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 "SkDevice.h"
  12 #include "SkReadBuffer.h"
  13 #include "SkWriteBuffer.h"
  14 #include "SkValidationUtils.h"
  15
  16 ////////////////////////////////////////////////////////////////////////////////
  17 #if SK_SUPPORT_GPU
  18 #include "GrInvariantOutput.h"
  19 #include "effects/GrSingleTextureEffect.h"
  20 #include "glsl/GrGLSLFragmentProcessor.h"
  21 #include "glsl/GrGLSLFragmentShaderBuilder.h"
  22 #include "glsl/GrGLSLProgramBuilder.h"
  23 #include "glsl/GrGLSLProgramDataManager.h"
  24
  25 class GrMagnifierEffect : public GrSingleTextureEffect {
  26
  27 public:
  28     static GrFragmentProcessor* Create(GrTexture* texture,
  29                                        const SkRect& bounds,
  30                                        float xOffset,
  31                                        float yOffset,
  32                                        float xInvZoom,
  33                                        float yInvZoom,
  34                                        float xInvInset,
  35                                        float yInvInset) {
  36         return new GrMagnifierEffect(texture, bounds, xOffset, yOffset, xInvZoom, yInvZoom, xInvInset,
  37                                      yInvInset);
  38     }
  39
  40     virtual ~GrMagnifierEffect() {};
  41
  42     const char* name() const override { return "Magnifier"; }
  43
  44     const SkRect& bounds() const { return fBounds; }    // Bounds of source image.
  45     // Offset to apply to zoomed pixels, (srcRect position / texture size).
  46     float x_offset() const { return fXOffset; }
  47     float y_offset() const { return fYOffset; }
  48
  49     // Scale to apply to zoomed pixels (srcRect size / bounds size).
  50     float x_inv_zoom() const { return fXInvZoom; }
  51     float y_inv_zoom() const { return fYInvZoom; }
  52
  53     // 1/radius over which to transition from unzoomed to zoomed pixels (bounds size / inset).
  54     float x_inv_inset() const { return fXInvInset; }
  55     float y_inv_inset() const { return fYInvInset; }
  56
  57 private:
  58     GrMagnifierEffect(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(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     GrGLSLFragmentProcessor* onCreateGLSLInstance() const override;
  78
  79     void onGetGLSLProcessorKey(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 GrGLSLProgramDataManager::UniformHandle UniformHandle;
 100
 101 class GrGLMagnifierEffect : public GrGLSLFragmentProcessor {
 102 public:
 103     GrGLMagnifierEffect(const GrProcessor&);
 104
 105     virtual void emitCode(EmitArgs&) override;
 106
 107 protected:
 108     void onSetData(const GrGLSLProgramDataManager&, const GrProcessor&) override;
 109
 110 private:
 111     UniformHandle       fOffsetVar;
 112     UniformHandle       fInvZoomVar;
 113     UniformHandle       fInvInsetVar;
 114     UniformHandle       fBoundsVar;
 115
 116     typedef GrGLSLFragmentProcessor INHERITED;
 117 };
 118
 119 GrGLMagnifierEffect::GrGLMagnifierEffect(const GrProcessor&) {
 120 }
 121
 122 void GrGLMagnifierEffect::emitCode(EmitArgs& args) {
 123     fOffsetVar = args.fBuilder->addUniform(
 124         GrGLSLProgramBuilder::kFragment_Visibility,
 125         kVec2f_GrSLType, kDefault_GrSLPrecision, "Offset");
 126     fInvZoomVar = args.fBuilder->addUniform(
 127         GrGLSLProgramBuilder::kFragment_Visibility,
 128         kVec2f_GrSLType, kDefault_GrSLPrecision, "InvZoom");
 129     fInvInsetVar = args.fBuilder->addUniform(
