SkBicubicImageFilter.cpp revision 74a3a2135ca82ab9324b7e499caa3280348a4fda 
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#include "SkImageFilterUtils.h"
23#endif
24
25SkBicubicImageFilter::SkBicubicImageFilter(const SkSize& scale, const SkScalar coefficients[16], SkImageFilter* input)
26  : INHERITED(input),
27    fScale(scale) {
28    memcpy(fCoefficients, coefficients, sizeof(fCoefficients));
29}
30
31#define DS(x) SkDoubleToScalar(x)
32
33SkBicubicImageFilter* SkBicubicImageFilter::CreateMitchell(const SkSize& scale,
34                                                           SkImageFilter* input) {
35    static const SkScalar coefficients[16] = {
36        DS( 1.0 / 18.0), DS(-9.0 / 18.0), DS( 15.0 / 18.0), DS( -7.0 / 18.0),
37        DS(16.0 / 18.0), DS( 0.0 / 18.0), DS(-36.0 / 18.0), DS( 21.0 / 18.0),
38        DS( 1.0 / 18.0), DS( 9.0 / 18.0), DS( 27.0 / 18.0), DS(-21.0 / 18.0),
39        DS( 0.0 / 18.0), DS( 0.0 / 18.0), DS( -6.0 / 18.0), DS(  7.0 / 18.0),
40    };
41    return SkNEW_ARGS(SkBicubicImageFilter, (scale, coefficients, input));
42}
43
44SkBicubicImageFilter::SkBicubicImageFilter(SkFlattenableReadBuffer& buffer) : INHERITED(buffer) {
45    SkDEBUGCODE(uint32_t readSize =) buffer.readScalarArray(fCoefficients);
46    SkASSERT(readSize == 16);
47    fScale.fWidth = buffer.readScalar();
48    fScale.fHeight = buffer.readScalar();
49}
50
51void SkBicubicImageFilter::flatten(SkFlattenableWriteBuffer& buffer) const {
52    this->INHERITED::flatten(buffer);
53    buffer.writeScalarArray(fCoefficients, 16);
54    buffer.writeScalar(fScale.fWidth);
55    buffer.writeScalar(fScale.fHeight);
56}
57
58SkBicubicImageFilter::~SkBicubicImageFilter() {
59}
60
61inline SkPMColor cubicBlend(const SkScalar c[16], SkScalar t, SkPMColor c0, SkPMColor c1, SkPMColor c2, SkPMColor c3) {
62    SkScalar t2 = t * t, t3 = t2 * t;
63    SkScalar cc[4];
64    // FIXME:  For the fractx case, this should be refactored out of this function.
65    cc[0] = c[0]  + SkScalarMul(c[1], t) + SkScalarMul(c[2], t2) + SkScalarMul(c[3], t3);
66    cc[1] = c[4]  + SkScalarMul(c[5], t) + SkScalarMul(c[6], t2) + SkScalarMul(c[7], t3);
67    cc[2] = c[8]  + SkScalarMul(c[9], t) + SkScalarMul(c[10], t2) + SkScalarMul(c[11], t3);
68    cc[3] = c[12] + SkScalarMul(c[13], t) + SkScalarMul(c[14], t2) + SkScalarMul(c[15], t3);
69    SkScalar a = SkScalarClampMax(SkScalarMul(cc[0], SkGetPackedA32(c0)) + SkScalarMul(cc[1], SkGetPackedA32(c1)) + SkScalarMul(cc[2], SkGetPackedA32(c2)) + SkScalarMul(cc[3], SkGetPackedA32(c3)), 255);
70    SkScalar r = SkScalarMul(cc[0], SkGetPackedR32(c0)) + SkScalarMul(cc[1], SkGetPackedR32(c1)) + SkScalarMul(cc[2], SkGetPackedR32(c2)) + SkScalarMul(cc[3], SkGetPackedR32(c3));
71    SkScalar g = SkScalarMul(cc[0], SkGetPackedG32(c0)) + SkScalarMul(cc[1], SkGetPackedG32(c1)) + SkScalarMul(cc[2], SkGetPackedG32(c2)) + SkScalarMul(cc[3], SkGetPackedG32(c3));
72    SkScalar b = SkScalarMul(cc[0], SkGetPackedB32(c0)) + SkScalarMul(cc[1], SkGetPackedB32(c1)) + SkScalarMul(cc[2], SkGetPackedB32(c2)) + SkScalarMul(cc[3], SkGetPackedB32(c3));
73    return SkPackARGB32(SkScalarRoundToInt(a),
74                        SkScalarRoundToInt(SkScalarClampMax(r, a)),
75                        SkScalarRoundToInt(SkScalarClampMax(g, a)),
76                        SkScalarRoundToInt(SkScalarClampMax(b, a)));
77}
78
79bool SkBicubicImageFilter::onFilterImage(Proxy* proxy,
80                                         const SkBitmap& source,
81                                         const SkMatrix& matrix,
82                                         SkBitmap* result,
83                                         SkIPoint* loc) {
84    SkBitmap src = source;
85    if (getInput(0) && !getInput(0)->filterImage(proxy, source, matrix, &src, loc)) {
86        return false;
87    }
88
89    if (src.config() != SkBitmap::kARGB_8888_Config) {
90        return false;
91    }
92
93    SkAutoLockPixels alp(src);
94    if (!src.getPixels()) {
95        return false;
96    }
97
