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/GrGLFragmentProcessor.h"
  20 #include "gl/GrGLTexture.h"
  21 #include "gl/builders/GrGLProgramBuilder.h"
  22
  23 class GrMagnifierEffect : public GrSingleTextureEffect {
  24
  25 public:
  26     static GrFragmentProcessor* Create(GrProcessorDataManager* procDataManager,
  27                                        GrTexture* texture,
  28                                        const SkRect& bounds,
  29                                        float xOffset,
  30                                        float yOffset,
  31                                        float xInvZoom,
  32                                        float yInvZoom,
  33                                        float xInvInset,
  34                                        float yInvInset) {
  35         return new GrMagnifierEffect(procDataManager, texture, bounds, xOffset, yOffset, xInvZoom,
  36                                      yInvZoom, xInvInset, yInvInset);
  37     }
  38
  39     virtual ~GrMagnifierEffect() {};
  40
  41     const char* name() const override { return "Magnifier"; }
  42
  43     const SkRect& bounds() const { return fBounds; }    // Bounds of source image.
  44     // Offset to apply to zoomed pixels, (srcRect position / texture size).
  45     float x_offset() const { return fXOffset; }
  46     float y_offset() const { return fYOffset; }
  47
  48     // Scale to apply to zoomed pixels (srcRect size / bounds size).
  49     float x_inv_zoom() const { return fXInvZoom; }
  50     float y_inv_zoom() const { return fYInvZoom; }
  51
  52     // 1/radius over which to transition from unzoomed to zoomed pixels (bounds size / inset).
  53     float x_inv_inset() const { return fXInvInset; }
  54     float y_inv_inset() const { return fYInvInset; }
  55
  56 private:
  57     GrMagnifierEffect(GrProcessorDataManager* procDataManager,
  58                       GrTexture* texture,
  59                       const SkRect& bounds,
  60                       float xOffset,
  61                       float yOffset,
  62                       float xInvZoom,
  63                       float yInvZoom,
  64                       float xInvInset,
  65                       float yInvInset)
  66         : INHERITED(procDataManager, texture, GrCoordTransform::MakeDivByTextureWHMatrix(texture))
  67         , fBounds(bounds)
  68         , fXOffset(xOffset)
  69         , fYOffset(yOffset)
  70         , fXInvZoom(xInvZoom)
  71         , fYInvZoom(yInvZoom)
  72         , fXInvInset(xInvInset)
  73         , fYInvInset(yInvInset) {
  74         this->initClassID<GrMagnifierEffect>();
  75     }
  76
  77     GrGLFragmentProcessor* onCreateGLInstance() const override;
  78
  79     void onGetGLProcessorKey(const GrGLSLCaps&, GrProcessorKeyBuilder*) const override;
  80
  81     bool onIsEqual(const GrFragmentProcessor&) const override;
  82
  83     void onComputeInvariantOutput(GrInvariantOutput* inout) const override;
  84
  85     GR_DECLARE_FRAGMENT_PROCESSOR_TEST;
  86
  87     SkRect fBounds;
  88     float fXOffset;
  89     float fYOffset;
  90     float fXInvZoom;
  91     float fYInvZoom;
  92     float fXInvInset;
  93     float fYInvInset;
  94
  95     typedef GrSingleTextureEffect INHERITED;
  96 };
  97
  98 // For brevity
  99 typedef GrGLProgramDataManager::UniformHandle UniformHandle;
 100
 101 class GrGLMagnifierEffect : public GrGLFragmentProcessor {
 102 public:
 103     GrGLMagnifierEffect(const GrProcessor&);
 104
 105     virtual void emitCode(EmitArgs&) override;
 106
 107 protected:
 108     void onSetData(const GrGLProgramDataManager&, const GrProcessor&) override;
 109
 110 private:
 111     UniformHandle       fOffsetVar;
 112     UniformHandle       fInvZoomVar;
 113     UniformHandle       fInvInsetVar;
 114     UniformHandle       fBoundsVar;
 115
 116     typedef GrGLFragmentProcessor INHERITED;
 117 };
 118
 119 GrGLMagnifierEffect::GrGLMagnifierEffect(const GrProcessor&) {
 120 }
 121
 122 void GrGLMagnifierEffect::emitCode(EmitArgs& args) {
 123     fOffsetVar = args.fBuilder->addUniform(
 124         GrGLProgramBuilder::kFragment_Visibility |
