SkMatrixConvolutionImageFilter.cpp revision 478884f7d3b8c7be8b62f3fa2b79192f411c3fec 
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 "SkMatrixConvolutionImageFilter.h"
9#include "SkBitmap.h"
10#include "SkColorPriv.h"
11#include "SkFlattenableBuffers.h"
12#include "SkRect.h"
13#include "SkUnPreMultiply.h"
14
15#if SK_SUPPORT_GPU
16#include "gl/GrGLEffect.h"
17#include "gl/GrGLEffectMatrix.h"
18#include "effects/GrSingleTextureEffect.h"
19#include "GrTBackendEffectFactory.h"
20#include "GrTexture.h"
21#include "SkMatrix.h"
22
23#endif
24
25SkMatrixConvolutionImageFilter::SkMatrixConvolutionImageFilter(const SkISize& kernelSize, const SkScalar* kernel, SkScalar gain, SkScalar bias, const SkIPoint& target, TileMode tileMode, bool convolveAlpha, SkImageFilter* input)
26  : INHERITED(input),
27    fKernelSize(kernelSize),
28    fGain(gain),
29    fBias(bias),
30    fTarget(target),
31    fTileMode(tileMode),
32    fConvolveAlpha(convolveAlpha) {
33    uint32_t size = fKernelSize.fWidth * fKernelSize.fHeight;
34    fKernel = SkNEW_ARRAY(SkScalar, size);
35    memcpy(fKernel, kernel, size * sizeof(SkScalar));
36    SkASSERT(kernelSize.fWidth >= 1 && kernelSize.fHeight >= 1);
37    SkASSERT(target.fX >= 0 && target.fX < kernelSize.fWidth);
38    SkASSERT(target.fY >= 0 && target.fY < kernelSize.fHeight);
39}
40
41SkMatrixConvolutionImageFilter::SkMatrixConvolutionImageFilter(SkFlattenableReadBuffer& buffer) : INHERITED(buffer) {
42    fKernelSize.fWidth = buffer.readInt();
43    fKernelSize.fHeight = buffer.readInt();
44    uint32_t size = fKernelSize.fWidth * fKernelSize.fHeight;
45    fKernel = SkNEW_ARRAY(SkScalar, size);
46    SkDEBUGCODE(uint32_t readSize = )buffer.readScalarArray(fKernel);
47    SkASSERT(readSize == size);
48    fGain = buffer.readScalar();
49    fBias = buffer.readScalar();
50    fTarget.fX = buffer.readInt();
51    fTarget.fY = buffer.readInt();
52    fTileMode = (TileMode) buffer.readInt();
53    fConvolveAlpha = buffer.readBool();
54}
55
56void SkMatrixConvolutionImageFilter::flatten(SkFlattenableWriteBuffer& buffer) const {
57    this->INHERITED::flatten(buffer);
58    buffer.writeInt(fKernelSize.fWidth);
59    buffer.writeInt(fKernelSize.fHeight);
60    buffer.writeScalarArray(fKernel, fKernelSize.fWidth * fKernelSize.fHeight);
61    buffer.writeScalar(fGain);
62    buffer.writeScalar(fBias);
63    buffer.writeInt(fTarget.fX);
64    buffer.writeInt(fTarget.fY);
65    buffer.writeInt((int) fTileMode);
66    buffer.writeBool(fConvolveAlpha);
67}
68
69SkMatrixConvolutionImageFilter::~SkMatrixConvolutionImageFilter() {
70    delete[] fKernel;
71}
72
73class UncheckedPixelFetcher {
74public:
75    static inline SkPMColor fetch(const SkBitmap& src, int x, int y) {
76        return *src.getAddr32(x, y);
77    }
78};
79
80class ClampPixelFetcher {
81public:
82    static inline SkPMColor fetch(const SkBitmap& src, int x, int y) {
83        x = SkClampMax(x, src.width() - 1);
84        y = SkClampMax(y, src.height() - 1);
85        return *src.getAddr32(x, y);
86    }
87};
88
89class RepeatPixelFetcher {
90public:
91    static inline SkPMColor fetch(const SkBitmap& src, int x, int y) {
92        x %= src.width();
93        y %= src.height();
94        if (x < 0) {
95            x += src.width();
96        }
97        if (y < 0) {
98            y += src.height();
99        }
100        return *src.getAddr32(x, y);
101    }
102};
103
104class ClampToBlackPixelFetcher {
105public:
106    static inline SkPMColor fetch(const SkBitmap& src, int x, int y) {
107        if (x < 0 || x >= src.width() || y < 0 || y >= src.height()) {
108            return 0;
109        } else {
110            return *src.getAddr32(x, y);
111        }
112    }
113};
