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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 "core/rendering/style/ShadowList.h"
     33 
     34 #include "platform/geometry/FloatRect.h"
     35 #include "wtf/OwnPtr.h"
     36 
     37 namespace blink {
     38 
     39 static inline void calculateShadowExtent(const ShadowList* shadowList, float& shadowLeft, float& shadowRight, float& shadowTop, float& shadowBottom)
     40 {
     41     ASSERT(shadowList);
     42     size_t shadowCount = shadowList->shadows().size();
     43     for (size_t i = 0; i < shadowCount; ++i) {
     44         const ShadowData& shadow = shadowList->shadows()[i];
     45         if (shadow.style() == Inset)
     46             continue;
     47         float blurAndSpread = shadow.blur() + shadow.spread();
     48         shadowLeft = std::min(shadow.x() - blurAndSpread, shadowLeft);
     49         shadowRight = std::max(shadow.x() + blurAndSpread, shadowRight);
     50         shadowTop = std::min(shadow.y() - blurAndSpread, shadowTop);
     51         shadowBottom = std::max(shadow.y() + blurAndSpread, shadowBottom);
     52     }
     53 }
     54 
     55 void ShadowList::adjustRectForShadow(LayoutRect& rect) const
     56 {
     57     FloatRect floatRect(rect);
     58     adjustRectForShadow(floatRect);
     59     rect = LayoutRect(floatRect);
     60 }
     61 
     62 void ShadowList::adjustRectForShadow(FloatRect& rect) const
     63 {
     64     float shadowLeft = 0;
     65     float shadowRight = 0;
     66     float shadowTop = 0;
     67     float shadowBottom = 0;
     68     calculateShadowExtent(this, shadowLeft, shadowRight, shadowTop, shadowBottom);
     69 
     70     rect.move(shadowLeft, shadowTop);
     71     rect.setWidth(rect.width() - shadowLeft + shadowRight);
     72     rect.setHeight(rect.height() - shadowTop + shadowBottom);
     73 }
     74 
     75 PassRefPtr<ShadowList> ShadowList::blend(const ShadowList* from, const ShadowList* to, double progress)
     76 {
     77     size_t fromLength = from ? from->shadows().size() : 0;
     78     size_t toLength = to ? to->shadows().size() : 0;
     79     if (!fromLength && !toLength)
     80         return nullptr;
     81 
     82     ShadowDataVector shadows;
     83 
     84     DEFINE_STATIC_LOCAL(ShadowData, defaultShadowData, (FloatPoint(), 0, 0, Normal, Color::transparent));
     85     DEFINE_STATIC_LOCAL(ShadowData, defaultInsetShadowData, (FloatPoint(), 0, 0, Inset, Color::transparent));
     86 
     87     size_t maxLength = std::max(fromLength, toLength);
     88     for (size_t i = 0; i < maxLength; ++i) {
     89         const ShadowData* fromShadow = i < fromLength ? &from->shadows()[i] : 0;
     90         const ShadowData* toShadow = i < toLength ? &to->shadows()[i] : 0;
     91         if (!fromShadow)
     92             fromShadow = toShadow->style() == Inset ? &defaultInsetShadowData : &defaultShadowData;
     93         else if (!toShadow)
     94             toShadow = fromShadow->style() == Inset ? &defaultInsetShadowData : &defaultShadowData;
     95         shadows.append(toShadow->blend(*fromShadow, progress));
     96     }
     97 
     98     return ShadowList::adopt(shadows);
     99 }
    100 
    101 PassOwnPtr<DrawLooperBuilder> ShadowList::createDrawLooper(DrawLooperBuilder::ShadowAlphaMode alphaMode, bool isHorizontal) const
    102 {
    103     OwnPtr<DrawLooperBuilder> drawLooperBuilder = DrawLooperBuilder::create();
    104     for (size_t i = shadows().size(); i--; ) {
    105         const ShadowData& shadow = shadows()[i];
    106         float shadowX = isHorizontal ? shadow.x() : shadow.y();
    107         float shadowY = isHorizontal ? shadow.y() : -shadow.x();
    108         drawLooperBuilder->addShadow(FloatSize(shadowX, shadowY), shadow.blur(), shadow.color(),
    109             DrawLooperBuilder::ShadowRespectsTransforms, alphaMode);
    110     }
    111     drawLooperBuilder->addUnmodifiedContent();
    112     return drawLooperBuilder.release();
    113 }
    114 
    115 } // namespace blink
    116