 130         GrGLSLProgramBuilder::kFragment_Visibility,
 131         kVec2f_GrSLType, kDefault_GrSLPrecision, "InvInset");
 132     fBoundsVar = args.fBuilder->addUniform(
 133         GrGLSLProgramBuilder::kFragment_Visibility,
 134         kVec4f_GrSLType, kDefault_GrSLPrecision, "Bounds");
 135
 136     GrGLSLFragmentBuilder* fragBuilder = args.fFragBuilder;
 137     SkString coords2D = fragBuilder->ensureFSCoords2D(args.fCoords, 0);
 138     fragBuilder->codeAppendf("\t\tvec2 coord = %s;\n", coords2D.c_str());
 139     fragBuilder->codeAppendf("\t\tvec2 zoom_coord = %s + %s * %s;\n",
 140                              args.fBuilder->getUniformCStr(fOffsetVar),
 141                              coords2D.c_str(),
 142                              args.fBuilder->getUniformCStr(fInvZoomVar));
 143     const char* bounds = args.fBuilder->getUniformCStr(fBoundsVar);
 144     fragBuilder->codeAppendf("\t\tvec2 delta = (coord - %s.xy) * %s.zw;\n", bounds, bounds);
 145     fragBuilder->codeAppendf("\t\tdelta = min(delta, vec2(1.0, 1.0) - delta);\n");
 146     fragBuilder->codeAppendf("\t\tdelta = delta * %s;\n",
 147                              args.fBuilder->getUniformCStr(fInvInsetVar));
 148
 149     fragBuilder->codeAppend("\t\tfloat weight = 0.0;\n");
 150     fragBuilder->codeAppend("\t\tif (delta.s < 2.0 && delta.t < 2.0) {\n");
 151     fragBuilder->codeAppend("\t\t\tdelta = vec2(2.0, 2.0) - delta;\n");
 152     fragBuilder->codeAppend("\t\t\tfloat dist = length(delta);\n");
 153     fragBuilder->codeAppend("\t\t\tdist = max(2.0 - dist, 0.0);\n");
 154     fragBuilder->codeAppend("\t\t\tweight = min(dist * dist, 1.0);\n");
 155     fragBuilder->codeAppend("\t\t} else {\n");
 156     fragBuilder->codeAppend("\t\t\tvec2 delta_squared = delta * delta;\n");
 157     fragBuilder->codeAppend("\t\t\tweight = min(min(delta_squared.x, delta_squared.y), 1.0);\n");
 158     fragBuilder->codeAppend("\t\t}\n");
 159
 160     fragBuilder->codeAppend("\t\tvec2 mix_coord = mix(coord, zoom_coord, weight);\n");
 161     fragBuilder->codeAppend("\t\tvec4 output_color = ");
 162     fragBuilder->appendTextureLookup(args.fSamplers[0], "mix_coord");
 163     fragBuilder->codeAppend(";\n");
 164
 165     fragBuilder->codeAppendf("\t\t%s = output_color;", args.fOutputColor);
 166     SkString modulate;
 167     GrGLSLMulVarBy4f(&modulate, args.fOutputColor, args.fInputColor);
 168     fragBuilder->codeAppend(modulate.c_str());
 169 }
 170
 171 void GrGLMagnifierEffect::onSetData(const GrGLSLProgramDataManager& pdman,
 172                                     const GrProcessor& effect) {
 173     const GrMagnifierEffect& zoom = effect.cast<GrMagnifierEffect>();
 174     pdman.set2f(fOffsetVar, zoom.x_offset(), zoom.y_offset());
 175     pdman.set2f(fInvZoomVar, zoom.x_inv_zoom(), zoom.y_inv_zoom());
 176     pdman.set2f(fInvInsetVar, zoom.x_inv_inset(), zoom.y_inv_inset());
 177     pdman.set4f(fBoundsVar, zoom.bounds().x(), zoom.bounds().y(),
 178                             zoom.bounds().width(), zoom.bounds().height());
 179 }
 180
 181 /////////////////////////////////////////////////////////////////////
 182
 183 void GrMagnifierEffect::onGetGLSLProcessorKey(const GrGLSLCaps& caps,
 184                                               GrProcessorKeyBuilder* b) const {
 185     GrGLMagnifierEffect::GenKey(*this, caps, b);
 186 }
 187
 188 GrGLSLFragmentProcessor* GrMagnifierEffect::onCreateGLSLInstance() const {
 189     return new GrGLMagnifierEffect(*this);
 190 }
 191
 192 GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrMagnifierEffect);
 193
