srcRect)) {
 243         return NULL;
 244     }
 245     // Negative numbers in src rect are not supported
 246     if (srcRect.fLeft < 0 || srcRect.fTop < 0) {
 247         return NULL;
 248     }
 249     return SkNEW_ARGS(SkMagnifierImageFilter, (srcRect, inset, input));
 250 }
 251
 252
 253 SkMagnifierImageFilter::SkMagnifierImageFilter(const SkRect& srcRect, SkScalar inset,
 254                                                SkImageFilter* input)
 255     : INHERITED(1, &input), fSrcRect(srcRect), fInset(inset) {
 256     SkASSERT(srcRect.x() >= 0 && srcRect.y() >= 0 && inset >= 0);
 257 }
 258
 259 #if SK_SUPPORT_GPU
 260 bool SkMagnifierImageFilter::asFragmentProcessor(GrFragmentProcessor** fp, GrTexture* texture,
 261                                                  const SkMatrix&, const SkIRect&) const {
 262     if (fp) {
 263         SkScalar yOffset = (texture->origin() == kTopLeft_GrSurfaceOrigin) ? fSrcRect.y() :
 264                            (texture->height() - (fSrcRect.y() + fSrcRect.height()));
 265         SkScalar invInset = fInset > 0 ? SkScalarInvert(fInset) : SK_Scalar1;
 266         *fp = GrMagnifierEffect::Create(texture,
 267                                         fSrcRect.x() / texture->width(),
 268                                         yOffset / texture->height(),
 269                                         fSrcRect.width() / texture->width(),
 270                                         fSrcRect.height() / texture->height(),
 271                                         texture->width() * invInset,
 272                                         texture->height() * invInset);
 273     }
 274     return true;
 275 }
 276 #endif
 277
 278 SkFlattenable* SkMagnifierImageFilter::CreateProc(SkReadBuffer& buffer) {
 279     SK_IMAGEFILTER_UNFLATTEN_COMMON(common, 1);
 280     SkRect src;
 281     buffer.readRect(&src);
 282     return Create(src, buffer.readScalar(), common.getInput(0));
 283 }
 284
 285 void SkMagnifierImageFilter::flatten(SkWriteBuffer& buffer) const {
 286     this->INHERITED::flatten(buffer);
 287     buffer.writeRect(fSrcRect);
 288     buffer.writeScalar(fInset);
 289 }
 290
 291 bool SkMagnifierImageFilter::onFilterImage(Proxy*, const SkBitmap& src,
 292                                            const Context&, SkBitmap* dst,
 293                                            SkIPoint* offset) const {
 294     if ((src.colorType() != kN32_SkColorType) ||
 295         (fSrcRect.width() >= src.width()) ||
 296         (fSrcRect.height() >= src.height())) {
 297       return false;
 298     }
 299
 300     SkAutoLockPixels alp(src);
 301     SkASSERT(src.getPixels());
 302     if (!src.getPixels() || src.width() <= 0 || src.height() <= 0) {
 303       return false;
 304     }
 305
 306     if (!dst->tryAllocPixels(src.info())) {
 307         return false;
 308     }
 309
 310     SkScalar inv_inset = fInset > 0 ? SkScalarInvert(fInset) : SK_Scalar1;
 311
 312     SkScalar inv_x_zoom = fSrcRect.width() / src.width();
 313     SkScalar inv_y_zoom = fSrcRect.height() / src.height();
 314
 315     SkColor* sptr = src.getAddr32(0, 0);
 316     SkColor* dptr = dst->getAddr32(0, 0);
 317     int width = src.width(), height = src.height();
 318     for (int y = 0; y < height; ++y) {
 319         for (int x = 0; x < width; ++x) {
 320             SkScalar x_dist = SkMin32(x, width - x - 1) * inv_inset;
 321             SkScalar y_dist = SkMin32(y, height - y - 1) * inv_inset;
 322             SkScalar weight = 0;
 323
 324             static const SkScalar kScalar2 = SkScalar(2);
 325
 326             // To create a smooth curve at the corners, we need to work on
 327             // a square twice the size of the inset.
 328             if (x_dist < kScalar2 && y_dist < kScalar2) {
 329                 x_dist = kScalar2 - x_dist;
 330                 y_dist = kScalar2 - y_dist;
 331
 332                 SkScalar dist = SkScalarSqrt(SkScalarSquare(x_dist) +
 333                                              SkScalarSquare(y_dist));
 334                 dist = SkMaxScalar(kScalar2 - dist, 0);
 335                 weight = SkMinScalar(SkScalarSquare(dist), SK_Scalar1);
 336             } else {
 337                 SkScalar sqDist = SkMinScalar(SkScalarSquare(x_dist),
 338                                               SkScalarSquare(y_dist));
 339                 weight = SkMinScalar(sqDist, SK_Scalar1);
 340             }
 341
 342             SkScalar x_interp = SkScalarMul(weight, (fSrcRect.x() + x * inv_x_zoom)) +
 343                            (SK_Scalar1 - weight) * x;
 344             SkScalar y_interp = SkScalarMul(weight, (fSrcRect.y() + y * inv_y_zoom)) +
 345                            (SK_Scalar1 - weight) * y;
 346
 347             int x_val = SkPin32(SkScalarFloorToInt(x_interp), 0, width - 1);
 348             int y_val = SkPin32(SkScalarFloorToInt(y_interp), 0, height - 1);
 349
 350             *dptr = sptr[y_val * width + x_val];
 351             dptr++;
 352         }
 353     }
 354     return true;
 355 }
 356
 357 #ifndef SK_IGNORE_TO_STRING
 358 void SkMagnifierImageFilter::toString(SkString* str) const {
 359     str->appendf("SkMagnifierImageFilter: (");
 360     str->appendf("src: (%f,%f,%f,%f) ",
 361                  fSrcRect.fLeft, fSrcRect.fTop, fSrcRect.fRight, fSrcRect.fBottom);
 362     str->appendf("inset: %f", fInset);
 363     str->append(")");
 364 }
 365 #endif