1 /*
2 * Copyright 2011 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 "SkBlurImageFilter.h"
10 #include "SkColorPriv.h"
11 #include "SkFlattenableBuffers.h"
12 #include "SkGpuBlurUtils.h"
13 #include "SkBlurImage_opts.h"
14 #if SK_SUPPORT_GPU
15 #include "GrContext.h"
16 #include "SkImageFilterUtils.h"
17 #endif
18
SkBlurImageFilter(SkFlattenableReadBuffer & buffer)19 SkBlurImageFilter::SkBlurImageFilter(SkFlattenableReadBuffer& buffer)
20 : INHERITED(1, buffer) {
21 fSigma.fWidth = buffer.readScalar();
22 fSigma.fHeight = buffer.readScalar();
23 buffer.validate(SkScalarIsFinite(fSigma.fWidth) &&
24 SkScalarIsFinite(fSigma.fHeight) &&
25 (fSigma.fWidth >= 0) &&
26 (fSigma.fHeight >= 0));
27 }
28
SkBlurImageFilter(SkScalar sigmaX,SkScalar sigmaY,SkImageFilter * input,const CropRect * cropRect)29 SkBlurImageFilter::SkBlurImageFilter(SkScalar sigmaX,
30 SkScalar sigmaY,
31 SkImageFilter* input,
32 const CropRect* cropRect)
33 : INHERITED(input, cropRect), fSigma(SkSize::Make(sigmaX, sigmaY)) {
34 SkASSERT(sigmaX >= 0 && sigmaY >= 0);
35 }
36
flatten(SkFlattenableWriteBuffer & buffer) const37 void SkBlurImageFilter::flatten(SkFlattenableWriteBuffer& buffer) const {
38 this->INHERITED::flatten(buffer);
39 buffer.writeScalar(fSigma.fWidth);
40 buffer.writeScalar(fSigma.fHeight);
41 }
42
43 enum BlurDirection {
44 kX, kY
45 };
46
47 /**
48 *
49 * In order to make memory accesses cache-friendly, we reorder the passes to
50 * use contiguous memory reads wherever possible.
51 *
52 * For example, the 6 passes of the X-and-Y blur case are rewritten as
53 * follows. Instead of 3 passes in X and 3 passes in Y, we perform
54 * 2 passes in X, 1 pass in X transposed to Y on write, 2 passes in X,
55 * then 1 pass in X transposed to Y on write.
56 *
57 * +----+ +----+ +----+ +---+ +---+ +---+ +----+
58 * + AB + ----> | AB | ----> | AB | -----> | A | ----> | A | ----> | A | -----> | AB |
59 * +----+ blurX +----+ blurX +----+ blurXY | B | blurX | B | blurX | B | blurXY +----+
60 * +---+ +---+ +---+
61 *
62 * In this way, two of the y-blurs become x-blurs applied to transposed
63 * images, and all memory reads are contiguous.