98    SkRect dstRect = SkRect::MakeWH(SkScalarMul(SkIntToScalar(src.width()), fScale.fWidth),
99                                    SkScalarMul(SkIntToScalar(src.height()), fScale.fHeight));
100    SkIRect dstIRect;
101    dstRect.roundOut(&dstIRect);
102    result->setConfig(src.config(), dstIRect.width(), dstIRect.height());
103    result->allocPixels();
104    if (!result->getPixels()) {
105        return false;
106    }
107
108    SkRect srcRect;
109    src.getBounds(&srcRect);
110    SkMatrix inverse;
111    inverse.setRectToRect(dstRect, srcRect, SkMatrix::kFill_ScaleToFit);
112    inverse.postTranslate(SkFloatToScalar(-0.5f), SkFloatToScalar(-0.5f));
113
114    for (int y = dstIRect.fTop; y < dstIRect.fBottom; ++y) {
115        SkPMColor* dptr = result->getAddr32(dstIRect.fLeft, y);
116        for (int x = dstIRect.fLeft; x < dstIRect.fRight; ++x) {
117            SkPoint srcPt, dstPt = SkPoint::Make(SkIntToScalar(x), SkIntToScalar(y));
118            inverse.mapPoints(&srcPt, &dstPt, 1);
119            SkScalar fractx = srcPt.fX - SkScalarFloorToScalar(srcPt.fX);
120            SkScalar fracty = srcPt.fY - SkScalarFloorToScalar(srcPt.fY);
121            int sx = SkScalarFloorToInt(srcPt.fX);
122            int sy = SkScalarFloorToInt(srcPt.fY);
123            int x0 = SkClampMax(sx - 1, src.width() - 1);
124            int x1 = SkClampMax(sx    , src.width() - 1);
125            int x2 = SkClampMax(sx + 1, src.width() - 1);
126            int x3 = SkClampMax(sx + 2, src.width() - 1);
127            int y0 = SkClampMax(sy - 1, src.height() - 1);
128            int y1 = SkClampMax(sy    , src.height() - 1);
129            int y2 = SkClampMax(sy + 1, src.height() - 1);
130            int y3 = SkClampMax(sy + 2, src.height() - 1);
131            SkPMColor s00 = *src.getAddr32(x0, y0);
132            SkPMColor s10 = *src.getAddr32(x1, y0);
133            SkPMColor s20 = *src.getAddr32(x2, y0);
134            SkPMColor s30 = *src.getAddr32(x3, y0);
135            SkPMColor s0 = cubicBlend(fCoefficients, fractx, s00, s10, s20, s30);
136            SkPMColor s01 = *src.getAddr32(x0, y1);
137            SkPMColor s11 = *src.getAddr32(x1, y1);
138            SkPMColor s21 = *src.getAddr32(x2, y1);
139            SkPMColor s31 = *src.getAddr32(x3, y1);
140            SkPMColor s1 = cubicBlend(fCoefficients, fractx, s01, s11, s21, s31);
141            SkPMColor s02 = *src.getAddr32(x0, y2);
142            SkPMColor s12 = *src.getAddr32(x1, y2);
143            SkPMColor s22 = *src.getAddr32(x2, y2);
144            SkPMColor s32 = *src.getAddr32(x3, y2);
145            SkPMColor s2 = cubicBlend(fCoefficients, fractx, s02, s12, s22, s32);
146            SkPMColor s03 = *src.getAddr32(x0, y3);
147            SkPMColor s13 = *src.getAddr32(x1, y3);
148            SkPMColor s23 = *src.getAddr32(x2, y3);
149            SkPMColor s33 = *src.getAddr32(x3, y3);
150            SkPMColor s3 = cubicBlend(fCoefficients, fractx, s03, s13, s23, s33);
151            *dptr++ = cubicBlend(fCoefficients, fracty, s0, s1, s2, s3);
152        }
153    }
154    return true;
155}
156
157///////////////////////////////////////////////////////////////////////////////
158
159#if SK_SUPPORT_GPU
160class GrGLBicubicEffect;
161
162class GrBicubicEffect : public GrSingleTextureEffect {
163public:
164    virtual ~GrBicubicEffect();
165
166    static const char* Name() { return "Bicubic"; }
167    const float* coefficients() const { return fCoefficients; }
168
169    typedef GrGLBicubicEffect GLEffect;
170
171    virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE;
172    virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const SK_OVERRIDE;
173
174    static GrEffectRef* Create(GrTexture* tex, const SkScalar coefficients[16]) {
175        AutoEffectUnref effect(SkNEW_ARGS(GrBicubicEffect, (tex, coefficients)));
176        return CreateEffectRef(effect);
177    }
178
179private:
180    GrBicubicEffect(GrTexture*, const SkScalar coefficients[16]);
181    virtual bool onIsEqual(const GrEffect&) const SK_OVERRIDE;
182    float    fCoefficients[16];
