Home | History | Annotate | Download | only in effects 
      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 
     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 
     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 
     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 
     50 void SkBlurImageFilter::flatten(SkWriteBuffer& buffer) const {
     51     this->INHERITED::flatten(buffer);
     52     buffer.writeScalar(fSigma.fWidth);
     53     buffer.writeScalar(fSigma.fHeight);
     54 }
     55 
     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 
     72 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 
    182 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 
    193 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 
    201 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
    251 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