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      1 /*
      2  * Copyright (C) 2013 Google Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions are
      6  * met:
      7  *
      8  *     * Redistributions of source code must retain the above copyright
      9  * notice, this list of conditions and the following disclaimer.
     10  *     * Redistributions in binary form must reproduce the above
     11  * copyright notice, this list of conditions and the following disclaimer
     12  * in the documentation and/or other materials provided with the
     13  * distribution.
     14  *     * Neither the name of Google Inc. nor the names of its
     15  * contributors may be used to endorse or promote products derived from
     16  * this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #include "config.h"
     32 #include "platform/graphics/DrawLooper.h"
     33 
     34 #include "platform/geometry/FloatSize.h"
     35 #include "platform/graphics/Color.h"
     36 #include "third_party/skia/include/core/SkColor.h"
     37 #include "third_party/skia/include/core/SkColorFilter.h"
     38 #include "third_party/skia/include/core/SkDrawLooper.h"
     39 #include "third_party/skia/include/core/SkPaint.h"
     40 #include "third_party/skia/include/core/SkXfermode.h"
     41 #include "third_party/skia/include/effects/SkBlurMaskFilter.h"
     42 #include "third_party/skia/include/effects/SkLayerDrawLooper.h"
     43 
     44 namespace WebCore {
     45 
     46 DrawLooper::DrawLooper() : m_skDrawLooper(adoptRef(new SkLayerDrawLooper)) { }
     47 
     48 DrawLooper::~DrawLooper() { }
     49 
     50 SkDrawLooper* DrawLooper::skDrawLooper() const
     51 {
     52     return m_skDrawLooper.get();
     53 }
     54 
     55 void DrawLooper::addUnmodifiedContent()
     56 {
     57     SkLayerDrawLooper::LayerInfo info;
     58     m_skDrawLooper->addLayerOnTop(info);
     59 }
     60 
     61 void DrawLooper::addShadow(const FloatSize& offset, float blur, const Color& color,
     62     ShadowTransformMode shadowTransformMode, ShadowAlphaMode shadowAlphaMode)
     63 {
     64     // Detect when there's no effective shadow.
     65     if (!color.isValid() || !color.alpha())
     66         return;
     67 
     68     SkColor skColor;
     69     if (color.isValid())
     70         skColor = color.rgb();
     71     else
     72         skColor = SkColorSetARGB(0xFF / 3, 0, 0, 0); // "std" apple shadow color.
     73 
     74     SkLayerDrawLooper::LayerInfo info;
     75 
     76     switch (shadowAlphaMode) {
     77     case ShadowRespectsAlpha:
     78         info.fColorMode = SkXfermode::kDst_Mode;
     79         break;
     80     case ShadowIgnoresAlpha:
     81         info.fColorMode = SkXfermode::kSrc_Mode;
     82         break;
     83     default:
     84         ASSERT_NOT_REACHED();
     85     }
     86 
     87     if (blur)
     88         info.fPaintBits |= SkLayerDrawLooper::kMaskFilter_Bit; // our blur
     89     info.fPaintBits |= SkLayerDrawLooper::kColorFilter_Bit;
     90     info.fOffset.set(offset.width(), offset.height());
     91     info.fPostTranslate = (shadowTransformMode == ShadowIgnoresTransforms);
     92 
     93     SkPaint* paint = m_skDrawLooper->addLayerOnTop(info);
     94 
     95     if (blur) {
     96         uint32_t mfFlags = SkBlurMaskFilter::kHighQuality_BlurFlag;
     97         if (shadowTransformMode == ShadowIgnoresTransforms)
     98             mfFlags |= SkBlurMaskFilter::kIgnoreTransform_BlurFlag;
     99         RefPtr<SkMaskFilter> mf = adoptRef(SkBlurMaskFilter::Create(
    100             (double)blur / 2.0, SkBlurMaskFilter::kNormal_BlurStyle, mfFlags));
    101         paint->setMaskFilter(mf.get());
    102     }
    103 
    104     RefPtr<SkColorFilter> cf = adoptRef(SkColorFilter::CreateModeFilter(skColor, SkXfermode::kSrcIn_Mode));
    105     paint->setColorFilter(cf.get());
    106 }
    107 
    108 } // namespace WebCore
    109