 194 const GrFragmentProcessor* GrMagnifierEffect::TestCreate(GrProcessorTestData* d) {
 195     GrTexture* texture = d->fTextures[0];
 196     const int kMaxWidth = 200;
 197     const int kMaxHeight = 200;
 198     const int kMaxInset = 20;
 199     uint32_t width = d->fRandom->nextULessThan(kMaxWidth);
 200     uint32_t height = d->fRandom->nextULessThan(kMaxHeight);
 201     uint32_t x = d->fRandom->nextULessThan(kMaxWidth - width);
 202     uint32_t y = d->fRandom->nextULessThan(kMaxHeight - height);
 203     uint32_t inset = d->fRandom->nextULessThan(kMaxInset);
 204
 205     GrFragmentProcessor* effect = GrMagnifierEffect::Create(
 206         texture,
 207         SkRect::MakeWH(SkIntToScalar(kMaxWidth), SkIntToScalar(kMaxHeight)),
 208         (float) width / texture->width(),
 209         (float) height / texture->height(),
 210         texture->width() / (float) x,
 211         texture->height() / (float) y,
 212         (float) inset / texture->width(),
 213         (float) inset / texture->height());
 214     SkASSERT(effect);
 215     return effect;
 216 }
 217
 218 ///////////////////////////////////////////////////////////////////////////////
 219
 220 bool GrMagnifierEffect::onIsEqual(const GrFragmentProcessor& sBase) const {
 221     const GrMagnifierEffect& s = sBase.cast<GrMagnifierEffect>();
 222     return (this->fBounds == s.fBounds &&
 223             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 nullptr;
 244     }
 245     // Negative numbers in src rect are not supported
 246     if (srcRect.fLeft < 0 || srcRect.fTop < 0) {
 247         return nullptr;
 248     }
 249     return new 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,
 261                                                  GrTexture* texture, const SkMatrix&,
 262                                                  const SkIRect&bounds) const {
 263     if (fp) {
 264         SkScalar yOffset = texture->origin() == kTopLeft_GrSurfaceOrigin ? fSrcRect.y() :
 265            texture->height() - fSrcRect.height() * texture->height() / bounds.height()
 266                              - fSrcRect.y();
 267         int boundsY = (texture->origin() == kTopLeft_GrSurfaceOrigin) ? bounds.y() :
 268                       (texture->height() - bounds.height());
 269         SkRect effectBounds = SkRect::MakeXYWH(
 270             SkIntToScalar(bounds.x()) / texture->width(),
 271             SkIntToScalar(boundsY) / texture->height(),
 272             SkIntToScalar(texture->width()) / bounds.width(),
 273             SkIntToScalar(texture->height()) / bounds.height());
 274         SkScalar invInset = fInset > 0 ? SkScalarInvert(fInset) : SK_Scalar1;
 275         *fp = GrMagnifierEffect::Create(texture,
 276                                         effectBounds,
 277                                         fSrcRect.x() / texture->width(),
 278                                         yOffset / texture->height(),
 279                                         fSrcRect.width() / bounds.width(),
 280                                         fSrcRect.height() / bounds.height(),
 281                                         bounds.width() * invInset,
 282                                         bounds.height() * invInset);
 283     }
 284     return true;
 285 }
 286 #endif
 287
 288 SkFlattenable* SkMagnifierImageFilter::CreateProc(SkReadBuffer& buffer) {
 289     SK_IMAGEFILTER_UNFLATTEN_COMMON(common, 1);
 290     SkRect src;
 291     buffer.readRect(&src);
 292     return Create(src, buffer.readScalar(), common.getInput(0));
 293 }
 294
