third_party/WebKit/Source/core/style/ShadowData.h

/*
 * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
 *           (C) 2000 Antti Koivisto (koivisto@kde.org)
 *           (C) 2000 Dirk Mueller (mueller@kde.org)
 * Copyright (C) 2003, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights
 * reserved.
 * Copyright (C) 2006 Graham Dennis (graham.dennis@gmail.com)
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

#ifndef ShadowData_h
#define ShadowData_h

#include "core/css/StyleColor.h"
#include "platform/geometry/FloatPoint.h"
#include "platform/geometry/FloatRectOutsets.h"
#include "platform/graphics/skia/SkiaUtils.h"

namespace blink {

enum ShadowStyle { Normal, Inset };

// This class holds information about shadows for the text-shadow and box-shadow
// properties.
class ShadowData {
  USING_FAST_MALLOC(ShadowData);

 public:
  ShadowData(const FloatPoint& location,
             float blur,
             float spread,
             ShadowStyle style,
             StyleColor color)
      : m_location(location),
        m_blur(blur),
        m_spread(spread),
        m_color(color),
        m_style(style) {}

  bool operator==(const ShadowData&) const;
  bool operator!=(const ShadowData& o) const { return !(*this == o); }

  ShadowData blend(const ShadowData& from,
                   double progress,
                   const Color& currentColor) const;

  float x() const { return m_location.x(); }
  float y() const { return m_location.y(); }
  FloatPoint location() const { return m_location; }
  float blur() const { return m_blur; }
  float spread() const { return m_spread; }
  ShadowStyle style() const { return m_style; }
  StyleColor color() const { return m_color; }

  // Outsets needed to adjust a source rectangle to the one cast by this
  // shadow.
  FloatRectOutsets rectOutsets() const {
    // 3 * skBlurRadiusToSigma(blur()) is how Skia implements the radius of a
    // blur. See also https://crbug.com/624175.
    float blurAndSpread = ceil(3 * skBlurRadiusToSigma(blur())) + spread();
    return FloatRectOutsets(
        blurAndSpread - y() /* top */, blurAndSpread + x() /* right */,
        blurAndSpread + y() /* bottom */, blurAndSpread - x() /* left */);
  }

 private:
  FloatPoint m_location;
  float m_blur;
  float m_spread;
  StyleColor m_color;
  ShadowStyle m_style;
};

}  // namespace blink

#endif  // ShadowData_h