114
115template<class PixelFetcher, bool convolveAlpha>
116void SkMatrixConvolutionImageFilter::filterPixels(const SkBitmap& src, SkBitmap* result, const SkIRect& rect) {
117    for (int y = rect.fTop; y < rect.fBottom; ++y) {
118        SkPMColor* dptr = result->getAddr32(rect.fLeft, y);
119        for (int x = rect.fLeft; x < rect.fRight; ++x) {
120            SkScalar sumA = 0, sumR = 0, sumG = 0, sumB = 0;
121            for (int cy = 0; cy < fKernelSize.fHeight; cy++) {
122                for (int cx = 0; cx < fKernelSize.fWidth; cx++) {
123                    SkPMColor s = PixelFetcher::fetch(src, x + cx - fTarget.fX, y + cy - fTarget.fY);
124                    SkScalar k = fKernel[cy * fKernelSize.fWidth + cx];
125                    if (convolveAlpha) {
126                        sumA += SkScalarMul(SkIntToScalar(SkGetPackedA32(s)), k);
127                    }
128                    sumR += SkScalarMul(SkIntToScalar(SkGetPackedR32(s)), k);
129                    sumG += SkScalarMul(SkIntToScalar(SkGetPackedG32(s)), k);
130                    sumB += SkScalarMul(SkIntToScalar(SkGetPackedB32(s)), k);
131                }
132            }
133            int a = convolveAlpha
134                  ? SkClampMax(SkScalarFloorToInt(SkScalarMul(sumA, fGain) + fBias), 255)
135                  : 255;
136            int r = SkClampMax(SkScalarFloorToInt(SkScalarMul(sumR, fGain) + fBias), a);
137            int g = SkClampMax(SkScalarFloorToInt(SkScalarMul(sumG, fGain) + fBias), a);
138            int b = SkClampMax(SkScalarFloorToInt(SkScalarMul(sumB, fGain) + fBias), a);
139            if (!convolveAlpha) {
140                a = SkGetPackedA32(PixelFetcher::fetch(src, x, y));
141                *dptr++ = SkPreMultiplyARGB(a, r, g, b);
142            } else {
143                *dptr++ = SkPackARGB32(a, r, g, b);
144            }
145        }
146    }
147}
148
149template<class PixelFetcher>
150void SkMatrixConvolutionImageFilter::filterPixels(const SkBitmap& src, SkBitmap* result, const SkIRect& rect) {
151    if (fConvolveAlpha) {
152        filterPixels<PixelFetcher, true>(src, result, rect);
153    } else {
154        filterPixels<PixelFetcher, false>(src, result, rect);
155    }
156}
157
158void SkMatrixConvolutionImageFilter::filterInteriorPixels(const SkBitmap& src, SkBitmap* result, const SkIRect& rect) {
159    filterPixels<UncheckedPixelFetcher>(src, result, rect);
160}
161
162void SkMatrixConvolutionImageFilter::filterBorderPixels(const SkBitmap& src, SkBitmap* result, const SkIRect& rect) {
163    switch (fTileMode) {
164        case kClamp_TileMode:
165            filterPixels<ClampPixelFetcher>(src, result, rect);
166            break;
167        case kRepeat_TileMode:
168            filterPixels<RepeatPixelFetcher>(src, result, rect);
169            break;
170        case kClampToBlack_TileMode:
171            filterPixels<ClampToBlackPixelFetcher>(src, result, rect);
172            break;
173    }
174}
175
176// FIXME:  This should be refactored to SkImageFilterUtils for
177// use by other filters.  For now, we assume the input is always
178// premultiplied and unpremultiply it
179static SkBitmap unpremultiplyBitmap(const SkBitmap& src)
180{
181    SkAutoLockPixels alp(src);
182    if (!src.getPixels()) {
183        return SkBitmap();
184    }
185    SkBitmap result;
186    result.setConfig(src.config(), src.width(), src.height());
187    result.allocPixels();
188    if (!result.getPixels()) {
189        return SkBitmap();
190    }
191    for (int y = 0; y < src.height(); ++y) {
192        const uint32_t* srcRow = src.getAddr32(0, y);
193        uint32_t* dstRow = result.getAddr32(0, y);
194        for (int x = 0; x < src.width(); ++x) {
