SkBicubicImageFilter.cpp revision 2124446ebbb2e0d13f463bf0fede04a45907b9d3 
1/*
2 * Copyright 2013 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 "SkBicubicImageFilter.h"
9#include "SkBitmap.h"
10#include "SkColorPriv.h"
11#include "SkFlattenableBuffers.h"
12#include "SkMatrix.h"
13#include "SkRect.h"
14#include "SkUnPreMultiply.h"
15
16#if SK_SUPPORT_GPU
17#include "gl/GrGLEffectMatrix.h"
18#include "effects/GrSingleTextureEffect.h"
19#include "GrTBackendEffectFactory.h"
20#include "GrContext.h"
21#include "GrTexture.h"
22#endif
23
24SkBicubicImageFilter::SkBicubicImageFilter(const SkSize& scale, const SkScalar coefficients[16], SkImageFilter* input)
25  : INHERITED(input),
26    fScale(scale) {
27    memcpy(fCoefficients, coefficients, sizeof(fCoefficients));
28}
29
30#define DS(x) SkDoubleToScalar(x)
31
32SkBicubicImageFilter* SkBicubicImageFilter::CreateMitchell(const SkSize& scale,
33                                                           SkImageFilter* input) {
34    static const SkScalar coefficients[16] = {
35        DS( 1.0 / 18.0), DS(-9.0 / 18.0), DS( 15.0 / 18.0), DS( -7.0 / 18.0),
36        DS(16.0 / 18.0), DS( 0.0 / 18.0), DS(-36.0 / 18.0), DS( 21.0 / 18.0),
37        DS( 1.0 / 18.0), DS( 9.0 / 18.0), DS( 27.0 / 18.0), DS(-21.0 / 18.0),
38        DS( 0.0 / 18.0), DS( 0.0 / 18.0), DS( -6.0 / 18.0), DS(  7.0 / 18.0),
39    };
40    return SkNEW_ARGS(SkBicubicImageFilter, (scale, coefficients, input));
41}
42
43SkBicubicImageFilter::SkBicubicImageFilter(SkFlattenableReadBuffer& buffer) : INHERITED(buffer) {
44    SkDEBUGCODE(uint32_t readSize =) buffer.readScalarArray(fCoefficients);
45    SkASSERT(readSize == 16);
46    fScale.fWidth = buffer.readScalar();
47    fScale.fHeight = buffer.readScalar();
48}
49
50void SkBicubicImageFilter::flatten(SkFlattenableWriteBuffer& buffer) const {
51    this->INHERITED::flatten(buffer);
52    buffer.writeScalarArray(fCoefficients, 16);
53    buffer.writeScalar(fScale.fWidth);
54    buffer.writeScalar(fScale.fHeight);
55}
56
57SkBicubicImageFilter::~SkBicubicImageFilter() {
58}
59
60inline SkPMColor cubicBlend(const SkScalar c[16], SkScalar t, SkPMColor c0, SkPMColor c1, SkPMColor c2, SkPMColor c3) {
61    SkScalar t2 = t * t, t3 = t2 * t;
62    SkScalar cc[4];
63    // FIXME:  For the fractx case, this should be refactored out of this function.
