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/GrGLEffect.h"
  19 #include "gl/GrGLSL.h"
  20 #include "gl/GrGLTexture.h"
  21 #include "GrTBackendEffectFactory.h"
  22
  23 class GrGLMagnifierEffect;
  24
  25 class GrMagnifierEffect : public GrSingleTextureEffect {
  26
  27 public:
  28     static GrEffectRef* Create(GrTexture* texture,
  29                                float xOffset,
  30                                float yOffset,
  31                                float xInvZoom,
  32                                float yInvZoom,
  33                                float xInvInset,
  34                                float yInvInset) {
  35         AutoEffectUnref effect(SkNEW_ARGS(GrMagnifierEffect, (texture,
  36                                                               xOffset,
  37                                                               yOffset,
  38                                                               xInvZoom,
  39                                                               yInvZoom,
  40                                                               xInvInset,
  41                                                               yInvInset)));
  42         return CreateEffectRef(effect);
  43     }
  44
  45     virtual ~GrMagnifierEffect() {};
  46
  47     static const char* Name() { return "Magnifier"; }
  48
  49     virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE;
  50     virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const SK_OVERRIDE;
  51
  52     float x_offset() const { return fXOffset; }
  53     float y_offset() const { return fYOffset; }
  54     float x_inv_zoom() const { return fXInvZoom; }
  55     float y_inv_zoom() const { return fYInvZoom; }
  56     float x_inv_inset() const { return fXInvInset; }
  57     float y_inv_inset() const { return fYInvInset; }
  58
  59     typedef GrGLMagnifierEffect GLEffect;
  60
  61 private:
  62     GrMagnifierEffect(GrTexture* texture,
  63                       float xOffset,
  64                       float yOffset,
  65                       float xInvZoom,
  66                       float yInvZoom,
  67                       float xInvInset,
  68                       float yInvInset)
  69         : GrSingleTextureEffect(texture, MakeDivByTextureWHMatrix(texture))
  70         , fXOffset(xOffset)
  71         , fYOffset(yOffset)
  72         , fXInvZoom(xInvZoom)
  73         , fYInvZoom(yInvZoom)
  74         , fXInvInset(xInvInset)
  75         , fYInvInset(yInvInset) {}
  76
  77     virtual bool onIsEqual(const GrEffect&) const SK_OVERRIDE;
  78
  79     GR_DECLARE_EFFECT_TEST;
  80
  81     float fXOffset;
  82     float fYOffset;
  83     float fXInvZoom;
  84     float fYInvZoom;
  85     float fXInvInset;
  86     float fYInvInset;
  87
  88     typedef GrSingleTextureEffect INHERITED;
  89 };
  90
  91 // For brevity
  92 typedef GrGLUniformManager::UniformHandle UniformHandle;
  93
  94 class GrGLMagnifierEffect : public GrGLEffect {
  95 public:
  96     GrGLMagnifierEffect(const GrBackendEffectFactory&, const GrDrawEffect&);
  97
  98     virtual void emitCode(GrGLShaderBuilder*,
  99                           const GrDrawEffect&,
 100                           EffectKey,
 101                           const char* outputColor,
 102                           const char* inputColor,
 103                           const TransformedCoordsArray&,
 104                           const TextureSamplerArray&) SK_OVERRIDE;
 105
 106     virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE;
 107
 108 private:
 109     UniformHandle       fOffsetVar;
 110     UniformHandle       fInvZoomVar;
