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 "SkDevice.h"
12 #include "SkGpuBlurUtils.h"
13 #include "SkOpts.h"
14 #include "SkReadBuffer.h"
15 #include "SkWriteBuffer.h"
16 #if SK_SUPPORT_GPU
17 #include "GrContext.h"
18 #include "SkGr.h"
19 #endif
20 
21 // This rather arbitrary-looking value results in a maximum box blur kernel size
22 // of 1000 pixels on the raster path, which matches the WebKit and Firefox
23 // implementations. Since the GPU path does not compute a box blur, putting
24 // the limit on sigma ensures consistent behaviour between the GPU and
25 // raster paths.
26 #define MAX_SIGMA SkIntToScalar(532)
27 
map_sigma(const SkSize & localSigma,const SkMatrix & ctm)28 static SkVector map_sigma(const SkSize& localSigma, const SkMatrix& ctm) {
29     SkVector sigma = SkVector::Make(localSigma.width(), localSigma.height());
30     ctm.mapVectors(&sigma, 1);
31     sigma.fX = SkMinScalar(SkScalarAbs(sigma.fX), MAX_SIGMA);
32     sigma.fY = SkMinScalar(SkScalarAbs(sigma.fY), MAX_SIGMA);
33     return sigma;
34 }
35 
SkBlurImageFilter(SkScalar sigmaX,SkScalar sigmaY,SkImageFilter * input,const CropRect * cropRect)36 SkBlurImageFilter::SkBlurImageFilter(SkScalar sigmaX,
37                                      SkScalar sigmaY,
38                                      SkImageFilter* input,
39                                      const CropRect* cropRect)
40     : INHERITED(1, &input, cropRect), fSigma(SkSize::Make(sigmaX, sigmaY)) {
41 }
42 
CreateProc(SkReadBuffer & buffer)43 SkFlattenable* SkBlurImageFilter::CreateProc(SkReadBuffer& buffer) {
44     SK_IMAGEFILTER_UNFLATTEN_COMMON(common, 1);
45     SkScalar sigmaX = buffer.readScalar();
46     SkScalar sigmaY = buffer.readScalar();
47     return Create(sigmaX, sigmaY, common.getInput(0), &common.cropRect());
48 }
49 
flatten(SkWriteBuffer & buffer) const50 void SkBlurImageFilter::flatten(SkWriteBuffer& buffer) const {
51     this->INHERITED::flatten(buffer);
52     buffer.writeScalar(fSigma.fWidth);
53     buffer.writeScalar(fSigma.fHeight);
54 }
55 
getBox3Params(SkScalar s,int * kernelSize,int * kernelSize3,int * lowOffset,int * highOffset)56 static void getBox3Params(SkScalar s, int *kernelSize, int* kernelSize3, int *lowOffset,
57                           int *highOffset)
58 {
59     float pi = SkScalarToFloat(SK_ScalarPI);
60     int d = static_cast<int>(floorf(SkScalarToFloat(s) * 3.0f * sqrtf(2.0f * pi) / 4.0f + 0.5f));
61     *kernelSize = d;
62     if (d % 2 == 1) {
63         *lowOffset = *highOffset = (d - 1) / 2;
64         *kernelSize3 = d;
65     } else {
66         *highOffset = d / 2;
67         *lowOffset = *highOffset - 1;
68         *kernelSize3 = d + 1;
69     }
70 }
71 
onFilterImageDeprecated(Proxy * proxy,const SkBitmap & source,const Context & ctx,SkBitmap * dst,SkIPoint * offset) const72 bool SkBlurImageFilter::onFilterImageDeprecated(Proxy* proxy,
73                                                 const SkBitmap& source, const Context& ctx,
74                                                 SkBitmap* dst, SkIPoint* offset) const {
75     SkBitmap src = source;
76     SkIPoint srcOffset = SkIPoint::Make(0, 0);
77     if (!this->filterInputDeprecated(0, proxy, source, ctx, &src, &srcOffset)) {
78         return false;
79     }
80 
81     if (src.colorType() != kN32_SkColorType) {