 295 void SkMagnifierImageFilter::flatten(SkWriteBuffer& buffer) const {
 296     this->INHERITED::flatten(buffer);
 297     buffer.writeRect(fSrcRect);
 298     buffer.writeScalar(fInset);
 299 }
 300
 301 bool SkMagnifierImageFilter::onFilterImage(Proxy* proxy, const SkBitmap& src,
 302                                            const Context&, SkBitmap* dst,
 303                                            SkIPoint* offset) const {
 304     if ((src.colorType() != kN32_SkColorType) ||
 305         (fSrcRect.width() >= src.width()) ||
 306         (fSrcRect.height() >= src.height())) {
 307       return false;
 308     }
 309
 310     SkAutoLockPixels alp(src);
 311     SkASSERT(src.getPixels());
 312     if (!src.getPixels() || src.width() <= 0 || src.height() <= 0) {
 313       return false;
 314     }
 315
 316     SkAutoTUnref<SkBaseDevice> device(proxy->createDevice(src.width(), src.height()));
 317     if (!device) {
 318         return false;
 319     }
 320     *dst = device->accessBitmap(false);
 321     SkAutoLockPixels alp_dst(*dst);
 322
 323     SkScalar inv_inset = fInset > 0 ? SkScalarInvert(fInset) : SK_Scalar1;
 324
 325     SkScalar inv_x_zoom = fSrcRect.width() / src.width();
 326     SkScalar inv_y_zoom = fSrcRect.height() / src.height();
 327
 328     SkColor* sptr = src.getAddr32(0, 0);
 329     SkColor* dptr = dst->getAddr32(0, 0);
 330     int width = src.width(), height = src.height();
 331     for (int y = 0; y < height; ++y) {
 332         for (int x = 0; x < width; ++x) {
 333             SkScalar x_dist = SkMin32(x, width - x - 1) * inv_inset;
 334             SkScalar y_dist = SkMin32(y, height - y - 1) * inv_inset;
 335             SkScalar weight = 0;
 336
 337             static const SkScalar kScalar2 = SkScalar(2);
 338
 339             // To create a smooth curve at the corners, we need to work on
 340             // a square twice the size of the inset.
 341             if (x_dist < kScalar2 && y_dist < kScalar2) {
 342                 x_dist = kScalar2 - x_dist;
 343                 y_dist = kScalar2 - y_dist;
 344
 345                 SkScalar dist = SkScalarSqrt(SkScalarSquare(x_dist) +
 346                                              SkScalarSquare(y_dist));
 347                 dist = SkMaxScalar(kScalar2 - dist, 0);
 348                 weight = SkMinScalar(SkScalarSquare(dist), SK_Scalar1);
 349             } else {
 350                 SkScalar sqDist = SkMinScalar(SkScalarSquare(x_dist),
 351                                               SkScalarSquare(y_dist));
 352                 weight = SkMinScalar(sqDist, SK_Scalar1);
 353             }
 354
 355             SkScalar x_interp = SkScalarMul(weight, (fSrcRect.x() + x * inv_x_zoom)) +
 356                            (SK_Scalar1 - weight) * x;
 357             SkScalar y_interp = SkScalarMul(weight, (fSrcRect.y() + y * inv_y_zoom)) +
 358                            (SK_Scalar1 - weight) * y;
 359
 360             int x_val = SkTPin(SkScalarFloorToInt(x_interp), 0, width - 1);
 361             int y_val = SkTPin(SkScalarFloorToInt(y_interp), 0, height - 1);
 362
 363             *dptr = sptr[y_val * width + x_val];
 364             dptr++;
 365         }
 366     }
 367     return true;
 368 }
 369
 370 #ifndef SK_IGNORE_TO_STRING
 371 void SkMagnifierImageFilter::toString(SkString* str) const {
 372     str->appendf("SkMagnifierImageFilter: (");
 373     str->appendf("src: (%f,%f,%f,%f) ",
 374                  fSrcRect.fLeft, fSrcRect.fTop, fSrcRect.fRight, fSrcRect.fBottom);
 375     str->appendf("inset: %f", fInset);
 376     str->append(")");
 377 }
 378 #endif