183
184    GR_DECLARE_EFFECT_TEST;
185
186    typedef GrSingleTextureEffect INHERITED;
187};
188
189class GrGLBicubicEffect : public GrGLEffect {
190public:
191    GrGLBicubicEffect(const GrBackendEffectFactory& factory,
192                      const GrDrawEffect&);
193    virtual void emitCode(GrGLShaderBuilder*,
194                          const GrDrawEffect&,
195                          EffectKey,
196                          const char* outputColor,
197                          const char* inputColor,
198                          const TextureSamplerArray&) SK_OVERRIDE;
199
200    static inline EffectKey GenKey(const GrDrawEffect&, const GrGLCaps&);
201
202    virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE;
203
204private:
205    typedef GrGLUniformManager::UniformHandle        UniformHandle;
206
207    UniformHandle       fCoefficientsUni;
208    UniformHandle       fImageIncrementUni;
209
210    GrGLEffectMatrix    fEffectMatrix;
211
212    typedef GrGLEffect INHERITED;
213};
214
215GrGLBicubicEffect::GrGLBicubicEffect(const GrBackendEffectFactory& factory,
216                                     const GrDrawEffect& drawEffect)
217    : INHERITED(factory)
218    , fEffectMatrix(drawEffect.castEffect<GrBicubicEffect>().coordsType()) {
219}
220
221void GrGLBicubicEffect::emitCode(GrGLShaderBuilder* builder,
222                                 const GrDrawEffect&,
223                                 EffectKey key,
224                                 const char* outputColor,
225                                 const char* inputColor,
226                                 const TextureSamplerArray& samplers) {
227    SkString coords;
228    fEffectMatrix.emitCodeMakeFSCoords2D(builder, key, &coords);
229    fCoefficientsUni = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
230                                           kMat44f_GrSLType, "Coefficients");
231    fImageIncrementUni = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
232                                             kVec2f_GrSLType, "ImageIncrement");
233
234    const char* imgInc = builder->getUniformCStr(fImageIncrementUni);
235    const char* coeff = builder->getUniformCStr(fCoefficientsUni);
236
237    SkString cubicBlendName;
238
239    static const GrGLShaderVar gCubicBlendArgs[] = {
240        GrGLShaderVar("coefficients",  kMat44f_GrSLType),
241        GrGLShaderVar("t",             kFloat_GrSLType),
242        GrGLShaderVar("c0",            kVec4f_GrSLType),
243        GrGLShaderVar("c1",            kVec4f_GrSLType),
244        GrGLShaderVar("c2",            kVec4f_GrSLType),
245        GrGLShaderVar("c3",            kVec4f_GrSLType),
246    };
247    builder->fsEmitFunction(kVec4f_GrSLType,
248                            "cubicBlend",
249                            SK_ARRAY_COUNT(gCubicBlendArgs),
250                            gCubicBlendArgs,
251                            "\tvec4 ts = vec4(1.0, t, t * t, t * t * t);\n"
252                            "\tvec4 c = coefficients * ts;\n"
253                            "\treturn c.x * c0 + c.y * c1 + c.z * c2 + c.w * c3;\n",
254                            &cubicBlendName);
255    builder->fsCodeAppendf("\tvec2 coord = %s - %s * vec2(0.5, 0.5);\n", coords.c_str(), imgInc);
256    builder->fsCodeAppendf("\tvec2 f = fract(coord / %s);\n", imgInc);
257    for (int y = 0; y < 4; ++y) {
258        for (int x = 0; x < 4; ++x) {
259            SkString coord;
260            coord.printf("coord + %s * vec2(%d, %d)", imgInc, x - 1, y - 1);
261            builder->fsCodeAppendf("\tvec4 s%d%d = ", x, y);
262            builder->fsAppendTextureLookup(samplers[0], coord.c_str());
263            builder->fsCodeAppend(";\n");
264        }
265        builder->fsCodeAppendf("\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);
266    }
267    builder->fsCodeAppendf("\t%s = %s(%s, f.y, s0, s1, s2, s3);\n", outputColor, cubicBlendName.c_str(), coeff);
268}
269
270GrGLEffect::EffectKey GrGLBicubicEffect::GenKey(const GrDrawEffect& drawEffect, const GrGLCaps&) {
