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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:
Create(GrTexture * texture,const SkRect & bounds,float xOffset,float yOffset,float xInvZoom,float yInvZoom,float xInvInset,float yInvInset)27     static GrFragmentProcessor* Create(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 SkNEW_ARGS(GrMagnifierEffect, (texture,
36                                               bounds,
37                                               xOffset,
38                                               yOffset,
39                                               xInvZoom,
40                                               yInvZoom,
41                                               xInvInset,
42                                               yInvInset));
43     }
44 
~GrMagnifierEffect()45     virtual ~GrMagnifierEffect() {};
46 
name() const47     const char* name() const override { return "Magnifier"; }
48 
49     void getGLProcessorKey(const GrGLSLCaps&, GrProcessorKeyBuilder*) const override;
50 
51     GrGLFragmentProcessor* createGLInstance() const override;
52 
bounds() const53     const SkRect& bounds() const { return fBounds; }    // Bounds of source image.
54     // Offset to apply to zoomed pixels, (srcRect position / texture size).
x_offset() const55     float x_offset() const { return fXOffset; }
y_offset() const56     float y_offset() const { return fYOffset; }
57 
58     // Scale to apply to zoomed pixels (srcRect size / bounds size).
x_inv_zoom() const59     float x_inv_zoom() const { return fXInvZoom; }
y_inv_zoom() const60     float y_inv_zoom() const { return fYInvZoom; }
61 
62     // 1/radius over which to transition from unzoomed to zoomed pixels (bounds size / inset).
x_inv_inset() const63     float x_inv_inset() const { return fXInvInset; }
y_inv_inset() const64     float y_inv_inset() const { return fYInvInset; }
65 
66 private:
GrMagnifierEffect(GrTexture * texture,const SkRect & bounds,float xOffset,float yOffset,float xInvZoom,float yInvZoom,float xInvInset,float yInvInset)67     GrMagnifierEffect(GrTexture* texture,
68                       const SkRect& bounds,
69                       float xOffset,
70                       float yOffset,
71                       float xInvZoom,
72                       float yInvZoom,
73                       float xInvInset,
74                       float yInvInset)
75         : GrSingleTextureEffect(texture, GrCoordTransform::MakeDivByTextureWHMatrix(texture))
76         , fBounds(bounds)
77         , fXOffset(xOffset)
78         , fYOffset(yOffset)
79         , fXInvZoom(xInvZoom)
80         , fYInvZoom(yInvZoom)
81         , fXInvInset(xInvInset)
82         , fYInvInset(yInvInset) {
83         this->initClassID<GrMagnifierEffect>();
84     }
85 
86     bool onIsEqual(const GrFragmentProcessor&) const override;
87 
88     void onComputeInvariantOutput(GrInvariantOutput* inout) const override;
89 
90     GR_DECLARE_FRAGMENT_PROCESSOR_TEST;
91 
92     SkRect fBounds;
93     float fXOffset;
94     float fYOffset;
95     float fXInvZoom;
96     float fYInvZoom;
97     float fXInvInset;
98     float fYInvInset;
99 
100     typedef GrSingleTextureEffect INHERITED;
101 };
102 
103 // For brevity
104 typedef GrGLProgramDataManager::UniformHandle UniformHandle;
105 
106 class GrGLMagnifierEffect : public GrGLFragmentProcessor {
107 public:
108     GrGLMagnifierEffect(const GrProcessor&);
109 
110     virtual void emitCode(GrGLFPBuilder*,
111                           const GrFragmentProcessor&,
112                           const char* outputColor,
