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/GrGLTexture.h"
  21 #include "gl/builders/GrGLProgramBuilder.h"
  22
  23 class GrMagnifierEffect : public GrSingleTextureEffect {
  24
  25 public:
  26     static GrFragmentProcessor* Create(GrTexture* texture,
  27                                        const SkRect& bounds,
  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                                               bounds,
  36                                               xOffset,
  37                                               yOffset,
  38                                               xInvZoom,
  39                                               yInvZoom,
  40                                               xInvInset,
  41                                               yInvInset));
  42     }
  43
  44     virtual ~GrMagnifierEffect() {};
  45
  46     const char* name() const override { return "Magnifier"; }
  47
  48     void getGLProcessorKey(const GrGLSLCaps&, GrProcessorKeyBuilder*) const override;
  49
  50     GrGLFragmentProcessor* createGLInstance() const override;
  51
  52     const SkRect& bounds() const { return fBounds; }    // Bounds of source image.
  53     // Offset to apply to zoomed pixels, (srcRect position / texture size).
  54     float x_offset() const { return fXOffset; }
  55     float y_offset() const { return fYOffset; }
  56
  57     // Scale to apply to zoomed pixels (srcRect size / bounds size).
  58     float x_inv_zoom() const { return fXInvZoom; }
  59     float y_inv_zoom() const { return fYInvZoom; }
  60
  61     // 1/radius over which to transition from unzoomed to zoomed pixels (bounds size / inset).
  62     float x_inv_inset() const { return fXInvInset; }
  63     float y_inv_inset() const { return fYInvInset; }
  64
  65 private:
  66     GrMagnifierEffect(GrTexture* texture,
  67                       const SkRect& bounds,
  68                       float xOffset,
  69                       float yOffset,
  70                       float xInvZoom,
  71                       float yInvZoom,
  72                       float xInvInset,
  73                       float yInvInset)
  74         : GrSingleTextureEffect(texture, GrCoordTransform::MakeDivByTextureWHMatrix(texture))
  75         , fBounds(bounds)
  76         , fXOffset(xOffset)
  77         , fYOffset(yOffset)
  78         , fXInvZoom(xInvZoom)
  79         , fYInvZoom(yInvZoom)
  80         , fXInvInset(xInvInset)
  81         , fYInvInset(yInvInset) {
  82         this->initClassID<GrMagnifierEffect>();
  83     }
  84
  85     bool onIsEqual(const GrFragmentProcessor&) const override;
  86
  87     void onComputeInvariantOutput(GrInvariantOutput* inout) const override;
  88
  89     GR_DECLARE_FRAGMENT_PROCESSOR_TEST;
  90
  91     SkRect fBounds;
  92     float fXOffset;
  93     float fYOffset;
  94     float fXInvZoom;
  95     float fYInvZoom;
  96     float fXInvInset;
  97     float fYInvInset;
  98
  99     typedef GrSingleTextureEffect INHERITED;
 100 };
 101
 102 // For brevity
 103 typedef GrGLProgramDataManager::UniformHandle UniformHandle;
 104
 105 class GrGLMagnifierEffect : public GrGLFragmentProcessor {
 106 public:
 107     GrGLMagnifierEffect(const GrProcessor&);
 108
 109     virtual void emitCode(GrGLFPBuilder*,
 110                           const GrFragmentProcessor&,
 111                           const char* outputColor,
 112                           const char* inputColor,
 113                           const TransformedCoordsArray&,
 114                           const TextureSamplerArray&) override;
 115
 116     void setData(const GrGLProgramDataManager&, const GrProcessor&) override;
 117
 118 private:
 119     UniformHandle       fOffsetVar;
 120     UniformHandle       fInvZoomVar;
 121     UniformHandle       fInvInsetVar;
 122     UniformHandle       fBoundsVar;
 123
 124     typedef GrGLFragmentProcessor INHERITED;
 125 };
 126
 127 GrGLMagnifierEffect::GrGLMagnifierEffect(const GrProcessor&) {
 128 }
 129
 130 void GrGLMagnifierEffect::emitCode(GrGLFPBuilder* builder,
 131                                    const GrFragmentProcessor&,