64 */
65
66 template<BlurDirection srcDirection, BlurDirection dstDirection>
boxBlur(const SkPMColor * src,int srcStride,SkPMColor * dst,int kernelSize,int leftOffset,int rightOffset,int width,int height)67 static void boxBlur(const SkPMColor* src, int srcStride, SkPMColor* dst, int kernelSize,
68 int leftOffset, int rightOffset, int width, int height)
69 {
70 int rightBorder = SkMin32(rightOffset + 1, width);
71 int srcStrideX = srcDirection == kX ? 1 : srcStride;
72 int dstStrideX = dstDirection == kX ? 1 : height;
73 int srcStrideY = srcDirection == kX ? srcStride : 1;
74 int dstStrideY = dstDirection == kX ? width : 1;
75 uint32_t scale = (1 << 24) / kernelSize;
76 uint32_t half = 1 << 23;
77 for (int y = 0; y < height; ++y) {
78 int sumA = 0, sumR = 0, sumG = 0, sumB = 0;
79 const SkPMColor* p = src;
80 for (int i = 0; i < rightBorder; ++i) {
81 sumA += SkGetPackedA32(*p);
82 sumR += SkGetPackedR32(*p);
83 sumG += SkGetPackedG32(*p);
84 sumB += SkGetPackedB32(*p);
85 p += srcStrideX;
86 }
87
88 const SkPMColor* sptr = src;
89 SkColor* dptr = dst;
90 for (int x = 0; x < width; ++x) {
91 *dptr = SkPackARGB32((sumA * scale + half) >> 24,
92 (sumR * scale + half) >> 24,
93 (sumG * scale + half) >> 24,
94 (sumB * scale + half) >> 24);
95 if (x >= leftOffset) {
96 SkColor l = *(sptr - leftOffset * srcStrideX);
97 sumA -= SkGetPackedA32(l);
98 sumR -= SkGetPackedR32(l);
99 sumG -= SkGetPackedG32(l);
100 sumB -= SkGetPackedB32(l);
101 }
102 if (x + rightOffset + 1 < width) {
103 SkColor r = *(sptr + (rightOffset + 1) * srcStrideX);
104 sumA += SkGetPackedA32(r);
105 sumR += SkGetPackedR32(r);
106 sumG += SkGetPackedG32(r);
107 sumB += SkGetPackedB32(r);
108 }
109 sptr += srcStrideX;
110 if (srcDirection == kY) {
111 SK_PREFETCH(sptr + (rightOffset + 1) * srcStrideX);
112 }
113 dptr += dstStrideX;
114 }
115 src += srcStrideY;
116 dst += dstStrideY;
117 }
118 }
119
getBox3Params(SkScalar s,int * kernelSize,int * kernelSize3,int * lowOffset,int * highOffset)120 static void getBox3Params(SkScalar s, int *kernelSize, int* kernelSize3, int *lowOffset,
121 int *highOffset)
122 {
123 float pi = SkScalarToFloat(SK_ScalarPI);
124 int d = static_cast<int>(floorf(SkScalarToFloat(s) * 3.0f * sqrtf(2.0f * pi) / 4.0f + 0.5f));
125 *kernelSize = d;
126 if (d % 2 == 1) {
127 *lowOffset = *highOffset = (d - 1) / 2;
128 *kernelSize3 = d;
129 } else {
130 *highOffset = d / 2;
131 *lowOffset = *highOffset - 1;
132 *kernelSize3 = d + 1;
133 }
134 }
135
onFilterImage(Proxy * proxy,const SkBitmap & source,const SkMatrix & ctm,SkBitmap * dst,SkIPoint * offset)136 bool SkBlurImageFilter::onFilterImage(Proxy* proxy,
137 const SkBitmap& source, const SkMatrix& ctm,
138 SkBitmap* dst, SkIPoint* offset) {
139 SkBitmap src = source;
140 if (getInput(0) && !getInput(0)->filterImage(proxy, source, ctm, &src, offset)) {
141 return false;
142 }
143
144 if (src.config() != SkBitmap::kARGB_8888_Config) {
145 return false;
146 }
147
148 SkAutoLockPixels alp(src);
149 if (!src.getPixels()) {
150 return false;
151 }
152
153 SkIRect srcBounds, dstBounds;
154 src.getBounds(&srcBounds);
155 if (!this->applyCropRect(&srcBounds, ctm)) {
156 return false;
157 }
158
159 dst->setConfig(src.config(), srcBounds.width(), srcBounds.height());
160 dst->getBounds(&dstBounds);