195            dstRow[x] = SkUnPreMultiply::PMColorToColor(srcRow[x]);
196        }
197    }
198    return result;
199}
200
201bool SkMatrixConvolutionImageFilter::onFilterImage(Proxy* proxy,
202                                                   const SkBitmap& source,
203                                                   const SkMatrix& matrix,
204                                                   SkBitmap* result,
205                                                   SkIPoint* loc) {
206    SkBitmap src = source;
207    if (getInput(0) && !getInput(0)->filterImage(proxy, source, matrix, &src, loc)) {
208        return false;
209    }
210
211    if (src.config() != SkBitmap::kARGB_8888_Config) {
212        return false;
213    }
214
215    if (!fConvolveAlpha && !src.isOpaque()) {
216        src = unpremultiplyBitmap(src);
217    }
218
219    SkAutoLockPixels alp(src);
220    if (!src.getPixels()) {
221        return false;
222    }
223
224    result->setConfig(src.config(), src.width(), src.height());
225    result->allocPixels();
226
227    SkIRect interior = SkIRect::MakeXYWH(fTarget.fX, fTarget.fY,
228                                         src.width() - fKernelSize.fWidth + 1,
229                                         src.height() - fKernelSize.fHeight + 1);
230    SkIRect top = SkIRect::MakeWH(src.width(), fTarget.fY);
231    SkIRect bottom = SkIRect::MakeLTRB(0, interior.bottom(),
232                                       src.width(), src.height());
233    SkIRect left = SkIRect::MakeXYWH(0, interior.top(),
234                                     fTarget.fX, interior.height());
235    SkIRect right = SkIRect::MakeLTRB(interior.right(), interior.top(),
236                                      src.width(), interior.bottom());
237    filterBorderPixels(src, result, top);
238    filterBorderPixels(src, result, left);
239    filterInteriorPixels(src, result, interior);
240    filterBorderPixels(src, result, right);
241    filterBorderPixels(src, result, bottom);
242    return true;
243}
244
245#if SK_SUPPORT_GPU
246
247///////////////////////////////////////////////////////////////////////////////
248
249class GrGLMatrixConvolutionEffect;
250
251class GrMatrixConvolutionEffect : public GrSingleTextureEffect {
252public:
253    typedef SkMatrixConvolutionImageFilter::TileMode TileMode;
254    static GrEffectRef* Create(GrTexture* texture,
255                               const SkISize& kernelSize,
256                               const SkScalar* kernel,
257                               SkScalar gain,
258                               SkScalar bias,
259                               const SkIPoint& target,
260                               TileMode tileMode,
261                               bool convolveAlpha) {
262        AutoEffectUnref effect(SkNEW_ARGS(GrMatrixConvolutionEffect, (texture,
263                                                                      kernelSize,
264                                                                      kernel,
265                                                                      gain,
266                                                                      bias,
267                                                                      target,
268                                                                      tileMode,
269                                                                      convolveAlpha)));
270        return CreateEffectRef(effect);
271    }
272    virtual ~GrMatrixConvolutionEffect();
273
274    virtual void getConstantColorComponents(GrColor* color,
275                                            uint32_t* validFlags) const SK_OVERRIDE {
276        // TODO: Try to do better?
