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/*
* Copyright (C) 2021 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Apple Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS 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 APPLE OR ITS 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) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "FloatLine.h"
namespace WebCore {
const FloatPoint FloatLine::pointAtAbsoluteDistance(float absoluteDistance) const
{
if (!length())
return m_start;
auto relativeDistance = absoluteDistance / length();
return pointAtRelativeDistance(relativeDistance);
}
const FloatPoint FloatLine::pointAtRelativeDistance(float relativeDistance) const
{
return {
m_start.x() - (relativeDistance * (m_start.x() - m_end.x())),
m_start.y() - (relativeDistance * (m_start.y() - m_end.y())),
};
}
const FloatLine FloatLine::extendedToBounds(const FloatRect& bounds) const
{
if (std::abs(m_start.x() - m_end.x()) <= std::abs(m_start.y() - m_end.y())) {
// The line is roughly vertical, so construct points at the top and bottom of the bounds.
FloatPoint top = { (((bounds.y() - m_start.y()) * (m_end.x() - m_start.x())) / (m_end.y() - m_start.y())) + m_start.x(), bounds.y() };
FloatPoint bottom = { (((bounds.y() + bounds.height() - m_start.y()) * (m_end.x() - m_start.x())) / (m_end.y() - m_start.y())) + m_start.x(), bounds.y() + bounds.height() };
return { top, bottom };
}
// The line is roughly horizontal, so construct points at the left and right of the bounds.
FloatPoint left = { bounds.x(), (((bounds.x() - m_start.x()) * (m_end.y() - m_start.y())) / (m_end.x() - m_start.x())) + m_start.y() };
FloatPoint right = { bounds.x() + bounds.width(), (((bounds.x() + bounds.width() - m_start.x()) * (m_end.y() - m_start.y())) / (m_end.x() - m_start.x())) + m_start.y() };
return { left, right };
}
const std::optional<FloatPoint> FloatLine::intersectionWith(const FloatLine& otherLine) const
{
float denominator = ((m_start.x() - m_end.x()) * (otherLine.start().y() - otherLine.end().y())) - ((m_start.y() - m_end.y()) * (otherLine.start().x() - otherLine.end().x()));
// A denominator of zero indicates the lines are parallel or coincident, which means there is no true intersection.
if (!denominator)
return std::nullopt;
float thisLineCommonNumeratorFactor = (m_start.x() * m_end.y()) - (m_start.y() * m_end.x());
float otherLineCommonNumeratorFactor = (otherLine.start().x() * otherLine.end().y()) - (otherLine.start().y() * otherLine.end().x());
return {{
((thisLineCommonNumeratorFactor * (otherLine.start().x() - otherLine.end().x())) - (otherLineCommonNumeratorFactor * (m_start.x() - m_end.x()))) / denominator,
((thisLineCommonNumeratorFactor * (otherLine.start().y() - otherLine.end().y())) - (otherLineCommonNumeratorFactor * (m_start.y() - m_end.y()))) / denominator,
}};
}
}
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