SkMatrixConvolutionImageFilter.cpp revision 8a252f79629b189a03de22cd8ff0312c5bccedd1 
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 SkSingleInputImageFilter 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 = this->getInputResult(proxy, source, matrix, loc);
207    if (src.config() != SkBitmap::kARGB_8888_Config) {
208        return false;
209    }
210
211    if (!fConvolveAlpha && !src.isOpaque()) {
212        src = unpremultiplyBitmap(src);
213    }
214
215    SkAutoLockPixels alp(src);
216    if (!src.getPixels()) {
217        return false;
218    }
219
220    result->setConfig(src.config(), src.width(), src.height());
221    result->allocPixels();
222
223    SkIRect interior = SkIRect::MakeXYWH(fTarget.fX, fTarget.fY,
224                                         src.width() - fKernelSize.fWidth + 1,
225                                         src.height() - fKernelSize.fHeight + 1);
226    SkIRect top = SkIRect::MakeWH(src.width(), fTarget.fY);
227    SkIRect bottom = SkIRect::MakeLTRB(0, interior.bottom(),
228                                       src.width(), src.height());
229    SkIRect left = SkIRect::MakeXYWH(0, interior.top(),
230                                     fTarget.fX, interior.height());
231    SkIRect right = SkIRect::MakeLTRB(interior.right(), interior.top(),
232                                      src.width(), interior.bottom());
233    filterBorderPixels(src, result, top);
234    filterBorderPixels(src, result, left);
235    filterInteriorPixels(src, result, interior);
236    filterBorderPixels(src, result, right);
237    filterBorderPixels(src, result, bottom);
238    return true;
239}
240
241#if SK_SUPPORT_GPU
242
243///////////////////////////////////////////////////////////////////////////////
244
245class GrGLMatrixConvolutionEffect;
246
247class GrMatrixConvolutionEffect : public GrSingleTextureEffect {
248public:
249    typedef SkMatrixConvolutionImageFilter::TileMode TileMode;
250    static GrEffectRef* Create(GrTexture* texture,
251                               const SkISize& kernelSize,
252                               const SkScalar* kernel,
253                               SkScalar gain,
254                               SkScalar bias,
255                               const SkIPoint& target,
256                               TileMode tileMode,
257                               bool convolveAlpha) {
258        AutoEffectUnref effect(SkNEW_ARGS(GrMatrixConvolutionEffect, (texture,
259                                                                      kernelSize,
260                                                                      kernel,
261                                                                      gain,
262                                                                      bias,
263                                                                      target,
264                                                                      tileMode,
265                                                                      convolveAlpha)));
266        return CreateEffectRef(effect);
267    }
268    virtual ~GrMatrixConvolutionEffect();
269
270    virtual void getConstantColorComponents(GrColor* color,
271                                            uint32_t* validFlags) const SK_OVERRIDE {
272        // TODO: Try to do better?
273        *validFlags = 0;
274    }
275
276    static const char* Name() { return "MatrixConvolution"; }
277    const SkISize& kernelSize() const { return fKernelSize; }
278    const float* target() const { return fTarget; }
279    const float* kernel() const { return fKernel; }
280    float gain() const { return fGain; }
281    float bias() const { return fBias; }
282    TileMode tileMode() const { return fTileMode; }
283    bool convolveAlpha() const { return fConvolveAlpha; }
284
285    typedef GrGLMatrixConvolutionEffect GLEffect;
286
287
288
289    virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE;
290
291private:
292    GrMatrixConvolutionEffect(GrTexture*,
293                              const SkISize& kernelSize,
294                              const SkScalar* kernel,
295                              SkScalar gain,
296                              SkScalar bias,
297                              const SkIPoint& target,
298                              TileMode tileMode,
299                              bool convolveAlpha);
300
301    virtual bool onIsEqual(const GrEffect&) const SK_OVERRIDE;
302
303    SkISize  fKernelSize;