82         return false;
83     }
84 
85     SkIRect srcBounds = src.bounds();
86     srcBounds.offset(srcOffset);
87     SkIRect dstBounds;
88     if (!this->applyCropRect(this->mapContext(ctx), srcBounds, &dstBounds)) {
89         return false;
90     }
91     if (!srcBounds.intersect(dstBounds)) {
92         return false;
93     }
94 
95     SkVector sigma = map_sigma(fSigma, ctx.ctm());
96 
97     int kernelSizeX, kernelSizeX3, lowOffsetX, highOffsetX;
98     int kernelSizeY, kernelSizeY3, lowOffsetY, highOffsetY;
99     getBox3Params(sigma.x(), &kernelSizeX, &kernelSizeX3, &lowOffsetX, &highOffsetX);
100     getBox3Params(sigma.y(), &kernelSizeY, &kernelSizeY3, &lowOffsetY, &highOffsetY);
101 
102     if (kernelSizeX < 0 || kernelSizeY < 0) {
103         return false;
104     }
105 
106     if (kernelSizeX == 0 && kernelSizeY == 0) {
107         src.extractSubset(dst, srcBounds);
108         offset->fX = srcBounds.x();
109         offset->fY = srcBounds.y();
110         return true;
111     }
112 
113     SkAutoLockPixels alp(src);
114     if (!src.getPixels()) {
115         return false;
116     }
117 
118     SkAutoTUnref<SkBaseDevice> device(proxy->createDevice(dstBounds.width(), dstBounds.height()));
119     if (!device) {
120         return false;
121     }
122     *dst = device->accessBitmap(false);
123     SkAutoLockPixels alp_dst(*dst);
124 
125     SkAutoTUnref<SkBaseDevice> tempDevice(proxy->createDevice(dst->width(), dst->height()));
126     if (!tempDevice) {
127         return false;
128     }
129     SkBitmap temp = tempDevice->accessBitmap(false);
130     SkAutoLockPixels alpTemp(temp);
131 
132     offset->fX = dstBounds.fLeft;
133     offset->fY = dstBounds.fTop;
134     SkPMColor* t = temp.getAddr32(0, 0);
135     SkPMColor* d = dst->getAddr32(0, 0);
136     int w = dstBounds.width(), h = dstBounds.height();
137     const SkPMColor* s = src.getAddr32(srcBounds.x() - srcOffset.x(), srcBounds.y() - srcOffset.y());
138     srcBounds.offset(-dstBounds.x(), -dstBounds.y());
139     dstBounds.offset(-dstBounds.x(), -dstBounds.y());
140     SkIRect srcBoundsT = SkIRect::MakeLTRB(srcBounds.top(), srcBounds.left(), srcBounds.bottom(), srcBounds.right());
141     SkIRect dstBoundsT = SkIRect::MakeWH(dstBounds.height(), dstBounds.width());
142     int sw = src.rowBytesAsPixels();
143 
144     /**
145      *
146      * In order to make memory accesses cache-friendly, we reorder the passes to
147      * use contiguous memory reads wherever possible.
148      *
149      * For example, the 6 passes of the X-and-Y blur case are rewritten as
150      * follows. Instead of 3 passes in X and 3 passes in Y, we perform
151      * 2 passes in X, 1 pass in X transposed to Y on write, 2 passes in X,
152      * then 1 pass in X transposed to Y on write.
153      *
154      * +----+       +----+       +----+        +---+       +---+       +---+        +----+
155      * + AB + ----> | AB | ----> | AB | -----> | A | ----> | A | ----> | A | -----> | AB |
156      * +----+ blurX +----+ blurX +----+ blurXY | B | blurX | B | blurX | B | blurXY +----+
157      *                                         +---+       +---+       +---+
158      *
159      * In this way, two of the y-blurs become x-blurs applied to transposed
160      * images, and all memory reads are contiguous.
