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      1 /*
      2  * Copyright (C) 2004, 2005, 2006, 2007 Nikolas Zimmermann <zimmermann (at) kde.org>
      3  * Copyright (C) 2004, 2005 Rob Buis <buis (at) kde.org>
      4  * Copyright (C) 2005 Eric Seidel <eric (at) webkit.org>
      5  * Copyright (C) 2009 Dirk Schulze <krit (at) webkit.org>
      6  * Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies)
      7  * Copyright (C) 2013 Google Inc. All rights reserved.
      8  *
      9  * This library is free software; you can redistribute it and/or
     10  * modify it under the terms of the GNU Library General Public
     11  * License as published by the Free Software Foundation; either
     12  * version 2 of the License, or (at your option) any later version.
     13  *
     14  * This library is distributed in the hope that it will be useful,
     15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
     16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     17  * Library General Public License for more details.
     18  *
     19  * You should have received a copy of the GNU Library General Public License
     20  * along with this library; see the file COPYING.LIB.  If not, write to
     21  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     22  * Boston, MA 02110-1301, USA.
     23  */
     24 
     25 #include "config.h"
     26 #include "platform/graphics/filters/FEBlend.h"
     27 
     28 #include "SkBitmapSource.h"
     29 #include "SkXfermodeImageFilter.h"
     30 #include "platform/graphics/GraphicsContext.h"
     31 #include "platform/graphics/cpu/arm/filters/FEBlendNEON.h"
     32 #include "platform/graphics/filters/SkiaImageFilterBuilder.h"
     33 #include "platform/graphics/skia/NativeImageSkia.h"
     34 #include "platform/text/TextStream.h"
     35 #include "wtf/Uint8ClampedArray.h"
     36 
     37 typedef unsigned char (*BlendType)(unsigned char colorA, unsigned char colorB, unsigned char alphaA, unsigned char alphaB);
     38 
     39 namespace WebCore {
     40 
     41 FEBlend::FEBlend(Filter* filter, BlendModeType mode)
     42     : FilterEffect(filter)
     43     , m_mode(mode)
     44 {
     45 }
     46 
     47 PassRefPtr<FEBlend> FEBlend::create(Filter* filter, BlendModeType mode)
     48 {
     49     return adoptRef(new FEBlend(filter, mode));
     50 }
     51 
     52 BlendModeType FEBlend::blendMode() const
     53 {
     54     return m_mode;
     55 }
     56 
     57 bool FEBlend::setBlendMode(BlendModeType mode)
     58 {
     59     if (m_mode == mode)
     60         return false;
     61     m_mode = mode;
     62     return true;
     63 }
     64 
     65 static inline unsigned char fastDivideBy255(uint16_t value)
     66 {
     67     // This is an approximate algorithm for division by 255, but it gives accurate results for 16bit values.
     68     uint16_t quotient = value >> 8;
     69     uint16_t remainder = value - (quotient * 255) + 1;
     70     return quotient + (remainder >> 8);
     71 }
     72 
     73 inline unsigned char feBlendNormal(unsigned char colorA, unsigned char colorB, unsigned char alphaA, unsigned char)
     74 {
     75     return fastDivideBy255((255 - alphaA) * colorB + colorA * 255);
     76 }
     77 
     78 inline unsigned char feBlendMultiply(unsigned char colorA, unsigned char colorB, unsigned char alphaA, unsigned char alphaB)
     79 {
     80     return fastDivideBy255((255 - alphaA) * colorB + (255 - alphaB + colorB) * colorA);
     81 }
     82 
     83 inline unsigned char feBlendScreen(unsigned char colorA, unsigned char colorB, unsigned char, unsigned char)
     84 {
     85     return fastDivideBy255((colorB + colorA) * 255 - colorA * colorB);
     86 }
     87 
     88 inline unsigned char feBlendDarken(unsigned char colorA, unsigned char colorB, unsigned char alphaA, unsigned char alphaB)
     89 {
     90     return fastDivideBy255(std::min((255 - alphaA) * colorB + colorA * 255, (255 - alphaB) * colorA + colorB * 255));
     91 }
     92 