113                           const char* inputColor,
114                           const TransformedCoordsArray&,
115                           const TextureSamplerArray&) override;
116 
117     void setData(const GrGLProgramDataManager&, const GrProcessor&) override;
118 
119 private:
120     UniformHandle       fOffsetVar;
121     UniformHandle       fInvZoomVar;
122     UniformHandle       fInvInsetVar;
123     UniformHandle       fBoundsVar;
124 
125     typedef GrGLFragmentProcessor INHERITED;
126 };
127 
GrGLMagnifierEffect(const GrProcessor &)128 GrGLMagnifierEffect::GrGLMagnifierEffect(const GrProcessor&) {
129 }
130 
emitCode(GrGLFPBuilder * builder,const GrFragmentProcessor &,const char * outputColor,const char * inputColor,const TransformedCoordsArray & coords,const TextureSamplerArray & samplers)131 void GrGLMagnifierEffect::emitCode(GrGLFPBuilder* builder,
132                                    const GrFragmentProcessor&,
133                                    const char* outputColor,
134                                    const char* inputColor,
135                                    const TransformedCoordsArray& coords,
136                                    const TextureSamplerArray& samplers) {
137     fOffsetVar = builder->addUniform(
138         GrGLProgramBuilder::kFragment_Visibility |
139         GrGLProgramBuilder::kVertex_Visibility,
140         kVec2f_GrSLType, kDefault_GrSLPrecision, "Offset");
141     fInvZoomVar = builder->addUniform(
142         GrGLProgramBuilder::kFragment_Visibility |
143         GrGLProgramBuilder::kVertex_Visibility,
144         kVec2f_GrSLType, kDefault_GrSLPrecision, "InvZoom");
145     fInvInsetVar = builder->addUniform(
146         GrGLProgramBuilder::kFragment_Visibility |
147         GrGLProgramBuilder::kVertex_Visibility,
148         kVec2f_GrSLType, kDefault_GrSLPrecision, "InvInset");
149     fBoundsVar = builder->addUniform(
150         GrGLProgramBuilder::kFragment_Visibility |
151         GrGLProgramBuilder::kVertex_Visibility,
152         kVec4f_GrSLType, kDefault_GrSLPrecision, "Bounds");
153 
154     GrGLFragmentBuilder* fsBuilder = builder->getFragmentShaderBuilder();
155     SkString coords2D = fsBuilder->ensureFSCoords2D(coords, 0);
156     fsBuilder->codeAppendf("\t\tvec2 coord = %s;\n", coords2D.c_str());
157     fsBuilder->codeAppendf("\t\tvec2 zoom_coord = %s + %s * %s;\n",
158                            builder->getUniformCStr(fOffsetVar),
159                            coords2D.c_str(),
160                            builder->getUniformCStr(fInvZoomVar));
161     const char* bounds = builder->getUniformCStr(fBoundsVar);
162     fsBuilder->codeAppendf("\t\tvec2 delta = (coord - %s.xy) * %s.zw;\n", bounds, bounds);
163     fsBuilder->codeAppendf("\t\tdelta = min(delta, vec2(1.0, 1.0) - delta);\n");
164     fsBuilder->codeAppendf("\t\tdelta = delta * %s;\n", builder->getUniformCStr(fInvInsetVar));
165 
166     fsBuilder->codeAppend("\t\tfloat weight = 0.0;\n");
167     fsBuilder->codeAppend("\t\tif (delta.s < 2.0 && delta.t < 2.0) {\n");
168     fsBuilder->codeAppend("\t\t\tdelta = vec2(2.0, 2.0) - delta;\n");
169     fsBuilder->codeAppend("\t\t\tfloat dist = length(delta);\n");
170     fsBuilder->codeAppend("\t\t\tdist = max(2.0 - dist, 0.0);\n");
171     fsBuilder->codeAppend("\t\t\tweight = min(dist * dist, 1.0);\n");
172     fsBuilder->codeAppend("\t\t} else {\n");
173     fsBuilder->codeAppend("\t\t\tvec2 delta_squared = delta * delta;\n");
174     fsBuilder->codeAppend("\t\t\tweight = min(min(delta_squared.x, delta_squared.y), 1.0);\n");
