86 lines
2.5 KiB
C++
86 lines
2.5 KiB
C++
/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef MOZILLA_GFX_SCALEFACTOR_H_
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#define MOZILLA_GFX_SCALEFACTOR_H_
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#include "mozilla/Attributes.h"
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#include "gfxPoint.h"
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namespace mozilla {
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namespace gfx {
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/*
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* This class represents a scaling factor between two different pixel unit
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* systems. This is effectively a type-safe float, intended to be used in
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* combination with the known-type instances of gfx::Point, gfx::Rect, etc.
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*
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* This class is meant to be used in cases where a single scale applies to
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* both the x and y axes. For cases where two diferent scales apply, use
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* ScaleFactors2D.
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*/
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template<class src, class dst>
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struct ScaleFactor {
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float scale;
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constexpr ScaleFactor() : scale(1.0) {}
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constexpr ScaleFactor(const ScaleFactor<src, dst>& aCopy) : scale(aCopy.scale) {}
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explicit constexpr ScaleFactor(float aScale) : scale(aScale) {}
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ScaleFactor<dst, src> Inverse() {
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return ScaleFactor<dst, src>(1 / scale);
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}
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bool operator==(const ScaleFactor<src, dst>& aOther) const {
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return scale == aOther.scale;
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}
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bool operator!=(const ScaleFactor<src, dst>& aOther) const {
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return !(*this == aOther);
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}
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bool operator<(const ScaleFactor<src, dst>& aOther) const {
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return scale < aOther.scale;
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}
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bool operator<=(const ScaleFactor<src, dst>& aOther) const {
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return scale <= aOther.scale;
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}
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bool operator>(const ScaleFactor<src, dst>& aOther) const {
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return scale > aOther.scale;
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}
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bool operator>=(const ScaleFactor<src, dst>& aOther) const {
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return scale >= aOther.scale;
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}
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template<class other>
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ScaleFactor<other, dst> operator/(const ScaleFactor<src, other>& aOther) const {
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return ScaleFactor<other, dst>(scale / aOther.scale);
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}
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template<class other>
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ScaleFactor<src, other> operator/(const ScaleFactor<other, dst>& aOther) const {
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return ScaleFactor<src, other>(scale / aOther.scale);
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}
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template<class other>
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ScaleFactor<src, other> operator*(const ScaleFactor<dst, other>& aOther) const {
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return ScaleFactor<src, other>(scale * aOther.scale);
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}
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template<class other>
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ScaleFactor<other, dst> operator*(const ScaleFactor<other, src>& aOther) const {
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return ScaleFactor<other, dst>(scale * aOther.scale);
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}
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};
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} // namespace gfx
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} // namespace mozilla
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#endif /* MOZILLA_GFX_SCALEFACTOR_H_ */
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