304    float   *fKernel;
305    float    fGain;
306    float    fBias;
307    float    fTarget[2];
308    TileMode fTileMode;
309    bool     fConvolveAlpha;
310
311    GR_DECLARE_EFFECT_TEST;
312
313    typedef GrSingleTextureEffect INHERITED;
314};
315
316class GrGLMatrixConvolutionEffect : public GrGLEffect {
317public:
318    GrGLMatrixConvolutionEffect(const GrBackendEffectFactory& factory,
319                                const GrEffectRef& effect);
320    virtual void emitCode(GrGLShaderBuilder*,
321                          const GrEffectStage&,
322                          EffectKey,
323                          const char* vertexCoords,
324                          const char* outputColor,
325                          const char* inputColor,
326                          const TextureSamplerArray&) SK_OVERRIDE;
327
328    static inline EffectKey GenKey(const GrEffectStage&, const GrGLCaps&);
329
330    virtual void setData(const GrGLUniformManager&, const GrEffectStage&) SK_OVERRIDE;
331
332private:
333    typedef GrGLUniformManager::UniformHandle        UniformHandle;
334    typedef SkMatrixConvolutionImageFilter::TileMode TileMode;
335    SkISize             fKernelSize;
336    TileMode            fTileMode;
337    bool                fConvolveAlpha;
338
339    UniformHandle       fKernelUni;
340    UniformHandle       fImageIncrementUni;
341    UniformHandle       fTargetUni;
342    UniformHandle       fGainUni;
343    UniformHandle       fBiasUni;
344
345    GrGLEffectMatrix    fEffectMatrix;
346
347    typedef GrGLEffect INHERITED;
348};
349
350GrGLMatrixConvolutionEffect::GrGLMatrixConvolutionEffect(const GrBackendEffectFactory& factory,
351                                                         const GrEffectRef& effect)
352    : INHERITED(factory)
353    , fKernelUni(GrGLUniformManager::kInvalidUniformHandle)
354    , fImageIncrementUni(GrGLUniformManager::kInvalidUniformHandle)
355    , fTargetUni(GrGLUniformManager::kInvalidUniformHandle)
356    , fGainUni(GrGLUniformManager::kInvalidUniformHandle)
357    , fBiasUni(GrGLUniformManager::kInvalidUniformHandle) {
358    const GrMatrixConvolutionEffect& m = CastEffect<GrMatrixConvolutionEffect>(effect);
359    fKernelSize = m.kernelSize();
360    fTileMode = m.tileMode();
361    fConvolveAlpha = m.convolveAlpha();
362}
363
364static void appendTextureLookup(GrGLShaderBuilder* builder,
365                                const GrGLShaderBuilder::TextureSampler& sampler,
366                                const char* coord,
367                                SkMatrixConvolutionImageFilter::TileMode tileMode) {
368    SkString* code = &builder->fFSCode;
369    SkString clampedCoord;
370    switch (tileMode) {
371        case SkMatrixConvolutionImageFilter::kClamp_TileMode:
372            clampedCoord.printf("clamp(%s, 0.0, 1.0)", coord);
373            coord = clampedCoord.c_str();
374            break;
375        case SkMatrixConvolutionImageFilter::kRepeat_TileMode:
376            clampedCoord.printf("fract(%s)", coord);
377            coord = clampedCoord.c_str();
378            break;
379        case SkMatrixConvolutionImageFilter::kClampToBlack_TileMode:
380            code->appendf("clamp(%s, 0.0, 1.0) != %s ? vec4(0, 0, 0, 0) : ", coord, coord);
381            break;
382    }
383    builder->appendTextureLookup(code, sampler, coord);
384}
385
386void GrGLMatrixConvolutionEffect::emitCode(GrGLShaderBuilder* builder,
387                                           const GrEffectStage&,
388                                           EffectKey key,
389                                           const char* vertexCoords,
390                                           const char* outputColor,
391                                           const char* inputColor,
392                                           const TextureSamplerArray& samplers) {
393    const char* coords;
394    fEffectMatrix.emitCodeMakeFSCoords2D(builder, key, vertexCoords, &coords);
395    fImageIncrementUni = builder->addUniform(GrGLShaderBuilder::kFragment_ShaderType,
396                                             kVec2f_GrSLType, "ImageIncrement");
397    fKernelUni = builder->addUniformArray(GrGLShaderBuilder::kFragment_ShaderType,
398                                             kFloat_GrSLType, "Kernel", fKernelSize.width() * fKernelSize.height());
399    fTargetUni = builder->addUniform(GrGLShaderBuilder::kFragment_ShaderType,
400                                             kVec2f_GrSLType, "Target");
