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/*
* Authors:
* Thomas Holder
* Sergei Izmailov
*
* Copyright 2020 Authors
*
* SPDX-License-Identifier: LGPL-2.1 or MPL-1.1
*/
#ifndef LIB2GEOM_SEEN_PARALLELOGRAM_H
#define LIB2GEOM_SEEN_PARALLELOGRAM_H
#include <2geom/affine.h>
#include <2geom/rect.h>
namespace Geom {
/**
* Paralellogram, representing a linear transformation of a rectangle.
*
* Implements efficient "contains" and "intersects" operations.
*/
class Parallelogram {
Affine m_affine;
/// Transformed unit rectangle
Parallelogram(Affine const &affine)
: m_affine(affine)
{
}
public:
explicit Parallelogram(Rect const &rect)
: m_affine(rect.width(), 0, 0, rect.height(), rect.left(), rect.top())
{
}
Point corner(unsigned i) const;
Point midpoint() const { return Point(0.5, 0.5) * m_affine; }
/// Area (non-negative)
Coord area() const { return m_affine.descrim2(); }
/// Axis-aligned bounding box
Rect bounds() const;
bool intersects(Parallelogram const &) const;
bool intersects(Rect const &rect) const { return intersects(Parallelogram(rect)); }
bool contains(Point const &) const;
bool contains(Parallelogram const &) const;
bool contains(Rect const &rect) const { return contains(Parallelogram(rect)); }
/// Returns shorter side length
Coord minExtent() const;
/// Returns longer side length
Coord maxExtent() const;
/// Return a new transformed parallelogram
Parallelogram operator*(Affine const &affine) const { return m_affine * affine; }
Parallelogram &operator*=(Affine const &affine) { m_affine *= affine; return *this; }
/// True if this parallelogram does not have right angles
bool isSheared(Coord eps = EPSILON) const;
};
} // namespace Geom
#endif
/*
Local Variables:
mode:c++
c-file-style:"stroustrup"
c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
indent-tabs-mode:nil
fill-column:99
End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :
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