 125         GrGLProgramBuilder::kVertex_Visibility,
 126         kVec2f_GrSLType, kDefault_GrSLPrecision, "Offset");
 127     fInvZoomVar = args.fBuilder->addUniform(
 128         GrGLProgramBuilder::kFragment_Visibility |
 129         GrGLProgramBuilder::kVertex_Visibility,
 130         kVec2f_GrSLType, kDefault_GrSLPrecision, "InvZoom");
 131     fInvInsetVar = args.fBuilder->addUniform(
 132         GrGLProgramBuilder::kFragment_Visibility |
 133         GrGLProgramBuilder::kVertex_Visibility,
 134         kVec2f_GrSLType, kDefault_GrSLPrecision, "InvInset");
 135     fBoundsVar = args.fBuilder->addUniform(
 136         GrGLProgramBuilder::kFragment_Visibility |
 137         GrGLProgramBuilder::kVertex_Visibility,
 138         kVec4f_GrSLType, kDefault_GrSLPrecision, "Bounds");
 139
 140     GrGLFragmentBuilder* fsBuilder = args.fBuilder->getFragmentShaderBuilder();
 141     SkString coords2D = fsBuilder->ensureFSCoords2D(args.fCoords, 0);
 142     fsBuilder->codeAppendf("\t\tvec2 coord = %s;\n", coords2D.c_str());
 143     fsBuilder->codeAppendf("\t\tvec2 zoom_coord = %s + %s * %s;\n",
 144                            args.fBuilder->getUniformCStr(fOffsetVar),
 145                            coords2D.c_str(),
 146                            args.fBuilder->getUniformCStr(fInvZoomVar));
 147     const char* bounds = args.fBuilder->getUniformCStr(fBoundsVar);
 148     fsBuilder->codeAppendf("\t\tvec2 delta = (coord - %s.xy) * %s.zw;\n", bounds, bounds);
 149     fsBuilder->codeAppendf("\t\tdelta = min(delta, vec2(1.0, 1.0) - delta);\n");
 150     fsBuilder->codeAppendf("\t\tdelta = delta * %s;\n",
 151                            args.fBuilder->getUniformCStr(fInvInsetVar));
 152
 153     fsBuilder->codeAppend("\t\tfloat weight = 0.0;\n");
 154     fsBuilder->codeAppend("\t\tif (delta.s < 2.0 && delta.t < 2.0) {\n");
 155     fsBuilder->codeAppend("\t\t\tdelta = vec2(2.0, 2.0) - delta;\n");
 156     fsBuilder->codeAppend("\t\t\tfloat dist = length(delta);\n");
 157     fsBuilder->codeAppend("\t\t\tdist = max(2.0 - dist, 0.0);\n");
 158     fsBuilder->codeAppend("\t\t\tweight = min(dist * dist, 1.0);\n");
 159     fsBuilder->codeAppend("\t\t} else {\n");
 160     fsBuilder->codeAppend("\t\t\tvec2 delta_squared = delta * delta;\n");
 161     fsBuilder->codeAppend("\t\t\tweight = min(min(delta_squared.x, delta_squared.y), 1.0);\n");
 162     fsBuilder->codeAppend("\t\t}\n");
 163
 164     fsBuilder->codeAppend("\t\tvec2 mix_coord = mix(coord, zoom_coord, weight);\n");
 165     fsBuilder->codeAppend("\t\tvec4 output_color = ");
 166     fsBuilder->appendTextureLookup(args.fSamplers[0], "mix_coord");
 167     fsBuilder->codeAppend(";\n");
 168
 169     fsBuilder->codeAppendf("\t\t%s = output_color;", args.fOutputColor);
 170     SkString modulate;
 171     GrGLSLMulVarBy4f(&modulate, args.fOutputColor, args.fInputColor);
 172     fsBuilder->codeAppend(modulate.c_str());
 173 }
 174
 175 void GrGLMagnifierEffect::onSetData(const GrGLProgramDataManager& pdman,
 176                                   const GrProcessor& effect) {
 177     const GrMagnifierEffect& zoom = effect.cast<GrMagnifierEffect>();
 178     pdman.set2f(fOffsetVar, zoom.x_offset(), zoom.y_offset());
 179     pdman.set2f(fInvZoomVar, zoom.x_inv_zoom(), zoom.y_inv_zoom());
 180     pdman.set2f(fInvInsetVar, zoom.x_inv_inset(), zoom.y_inv_inset());
 181     pdman.set4f(fBoundsVar, zoom.bounds().x(), zoom.bounds().y(),
 182                             zoom.bounds().width(), zoom.bounds().height());
 183 }
 184
 185 /////////////////////////////////////////////////////////////////////
 186
 187 void GrMagnifierEffect::onGetGLProcessorKey(const GrGLSLCaps& caps,
 188                                           GrProcessorKeyBuilder* b) const {
 189     GrGLMagnifierEffect::GenKey(*this, caps, b);
 190 }
 191
 192 GrGLFragmentProcessor* GrMagnifierEffect::onCreateGLInstance() const {
 193     return new GrGLMagnifierEffect(*this);
 194 }
 195
 196 GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrMagnifierEffect);
 197
 198 GrFragmentProcessor* GrMagnifierEffect::TestCreate(GrProcessorTestData* d) {