161      */
162     if (kernelSizeX > 0 && kernelSizeY > 0) {
163         SkOpts::box_blur_xx(s, sw,  srcBounds,  t, kernelSizeX,  lowOffsetX,  highOffsetX, w, h);
164         SkOpts::box_blur_xx(t,  w,  dstBounds,  d, kernelSizeX,  highOffsetX, lowOffsetX,  w, h);
165         SkOpts::box_blur_xy(d,  w,  dstBounds,  t, kernelSizeX3, highOffsetX, highOffsetX, w, h);
166         SkOpts::box_blur_xx(t,  h,  dstBoundsT, d, kernelSizeY,  lowOffsetY,  highOffsetY, h, w);
167         SkOpts::box_blur_xx(d,  h,  dstBoundsT, t, kernelSizeY,  highOffsetY, lowOffsetY,  h, w);
168         SkOpts::box_blur_xy(t,  h,  dstBoundsT, d, kernelSizeY3, highOffsetY, highOffsetY, h, w);
169     } else if (kernelSizeX > 0) {
170         SkOpts::box_blur_xx(s, sw,  srcBounds,  d, kernelSizeX,  lowOffsetX,  highOffsetX, w, h);
171         SkOpts::box_blur_xx(d,  w,  dstBounds,  t, kernelSizeX,  highOffsetX, lowOffsetX,  w, h);
172         SkOpts::box_blur_xx(t,  w,  dstBounds,  d, kernelSizeX3, highOffsetX, highOffsetX, w, h);
173     } else if (kernelSizeY > 0) {
174         SkOpts::box_blur_yx(s, sw,  srcBoundsT, d, kernelSizeY,  lowOffsetY,  highOffsetY, h, w);
175         SkOpts::box_blur_xx(d,  h,  dstBoundsT, t, kernelSizeY,  highOffsetY, lowOffsetY,  h, w);
176         SkOpts::box_blur_xy(t,  h,  dstBoundsT, d, kernelSizeY3, highOffsetY, highOffsetY, h, w);
177     }
178     return true;
179 }
180 
181 
computeFastBounds(const SkRect & src,SkRect * dst) const182 void SkBlurImageFilter::computeFastBounds(const SkRect& src, SkRect* dst) const {
183     if (this->getInput(0)) {
184         this->getInput(0)->computeFastBounds(src, dst);
185     } else {
186         *dst = src;
187     }
188 
189     dst->outset(SkScalarMul(fSigma.width(), SkIntToScalar(3)),
190                 SkScalarMul(fSigma.height(), SkIntToScalar(3)));
191 }
192 
onFilterNodeBounds(const SkIRect & src,const SkMatrix & ctm,SkIRect * dst,MapDirection) const193 void SkBlurImageFilter::onFilterNodeBounds(const SkIRect& src, const SkMatrix& ctm,
194                                            SkIRect* dst, MapDirection) const {
195     *dst = src;
196     SkVector sigma = map_sigma(fSigma, ctm);
197     dst->outset(SkScalarCeilToInt(SkScalarMul(sigma.x(), SkIntToScalar(3))),
198                 SkScalarCeilToInt(SkScalarMul(sigma.y(), SkIntToScalar(3))));
199 }
200 
filterImageGPUDeprecated(Proxy * proxy,const SkBitmap & src,const Context & ctx,SkBitmap * result,SkIPoint * offset) const201 bool SkBlurImageFilter::filterImageGPUDeprecated(Proxy* proxy, const SkBitmap& src,
202                                                  const Context& ctx,
203                                                  SkBitmap* result, SkIPoint* offset) const {
204 #if SK_SUPPORT_GPU
205     SkBitmap input = src;
206     SkIPoint srcOffset = SkIPoint::Make(0, 0);
207     if (!this->filterInputGPUDeprecated(0, proxy, src, ctx, &input, &srcOffset)) {
208         return false;
209     }
210     SkIRect srcBounds = input.bounds();
211     srcBounds.offset(srcOffset);
212     SkIRect dstBounds;
213     if (!this->applyCropRect(this->mapContext(ctx), srcBounds, &dstBounds)) {
214         return false;
215     }
216     if (!srcBounds.intersect(dstBounds)) {
217         return false;
218     }
219     SkVector sigma = map_sigma(fSigma, ctx.ctm());
220     if (sigma.x() == 0 && sigma.y() == 0) {
221         input.extractSubset(result, srcBounds);
222         offset->fX = srcBounds.x();
223         offset->fY = srcBounds.y();
224         return true;
225     }
226     offset->fX = dstBounds.fLeft;
227     offset->fY = dstBounds.fTop;
228     srcBounds.offset(-srcOffset);
229     dstBounds.offset(-srcOffset);
230     SkRect srcBoundsF(SkRect::Make(srcBounds));
231     GrTexture* inputTexture = input.getTexture();
232     SkAutoTUnref<GrTexture> tex(SkGpuBlurUtils::GaussianBlur(inputTexture->getContext(),
233                                                              inputTexture,
234                                                              false,
235                                                              SkRect::Make(dstBounds),
236                                                              &srcBoundsF,
237                                                              sigma.x(),
238                                                              sigma.y()));
239     if (!tex) {
240         return false;
241     }
242     GrWrapTextureInBitmap(tex, dstBounds.width(), dstBounds.height(), false, result);
243     return true;
244 #else
245     SkDEBUGFAIL("Should not call in GPU-less build");
246     return false;
247 #endif
248 }
249 
250 #ifndef SK_IGNORE_TO_STRING
toString(SkString * str) const251 void SkBlurImageFilter::toString(SkString* str) const {
252     str->appendf("SkBlurImageFilter: (");
253     str->appendf("sigma: (%f, %f) input (", fSigma.fWidth, fSigma.fHeight);
254 
255     if (this->getInput(0)) {
256         this->getInput(0)->toString(str);
257     }
258 
259     str->append("))");
260 }
261 #endif
262