 132                                    const char* outputColor,
 133                                    const char* inputColor,
 134                                    const TransformedCoordsArray& coords,
 135                                    const TextureSamplerArray& samplers) {
 136     fOffsetVar = builder->addUniform(
 137         GrGLProgramBuilder::kFragment_Visibility |
 138         GrGLProgramBuilder::kVertex_Visibility,
 139         kVec2f_GrSLType, kDefault_GrSLPrecision, "Offset");
 140     fInvZoomVar = builder->addUniform(
 141         GrGLProgramBuilder::kFragment_Visibility |
 142         GrGLProgramBuilder::kVertex_Visibility,
 143         kVec2f_GrSLType, kDefault_GrSLPrecision, "InvZoom");
 144     fInvInsetVar = builder->addUniform(
 145         GrGLProgramBuilder::kFragment_Visibility |
 146         GrGLProgramBuilder::kVertex_Visibility,
 147         kVec2f_GrSLType, kDefault_GrSLPrecision, "InvInset");
 148     fBoundsVar = builder->addUniform(
 149         GrGLProgramBuilder::kFragment_Visibility |
 150         GrGLProgramBuilder::kVertex_Visibility,
 151         kVec4f_GrSLType, kDefault_GrSLPrecision, "Bounds");
 152
 153     GrGLFragmentBuilder* fsBuilder = builder->getFragmentShaderBuilder();
 154     SkString coords2D = fsBuilder->ensureFSCoords2D(coords, 0);
 155     fsBuilder->codeAppendf("\t\tvec2 coord = %s;\n", coords2D.c_str());
 156     fsBuilder->codeAppendf("\t\tvec2 zoom_coord = %s + %s * %s;\n",
 157                            builder->getUniformCStr(fOffsetVar),
 158                            coords2D.c_str(),
 159                            builder->getUniformCStr(fInvZoomVar));
 160     const char* bounds = builder->getUniformCStr(fBoundsVar);
 161     fsBuilder->codeAppendf("\t\tvec2 delta = (coord - %s.xy) * %s.zw;\n", bounds, bounds);
 162     fsBuilder->codeAppendf("\t\tdelta = min(delta, vec2(1.0, 1.0) - delta);\n");
 163     fsBuilder->codeAppendf("\t\tdelta = delta * %s;\n", builder->getUniformCStr(fInvInsetVar));
 164
 165     fsBuilder->codeAppend("\t\tfloat weight = 0.0;\n");
 166     fsBuilder->codeAppend("\t\tif (delta.s < 2.0 && delta.t < 2.0) {\n");
 167     fsBuilder->codeAppend("\t\t\tdelta = vec2(2.0, 2.0) - delta;\n");
 168     fsBuilder->codeAppend("\t\t\tfloat dist = length(delta);\n");
 169     fsBuilder->codeAppend("\t\t\tdist = max(2.0 - dist, 0.0);\n");
 170     fsBuilder->codeAppend("\t\t\tweight = min(dist * dist, 1.0);\n");
 171     fsBuilder->codeAppend("\t\t} else {\n");
 172     fsBuilder->codeAppend("\t\t\tvec2 delta_squared = delta * delta;\n");
 173     fsBuilder->codeAppend("\t\t\tweight = min(min(delta_squared.x, delta_squared.y), 1.0);\n");
 174     fsBuilder->codeAppend("\t\t}\n");
 175
 176     fsBuilder->codeAppend("\t\tvec2 mix_coord = mix(coord, zoom_coord, weight);\n");
 177     fsBuilder->codeAppend("\t\tvec4 output_color = ");
 178     fsBuilder->appendTextureLookup(samplers[0], "mix_coord");
 179     fsBuilder->codeAppend(";\n");
 180
 181     fsBuilder->codeAppendf("\t\t%s = output_color;", outputColor);
 182     SkString modulate;
 183     GrGLSLMulVarBy4f(&modulate, outputColor, inputColor);
 184     fsBuilder->codeAppend(modulate.c_str());
 185 }
 186
 187 void GrGLMagnifierEffect::setData(const GrGLProgramDataManager& pdman,
 188                                   const GrProcessor& effect) {
 189     const GrMagnifierEffect& zoom = effect.cast<GrMagnifierEffect>();
 190     pdman.set2f(fOffsetVar, zoom.x_offset(), zoom.y_offset());
 191     pdman.set2f(fInvZoomVar, zoom.x_inv_zoom(), zoom.y_inv_zoom());
 192     pdman.set2f(fInvInsetVar, zoom.x_inv_inset(), zoom.y_inv_inset());
 193     pdman.set4f(fBoundsVar, zoom.bounds().x(), zoom.bounds().y(),
 194                             zoom.bounds().width(), zoom.bounds().height());
 195 }
 196
 197 /////////////////////////////////////////////////////////////////////
 198
 199 void GrMagnifierEffect::getGLProcessorKey(const GrGLSLCaps& caps,
 200                                           GrProcessorKeyBuilder* b) const {
 201     GrGLMagnifierEffect::GenKey(*this, caps, b);
 202 }
 203
 204 GrGLFragmentProcessor* GrMagnifierEffect::createGLInstance() const {
 205     return SkNEW_ARGS(GrGLMagnifierEffect, (*this));