64    cc[0] = c[0]  + SkScalarMul(c[1], t) + SkScalarMul(c[2], t2) + SkScalarMul(c[3], t3);
65    cc[1] = c[4]  + SkScalarMul(c[5], t) + SkScalarMul(c[6], t2) + SkScalarMul(c[7], t3);
66    cc[2] = c[8]  + SkScalarMul(c[9], t) + SkScalarMul(c[10], t2) + SkScalarMul(c[11], t3);
67    cc[3] = c[12] + SkScalarMul(c[13], t) + SkScalarMul(c[14], t2) + SkScalarMul(c[15], t3);
68    SkScalar a = SkScalarMul(cc[0], SkGetPackedA32(c0)) + SkScalarMul(cc[1], SkGetPackedA32(c1)) + SkScalarMul(cc[2], SkGetPackedA32(c2)) + SkScalarMul(cc[3], SkGetPackedA32(c3));
69    SkScalar r = SkScalarMul(cc[0], SkGetPackedR32(c0)) + SkScalarMul(cc[1], SkGetPackedR32(c1)) + SkScalarMul(cc[2], SkGetPackedR32(c2)) + SkScalarMul(cc[3], SkGetPackedR32(c3));
70    SkScalar g = SkScalarMul(cc[0], SkGetPackedG32(c0)) + SkScalarMul(cc[1], SkGetPackedG32(c1)) + SkScalarMul(cc[2], SkGetPackedG32(c2)) + SkScalarMul(cc[3], SkGetPackedG32(c3));
71    SkScalar b = SkScalarMul(cc[0], SkGetPackedB32(c0)) + SkScalarMul(cc[1], SkGetPackedB32(c1)) + SkScalarMul(cc[2], SkGetPackedB32(c2)) + SkScalarMul(cc[3], SkGetPackedB32(c3));
72    return SkPackARGB32(SkScalarRoundToInt(SkScalarClampMax(a, 255)), SkScalarRoundToInt(SkScalarClampMax(r, 255)), SkScalarRoundToInt(SkScalarClampMax(g, 255)), SkScalarRoundToInt(SkScalarClampMax(b, 255)));
73}
74
75bool SkBicubicImageFilter::onFilterImage(Proxy* proxy,
76                                         const SkBitmap& source,
77                                         const SkMatrix& matrix,
78                                         SkBitmap* result,
79                                         SkIPoint* loc) {
80    SkBitmap src = this->getInputResult(proxy, source, matrix, loc);
81    if (src.config() != SkBitmap::kARGB_8888_Config) {
82        return false;
83    }
84
85    SkAutoLockPixels alp(src);
86    if (!src.getPixels()) {
87        return false;
88    }
89
90    SkRect dstRect = SkRect::MakeWH(SkScalarMul(SkIntToScalar(src.width()), fScale.fWidth),
91                                    SkScalarMul(SkIntToScalar(src.height()), fScale.fHeight));
92    SkIRect dstIRect;
93    dstRect.roundOut(&dstIRect);
94    result->setConfig(src.config(), dstIRect.width(), dstIRect.height());
95    result->allocPixels();
96    if (!result->getPixels()) {
97        return false;
98    }
99
100    SkRect srcRect;
101    src.getBounds(&srcRect);
102    SkMatrix inverse;
103    inverse.setRectToRect(dstRect, srcRect, SkMatrix::kFill_ScaleToFit);
104    inverse.postTranslate(SkFloatToScalar(-0.5f), SkFloatToScalar(-0.5f));
105
106    for (int y = dstIRect.fTop; y < dstIRect.fBottom; ++y) {
107        SkPMColor* dptr = result->getAddr32(dstIRect.fLeft, y);
108        for (int x = dstIRect.fLeft; x < dstIRect.fRight; ++x) {
109            SkPoint srcPt, dstPt = SkPoint::Make(SkIntToScalar(x), SkIntToScalar(y));
110            inverse.mapPoints(&srcPt, &dstPt, 1);
111            SkScalar fractx = srcPt.fX - SkScalarFloorToScalar(srcPt.fX);
112            SkScalar fracty = srcPt.fY - SkScalarFloorToScalar(srcPt.fY);
113            int sx = SkScalarFloorToInt(srcPt.fX);
114            int sy = SkScalarFloorToInt(srcPt.fY);
115            int x0 = SkClampMax(sx - 1, src.width() - 1);
116            int x1 = SkClampMax(sx    , src.width() - 1);
117            int x2 = SkClampMax(sx + 1, src.width() - 1);
118            int x3 = SkClampMax(sx + 2, src.width() - 1);
119            int y0 = SkClampMax(sy - 1, src.height() - 1);
120            int y1 = SkClampMax(sy    , src.height() - 1);
121            int y2 = SkClampMax(sy + 1, src.height() - 1);
122            int y3 = SkClampMax(sy + 2, src.height() - 1);
123            SkPMColor s00 = *src.getAddr32(x0, y0);
124            SkPMColor s10 = *src.getAddr32(x1, y0);
125            SkPMColor s20 = *src.getAddr32(x2, y0);
126            SkPMColor s30 = *src.getAddr32(x3, y0);
127            SkPMColor s0 = cubicBlend(fCoefficients, fractx, s00, s10, s20, s30);