 199     GrTexture* texture = d->fTextures[0];
 200     const int kMaxWidth = 200;
 201     const int kMaxHeight = 200;
 202     const int kMaxInset = 20;
 203     uint32_t width = d->fRandom->nextULessThan(kMaxWidth);
 204     uint32_t height = d->fRandom->nextULessThan(kMaxHeight);
 205     uint32_t x = d->fRandom->nextULessThan(kMaxWidth - width);
 206     uint32_t y = d->fRandom->nextULessThan(kMaxHeight - height);
 207     uint32_t inset = d->fRandom->nextULessThan(kMaxInset);
 208
 209     GrFragmentProcessor* effect = GrMagnifierEffect::Create(
 210         d->fProcDataManager,
 211         texture,
 212         SkRect::MakeWH(SkIntToScalar(kMaxWidth), SkIntToScalar(kMaxHeight)),
 213         (float) width / texture->width(),
 214         (float) height / texture->height(),
 215         texture->width() / (float) x,
 216         texture->height() / (float) y,
 217         (float) inset / texture->width(),
 218         (float) inset / texture->height());
 219     SkASSERT(effect);
 220     return effect;
 221 }
 222
 223 ///////////////////////////////////////////////////////////////////////////////
 224
 225 bool GrMagnifierEffect::onIsEqual(const GrFragmentProcessor& sBase) const {
 226     const GrMagnifierEffect& s = sBase.cast<GrMagnifierEffect>();
 227     return (this->fBounds == s.fBounds &&
 228             this->fXOffset == s.fXOffset &&
 229             this->fYOffset == s.fYOffset &&
 230             this->fXInvZoom == s.fXInvZoom &&
 231             this->fYInvZoom == s.fYInvZoom &&
 232             this->fXInvInset == s.fXInvInset &&
 233             this->fYInvInset == s.fYInvInset);
 234 }
 235
 236 void GrMagnifierEffect::onComputeInvariantOutput(GrInvariantOutput* inout) const {
 237     this->updateInvariantOutputForModulation(inout);
 238 }
 239
 240 #endif
 241
 242 ////////////////////////////////////////////////////////////////////////////////
 243
 244 SkImageFilter* SkMagnifierImageFilter::Create(const SkRect& srcRect, SkScalar inset,
 245                                               SkImageFilter* input) {
 246
 247     if (!SkScalarIsFinite(inset) || !SkIsValidRect(srcRect)) {
 248         return NULL;
 249     }
 250     // Negative numbers in src rect are not supported
 251     if (srcRect.fLeft < 0 || srcRect.fTop < 0) {
 252         return NULL;
 253     }
 254     return new SkMagnifierImageFilter(srcRect, inset, input);
 255 }
 256
 257
 258 SkMagnifierImageFilter::SkMagnifierImageFilter(const SkRect& srcRect, SkScalar inset,
 259                                                SkImageFilter* input)
 260     : INHERITED(1, &input), fSrcRect(srcRect), fInset(inset) {
 261     SkASSERT(srcRect.x() >= 0 && srcRect.y() >= 0 && inset >= 0);
 262 }
 263
 264 #if SK_SUPPORT_GPU
 265 bool SkMagnifierImageFilter::asFragmentProcessor(GrFragmentProcessor** fp,
 266                                                  GrProcessorDataManager* procDataManager,
 267                                                  GrTexture* texture, const SkMatrix&,
 268                                                  const SkIRect&bounds) const {
 269     if (fp) {
 270         SkScalar yOffset = texture->origin() == kTopLeft_GrSurfaceOrigin ? fSrcRect.y() :
 271            texture->height() - fSrcRect.height() * texture->height() / bounds.height()
 272                              - fSrcRect.y();
 273         int boundsY = (texture->origin() == kTopLeft_GrSurfaceOrigin) ? bounds.y() :
 274                       (texture->height() - bounds.height());
 275         SkRect effectBounds = SkRect::MakeXYWH(
 276             SkIntToScalar(bounds.x()) / texture->width(),
 277             SkIntToScalar(boundsY) / texture->height(),
 278             SkIntToScalar(texture->width()) / bounds.width(),
 279             SkIntToScalar(texture->height()) / bounds.height());
 280         SkScalar invInset = fInset > 0 ? SkScalarInvert(fInset) : SK_Scalar1;
 281         *fp = GrMagnifierEffect::Create(procDataManager,
 282                                         texture,
 283                                         effectBounds,
 284                                         fSrcRect.x() / texture->width(),