175     fsBuilder->codeAppend("\t\t}\n");
176 
177     fsBuilder->codeAppend("\t\tvec2 mix_coord = mix(coord, zoom_coord, weight);\n");
178     fsBuilder->codeAppend("\t\tvec4 output_color = ");
179     fsBuilder->appendTextureLookup(samplers[0], "mix_coord");
180     fsBuilder->codeAppend(";\n");
181 
182     fsBuilder->codeAppendf("\t\t%s = output_color;", outputColor);
183     SkString modulate;
184     GrGLSLMulVarBy4f(&modulate, outputColor, inputColor);
185     fsBuilder->codeAppend(modulate.c_str());
186 }
187 
setData(const GrGLProgramDataManager & pdman,const GrProcessor & effect)188 void GrGLMagnifierEffect::setData(const GrGLProgramDataManager& pdman,
189                                   const GrProcessor& effect) {
190     const GrMagnifierEffect& zoom = effect.cast<GrMagnifierEffect>();
191     pdman.set2f(fOffsetVar, zoom.x_offset(), zoom.y_offset());
192     pdman.set2f(fInvZoomVar, zoom.x_inv_zoom(), zoom.y_inv_zoom());
193     pdman.set2f(fInvInsetVar, zoom.x_inv_inset(), zoom.y_inv_inset());
194     pdman.set4f(fBoundsVar, zoom.bounds().x(), zoom.bounds().y(),
195                             zoom.bounds().width(), zoom.bounds().height());
196 }
197 
198 /////////////////////////////////////////////////////////////////////
199 
getGLProcessorKey(const GrGLSLCaps & caps,GrProcessorKeyBuilder * b) const200 void GrMagnifierEffect::getGLProcessorKey(const GrGLSLCaps& caps,
201                                           GrProcessorKeyBuilder* b) const {
202     GrGLMagnifierEffect::GenKey(*this, caps, b);
203 }
204 
createGLInstance() const205 GrGLFragmentProcessor* GrMagnifierEffect::createGLInstance() const {
206     return SkNEW_ARGS(GrGLMagnifierEffect, (*this));
207 }
208 
209 GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrMagnifierEffect);
210 
TestCreate(SkRandom * random,GrContext * context,const GrDrawTargetCaps &,GrTexture ** textures)211 GrFragmentProcessor* GrMagnifierEffect::TestCreate(SkRandom* random,
212                                                    GrContext* context,
213                                                    const GrDrawTargetCaps&,
214                                                    GrTexture** textures) {
215     GrTexture* texture = textures[0];
216     const int kMaxWidth = 200;
217     const int kMaxHeight = 200;
218     const int kMaxInset = 20;
219     uint32_t width = random->nextULessThan(kMaxWidth);
220     uint32_t height = random->nextULessThan(kMaxHeight);
221     uint32_t x = random->nextULessThan(kMaxWidth - width);
222     uint32_t y = random->nextULessThan(kMaxHeight - height);
223     uint32_t inset = random->nextULessThan(kMaxInset);
224 
225     GrFragmentProcessor* effect = GrMagnifierEffect::Create(
226         texture,
227         SkRect::MakeWH(SkIntToScalar(kMaxWidth), SkIntToScalar(kMaxHeight)),
228         (float) width / texture->width(),
229         (float) height / texture->height(),
230         texture->width() / (float) x,
231         texture->height() / (float) y,
232         (float) inset / texture->width(),
233         (float) inset / texture->height());
234     SkASSERT(effect);
235     return effect;
236 }
237 
238 ///////////////////////////////////////////////////////////////////////////////
239 
onIsEqual(const GrFragmentProcessor & sBase) const240 bool GrMagnifierEffect::onIsEqual(const GrFragmentProcessor& sBase) const {
241     const GrMagnifierEffect& s = sBase.cast<GrMagnifierEffect>();
242     return (this->fBounds == s.fBounds &&
243             this->fXOffset == s.fXOffset &&