     93 inline unsigned char feBlendLighten(unsigned char colorA, unsigned char colorB, unsigned char alphaA, unsigned char alphaB)
     94 {
     95     return fastDivideBy255(std::max((255 - alphaA) * colorB + colorA * 255, (255 - alphaB) * colorA + colorB * 255));
     96 }
     97 
     98 inline unsigned char feBlendUnknown(unsigned char, unsigned char, unsigned char, unsigned char)
     99 {
    100     return 0;
    101 }
    102 
    103 template<BlendType BlendFunction>
    104 static void platformApply(unsigned char* sourcePixelA, unsigned char* sourcePixelB,
    105                           unsigned char* destinationPixel, unsigned pixelArrayLength)
    106 {
    107     unsigned len = pixelArrayLength / 4;
    108     for (unsigned pixelOffset = 0; pixelOffset < len; pixelOffset++) {
    109         unsigned char alphaA = sourcePixelA[3];
    110         unsigned char alphaB = sourcePixelB[3];
    111         destinationPixel[0] = BlendFunction(sourcePixelA[0], sourcePixelB[0], alphaA, alphaB);
    112         destinationPixel[1] = BlendFunction(sourcePixelA[1], sourcePixelB[1], alphaA, alphaB);
    113         destinationPixel[2] = BlendFunction(sourcePixelA[2], sourcePixelB[2], alphaA, alphaB);
    114         destinationPixel[3] = 255 - fastDivideBy255((255 - alphaA) * (255 - alphaB));
    115         sourcePixelA += 4;
    116         sourcePixelB += 4;
    117         destinationPixel += 4;
    118     }
    119 }
    120 
    121 void FEBlend::platformApplyGeneric(unsigned char* sourcePixelA, unsigned char* sourcePixelB,
    122                                    unsigned char* destinationPixel, unsigned pixelArrayLength)
    123 {
    124     switch (m_mode) {
    125     case FEBLEND_MODE_NORMAL:
    126         platformApply<feBlendNormal>(sourcePixelA, sourcePixelB, destinationPixel, pixelArrayLength);
    127         break;
    128     case FEBLEND_MODE_MULTIPLY:
    129         platformApply<feBlendMultiply>(sourcePixelA, sourcePixelB, destinationPixel, pixelArrayLength);
    130         break;
    131     case FEBLEND_MODE_SCREEN:
    132         platformApply<feBlendScreen>(sourcePixelA, sourcePixelB, destinationPixel, pixelArrayLength);
    133         break;
    134     case FEBLEND_MODE_DARKEN:
    135         platformApply<feBlendDarken>(sourcePixelA, sourcePixelB, destinationPixel, pixelArrayLength);
    136         break;
    137     case FEBLEND_MODE_LIGHTEN:
    138         platformApply<feBlendLighten>(sourcePixelA, sourcePixelB, destinationPixel, pixelArrayLength);
    139         break;
    140     case FEBLEND_MODE_UNKNOWN:
    141         platformApply<feBlendUnknown>(sourcePixelA, sourcePixelB, destinationPixel, pixelArrayLength);
    142         break;
    143     }
    144 }
    145 
    146 void FEBlend::applySoftware()
    147 {
    148     FilterEffect* in = inputEffect(0);
    149     FilterEffect* in2 = inputEffect(1);
    150 
    151     ASSERT(m_mode > FEBLEND_MODE_UNKNOWN);
    152     ASSERT(m_mode <= FEBLEND_MODE_LIGHTEN);
    153 
    154     Uint8ClampedArray* dstPixelArray = createPremultipliedImageResult();
    155     if (!dstPixelArray)
    156         return;
    157 
    158     IntRect effectADrawingRect = requestedRegionOfInputImageData(in->absolutePaintRect());
    159     RefPtr<Uint8ClampedArray> srcPixelArrayA = in->asPremultipliedImage(effectADrawingRect);
    160 
    161     IntRect effectBDrawingRect = requestedRegionOfInputImageData(in2->absolutePaintRect());
    162     RefPtr<Uint8ClampedArray> srcPixelArrayB = in2->asPremultipliedImage(effectBDrawingRect);
    163 
    164     unsigned pixelArrayLength = srcPixelArrayA->length();
    165     ASSERT(pixelArrayLength == srcPixelArrayB->length());
    166 
    167 #if HAVE(ARM_NEON_INTRINSICS)
    168     if (pixelArrayLength >= 8) {
    169         platformApplyNEON(srcPixelArrayA->data(), srcPixelArrayB->data(), dstPixelArray->data(), pixelArrayLength);
    170     }
    171     else { // If there is just one pixel we expand it to two.