277        *validFlags = 0;
278    }
279
280    static const char* Name() { return "MatrixConvolution"; }
281    const SkISize& kernelSize() const { return fKernelSize; }
282    const float* target() const { return fTarget; }
283    const float* kernel() const { return fKernel; }
284    float gain() const { return fGain; }
285    float bias() const { return fBias; }
286    TileMode tileMode() const { return fTileMode; }
287    bool convolveAlpha() const { return fConvolveAlpha; }
288
289    typedef GrGLMatrixConvolutionEffect GLEffect;
290
291    virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE;
292
293private:
294    GrMatrixConvolutionEffect(GrTexture*,
295                              const SkISize& kernelSize,
296                              const SkScalar* kernel,
297                              SkScalar gain,
298                              SkScalar bias,
299                              const SkIPoint& target,
300                              TileMode tileMode,
301                              bool convolveAlpha);
302
303    virtual bool onIsEqual(const GrEffect&) const SK_OVERRIDE;
304
305    SkISize  fKernelSize;
306    float   *fKernel;
307    float    fGain;
308    float    fBias;
309    float    fTarget[2];
310    TileMode fTileMode;
311    bool     fConvolveAlpha;
312
313    GR_DECLARE_EFFECT_TEST;
314
315    typedef GrSingleTextureEffect INHERITED;
316};
317
318class GrGLMatrixConvolutionEffect : public GrGLEffect {
319public:
320    GrGLMatrixConvolutionEffect(const GrBackendEffectFactory& factory,
321                                const GrDrawEffect& effect);
322    virtual void emitCode(GrGLShaderBuilder*,
323                          const GrDrawEffect&,
324                          EffectKey,
325                          const char* outputColor,
326                          const char* inputColor,
327                          const TextureSamplerArray&) SK_OVERRIDE;
328
329    static inline EffectKey GenKey(const GrDrawEffect&, const GrGLCaps&);
330
331    virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE;
332
333private:
334    typedef GrGLUniformManager::UniformHandle        UniformHandle;
335    typedef SkMatrixConvolutionImageFilter::TileMode TileMode;
336    SkISize             fKernelSize;
337    TileMode            fTileMode;
338    bool                fConvolveAlpha;
339
340    UniformHandle       fKernelUni;
341    UniformHandle       fImageIncrementUni;
342    UniformHandle       fTargetUni;
343    UniformHandle       fGainUni;
344    UniformHandle       fBiasUni;
345
346    GrGLEffectMatrix    fEffectMatrix;
347
348    typedef GrGLEffect INHERITED;
349};
350
351GrGLMatrixConvolutionEffect::GrGLMatrixConvolutionEffect(const GrBackendEffectFactory& factory,
352                                                         const GrDrawEffect& drawEffect)
353    : INHERITED(factory)
354    , fEffectMatrix(drawEffect.castEffect<GrMatrixConvolutionEffect>().coordsType()) {
355    const GrMatrixConvolutionEffect& m = drawEffect.castEffect<GrMatrixConvolutionEffect>();
356    fKernelSize = m.kernelSize();
357    fTileMode = m.tileMode();
358    fConvolveAlpha = m.convolveAlpha();
359}
360
361static void appendTextureLookup(GrGLShaderBuilder* builder,
362                                const GrGLShaderBuilder::TextureSampler& sampler,
363                                const char* coord,
364                                SkMatrixConvolutionImageFilter::TileMode tileMode) {
365    SkString clampedCoord;
366    switch (tileMode) {
367        case SkMatrixConvolutionImageFilter::kClamp_TileMode:
368            clampedCoord.printf("clamp(%s, 0.0, 1.0)", coord);
