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123 lines
3.4 KiB
C++
123 lines
3.4 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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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_BASEPOINT_H_
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#define MOZILLA_GFX_BASEPOINT_H_
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#include <cmath>
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#include <ostream>
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#include <type_traits>
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#include "mozilla/Attributes.h"
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#include "mozilla/FloatingPoint.h"
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namespace mozilla {
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namespace gfx {
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/**
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* Do not use this class directly. Subclass it, pass that subclass as the
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* Sub parameter, and only use that subclass. This allows methods to safely
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* cast 'this' to 'Sub*'.
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*/
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template <class T, class Sub, class Coord = T>
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struct BasePoint {
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union {
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struct {
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Coord x, y;
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};
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Coord components[2];
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};
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// Constructors
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constexpr BasePoint() : x(0), y(0) {}
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constexpr BasePoint(Coord aX, Coord aY) : x(aX), y(aY) {}
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MOZ_ALWAYS_INLINE Coord X() const { return x; }
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MOZ_ALWAYS_INLINE Coord Y() const { return y; }
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void MoveTo(Coord aX, Coord aY) {
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x = aX;
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y = aY;
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}
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void MoveBy(Coord aDx, Coord aDy) {
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x += aDx;
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y += aDy;
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}
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// Note that '=' isn't defined so we'll get the
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// compiler generated default assignment operator
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bool operator==(const Sub& aPoint) const {
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return x == aPoint.x && y == aPoint.y;
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}
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bool operator!=(const Sub& aPoint) const {
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return x != aPoint.x || y != aPoint.y;
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}
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Sub operator+(const Sub& aPoint) const {
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return Sub(x + aPoint.x, y + aPoint.y);
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}
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Sub operator-(const Sub& aPoint) const {
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return Sub(x - aPoint.x, y - aPoint.y);
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}
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Sub& operator+=(const Sub& aPoint) {
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x += aPoint.x;
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y += aPoint.y;
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return *static_cast<Sub*>(this);
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}
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Sub& operator-=(const Sub& aPoint) {
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x -= aPoint.x;
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y -= aPoint.y;
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return *static_cast<Sub*>(this);
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}
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Sub operator*(T aScale) const { return Sub(x * aScale, y * aScale); }
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Sub operator/(T aScale) const { return Sub(x / aScale, y / aScale); }
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Sub operator-() const { return Sub(-x, -y); }
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T DotProduct(const Sub& aPoint) const {
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return x.value * aPoint.x.value + y.value * aPoint.y.value;
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}
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// FIXME: Maybe Length() should return a float Coord event for integer Points?
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Coord Length() const {
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return static_cast<decltype(x.value)>(hypot(x.value, y.value));
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}
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T LengthSquare() const { return x.value * x.value + y.value * y.value; }
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// Round() is *not* rounding to nearest integer if the values are negative.
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// They are always rounding as floor(n + 0.5).
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// See https://bugzilla.mozilla.org/show_bug.cgi?id=410748#c14
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Sub& Round() {
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x = Coord(std::floor(T(x) + T(0.5f)));
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y = Coord(std::floor(T(y) + T(0.5f)));
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return *static_cast<Sub*>(this);
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}
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// "Finite" means not inf and not NaN
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bool IsFinite() const {
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using FloatType =
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std::conditional_t<std::is_same_v<T, float>, float, double>;
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return (std::isfinite(FloatType(x)) && std::isfinite(FloatType(y)));
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}
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void Clamp(Coord aMaxAbsValue) {
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x = std::max(std::min(x, aMaxAbsValue), -aMaxAbsValue);
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y = std::max(std::min(y, aMaxAbsValue), -aMaxAbsValue);
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}
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friend std::ostream& operator<<(std::ostream& stream,
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const BasePoint<T, Sub, Coord>& aPoint) {
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return stream << '(' << aPoint.x << ',' << aPoint.y << ')';
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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_BASEPOINT_H_ */
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