128            SkPMColor s01 = *src.getAddr32(x0, y1);
129            SkPMColor s11 = *src.getAddr32(x1, y1);
130            SkPMColor s21 = *src.getAddr32(x2, y1);
131            SkPMColor s31 = *src.getAddr32(x3, y1);
132            SkPMColor s1 = cubicBlend(fCoefficients, fractx, s01, s11, s21, s31);
133            SkPMColor s02 = *src.getAddr32(x0, y2);
134            SkPMColor s12 = *src.getAddr32(x1, y2);
135            SkPMColor s22 = *src.getAddr32(x2, y2);
136            SkPMColor s32 = *src.getAddr32(x3, y2);
137            SkPMColor s2 = cubicBlend(fCoefficients, fractx, s02, s12, s22, s32);
138            SkPMColor s03 = *src.getAddr32(x0, y3);
139            SkPMColor s13 = *src.getAddr32(x1, y3);
140            SkPMColor s23 = *src.getAddr32(x2, y3);
141            SkPMColor s33 = *src.getAddr32(x3, y3);
142            SkPMColor s3 = cubicBlend(fCoefficients, fractx, s03, s13, s23, s33);
143            *dptr++ = cubicBlend(fCoefficients, fracty, s0, s1, s2, s3);
144        }
145    }
146    return true;
147}
148
149///////////////////////////////////////////////////////////////////////////////
150
151#if SK_SUPPORT_GPU
152
153class GrGLBicubicEffect;
154
155class GrBicubicEffect : public GrSingleTextureEffect {
156public:
157    virtual ~GrBicubicEffect();
158
159    static const char* Name() { return "Bicubic"; }
160    const float* coefficients() const { return fCoefficients; }
161
162    typedef GrGLBicubicEffect GLEffect;
163
164    virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE;
165    virtual bool onIsEqual(const GrEffect&) const SK_OVERRIDE;
166    virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const SK_OVERRIDE;
167
168    static GrEffectRef* Create(GrTexture* tex, const SkScalar coefficients[16]) {
169        SkAutoTUnref<GrEffect> effect(SkNEW_ARGS(GrBicubicEffect, (tex, coefficients)));
170        return CreateEffectRef(effect);
171    }
172
173private:
174    GrBicubicEffect(GrTexture*, const SkScalar coefficients[16]);
175    float    fCoefficients[16];
176
177    GR_DECLARE_EFFECT_TEST;
178
179    typedef GrSingleTextureEffect INHERITED;
180};
181
182class GrGLBicubicEffect : public GrGLEffect {
183public:
184    GrGLBicubicEffect(const GrBackendEffectFactory& factory,
185                                const GrEffect& effect);
186    virtual void emitCode(GrGLShaderBuilder*,
187                          const GrEffectStage&,
188                          EffectKey,
189                          const char* vertexCoords,
190                          const char* outputColor,
191                          const char* inputColor,
192                          const TextureSamplerArray&) SK_OVERRIDE;
193
194    static inline EffectKey GenKey(const GrEffectStage&, const GrGLCaps&);
195
196    virtual void setData(const GrGLUniformManager&, const GrEffectStage&) SK_OVERRIDE;
197
198private:
199    typedef GrGLUniformManager::UniformHandle        UniformHandle;
200
201    UniformHandle       fCoefficientsUni;
202    UniformHandle       fImageIncrementUni;
203
204    GrGLEffectMatrix    fEffectMatrix;
205
206    typedef GrGLEffect INHERITED;
207};
208
209GrGLBicubicEffect::GrGLBicubicEffect(const GrBackendEffectFactory& factory,
210                                     const GrEffect& effect)
211    : INHERITED(factory)
212    , fCoefficientsUni(GrGLUniformManager::kInvalidUniformHandle)
213    , fImageIncrementUni(GrGLUniformManager::kInvalidUniformHandle) {
214}
215
216void GrGLBicubicEffect::emitCode(GrGLShaderBuilder* builder,
217                                 const GrEffectStage&,
218                                 EffectKey key,
219                                 const char* vertexCoords,
220                                 const char* outputColor,
221                                 const char* inputColor,
222                                 const TextureSamplerArray& samplers) {
223    const char* coords;