401    fGainUni = builder->addUniform(GrGLShaderBuilder::kFragment_ShaderType,
402                                   kFloat_GrSLType, "Gain");
403    fBiasUni = builder->addUniform(GrGLShaderBuilder::kFragment_ShaderType,
404                                   kFloat_GrSLType, "Bias");
405
406    SkString* code = &builder->fFSCode;
407
408    const char* target = builder->getUniformCStr(fTargetUni);
409    const char* imgInc = builder->getUniformCStr(fImageIncrementUni);
410    const char* kernel = builder->getUniformCStr(fKernelUni);
411    const char* gain = builder->getUniformCStr(fGainUni);
412    const char* bias = builder->getUniformCStr(fBiasUni);
413    int kWidth = fKernelSize.width();
414    int kHeight = fKernelSize.height();
415
416    code->appendf("\t\tvec4 sum = vec4(0, 0, 0, 0);\n");
417    code->appendf("\t\tvec2 coord = %s - %s * %s;\n", coords, target, imgInc);
418    code->appendf("\t\tfor (int y = 0; y < %d; y++) {\n", kHeight);
419    code->appendf("\t\t\tfor (int x = 0; x < %d; x++) {\n", kWidth);
420    code->appendf("\t\t\t\tfloat k = %s[y * %d + x];\n", kernel, kWidth);
421    code->appendf("\t\t\t\tvec2 coord2 = coord + vec2(x, y) * %s;\n", imgInc);
422    code->appendf("\t\t\t\tvec4 c = ");
423    appendTextureLookup(builder, samplers[0], "coord2", fTileMode);
424    code->appendf(";\n");
425    if (!fConvolveAlpha) {
426        code->appendf("\t\t\t\tc.rgb /= c.a;\n");
427    }
428    code->appendf("\t\t\t\tsum += c * k;\n");
429    code->appendf("\t\t\t}\n");
430    code->appendf("\t\t}\n");
431    if (fConvolveAlpha) {
432        code->appendf("\t\t%s = sum * %s + %s;\n", outputColor, gain, bias);
433        code->appendf("\t\t%s.rgb = clamp(%s.rgb, 0.0, %s.a);\n", outputColor, outputColor, outputColor);
434    } else {
435        code->appendf("\t\tvec4 c = ");
436        appendTextureLookup(builder, samplers[0], coords, fTileMode);
437        code->appendf(";\n");
438        code->appendf("\t\t%s.a = c.a;\n", outputColor);
439        code->appendf("\t\t%s.rgb = sum.rgb * %s + %s;\n", outputColor, gain, bias);
440        code->appendf("\t\t%s.rgb *= %s.a;\n", outputColor, outputColor);
441    }
442}
443
444namespace {
445
446int encodeXY(int x, int y) {
447    SkASSERT(x >= 1 && y >= 1 && x * y <= 32);
448    if (y < x)
449        return 0x40 | encodeXY(y, x);
450    else
451        return (0x40 >> x) | (y - x);
452}
453
454};
455
456GrGLEffect::EffectKey GrGLMatrixConvolutionEffect::GenKey(const GrEffectStage& s, const GrGLCaps&) {
457    const GrMatrixConvolutionEffect& m = GetEffectFromStage<GrMatrixConvolutionEffect>(s);
458    EffectKey key = encodeXY(m.kernelSize().width(), m.kernelSize().height());
459    key |= m.tileMode() << 7;
460    key |= m.convolveAlpha() ? 1 << 9 : 0;
461    key <<= GrGLEffectMatrix::kKeyBits;
462    EffectKey matrixKey = GrGLEffectMatrix::GenKey(m.getMatrix(),
463                                                   s.getCoordChangeMatrix(),
464                                                   m.texture(0));
465    return key | matrixKey;
466}
467
468void GrGLMatrixConvolutionEffect::setData(const GrGLUniformManager& uman,
469                                          const GrEffectStage& stage) {
470    const GrMatrixConvolutionEffect& effect = GetEffectFromStage<GrMatrixConvolutionEffect>(stage);
471    GrTexture& texture = *effect.texture(0);
472    // the code we generated was for a specific kernel size
473    GrAssert(effect.kernelSize() == fKernelSize);
474    GrAssert(effect.tileMode() == fTileMode);
475    float imageIncrement[2];
476    float ySign = texture.origin() == GrSurface::kTopLeft_Origin ? 1.0f : -1.0f;
477    imageIncrement[0] = 1.0f / texture.width();
478    imageIncrement[1] = ySign / texture.height();
479    uman.set2fv(fImageIncrementUni, 0, 1, imageIncrement);
480    uman.set2fv(fTargetUni, 0, 1, effect.target());
481    uman.set1fv(fKernelUni, 0, fKernelSize.width() * fKernelSize.height(), effect.kernel());
482    uman.set1f(fGainUni, effect.gain());
483    uman.set1f(fBiasUni, effect.bias());
484    fEffectMatrix.setData(uman,
485                          effect.getMatrix(),
486                          stage.getCoordChangeMatrix(),
487                          effect.texture(0));
488}
489
490GrMatrixConvolutionEffect::GrMatrixConvolutionEffect(GrTexture* texture,
491                                                     const SkISize& kernelSize,
492                                                     const SkScalar* kernel,