 206 }
 207
 208 GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrMagnifierEffect);
 209
 210 GrFragmentProcessor* GrMagnifierEffect::TestCreate(GrProcessorTestData* d) {
 211     GrTexture* texture = d->fTextures[0];
 212     const int kMaxWidth = 200;
 213     const int kMaxHeight = 200;
 214     const int kMaxInset = 20;
 215     uint32_t width = d->fRandom->nextULessThan(kMaxWidth);
 216     uint32_t height = d->fRandom->nextULessThan(kMaxHeight);
 217     uint32_t x = d->fRandom->nextULessThan(kMaxWidth - width);
 218     uint32_t y = d->fRandom->nextULessThan(kMaxHeight - height);
 219     uint32_t inset = d->fRandom->nextULessThan(kMaxInset);
 220
 221     GrFragmentProcessor* effect = GrMagnifierEffect::Create(
 222         texture,
 223         SkRect::MakeWH(SkIntToScalar(kMaxWidth), SkIntToScalar(kMaxHeight)),
 224         (float) width / texture->width(),
 225         (float) height / texture->height(),
 226         texture->width() / (float) x,
 227         texture->height() / (float) y,
 228         (float) inset / texture->width(),
 229         (float) inset / texture->height());
 230     SkASSERT(effect);
 231     return effect;
 232 }
 233
 234 ///////////////////////////////////////////////////////////////////////////////
 235
 236 bool GrMagnifierEffect::onIsEqual(const GrFragmentProcessor& sBase) const {
 237     const GrMagnifierEffect& s = sBase.cast<GrMagnifierEffect>();
 238     return (this->fBounds == s.fBounds &&
 239             this->fXOffset == s.fXOffset &&
 240             this->fYOffset == s.fYOffset &&
 241             this->fXInvZoom == s.fXInvZoom &&
 242             this->fYInvZoom == s.fYInvZoom &&
 243             this->fXInvInset == s.fXInvInset &&
 244             this->fYInvInset == s.fYInvInset);
 245 }
 246
 247 void GrMagnifierEffect::onComputeInvariantOutput(GrInvariantOutput* inout) const {
 248     this->updateInvariantOutputForModulation(inout);
 249 }
 250
 251 #endif
 252
 253 ////////////////////////////////////////////////////////////////////////////////
 254
 255 SkImageFilter* SkMagnifierImageFilter::Create(const SkRect& srcRect, SkScalar inset,
 256                                               SkImageFilter* input) {
 257
 258     if (!SkScalarIsFinite(inset) || !SkIsValidRect(srcRect)) {
 259         return NULL;
 260     }
 261     // Negative numbers in src rect are not supported
 262     if (srcRect.fLeft < 0 || srcRect.fTop < 0) {
 263         return NULL;
 264     }
 265     return SkNEW_ARGS(SkMagnifierImageFilter, (srcRect, inset, input));
 266 }
 267
 268
 269 SkMagnifierImageFilter::SkMagnifierImageFilter(const SkRect& srcRect, SkScalar inset,
 270                                                SkImageFilter* input)
 271     : INHERITED(1, &input), fSrcRect(srcRect), fInset(inset) {
 272     SkASSERT(srcRect.x() >= 0 && srcRect.y() >= 0 && inset >= 0);
 273 }
 274
 275 #if SK_SUPPORT_GPU
 276 bool SkMagnifierImageFilter::asFragmentProcessor(GrFragmentProcessor** fp, GrShaderDataManager*,
 277                                                  GrTexture* texture, const SkMatrix&,
 278                                                  const SkIRect&bounds) const {
 279     if (fp) {
 280         SkScalar yOffset = texture->origin() == kTopLeft_GrSurfaceOrigin ? fSrcRect.y() :
 281            texture->height() - fSrcRect.height() * texture->height() / bounds.height()
 282                              - fSrcRect.y();
 283         int boundsY = (texture->origin() == kTopLeft_GrSurfaceOrigin) ? bounds.y() :
 284                       (texture->height() - bounds.height());
 285         SkRect effectBounds = SkRect::MakeXYWH(
 286             SkIntToScalar(bounds.x()) / texture->width(),
 287             SkIntToScalar(boundsY) / texture->height(),
 288             SkIntToScalar(texture->width()) / bounds.width(),
 289             SkIntToScalar(texture->height()) / bounds.height());
 290         SkScalar invInset = fInset > 0 ? SkScalarInvert(fInset) : SK_Scalar1;
 291         *fp = GrMagnifierEffect::Create(texture,
 292                                         effectBounds,
 293                                         fSrcRect.x() / texture->width(),