161 dst->allocPixels();
162 if (!dst->getPixels()) {
163 return false;
164 }
165
166 int kernelSizeX, kernelSizeX3, lowOffsetX, highOffsetX;
167 int kernelSizeY, kernelSizeY3, lowOffsetY, highOffsetY;
168 getBox3Params(fSigma.width(), &kernelSizeX, &kernelSizeX3, &lowOffsetX, &highOffsetX);
169 getBox3Params(fSigma.height(), &kernelSizeY, &kernelSizeY3, &lowOffsetY, &highOffsetY);
170
171 if (kernelSizeX < 0 || kernelSizeY < 0) {
172 return false;
173 }
174
175 if (kernelSizeX == 0 && kernelSizeY == 0) {
176 src.copyTo(dst, dst->config());
177 return true;
178 }
179
180 SkBitmap temp;
181 temp.setConfig(dst->config(), dst->width(), dst->height());
182 if (!temp.allocPixels()) {
183 return false;
184 }
185
186 const SkPMColor* s = src.getAddr32(srcBounds.left(), srcBounds.top());
187 SkPMColor* t = temp.getAddr32(0, 0);
188 SkPMColor* d = dst->getAddr32(0, 0);
189 int w = dstBounds.width(), h = dstBounds.height();
190 int sw = src.rowBytesAsPixels();
191 SkBoxBlurProc boxBlurX, boxBlurY, boxBlurXY, boxBlurYX;
192 if (!SkBoxBlurGetPlatformProcs(&boxBlurX, &boxBlurY, &boxBlurXY, &boxBlurYX)) {
193 boxBlurX = boxBlur<kX, kX>;
194 boxBlurY = boxBlur<kY, kY>;
195 boxBlurXY = boxBlur<kX, kY>;
196 boxBlurYX = boxBlur<kY, kX>;
197 }
198
199 if (kernelSizeX > 0 && kernelSizeY > 0) {
200 boxBlurX(s, sw, t, kernelSizeX, lowOffsetX, highOffsetX, w, h);
201 boxBlurX(t, w, d, kernelSizeX, highOffsetX, lowOffsetX, w, h);
202 boxBlurXY(d, w, t, kernelSizeX3, highOffsetX, highOffsetX, w, h);
203 boxBlurX(t, h, d, kernelSizeY, lowOffsetY, highOffsetY, h, w);
204 boxBlurX(d, h, t, kernelSizeY, highOffsetY, lowOffsetY, h, w);
205 boxBlurXY(t, h, d, kernelSizeY3, highOffsetY, highOffsetY, h, w);
206 } else if (kernelSizeX > 0) {
207 boxBlurX(s, sw, d, kernelSizeX, lowOffsetX, highOffsetX, w, h);
208 boxBlurX(d, w, t, kernelSizeX, highOffsetX, lowOffsetX, w, h);
209 boxBlurX(t, w, d, kernelSizeX3, highOffsetX, highOffsetX, w, h);
210 } else if (kernelSizeY > 0) {
211 boxBlurYX(s, sw, d, kernelSizeY, lowOffsetY, highOffsetY, h, w);
212 boxBlurX(d, h, t, kernelSizeY, highOffsetY, lowOffsetY, h, w);
213 boxBlurXY(t, h, d, kernelSizeY3, highOffsetY, highOffsetY, h, w);
214 }
215 offset->fX += srcBounds.fLeft;
216 offset->fY += srcBounds.fTop;
217 return true;
218 }
219
filterImageGPU(Proxy * proxy,const SkBitmap & src,const SkMatrix & ctm,SkBitmap * result,SkIPoint * offset)220 bool SkBlurImageFilter::filterImageGPU(Proxy* proxy, const SkBitmap& src, const SkMatrix& ctm,
221 SkBitmap* result, SkIPoint* offset) {
222 #if SK_SUPPORT_GPU
223 SkBitmap input;
224 if (!SkImageFilterUtils::GetInputResultGPU(getInput(0), proxy, src, ctm, &input, offset)) {
225 return false;
226 }
227 GrTexture* source = input.getTexture();
228 SkIRect rect;
229 src.getBounds(&rect);
230 if (!this->applyCropRect(&rect, ctm)) {
231 return false;
232 }
233 SkAutoTUnref<GrTexture> tex(SkGpuBlurUtils::GaussianBlur(source->getContext(),
234 source,
235 false,
236 SkRect::Make(rect),
237 true,
238 fSigma.width(),
239 fSigma.height()));
240 offset->fX += rect.fLeft;
241 offset->fY += rect.fTop;
242 return SkImageFilterUtils::WrapTexture(tex, rect.width(), rect.height(), result);
243 #else
244 SkDEBUGFAIL("Should not call in GPU-less build");
245 return false;
246 #endif
247 }
248