244             this->fYOffset == s.fYOffset &&
245             this->fXInvZoom == s.fXInvZoom &&
246             this->fYInvZoom == s.fYInvZoom &&
247             this->fXInvInset == s.fXInvInset &&
248             this->fYInvInset == s.fYInvInset);
249 }
250 
onComputeInvariantOutput(GrInvariantOutput * inout) const251 void GrMagnifierEffect::onComputeInvariantOutput(GrInvariantOutput* inout) const {
252     this->updateInvariantOutputForModulation(inout);
253 }
254 
255 #endif
256 
257 ////////////////////////////////////////////////////////////////////////////////
258 
Create(const SkRect & srcRect,SkScalar inset,SkImageFilter * input)259 SkImageFilter* SkMagnifierImageFilter::Create(const SkRect& srcRect, SkScalar inset,
260                                               SkImageFilter* input) {
261 
262     if (!SkScalarIsFinite(inset) || !SkIsValidRect(srcRect)) {
263         return NULL;
264     }
265     // Negative numbers in src rect are not supported
266     if (srcRect.fLeft < 0 || srcRect.fTop < 0) {
267         return NULL;
268     }
269     return SkNEW_ARGS(SkMagnifierImageFilter, (srcRect, inset, input));
270 }
271 
272 
SkMagnifierImageFilter(const SkRect & srcRect,SkScalar inset,SkImageFilter * input)273 SkMagnifierImageFilter::SkMagnifierImageFilter(const SkRect& srcRect, SkScalar inset,
274                                                SkImageFilter* input)
275     : INHERITED(1, &input), fSrcRect(srcRect), fInset(inset) {
276     SkASSERT(srcRect.x() >= 0 && srcRect.y() >= 0 && inset >= 0);
277 }
278 
279 #if SK_SUPPORT_GPU
asFragmentProcessor(GrFragmentProcessor ** fp,GrTexture * texture,const SkMatrix &,const SkIRect & bounds) const280 bool SkMagnifierImageFilter::asFragmentProcessor(GrFragmentProcessor** fp, GrTexture* texture,
281                                                  const SkMatrix&, const SkIRect&bounds) const {
282     if (fp) {
283         SkScalar yOffset = texture->origin() == kTopLeft_GrSurfaceOrigin ? fSrcRect.y() :
284            texture->height() - fSrcRect.height() * texture->height() / bounds.height()
285                              - fSrcRect.y();
286         int boundsY = (texture->origin() == kTopLeft_GrSurfaceOrigin) ? bounds.y() :
287                       (texture->height() - bounds.height());
288         SkRect effectBounds = SkRect::MakeXYWH(
289             SkIntToScalar(bounds.x()) / texture->width(),
290             SkIntToScalar(boundsY) / texture->height(),
291             SkIntToScalar(texture->width()) / bounds.width(),
292             SkIntToScalar(texture->height()) / bounds.height());
293         SkScalar invInset = fInset > 0 ? SkScalarInvert(fInset) : SK_Scalar1;
294         *fp = GrMagnifierEffect::Create(texture,
295                                         effectBounds,
296                                         fSrcRect.x() / texture->width(),
297                                         yOffset / texture->height(),
298                                         fSrcRect.width() / bounds.width(),
299                                         fSrcRect.height() / bounds.height(),
300                                         bounds.width() * invInset,
301                                         bounds.height() * invInset);
302     }
303     return true;
304 }
305 #endif
306 
CreateProc(SkReadBuffer & buffer)307 SkFlattenable* SkMagnifierImageFilter::CreateProc(SkReadBuffer& buffer) {
308     SK_IMAGEFILTER_UNFLATTEN_COMMON(common, 1);
309     SkRect src;
310     buffer.readRect(&src);
311     return Create(src, buffer.readScalar(), common.getInput(0));
312 }