 111     UniformHandle       fInvInsetVar;
 112
 113     typedef GrGLEffect INHERITED;
 114 };
 115
 116 GrGLMagnifierEffect::GrGLMagnifierEffect(const GrBackendEffectFactory& factory, const GrDrawEffect&)
 117     : INHERITED(factory) {
 118 }
 119
 120 void GrGLMagnifierEffect::emitCode(GrGLShaderBuilder* builder,
 121                                    const GrDrawEffect&,
 122                                    EffectKey key,
 123                                    const char* outputColor,
 124                                    const char* inputColor,
 125                                    const TransformedCoordsArray& coords,
 126                                    const TextureSamplerArray& samplers) {
 127     SkString coords2D = builder->ensureFSCoords2D(coords, 0);
 128     fOffsetVar = builder->addUniform(
 129         GrGLShaderBuilder::kFragment_Visibility |
 130         GrGLShaderBuilder::kVertex_Visibility,
 131         kVec2f_GrSLType, "Offset");
 132     fInvZoomVar = builder->addUniform(
 133         GrGLShaderBuilder::kFragment_Visibility |
 134         GrGLShaderBuilder::kVertex_Visibility,
 135         kVec2f_GrSLType, "InvZoom");
 136     fInvInsetVar = builder->addUniform(
 137         GrGLShaderBuilder::kFragment_Visibility |
 138         GrGLShaderBuilder::kVertex_Visibility,
 139         kVec2f_GrSLType, "InvInset");
 140
 141     builder->fsCodeAppendf("\t\tvec2 coord = %s;\n", coords2D.c_str());
 142     builder->fsCodeAppendf("\t\tvec2 zoom_coord = %s + %s * %s;\n",
 143                            builder->getUniformCStr(fOffsetVar),
 144                            coords2D.c_str(),
 145                            builder->getUniformCStr(fInvZoomVar));
 146
 147     builder->fsCodeAppend("\t\tvec2 delta = min(coord, vec2(1.0, 1.0) - coord);\n");
 148
 149     builder->fsCodeAppendf("\t\tdelta = delta * %s;\n", builder->getUniformCStr(fInvInsetVar));
 150
 151     builder->fsCodeAppend("\t\tfloat weight = 0.0;\n");
 152     builder->fsCodeAppend("\t\tif (delta.s < 2.0 && delta.t < 2.0) {\n");
 153     builder->fsCodeAppend("\t\t\tdelta = vec2(2.0, 2.0) - delta;\n");
 154     builder->fsCodeAppend("\t\t\tfloat dist = length(delta);\n");
 155     builder->fsCodeAppend("\t\t\tdist = max(2.0 - dist, 0.0);\n");
 156     builder->fsCodeAppend("\t\t\tweight = min(dist * dist, 1.0);\n");
 157     builder->fsCodeAppend("\t\t} else {\n");
 158     builder->fsCodeAppend("\t\t\tvec2 delta_squared = delta * delta;\n");
 159     builder->fsCodeAppend("\t\t\tweight = min(min(delta_squared.x, delta_squared.y), 1.0);\n");
 160     builder->fsCodeAppend("\t\t}\n");
 161
 162     builder->fsCodeAppend("\t\tvec2 mix_coord = mix(coord, zoom_coord, weight);\n");
 163     builder->fsCodeAppend("\t\tvec4 output_color = ");
 164     builder->fsAppendTextureLookup(samplers[0], "mix_coord");
 165     builder->fsCodeAppend(";\n");
 166
 167     builder->fsCodeAppendf("\t\t%s = output_color;", outputColor);
 168     SkString modulate;
 169     GrGLSLMulVarBy4f(&modulate, 2, outputColor, inputColor);
 170     builder->fsCodeAppend(modulate.c_str());
 171 }
 172
 173 void GrGLMagnifierEffect::setData(const GrGLUniformManager& uman,
 174                                   const GrDrawEffect& drawEffect) {
 175     const GrMagnifierEffect& zoom = drawEffect.castEffect<GrMagnifierEffect>();
 176     uman.set2f(fOffsetVar, zoom.x_offset(), zoom.y_offset());
 177     uman.set2f(fInvZoomVar, zoom.x_inv_zoom(), zoom.y_inv_zoom());
 178     uman.set2f(fInvInsetVar, zoom.x_inv_inset(), zoom.y_inv_inset());
 179 }
 180
 181 /////////////////////////////////////////////////////////////////////
 182