271    const GrBicubicEffect& bicubic = drawEffect.castEffect<GrBicubicEffect>();
272    EffectKey matrixKey = GrGLEffectMatrix::GenKey(bicubic.getMatrix(),
273                                                   drawEffect,
274                                                   bicubic.coordsType(),
275                                                   bicubic.texture(0));
276    return matrixKey;
277}
278
279void GrGLBicubicEffect::setData(const GrGLUniformManager& uman,
280                                const GrDrawEffect& drawEffect) {
281    const GrBicubicEffect& effect = drawEffect.castEffect<GrBicubicEffect>();
282    GrTexture& texture = *effect.texture(0);
283    float imageIncrement[2];
284    imageIncrement[0] = 1.0f / texture.width();
285    imageIncrement[1] = 1.0f / texture.height();
286    uman.set2fv(fImageIncrementUni, 0, 1, imageIncrement);
287    uman.setMatrix4f(fCoefficientsUni, effect.coefficients());
288    fEffectMatrix.setData(uman,
289                          effect.getMatrix(),
290                          drawEffect,
291                          effect.texture(0));
292}
293
294GrBicubicEffect::GrBicubicEffect(GrTexture* texture,
295                                 const SkScalar coefficients[16])
296  : INHERITED(texture, MakeDivByTextureWHMatrix(texture)) {
297    for (int y = 0; y < 4; y++) {
298        for (int x = 0; x < 4; x++) {
299            // Convert from row-major scalars to column-major floats.
300            fCoefficients[x * 4 + y] = SkScalarToFloat(coefficients[y * 4 + x]);
301        }
302    }
303}
304
305GrBicubicEffect::~GrBicubicEffect() {
306}
307
308const GrBackendEffectFactory& GrBicubicEffect::getFactory() const {
309    return GrTBackendEffectFactory<GrBicubicEffect>::getInstance();
310}
311
312bool GrBicubicEffect::onIsEqual(const GrEffect& sBase) const {
313    const GrBicubicEffect& s = CastEffect<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(SkMWCRandom* random,
327                                         GrContext* context,
328                                         const GrDrawTargetCaps&,
329                                         GrTexture* textures[]) {
330    int texIdx = random->nextBool() ? GrEffectUnitTest::kSkiaPMTextureIdx :
331                                      GrEffectUnitTest::kAlphaTextureIdx;
332    SkScalar coefficients[16];
333    for (int i = 0; i < 16; i++) {
334        coefficients[i] = random->nextSScalar1();
335    }
336    return GrBicubicEffect::Create(textures[texIdx], coefficients);
337}
338
339bool SkBicubicImageFilter::filterImageGPU(Proxy* proxy, const SkBitmap& src, const SkMatrix& ctm,
340                                          SkBitmap* result, SkIPoint* offset) {
341    SkBitmap srcBM;
342    if (!SkImageFilterUtils::GetInputResultGPU(getInput(0), proxy, src, ctm, &srcBM, offset)) {
343        return false;
344    }
345    GrTexture* srcTexture = srcBM.getTexture();
346    GrContext* context = srcTexture->getContext();
347
348    SkRect dstRect = SkRect::MakeWH(srcBM.width() * fScale.fWidth,
349                                    srcBM.height() * fScale.fHeight);
350
351    GrTextureDesc desc;
352    desc.fFlags = kRenderTarget_GrTextureFlagBit | kNoStencil_GrTextureFlagBit;
353    desc.fWidth = SkScalarCeilToInt(dstRect.width());
354    desc.fHeight = SkScalarCeilToInt(dstRect.height());
355    desc.fConfig = kSkia8888_GrPixelConfig;
356
357    GrAutoScratchTexture ast(context, desc);
358    SkAutoTUnref<GrTexture> dst(ast.detach());
359    if (!dst) {
360        return false;
361    }
362    GrContext::AutoRenderTarget art(context, dst->asRenderTarget());
363    GrPaint paint;
364    paint.addColorEffect(GrBicubicEffect::Create(srcTexture, fCoefficients))->unref();
365    SkRect srcRect;
366    srcBM.getBounds(&srcRect);
367    context->drawRectToRect(paint, dstRect, srcRect);
368    return SkImageFilterUtils::WrapTexture(dst, desc.fWidth, desc.fHeight, result);
369}
370#endif
371
372///////////////////////////////////////////////////////////////////////////////
373