third_party/WebKit/Source/core/style/ShadowList.cpp

/*
 * Copyright (C) 2013 Google Inc. All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
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 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
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 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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#include "core/style/ShadowList.h"

#include "platform/geometry/FloatRect.h"
#include <memory>

namespace blink {

FloatRectOutsets ShadowList::rectOutsetsIncludingOriginal() const {
  FloatRectOutsets outsets;
  for (const ShadowData& shadow : shadows()) {
    if (shadow.style() == Inset)
      continue;
    outsets.unite(shadow.rectOutsets());
  }
  return outsets;
}

void ShadowList::adjustRectForShadow(FloatRect& rect) const {
  rect.expand(rectOutsetsIncludingOriginal());
}

PassRefPtr<ShadowList> ShadowList::blend(const ShadowList* from,
                                         const ShadowList* to,
                                         double progress,
                                         const Color& currentColor) {
  size_t fromLength = from ? from->shadows().size() : 0;
  size_t toLength = to ? to->shadows().size() : 0;
  if (!fromLength && !toLength)
    return nullptr;

  ShadowDataVector shadows;

  DEFINE_STATIC_LOCAL(
      ShadowData, defaultShadowData,
      (FloatPoint(), 0, 0, Normal, StyleColor(Color::transparent)));
  DEFINE_STATIC_LOCAL(
      ShadowData, defaultInsetShadowData,
      (FloatPoint(), 0, 0, Inset, StyleColor(Color::transparent)));

  size_t maxLength = std::max(fromLength, toLength);
  for (size_t i = 0; i < maxLength; ++i) {
    const ShadowData* fromShadow = i < fromLength ? &from->shadows()[i] : 0;
    const ShadowData* toShadow = i < toLength ? &to->shadows()[i] : 0;
    if (!fromShadow)
      fromShadow = toShadow->style() == Inset ? &defaultInsetShadowData
                                              : &defaultShadowData;
    else if (!toShadow)
      toShadow = fromShadow->style() == Inset ? &defaultInsetShadowData
                                              : &defaultShadowData;
    shadows.append(toShadow->blend(*fromShadow, progress, currentColor));
  }

  return ShadowList::adopt(shadows);
}

sk_sp<SkDrawLooper> ShadowList::createDrawLooper(
    DrawLooperBuilder::ShadowAlphaMode alphaMode,
    const Color& currentColor,
    bool isHorizontal) const {
  DrawLooperBuilder drawLooperBuilder;
  for (size_t i = shadows().size(); i--;) {
    const ShadowData& shadow = shadows()[i];
    float shadowX = isHorizontal ? shadow.x() : shadow.y();
    float shadowY = isHorizontal ? shadow.y() : -shadow.x();
    drawLooperBuilder.addShadow(FloatSize(shadowX, shadowY), shadow.blur(),
                                shadow.color().resolve(currentColor),
                                DrawLooperBuilder::ShadowRespectsTransforms,
                                alphaMode);
  }
  drawLooperBuilder.addUnmodifiedContent();
  return drawLooperBuilder.detachDrawLooper();
}

}  // namespace blink