 183 GR_DEFINE_EFFECT_TEST(GrMagnifierEffect);
 184
 185 GrEffectRef* GrMagnifierEffect::TestCreate(SkRandom* random,
 186                                            GrContext* context,
 187                                            const GrDrawTargetCaps&,
 188                                            GrTexture** textures) {
 189     GrTexture* texture = textures[0];
 190     const int kMaxWidth = 200;
 191     const int kMaxHeight = 200;
 192     const int kMaxInset = 20;
 193     uint32_t width = random->nextULessThan(kMaxWidth);
 194     uint32_t height = random->nextULessThan(kMaxHeight);
 195     uint32_t x = random->nextULessThan(kMaxWidth - width);
 196     uint32_t y = random->nextULessThan(kMaxHeight - height);
 197     uint32_t inset = random->nextULessThan(kMaxInset);
 198
 199     GrEffectRef* effect = GrMagnifierEffect::Create(
 200         texture,
 201         (float) width / texture->width(),
 202         (float) height / texture->height(),
 203         texture->width() / (float) x,
 204         texture->height() / (float) y,
 205         (float) inset / texture->width(),
 206         (float) inset / texture->height());
 207     SkASSERT(NULL != effect);
 208     return effect;
 209 }
 210
 211 ///////////////////////////////////////////////////////////////////////////////
 212
 213 const GrBackendEffectFactory& GrMagnifierEffect::getFactory() const {
 214     return GrTBackendEffectFactory<GrMagnifierEffect>::getInstance();
 215 }
 216
 217 bool GrMagnifierEffect::onIsEqual(const GrEffect& sBase) const {
 218     const GrMagnifierEffect& s = CastEffect<GrMagnifierEffect>(sBase);
 219     return (this->texture(0) == s.texture(0) &&
 220             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::getConstantColorComponents(GrColor* color, uint32_t* validFlags) const {
 229     this->updateConstantColorComponentsForModulation(color, validFlags);
 230 }
 231
 232 #endif
 233
 234 ////////////////////////////////////////////////////////////////////////////////
 235 SkMagnifierImageFilter::SkMagnifierImageFilter(SkReadBuffer& buffer)
 236   : INHERITED(1, buffer) {
 237     float x = buffer.readScalar();
 238     float y = buffer.readScalar();
 239     float width = buffer.readScalar();
 240     float height = buffer.readScalar();
 241     fSrcRect = SkRect::MakeXYWH(x, y, width, height);
 242     fInset = buffer.readScalar();
 243
 244     buffer.validate(SkScalarIsFinite(fInset) && SkIsValidRect(fSrcRect) &&
 245                     // Negative numbers in src rect are not supported
 246                     (fSrcRect.fLeft >= 0) && (fSrcRect.fTop >= 0));
 247 }
 248
 249 // FIXME:  implement single-input semantics
 250 SkMagnifierImageFilter::SkMagnifierImageFilter(const SkRect& srcRect, SkScalar inset)
 251     : INHERITED(0), fSrcRect(srcRect), fInset(inset) {
 252     SkASSERT(srcRect.x() >= 0 && srcRect.y() >= 0 && inset >= 0);
 253 }
 254
 255 #if SK_SUPPORT_GPU
 256 bool SkMagnifierImageFilter::asNewEffect(GrEffectRef** effect, GrTexture* texture, const SkMatrix&, const SkIRect&) const {
 257     if (effect) {
 258         SkScalar yOffset = (texture->origin() == kTopLeft_GrSurfaceOrigin) ? fSrcRect.y() :
 259                            (texture->height() - (fSrcRect.y() + fSrcRect.height()));
 260         SkScalar invInset = fInset > 0 ? SkScalarInvert(fInset) : SK_Scalar1;
 261         *effect = GrMagnifierEffect::Create(texture,
 262                                             fSrcRect.x() / texture->width(),
 263                                             yOffset / texture->height(),
 264                                             fSrcRect.width() / texture->width(),