313 
flatten(SkWriteBuffer & buffer) const314 void SkMagnifierImageFilter::flatten(SkWriteBuffer& buffer) const {
315     this->INHERITED::flatten(buffer);
316     buffer.writeRect(fSrcRect);
317     buffer.writeScalar(fInset);
318 }
319 
onFilterImage(Proxy *,const SkBitmap & src,const Context &,SkBitmap * dst,SkIPoint * offset) const320 bool SkMagnifierImageFilter::onFilterImage(Proxy*, const SkBitmap& src,
321                                            const Context&, SkBitmap* dst,
322                                            SkIPoint* offset) const {
323     if ((src.colorType() != kN32_SkColorType) ||
324         (fSrcRect.width() >= src.width()) ||
325         (fSrcRect.height() >= src.height())) {
326       return false;
327     }
328 
329     SkAutoLockPixels alp(src);
330     SkASSERT(src.getPixels());
331     if (!src.getPixels() || src.width() <= 0 || src.height() <= 0) {
332       return false;
333     }
334 
335     if (!dst->tryAllocPixels(src.info())) {
336         return false;
337     }
338 
339     SkScalar inv_inset = fInset > 0 ? SkScalarInvert(fInset) : SK_Scalar1;
340 
341     SkScalar inv_x_zoom = fSrcRect.width() / src.width();
342     SkScalar inv_y_zoom = fSrcRect.height() / src.height();
343 
344     SkColor* sptr = src.getAddr32(0, 0);
345     SkColor* dptr = dst->getAddr32(0, 0);
346     int width = src.width(), height = src.height();
347     for (int y = 0; y < height; ++y) {
348         for (int x = 0; x < width; ++x) {
349             SkScalar x_dist = SkMin32(x, width - x - 1) * inv_inset;
350             SkScalar y_dist = SkMin32(y, height - y - 1) * inv_inset;
351             SkScalar weight = 0;
352 
353             static const SkScalar kScalar2 = SkScalar(2);
354 
355             // To create a smooth curve at the corners, we need to work on
356             // a square twice the size of the inset.
357             if (x_dist < kScalar2 && y_dist < kScalar2) {
358                 x_dist = kScalar2 - x_dist;
359                 y_dist = kScalar2 - y_dist;
360 
361                 SkScalar dist = SkScalarSqrt(SkScalarSquare(x_dist) +
362                                              SkScalarSquare(y_dist));
363                 dist = SkMaxScalar(kScalar2 - dist, 0);
364                 weight = SkMinScalar(SkScalarSquare(dist), SK_Scalar1);
365             } else {
366                 SkScalar sqDist = SkMinScalar(SkScalarSquare(x_dist),
367                                               SkScalarSquare(y_dist));
368                 weight = SkMinScalar(sqDist, SK_Scalar1);
369             }
370 
371             SkScalar x_interp = SkScalarMul(weight, (fSrcRect.x() + x * inv_x_zoom)) +
372                            (SK_Scalar1 - weight) * x;
373             SkScalar y_interp = SkScalarMul(weight, (fSrcRect.y() + y * inv_y_zoom)) +
374                            (SK_Scalar1 - weight) * y;
375 
376             int x_val = SkPin32(SkScalarFloorToInt(x_interp), 0, width - 1);
377             int y_val = SkPin32(SkScalarFloorToInt(y_interp), 0, height - 1);
378 
379             *dptr = sptr[y_val * width + x_val];
380             dptr++;
381         }
382     }
383     return true;
384 }
385 
386 #ifndef SK_IGNORE_TO_STRING
toString(SkString * str) const387 void SkMagnifierImageFilter::toString(SkString* str) const {
388     str->appendf("SkMagnifierImageFilter: (");
389     str->appendf("src: (%f,%f,%f,%f) ",
390                  fSrcRect.fLeft, fSrcRect.fTop, fSrcRect.fRight, fSrcRect.fBottom);
391     str->appendf("inset: %f", fInset);
392     str->append(")");
393 }
394 #endif
395