flutter_flutter/sky/engine/platform/geometry/FloatRoundedRect.cpp

/*
 * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
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 *    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 distribution.
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 * 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 HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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#include "flutter/sky/engine/platform/geometry/FloatRoundedRect.h"

#include <algorithm>

namespace blink {

FloatRoundedRect::FloatRoundedRect(float x, float y, float width, float height)
    : m_rect(x, y, width, height) {}

FloatRoundedRect::FloatRoundedRect(const FloatRect& rect, const Radii& radii)
    : m_rect(rect), m_radii(radii) {}

FloatRoundedRect::FloatRoundedRect(const FloatRect& rect,
                                   const FloatSize& topLeft,
                                   const FloatSize& topRight,
                                   const FloatSize& bottomLeft,
                                   const FloatSize& bottomRight)
    : m_rect(rect), m_radii(topLeft, topRight, bottomLeft, bottomRight) {}

bool FloatRoundedRect::Radii::isZero() const {
  return m_topLeft.isZero() && m_topRight.isZero() && m_bottomLeft.isZero() &&
         m_bottomRight.isZero();
}

void FloatRoundedRect::Radii::scale(float factor) {
  if (factor == 1)
    return;

  // If either radius on a corner becomes zero, reset both radii on that corner.
  m_topLeft.scale(factor);
  if (!m_topLeft.width() || !m_topLeft.height())
    m_topLeft = FloatSize();
  m_topRight.scale(factor);
  if (!m_topRight.width() || !m_topRight.height())
    m_topRight = FloatSize();
  m_bottomLeft.scale(factor);
  if (!m_bottomLeft.width() || !m_bottomLeft.height())
    m_bottomLeft = FloatSize();
  m_bottomRight.scale(factor);
  if (!m_bottomRight.width() || !m_bottomRight.height())
    m_bottomRight = FloatSize();
}

void FloatRoundedRect::Radii::expand(float topWidth,
                                     float bottomWidth,
                                     float leftWidth,
                                     float rightWidth) {
  if (m_topLeft.width() > 0 && m_topLeft.height() > 0) {
    m_topLeft.setWidth(std::max<float>(0, m_topLeft.width() + leftWidth));
    m_topLeft.setHeight(std::max<float>(0, m_topLeft.height() + topWidth));
  }
  if (m_topRight.width() > 0 && m_topRight.height() > 0) {
    m_topRight.setWidth(std::max<float>(0, m_topRight.width() + rightWidth));
    m_topRight.setHeight(std::max<float>(0, m_topRight.height() + topWidth));
  }
  if (m_bottomLeft.width() > 0 && m_bottomLeft.height() > 0) {
    m_bottomLeft.setWidth(std::max<float>(0, m_bottomLeft.width() + leftWidth));
    m_bottomLeft.setHeight(
        std::max<float>(0, m_bottomLeft.height() + bottomWidth));
  }
  if (m_bottomRight.width() > 0 && m_bottomRight.height() > 0) {
    m_bottomRight.setWidth(
        std::max<float>(0, m_bottomRight.width() + rightWidth));
    m_bottomRight.setHeight(
        std::max<float>(0, m_bottomRight.height() + bottomWidth));
  }
}

static inline float cornerRectIntercept(float y, const FloatRect& cornerRect) {
  ASSERT(cornerRect.height() > 0);
  return cornerRect.width() *
         sqrt(1 - (y * y) / (cornerRect.height() * cornerRect.height()));
}

bool FloatRoundedRect::xInterceptsAtY(float y,
                                      float& minXIntercept,
                                      float& maxXIntercept) const {
  if (y < rect().y() || y > rect().maxY())
    return false;

  if (!isRounded()) {
    minXIntercept = rect().x();
    maxXIntercept = rect().maxX();
    return true;
  }

  const FloatRect& topLeftRect = topLeftCorner();
  const FloatRect& bottomLeftRect = bottomLeftCorner();

  if (!topLeftRect.isEmpty() && y >= topLeftRect.y() && y < topLeftRect.maxY())
    minXIntercept = topLeftRect.maxX() -
                    cornerRectIntercept(topLeftRect.maxY() - y, topLeftRect);
  else if (!bottomLeftRect.isEmpty() && y >= bottomLeftRect.y() &&
           y <= bottomLeftRect.maxY())
    minXIntercept = bottomLeftRect.maxX() -
                    cornerRectIntercept(y - bottomLeftRect.y(), bottomLeftRect);
  else
    minXIntercept = m_rect.x();

  const FloatRect& topRightRect = topRightCorner();
  const FloatRect& bottomRightRect = bottomRightCorner();

  if (!topRightRect.isEmpty() && y >= topRightRect.y() &&
      y <= topRightRect.maxY())
    maxXIntercept = topRightRect.x() +
                    cornerRectIntercept(topRightRect.maxY() - y, topRightRect);
  else if (!bottomRightRect.isEmpty() && y >= bottomRightRect.y() &&
           y <= bottomRightRect.maxY())
    maxXIntercept =
        bottomRightRect.x() +
        cornerRectIntercept(y - bottomRightRect.y(), bottomRightRect);
  else
    maxXIntercept = m_rect.maxX();

  return true;
}

}  // namespace blink