369            coord = clampedCoord.c_str();
370            break;
371        case SkMatrixConvolutionImageFilter::kRepeat_TileMode:
372            clampedCoord.printf("fract(%s)", coord);
373            coord = clampedCoord.c_str();
374            break;
375        case SkMatrixConvolutionImageFilter::kClampToBlack_TileMode:
376            builder->fsCodeAppendf("clamp(%s, 0.0, 1.0) != %s ? vec4(0, 0, 0, 0) : ", coord, coord);
377            break;
378    }
379    builder->fsAppendTextureLookup(sampler, coord);
380}
381
382void GrGLMatrixConvolutionEffect::emitCode(GrGLShaderBuilder* builder,
383                                           const GrDrawEffect&,
384                                           EffectKey key,
385                                           const char* outputColor,
386                                           const char* inputColor,
387                                           const TextureSamplerArray& samplers) {
388    SkString coords;
389    fEffectMatrix.emitCodeMakeFSCoords2D(builder, key, &coords);
390    fImageIncrementUni = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
391                                             kVec2f_GrSLType, "ImageIncrement");
392    fKernelUni = builder->addUniformArray(GrGLShaderBuilder::kFragment_Visibility,
393                                             kFloat_GrSLType, "Kernel", fKernelSize.width() * fKernelSize.height());
394    fTargetUni = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
395                                             kVec2f_GrSLType, "Target");
396    fGainUni = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
397                                   kFloat_GrSLType, "Gain");
398    fBiasUni = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
399                                   kFloat_GrSLType, "Bias");
400
401    const char* target = builder->getUniformCStr(fTargetUni);
402    const char* imgInc = builder->getUniformCStr(fImageIncrementUni);
403    const char* kernel = builder->getUniformCStr(fKernelUni);
404    const char* gain = builder->getUniformCStr(fGainUni);
405    const char* bias = builder->getUniformCStr(fBiasUni);
406    int kWidth = fKernelSize.width();
407    int kHeight = fKernelSize.height();
408
409    builder->fsCodeAppend("\t\tvec4 sum = vec4(0, 0, 0, 0);\n");
410    builder->fsCodeAppendf("\t\tvec2 coord = %s - %s * %s;\n", coords.c_str(), target, imgInc);
411    builder->fsCodeAppendf("\t\tfor (int y = 0; y < %d; y++) {\n", kHeight);
412    builder->fsCodeAppendf("\t\t\tfor (int x = 0; x < %d; x++) {\n", kWidth);
413    builder->fsCodeAppendf("\t\t\t\tfloat k = %s[y * %d + x];\n", kernel, kWidth);
414    builder->fsCodeAppendf("\t\t\t\tvec2 coord2 = coord + vec2(x, y) * %s;\n", imgInc);
415    builder->fsCodeAppend("\t\t\t\tvec4 c = ");
416    appendTextureLookup(builder, samplers[0], "coord2", fTileMode);
417    builder->fsCodeAppend(";\n");
418    if (!fConvolveAlpha) {
419        builder->fsCodeAppend("\t\t\t\tc.rgb /= c.a;\n");
420    }
421    builder->fsCodeAppend("\t\t\t\tsum += c * k;\n");
422    builder->fsCodeAppend("\t\t\t}\n");
423    builder->fsCodeAppend("\t\t}\n");
424    if (fConvolveAlpha) {
425        builder->fsCodeAppendf("\t\t%s = sum * %s + %s;\n", outputColor, gain, bias);
426        builder->fsCodeAppendf("\t\t%s.rgb = clamp(%s.rgb, 0.0, %s.a);\n", outputColor, outputColor, outputColor);
427    } else {
428        builder->fsCodeAppend("\t\tvec4 c = ");
429        appendTextureLookup(builder, samplers[0], coords.c_str(), fTileMode);
430        builder->fsCodeAppend(";\n");
431        builder->fsCodeAppendf("\t\t%s.a = c.a;\n", outputColor);