 294                                         yOffset / texture->height(),
 295                                         fSrcRect.width() / bounds.width(),
 296                                         fSrcRect.height() / bounds.height(),
 297                                         bounds.width() * invInset,
 298                                         bounds.height() * invInset);
 299     }
 300     return true;
 301 }
 302 #endif
 303
 304 SkFlattenable* SkMagnifierImageFilter::CreateProc(SkReadBuffer& buffer) {
 305     SK_IMAGEFILTER_UNFLATTEN_COMMON(common, 1);
 306     SkRect src;
 307     buffer.readRect(&src);
 308     return Create(src, buffer.readScalar(), common.getInput(0));
 309 }
 310
 311 void SkMagnifierImageFilter::flatten(SkWriteBuffer& buffer) const {
 312     this->INHERITED::flatten(buffer);
 313     buffer.writeRect(fSrcRect);
 314     buffer.writeScalar(fInset);
 315 }
 316
 317 bool SkMagnifierImageFilter::onFilterImage(Proxy*, const SkBitmap& src,
 318                                            const Context&, SkBitmap* dst,
 319                                            SkIPoint* offset) const {
 320     if ((src.colorType() != kN32_SkColorType) ||
 321         (fSrcRect.width() >= src.width()) ||
 322         (fSrcRect.height() >= src.height())) {
 323       return false;
 324     }
 325
 326     SkAutoLockPixels alp(src);
 327     SkASSERT(src.getPixels());
 328     if (!src.getPixels() || src.width() <= 0 || src.height() <= 0) {
 329       return false;
 330     }
 331
 332     if (!dst->tryAllocPixels(src.info())) {
 333         return false;
 334     }
 335
 336     SkScalar inv_inset = fInset > 0 ? SkScalarInvert(fInset) : SK_Scalar1;
 337
 338     SkScalar inv_x_zoom = fSrcRect.width() / src.width();
 339     SkScalar inv_y_zoom = fSrcRect.height() / src.height();
 340
 341     SkColor* sptr = src.getAddr32(0, 0);
 342     SkColor* dptr = dst->getAddr32(0, 0);
 343     int width = src.width(), height = src.height();
 344     for (int y = 0; y < height; ++y) {
 345         for (int x = 0; x < width; ++x) {
 346             SkScalar x_dist = SkMin32(x, width - x - 1) * inv_inset;
 347             SkScalar y_dist = SkMin32(y, height - y - 1) * inv_inset;
 348             SkScalar weight = 0;
 349
 350             static const SkScalar kScalar2 = SkScalar(2);
 351
 352             // To create a smooth curve at the corners, we need to work on
 353             // a square twice the size of the inset.
 354             if (x_dist < kScalar2 && y_dist < kScalar2) {
 355                 x_dist = kScalar2 - x_dist;
 356                 y_dist = kScalar2 - y_dist;
 357
 358                 SkScalar dist = SkScalarSqrt(SkScalarSquare(x_dist) +
 359                                              SkScalarSquare(y_dist));
 360                 dist = SkMaxScalar(kScalar2 - dist, 0);
 361                 weight = SkMinScalar(SkScalarSquare(dist), SK_Scalar1);
 362             } else {
 363                 SkScalar sqDist = SkMinScalar(SkScalarSquare(x_dist),
 364                                               SkScalarSquare(y_dist));
 365                 weight = SkMinScalar(sqDist, SK_Scalar1);
 366             }
 367
 368             SkScalar x_interp = SkScalarMul(weight, (fSrcRect.x() + x * inv_x_zoom)) +
 369                            (SK_Scalar1 - weight) * x;
 370             SkScalar y_interp = SkScalarMul(weight, (fSrcRect.y() + y * inv_y_zoom)) +
 371                            (SK_Scalar1 - weight) * y;
 372
 373             int x_val = SkPin32(SkScalarFloorToInt(x_interp), 0, width - 1);
 374             int y_val = SkPin32(SkScalarFloorToInt(y_interp), 0, height - 1);
 375
 376             *dptr = sptr[y_val * width + x_val];
 377             dptr++;
 378         }
 379     }
 380     return true;
 381 }
 382
 383 #ifndef SK_IGNORE_TO_STRING
 384 void SkMagnifierImageFilter::toString(SkString* str) const {
 385     str->appendf("SkMagnifierImageFilter: (");
 386     str->appendf("src: (%f,%f,%f,%f) ",
 387                  fSrcRect.fLeft, fSrcRect.fTop, fSrcRect.fRight, fSrcRect.fBottom);
 388     str->appendf("inset: %f", fInset);
 389     str->append(")");
 390 }
 391 #endif