Source code

Revision control

Other Tools

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef MOZILLA_GFX_SCALEFACTOR_H_
#define MOZILLA_GFX_SCALEFACTOR_H_
#include <ostream>
#include "mozilla/Attributes.h"
#include "gfxPoint.h"
namespace mozilla {
namespace gfx {
/*
* This class represents a scaling factor between two different pixel unit
* systems. This is effectively a type-safe float, intended to be used in
* combination with the known-type instances of gfx::Point, gfx::Rect, etc.
*
* This class is meant to be used in cases where a single scale applies to
* both the x and y axes. For cases where two diferent scales apply, use
* ScaleFactors2D.
*/
template <class src, class dst>
struct ScaleFactor {
float scale;
constexpr ScaleFactor() : scale(1.0) {}
constexpr ScaleFactor(const ScaleFactor<src, dst>& aCopy)
: scale(aCopy.scale) {}
explicit constexpr ScaleFactor(float aScale) : scale(aScale) {}
ScaleFactor<dst, src> Inverse() { return ScaleFactor<dst, src>(1 / scale); }
ScaleFactor<src, dst>& operator=(const ScaleFactor<src, dst>&) = default;
bool operator==(const ScaleFactor<src, dst>& aOther) const {
return scale == aOther.scale;
}
bool operator!=(const ScaleFactor<src, dst>& aOther) const {
return !(*this == aOther);
}
bool operator<(const ScaleFactor<src, dst>& aOther) const {
return scale < aOther.scale;
}
bool operator<=(const ScaleFactor<src, dst>& aOther) const {
return scale <= aOther.scale;
}
bool operator>(const ScaleFactor<src, dst>& aOther) const {
return scale > aOther.scale;
}
bool operator>=(const ScaleFactor<src, dst>& aOther) const {
return scale >= aOther.scale;
}
template <class other>
ScaleFactor<other, dst> operator/(
const ScaleFactor<src, other>& aOther) const {
return ScaleFactor<other, dst>(scale / aOther.scale);
}
template <class other>
ScaleFactor<src, other> operator/(
const ScaleFactor<other, dst>& aOther) const {
return ScaleFactor<src, other>(scale / aOther.scale);
}
template <class other>
ScaleFactor<src, other> operator*(
const ScaleFactor<dst, other>& aOther) const {
return ScaleFactor<src, other>(scale * aOther.scale);
}
template <class other>
ScaleFactor<other, dst> operator*(
const ScaleFactor<other, src>& aOther) const {
return ScaleFactor<other, dst>(scale * aOther.scale);
}
friend std::ostream& operator<<(std::ostream& aStream,
const ScaleFactor<src, dst>& aSF) {
return aStream << aSF.scale;
}
};
} // namespace gfx
} // namespace mozilla
#endif /* MOZILLA_GFX_SCALEFACTOR_H_ */