432        builder->fsCodeAppendf("\t\t%s.rgb = sum.rgb * %s + %s;\n", outputColor, gain, bias);
433        builder->fsCodeAppendf("\t\t%s.rgb *= %s.a;\n", outputColor, outputColor);
434    }
435}
436
437namespace {
438
439int encodeXY(int x, int y) {
440    SkASSERT(x >= 1 && y >= 1 && x * y <= 32);
441    if (y < x)
442        return 0x40 | encodeXY(y, x);
443    else
444        return (0x40 >> x) | (y - x);
445}
446
447};
448
449GrGLEffect::EffectKey GrGLMatrixConvolutionEffect::GenKey(const GrDrawEffect& drawEffect,
450                                                          const GrGLCaps&) {
451    const GrMatrixConvolutionEffect& m = drawEffect.castEffect<GrMatrixConvolutionEffect>();
452    EffectKey key = encodeXY(m.kernelSize().width(), m.kernelSize().height());
453    key |= m.tileMode() << 7;
454    key |= m.convolveAlpha() ? 1 << 9 : 0;
455    key <<= GrGLEffectMatrix::kKeyBits;
456    EffectKey matrixKey = GrGLEffectMatrix::GenKey(m.getMatrix(),
457                                                   drawEffect,
458                                                   m.coordsType(),
459                                                   m.texture(0));
460    return key | matrixKey;
461}
462
463void GrGLMatrixConvolutionEffect::setData(const GrGLUniformManager& uman,
464                                          const GrDrawEffect& drawEffect) {
465    const GrMatrixConvolutionEffect& conv = drawEffect.castEffect<GrMatrixConvolutionEffect>();
466    GrTexture& texture = *conv.texture(0);
467    // the code we generated was for a specific kernel size
468    SkASSERT(conv.kernelSize() == fKernelSize);
469    SkASSERT(conv.tileMode() == fTileMode);
470    float imageIncrement[2];
471    float ySign = texture.origin() == kTopLeft_GrSurfaceOrigin ? 1.0f : -1.0f;
472    imageIncrement[0] = 1.0f / texture.width();
473    imageIncrement[1] = ySign / texture.height();
474    uman.set2fv(fImageIncrementUni, 0, 1, imageIncrement);
475    uman.set2fv(fTargetUni, 0, 1, conv.target());
476    uman.set1fv(fKernelUni, 0, fKernelSize.width() * fKernelSize.height(), conv.kernel());
477    uman.set1f(fGainUni, conv.gain());
478    uman.set1f(fBiasUni, conv.bias());
479    fEffectMatrix.setData(uman,
480                          conv.getMatrix(),
481                          drawEffect,
482                          conv.texture(0));
483}
484
485GrMatrixConvolutionEffect::GrMatrixConvolutionEffect(GrTexture* texture,
486                                                     const SkISize& kernelSize,
487                                                     const SkScalar* kernel,
488                                                     SkScalar gain,
489                                                     SkScalar bias,
490                                                     const SkIPoint& target,
491                                                     TileMode tileMode,
492                                                     bool convolveAlpha)
493  : INHERITED(texture, MakeDivByTextureWHMatrix(texture)),
494    fKernelSize(kernelSize),
495    fGain(SkScalarToFloat(gain)),
496    fBias(SkScalarToFloat(bias) / 255.0f),
497    fTileMode(tileMode),
498    fConvolveAlpha(convolveAlpha) {
499    fKernel = new float[kernelSize.width() * kernelSize.height()];
500    for (int i = 0; i < kernelSize.width() * kernelSize.height(); i++) {
501        fKernel[i] = SkScalarToFloat(kernel[i]);
502    }
503    fTarget[0] = static_cast<float>(target.x());
504    fTarget[1] = static_cast<float>(target.y());
505}
506
507GrMatrixConvolutionEffect::~GrMatrixConvolutionEffect() {
508    delete[] fKernel;
509}
510
511const GrBackendEffectFactory& GrMatrixConvolutionEffect::getFactory() const {