 285                                         yOffset / texture->height(),
 286                                         fSrcRect.width() / bounds.width(),
 287                                         fSrcRect.height() / bounds.height(),
 288                                         bounds.width() * invInset,
 289                                         bounds.height() * invInset);
 290     }
 291     return true;
 292 }
 293 #endif
 294
 295 SkFlattenable* SkMagnifierImageFilter::CreateProc(SkReadBuffer& buffer) {
 296     SK_IMAGEFILTER_UNFLATTEN_COMMON(common, 1);
 297     SkRect src;
 298     buffer.readRect(&src);
 299     return Create(src, buffer.readScalar(), common.getInput(0));
 300 }
 301
 302 void SkMagnifierImageFilter::flatten(SkWriteBuffer& buffer) const {
 303     this->INHERITED::flatten(buffer);
 304     buffer.writeRect(fSrcRect);
 305     buffer.writeScalar(fInset);
 306 }
 307
 308 bool SkMagnifierImageFilter::onFilterImage(Proxy*, const SkBitmap& src,
 309                                            const Context&, SkBitmap* dst,
 310                                            SkIPoint* offset) const {
 311     if ((src.colorType() != kN32_SkColorType) ||
 312         (fSrcRect.width() >= src.width()) ||
 313         (fSrcRect.height() >= src.height())) {
 314       return false;
 315     }
 316
 317     SkAutoLockPixels alp(src);
 318     SkASSERT(src.getPixels());
 319     if (!src.getPixels() || src.width() <= 0 || src.height() <= 0) {
 320       return false;
 321     }
 322
 323     if (!dst->tryAllocPixels(src.info())) {
 324         return false;
 325     }
 326
 327     SkScalar inv_inset = fInset > 0 ? SkScalarInvert(fInset) : SK_Scalar1;
 328
 329     SkScalar inv_x_zoom = fSrcRect.width() / src.width();
 330     SkScalar inv_y_zoom = fSrcRect.height() / src.height();
 331
 332     SkColor* sptr = src.getAddr32(0, 0);
 333     SkColor* dptr = dst->getAddr32(0, 0);
 334     int width = src.width(), height = src.height();
 335     for (int y = 0; y < height; ++y) {
 336         for (int x = 0; x < width; ++x) {
 337             SkScalar x_dist = SkMin32(x, width - x - 1) * inv_inset;
 338             SkScalar y_dist = SkMin32(y, height - y - 1) * inv_inset;
 339             SkScalar weight = 0;
 340
 341             static const SkScalar kScalar2 = SkScalar(2);
 342
 343             // To create a smooth curve at the corners, we need to work on
 344             // a square twice the size of the inset.
 345             if (x_dist < kScalar2 && y_dist < kScalar2) {
 346                 x_dist = kScalar2 - x_dist;
 347                 y_dist = kScalar2 - y_dist;
 348
 349                 SkScalar dist = SkScalarSqrt(SkScalarSquare(x_dist) +
 350                                              SkScalarSquare(y_dist));
 351                 dist = SkMaxScalar(kScalar2 - dist, 0);
 352                 weight = SkMinScalar(SkScalarSquare(dist), SK_Scalar1);
 353             } else {
 354                 SkScalar sqDist = SkMinScalar(SkScalarSquare(x_dist),
 355                                               SkScalarSquare(y_dist));
 356                 weight = SkMinScalar(sqDist, SK_Scalar1);
 357             }
 358
 359             SkScalar x_interp = SkScalarMul(weight, (fSrcRect.x() + x * inv_x_zoom)) +
 360                            (SK_Scalar1 - weight) * x;
 361             SkScalar y_interp = SkScalarMul(weight, (fSrcRect.y() + y * inv_y_zoom)) +
 362                            (SK_Scalar1 - weight) * y;
 363
 364             int x_val = SkPin32(SkScalarFloorToInt(x_interp), 0, width - 1);
 365             int y_val = SkPin32(SkScalarFloorToInt(y_interp), 0, height - 1);
 366
 367             *dptr = sptr[y_val * width + x_val];
 368             dptr++;
 369         }
 370     }
 371     return true;
 372 }
 373
 374 #ifndef SK_IGNORE_TO_STRING
 375 void SkMagnifierImageFilter::toString(SkString* str) const {
 376     str->appendf("SkMagnifierImageFilter: (");
 377     str->appendf("src: (%f,%f,%f,%f) ",
 378                  fSrcRect.fLeft, fSrcRect.fTop, fSrcRect.fRight, fSrcRect.fBottom);
 379     str->appendf("inset: %f", fInset);
 380     str->append(")");
 381 }
 382 #endif