493                                                     SkScalar gain,
494                                                     SkScalar bias,
495                                                     const SkIPoint& target,
496                                                     TileMode tileMode,
497                                                     bool convolveAlpha)
498  : INHERITED(texture, MakeDivByTextureWHMatrix(texture)),
499    fKernelSize(kernelSize),
500    fGain(SkScalarToFloat(gain)),
501    fBias(SkScalarToFloat(bias) / 255.0f),
502    fTileMode(tileMode),
503    fConvolveAlpha(convolveAlpha) {
504    fKernel = new float[kernelSize.width() * kernelSize.height()];
505    for (int i = 0; i < kernelSize.width() * kernelSize.height(); i++) {
506        fKernel[i] = SkScalarToFloat(kernel[i]);
507    }
508    fTarget[0] = static_cast<float>(target.x());
509    fTarget[1] = static_cast<float>(target.y());
510}
511
512GrMatrixConvolutionEffect::~GrMatrixConvolutionEffect() {
513    delete[] fKernel;
514}
515
516const GrBackendEffectFactory& GrMatrixConvolutionEffect::getFactory() const {
517    return GrTBackendEffectFactory<GrMatrixConvolutionEffect>::getInstance();
518}
519
520bool GrMatrixConvolutionEffect::onIsEqual(const GrEffect& sBase) const {
521    const GrMatrixConvolutionEffect& s = CastEffect<GrMatrixConvolutionEffect>(sBase);
522    return this->texture(0) == s.texture(0) &&
523           fKernelSize == s.kernelSize() &&
524           !memcmp(fKernel, s.kernel(), fKernelSize.width() * fKernelSize.height() * sizeof(float)) &&
525           fGain == s.gain() &&
526           fBias == s.bias() &&
527           fTarget == s.target() &&
528           fTileMode == s.tileMode() &&
529           fConvolveAlpha == s.convolveAlpha();
530}
531
532GR_DEFINE_EFFECT_TEST(GrMatrixConvolutionEffect);
533
534// A little bit less than the minimum # uniforms required by DX9SM2 (32).
535// Allows for a 5x5 kernel (or 25x1, for that matter).
536#define MAX_KERNEL_SIZE 25
537
538GrEffectRef* GrMatrixConvolutionEffect::TestCreate(SkRandom* random,
539                                                   GrContext* context,
540                                                   GrTexture* textures[]) {
541    int texIdx = random->nextBool() ? GrEffectUnitTest::kSkiaPMTextureIdx :
542                                      GrEffectUnitTest::kAlphaTextureIdx;
543    int width = random->nextRangeU(1, MAX_KERNEL_SIZE);
544    int height = random->nextRangeU(1, MAX_KERNEL_SIZE / width);
545    SkISize kernelSize = SkISize::Make(width, height);
546    SkScalar* kernel = new SkScalar[width * height];
547    for (int i = 0; i < width * height; i++) {
548        kernel[i] = random->nextSScalar1();
549    }
550    SkScalar gain = random->nextSScalar1();
551    SkScalar bias = random->nextSScalar1();
552    SkIPoint target = SkIPoint::Make(random->nextRangeU(0, kernelSize.width()),
553                                     random->nextRangeU(0, kernelSize.height()));
554    TileMode tileMode = static_cast<TileMode>(random->nextRangeU(0, 2));
555    bool convolveAlpha = random->nextBool();
556    return GrMatrixConvolutionEffect::Create(textures[texIdx],
557                                             kernelSize,
558                                             kernel,
559                                             gain,
560                                             bias,
561                                             target,
562                                             tileMode,
563                                             convolveAlpha);
564
565}
566
567bool SkMatrixConvolutionImageFilter::asNewEffect(GrEffectRef** effect,
568                                                 GrTexture* texture) const {
569    bool ok = fKernelSize.width() * fKernelSize.height() <= MAX_KERNEL_SIZE;
570    if (ok && effect) {
571        *effect = GrMatrixConvolutionEffect::Create(texture,
572                                                    fKernelSize,
573                                                    fKernel,
574                                                    fGain,
575                                                    fBias,
576                                                     fTarget,
577                                                     fTileMode,
578                                                     fConvolveAlpha);
579    }
580    return ok;
581}
582
583///////////////////////////////////////////////////////////////////////////////
584
585#endif
586