 265                                             fSrcRect.height() / texture->height(),
 266                                             texture->width() * invInset,
 267                                             texture->height() * invInset);
 268     }
 269     return true;
 270 }
 271 #endif
 272
 273 void SkMagnifierImageFilter::flatten(SkWriteBuffer& buffer) const {
 274     this->INHERITED::flatten(buffer);
 275     buffer.writeScalar(fSrcRect.x());
 276     buffer.writeScalar(fSrcRect.y());
 277     buffer.writeScalar(fSrcRect.width());
 278     buffer.writeScalar(fSrcRect.height());
 279     buffer.writeScalar(fInset);
 280 }
 281
 282 bool SkMagnifierImageFilter::onFilterImage(Proxy*, const SkBitmap& src,
 283                                            const Context&, SkBitmap* dst,
 284                                            SkIPoint* offset) const {
 285     SkASSERT(src.colorType() == kN32_SkColorType);
 286     SkASSERT(fSrcRect.width() < src.width());
 287     SkASSERT(fSrcRect.height() < src.height());
 288
 289     if ((src.colorType() != kN32_SkColorType) ||
 290         (fSrcRect.width() >= src.width()) ||
 291         (fSrcRect.height() >= src.height())) {
 292       return false;
 293     }
 294
 295     SkAutoLockPixels alp(src);
 296     SkASSERT(src.getPixels());
 297     if (!src.getPixels() || src.width() <= 0 || src.height() <= 0) {
 298       return false;
 299     }
 300
 301     if (!dst->allocPixels(src.info())) {
 302         return false;
 303     }
 304
 305     SkScalar inv_inset = fInset > 0 ? SkScalarInvert(fInset) : SK_Scalar1;
 306
 307     SkScalar inv_x_zoom = fSrcRect.width() / src.width();
 308     SkScalar inv_y_zoom = fSrcRect.height() / src.height();
 309
 310     SkColor* sptr = src.getAddr32(0, 0);
 311     SkColor* dptr = dst->getAddr32(0, 0);
 312     int width = src.width(), height = src.height();
 313     for (int y = 0; y < height; ++y) {
 314         for (int x = 0; x < width; ++x) {
 315             SkScalar x_dist = SkMin32(x, width - x - 1) * inv_inset;
 316             SkScalar y_dist = SkMin32(y, height - y - 1) * inv_inset;
 317             SkScalar weight = 0;
 318
 319             static const SkScalar kScalar2 = SkScalar(2);
 320
 321             // To create a smooth curve at the corners, we need to work on
 322             // a square twice the size of the inset.
 323             if (x_dist < kScalar2 && y_dist < kScalar2) {
 324                 x_dist = kScalar2 - x_dist;
 325                 y_dist = kScalar2 - y_dist;
 326
 327                 SkScalar dist = SkScalarSqrt(SkScalarSquare(x_dist) +
 328                                              SkScalarSquare(y_dist));
 329                 dist = SkMaxScalar(kScalar2 - dist, 0);
 330                 weight = SkMinScalar(SkScalarSquare(dist), SK_Scalar1);
 331             } else {
 332                 SkScalar sqDist = SkMinScalar(SkScalarSquare(x_dist),
 333                                               SkScalarSquare(y_dist));
 334                 weight = SkMinScalar(sqDist, SK_Scalar1);
 335             }
 336
 337             SkScalar x_interp = SkScalarMul(weight, (fSrcRect.x() + x * inv_x_zoom)) +
 338                            (SK_Scalar1 - weight) * x;
 339             SkScalar y_interp = SkScalarMul(weight, (fSrcRect.y() + y * inv_y_zoom)) +
 340                            (SK_Scalar1 - weight) * y;
 341
 342             int x_val = SkPin32(SkScalarFloorToInt(x_interp), 0, width - 1);
 343             int y_val = SkPin32(SkScalarFloorToInt(y_interp), 0, height - 1);
 344
 345             *dptr = sptr[y_val * width + x_val];
 346             dptr++;
 347         }
 348     }
 349     return true;
 350 }