224    fEffectMatrix.emitCodeMakeFSCoords2D(builder, key, vertexCoords, &coords);
225    fCoefficientsUni = builder->addUniform(GrGLShaderBuilder::kFragment_ShaderType,
226                                           kMat44f_GrSLType, "Coefficients");
227    fImageIncrementUni = builder->addUniform(GrGLShaderBuilder::kFragment_ShaderType,
228                                             kVec2f_GrSLType, "ImageIncrement");
229    SkString* code = &builder->fFSCode;
230
231    const char* imgInc = builder->getUniformCStr(fImageIncrementUni);
232    const char* coeff = builder->getUniformCStr(fCoefficientsUni);
233
234    SkString cubicBlendName;
235
236    static const GrGLShaderVar gCubicBlendArgs[] = {
237        GrGLShaderVar("coefficients",  kMat44f_GrSLType),
238        GrGLShaderVar("t",             kFloat_GrSLType),
239        GrGLShaderVar("c0",            kVec4f_GrSLType),
240        GrGLShaderVar("c1",            kVec4f_GrSLType),
241        GrGLShaderVar("c2",            kVec4f_GrSLType),
242        GrGLShaderVar("c3",            kVec4f_GrSLType),
243    };
244    builder->emitFunction(GrGLShaderBuilder::kFragment_ShaderType,
245                          kVec4f_GrSLType,
246                          "cubicBlend",
247                          SK_ARRAY_COUNT(gCubicBlendArgs),
248                          gCubicBlendArgs,
249                          "\tvec4 ts = vec4(1.0, t, t * t, t * t * t);\n"
250                          "\tvec4 c = coefficients * ts;\n"
251                          "\treturn c.x * c0 + c.y * c1 + c.z * c2 + c.w * c3;\n",
252                          &cubicBlendName);
253    code->appendf("\tvec2 coord = %s - %s * vec2(0.5, 0.5);\n", coords, imgInc);
254    code->appendf("\tvec2 f = fract(coord / %s);\n", imgInc);
255    for (int y = 0; y < 4; ++y) {
256        for (int x = 0; x < 4; ++x) {
257            SkString coord;
258            coord.printf("coord + %s * vec2(%d, %d)", imgInc, x - 1, y - 1);
259            code->appendf("\tvec4 s%d%d = ", x, y);
260            builder->appendTextureLookup(&builder->fFSCode, samplers[0], coord.c_str());
261            code->appendf(";\n");
262        }
263        code->appendf("\tvec4 s%d = %s(%s, f.x, s0%d, s1%d, s2%d, s3%d);\n", y, cubicBlendName.c_str(), coeff, y, y, y, y);
264    }
265    code->appendf("\t%s = %s(%s, f.y, s0, s1, s2, s3);\n", outputColor, cubicBlendName.c_str(), coeff);
266}
267
268GrGLEffect::EffectKey GrGLBicubicEffect::GenKey(const GrEffectStage& s, const GrGLCaps&) {
269    const GrBicubicEffect& m =
270        static_cast<const GrBicubicEffect&>(*s.getEffect());
271    EffectKey matrixKey = GrGLEffectMatrix::GenKey(m.getMatrix(),
272                                                   s.getCoordChangeMatrix(),
273                                                   m.texture(0));
274    return matrixKey;
275}
276
277void GrGLBicubicEffect::setData(const GrGLUniformManager& uman,
278                                const GrEffectStage& stage) {
279    const GrBicubicEffect& effect =
280        static_cast<const GrBicubicEffect&>(*stage.getEffect());
281    GrTexture& texture = *effect.texture(0);
282    float imageIncrement[2];
283    imageIncrement[0] = 1.0f / texture.width();
284    imageIncrement[1] = 1.0f / texture.height();
285    uman.set2fv(fImageIncrementUni, 0, 1, imageIncrement);
286    uman.setMatrix4f(fCoefficientsUni, effect.coefficients());
287    fEffectMatrix.setData(uman,
288                          effect.getMatrix(),
289                          stage.getCoordChangeMatrix(),
290                          effect.texture(0));
291}
292
293GrBicubicEffect::GrBicubicEffect(GrTexture* texture,
294                                 const SkScalar coefficients[16])
295  : INHERITED(texture, MakeDivByTextureWHMatrix(texture)) {
296    for (int y = 0; y < 4; y++) {
297        for (int x = 0; x < 4; x++) {
298            // Convert from row-major scalars to column-major floats.