512    return GrTBackendEffectFactory<GrMatrixConvolutionEffect>::getInstance();
513}
514
515bool GrMatrixConvolutionEffect::onIsEqual(const GrEffect& sBase) const {
516    const GrMatrixConvolutionEffect& s = CastEffect<GrMatrixConvolutionEffect>(sBase);
517    return this->texture(0) == s.texture(0) &&
518           fKernelSize == s.kernelSize() &&
519           !memcmp(fKernel, s.kernel(), fKernelSize.width() * fKernelSize.height() * sizeof(float)) &&
520           fGain == s.gain() &&
521           fBias == s.bias() &&
522           fTarget == s.target() &&
523           fTileMode == s.tileMode() &&
524           fConvolveAlpha == s.convolveAlpha();
525}
526
527GR_DEFINE_EFFECT_TEST(GrMatrixConvolutionEffect);
528
529// A little bit less than the minimum # uniforms required by DX9SM2 (32).
530// Allows for a 5x5 kernel (or 25x1, for that matter).
531#define MAX_KERNEL_SIZE 25
532
533GrEffectRef* GrMatrixConvolutionEffect::TestCreate(SkRandom* random,
534                                                   GrContext* context,
535                                                   const GrDrawTargetCaps&,
536                                                   GrTexture* textures[]) {
537    int texIdx = random->nextBool() ? GrEffectUnitTest::kSkiaPMTextureIdx :
538                                      GrEffectUnitTest::kAlphaTextureIdx;
539    int width = random->nextRangeU(1, MAX_KERNEL_SIZE);
540    int height = random->nextRangeU(1, MAX_KERNEL_SIZE / width);
541    SkISize kernelSize = SkISize::Make(width, height);
542    SkAutoTDeleteArray<SkScalar> kernel(new SkScalar[width * height]);
543    for (int i = 0; i < width * height; i++) {
544        kernel.get()[i] = random->nextSScalar1();
545    }
546    SkScalar gain = random->nextSScalar1();
547    SkScalar bias = random->nextSScalar1();
548    SkIPoint target = SkIPoint::Make(random->nextRangeU(0, kernelSize.width()),
549                                     random->nextRangeU(0, kernelSize.height()));
550    TileMode tileMode = static_cast<TileMode>(random->nextRangeU(0, 2));
551    bool convolveAlpha = random->nextBool();
552    return GrMatrixConvolutionEffect::Create(textures[texIdx],
553                                             kernelSize,
554                                             kernel.get(),
555                                             gain,
556                                             bias,
557                                             target,
558                                             tileMode,
559                                             convolveAlpha);
560}
561
562bool SkMatrixConvolutionImageFilter::asNewEffect(GrEffectRef** effect,
563                                                 GrTexture* texture,
564                                                 const SkMatrix&) const {
565    if (!effect) {
566        return fKernelSize.width() * fKernelSize.height() <= MAX_KERNEL_SIZE;
567    }
568    SkASSERT(fKernelSize.width() * fKernelSize.height() <= MAX_KERNEL_SIZE);
569    *effect = GrMatrixConvolutionEffect::Create(texture,
570                                                fKernelSize,
571                                                fKernel,
572                                                fGain,
573                                                fBias,
574                                                fTarget,
575                                                fTileMode,
576                                                fConvolveAlpha);
577    return true;
578}
579
580///////////////////////////////////////////////////////////////////////////////
581
582#endif
583