    172         ASSERT(pixelArrayLength > 0);
    173         uint32_t sourceA[2] = {0, 0};
    174         uint32_t sourceBAndDest[2] = {0, 0};
    175 
    176         sourceA[0] = reinterpret_cast<uint32_t*>(srcPixelArrayA->data())[0];
    177         sourceBAndDest[0] = reinterpret_cast<uint32_t*>(srcPixelArrayB->data())[0];
    178         platformApplyNEON(reinterpret_cast<uint8_t*>(sourceA), reinterpret_cast<uint8_t*>(sourceBAndDest), reinterpret_cast<uint8_t*>(sourceBAndDest), 8);
    179         reinterpret_cast<uint32_t*>(dstPixelArray->data())[0] = sourceBAndDest[0];
    180     }
    181 #else
    182     platformApplyGeneric(srcPixelArrayA->data(), srcPixelArrayB->data(), dstPixelArray->data(), pixelArrayLength);
    183 #endif
    184 }
    185 
    186 static SkXfermode::Mode toSkiaMode(BlendModeType mode)
    187 {
    188     switch (mode) {
    189     case FEBLEND_MODE_NORMAL:
    190         return SkXfermode::kSrcOver_Mode;
    191     case FEBLEND_MODE_MULTIPLY:
    192         return SkXfermode::kMultiply_Mode;
    193     case FEBLEND_MODE_SCREEN:
    194         return SkXfermode::kScreen_Mode;
    195     case FEBLEND_MODE_DARKEN:
    196         return SkXfermode::kDarken_Mode;
    197     case FEBLEND_MODE_LIGHTEN:
    198         return SkXfermode::kLighten_Mode;
    199     default:
    200         return SkXfermode::kSrcOver_Mode;
    201     }
    202 }
    203 
    204 PassRefPtr<SkImageFilter> FEBlend::createImageFilter(SkiaImageFilterBuilder* builder)
    205 {
    206     RefPtr<SkImageFilter> foreground(builder->build(inputEffect(0), operatingColorSpace()));
    207     RefPtr<SkImageFilter> background(builder->build(inputEffect(1), operatingColorSpace()));
    208     SkAutoTUnref<SkXfermode> mode(SkXfermode::Create(toSkiaMode(m_mode)));
    209     SkImageFilter::CropRect cropRect = getCropRect(builder->cropOffset());
    210     return adoptRef(SkXfermodeImageFilter::Create(mode, background.get(), foreground.get(), &cropRect));
    211 }
    212 
    213 static TextStream& operator<<(TextStream& ts, const BlendModeType& type)
    214 {
    215     switch (type) {
    216     case FEBLEND_MODE_UNKNOWN:
    217         ts << "UNKNOWN";
    218         break;
    219     case FEBLEND_MODE_NORMAL:
    220         ts << "NORMAL";
    221         break;
    222     case FEBLEND_MODE_MULTIPLY:
    223         ts << "MULTIPLY";
    224         break;
    225     case FEBLEND_MODE_SCREEN:
    226         ts << "SCREEN";
    227         break;
    228     case FEBLEND_MODE_DARKEN:
    229         ts << "DARKEN";
    230         break;
    231     case FEBLEND_MODE_LIGHTEN:
    232         ts << "LIGHTEN";
    233         break;
    234     }
    235     return ts;
    236 }
    237 
    238 TextStream& FEBlend::externalRepresentation(TextStream& ts, int indent) const
    239 {
    240     writeIndent(ts, indent);
    241     ts << "[feBlend";
    242     FilterEffect::externalRepresentation(ts);
    243     ts << " mode=\"" << m_mode << "\"]\n";
    244     inputEffect(0)->externalRepresentation(ts, indent + 1);
    245     inputEffect(1)->externalRepresentation(ts, indent + 1);
    246     return ts;
    247 }
    248 
    249 } // namespace WebCore
    250