299            fCoefficients[x * 4 + y] = SkScalarToFloat(coefficients[y * 4 + x]);
300        }
301    }
302}
303
304GrBicubicEffect::~GrBicubicEffect() {
305}
306
307const GrBackendEffectFactory& GrBicubicEffect::getFactory() const {
308    return GrTBackendEffectFactory<GrBicubicEffect>::getInstance();
309}
310
311bool GrBicubicEffect::onIsEqual(const GrEffect& sBase) const {
312    const GrBicubicEffect& s =
313        static_cast<const GrBicubicEffect&>(sBase);
314    return this->texture(0) == s.texture(0) &&
315           !memcmp(fCoefficients, s.coefficients(), 16);
316}
317
318void GrBicubicEffect::getConstantColorComponents(GrColor* color, uint32_t* validFlags) const {
319    // FIXME:  Perhaps we can do better.
320    *validFlags = 0;
321    return;
322}
323
324GR_DEFINE_EFFECT_TEST(GrBicubicEffect);
325
326GrEffectRef* GrBicubicEffect::TestCreate(SkRandom* random,
327                                         GrContext* context,
328                                         GrTexture* textures[]) {
329    int texIdx = random->nextBool() ? GrEffectUnitTest::kSkiaPMTextureIdx :
330                                      GrEffectUnitTest::kAlphaTextureIdx;
331    SkScalar coefficients[16];
332    for (int i = 0; i < 16; i++) {
333        coefficients[i] = random->nextSScalar1();
334    }
335    return GrBicubicEffect::Create(textures[texIdx], coefficients);
336}
337
338GrTexture* SkBicubicImageFilter::filterImageGPU(Proxy* proxy, GrTexture* src, const SkRect& rect) {
339    SkAutoTUnref<GrTexture> srcTexture(this->getInputResultAsTexture(proxy, src, rect));
340    GrContext* context = srcTexture->getContext();
341
342    SkRect dstRect = SkRect::MakeWH(rect.width() * fScale.fWidth,
343                                    rect.height() * fScale.fHeight);
344
345    GrTextureDesc desc;
346    desc.fFlags = kRenderTarget_GrTextureFlagBit | kNoStencil_GrTextureFlagBit;
347    desc.fWidth = SkScalarCeilToInt(dstRect.width());
348    desc.fHeight = SkScalarCeilToInt(dstRect.height());
349    desc.fConfig = kRGBA_8888_GrPixelConfig;
350
351    GrAutoScratchTexture ast(context, desc);
352    if (!ast.texture()) {
353        return NULL;
354    }
355    GrContext::AutoRenderTarget art(context, ast.texture()->asRenderTarget());
356    GrPaint paint;
357    paint.colorStage(0)->setEffect(GrBicubicEffect::Create(srcTexture, fCoefficients));
358    context->drawRectToRect(paint, dstRect, rect);
359    return ast.detach();
360}
361#endif
362
363///////////////////////////////////////////////////////////////////////////////
364