[kaka/rust-sdl-test.git] / src / common / geometry.rs

use std::ops::{Add, AddAssign, Sub, SubAssign, Mul, MulAssign, Div, DivAssign, Neg};

////////// POINT ///////////////////////////////////////////////////////////////

#[macro_export]
macro_rules! point {
    ( $x:expr, $y:expr ) => {
        Point { x: $x, y: $y }
    };
}

#[derive(Debug, Default, Copy, Clone, PartialEq)]
pub struct Point<T> {
    pub x: T,
    pub y: T,
}

impl Point<f64> {
    pub fn length(&self) -> f64 {
        ((self.x * self.x) + (self.y * self.y)).sqrt()
    }

    pub fn normalized(&self) -> Self {
	let l = self.length();
	Self {
	    x: self.x / l,
	    y: self.y / l,
	}
    }

    pub fn to_radians(&self) -> Radians {
	Radians(self.y.atan2(self.x))
    }

    pub fn to_degrees(&self) -> Degrees {
	self.to_radians().to_degrees()
    }

    pub fn to_i32(self) -> Point<i32> {
	Point {
	    x: self.x as i32,
	    y: self.y as i32,
	}
    }
}

macro_rules! point_op {
    ($op:tt, $trait:ident($fn:ident), $trait_assign:ident($fn_assign:ident), $rhs:ident = $Rhs:ty => $x:expr, $y:expr) => {
        impl<T: $trait<Output = T>> $trait<$Rhs> for Point<T> {
            type Output = Self;

            fn $fn(self, $rhs: $Rhs) -> Self {
                Self {
                    x: self.x $op $x,
                    y: self.y $op $y,
                }
            }
        }

        impl<T: $trait<Output = T> + Copy> $trait_assign<$Rhs> for Point<T> {
            fn $fn_assign(&mut self, $rhs: $Rhs) {
                *self = Self {
                    x: self.x $op $x,
                    y: self.y $op $y,
                }
            }
        }
    }
}

point_op!(+, Add(add), AddAssign(add_assign), rhs = Point<T> => rhs.x, rhs.y);
point_op!(-, Sub(sub), SubAssign(sub_assign), rhs = Point<T> => rhs.x, rhs.y);
point_op!(*, Mul(mul), MulAssign(mul_assign), rhs = Point<T> => rhs.x, rhs.y);
point_op!(/, Div(div), DivAssign(div_assign), rhs = Point<T> => rhs.x, rhs.y);
point_op!(+, Add(add), AddAssign(add_assign), rhs = (T, T) => rhs.0, rhs.1);
point_op!(-, Sub(sub), SubAssign(sub_assign), rhs = (T, T) => rhs.0, rhs.1);
point_op!(*, Mul(mul), MulAssign(mul_assign), rhs = (T, T) => rhs.0, rhs.1);
point_op!(/, Div(div), DivAssign(div_assign), rhs = (T, T) => rhs.0, rhs.1);

////////// multiply point with scalar //////////////////////////////////////////
impl<T: Mul<Output = T> + Copy> Mul<T> for Point<T> {
    type Output = Self;

    fn mul(self, rhs: T) -> Self {
	Self {
	    x: self.x * rhs,
	    y: self.y * rhs,
	}
    }
}

impl<T: Mul<Output = T> + Copy> MulAssign<T> for Point<T> {
    fn mul_assign(&mut self, rhs: T) {
	*self = Self {
	    x: self.x * rhs,
	    y: self.y * rhs,
	}
    }
}

////////// divide point with scalar ////////////////////////////////////////////
impl<T: Div<Output = T> + Copy> Div<T> for Point<T> {
    type Output = Self;

    fn div(self, rhs: T) -> Self {
	Self {
	    x: self.x / rhs,
	    y: self.y / rhs,
	}
    }
}

impl<T: Div<Output = T> + Copy> DivAssign<T> for Point<T> {
    fn div_assign(&mut self, rhs: T) {
	*self = Self {
	    x: self.x / rhs,
	    y: self.y / rhs,
	}
    }
}

impl<T: Neg<Output = T>> Neg for Point<T> {
    type Output = Self;

    fn neg(self) -> Self {
	Self {
	    x: -self.x,
	    y: -self.y,
	}
    }
}

impl<T> From<(T, T)> for Point<T> {
    fn from(item: (T, T)) -> Self {
        Point {
            x: item.0,
            y: item.1,
        }
    }
}

impl<T> From<Point<T>> for (T, T) {
    fn from(item: Point<T>) -> Self {
        (item.x, item.y)
    }
}

impl From<Degrees> for Point<f64> {
    fn from(item: Degrees) -> Self {
	let r = item.0.to_radians();
        Point {
            x: r.cos(),
            y: r.sin(),
        }
    }
}

impl From<Radians> for Point<f64> {
    fn from(item: Radians) -> Self {
        Point {
            x: item.0.cos(),
            y: item.0.sin(),
        }
    }
}

#[derive(Debug, Default, PartialEq, Clone, Copy)]
pub struct Degrees(pub f64);
#[derive(Debug, Default, PartialEq, Clone, Copy)]
pub struct Radians(pub f64);

impl Degrees {
    #[allow(dead_code)]
    fn to_radians(&self) -> Radians {
	Radians(self.0.to_radians())
    }
}

impl Radians {
    #[allow(dead_code)]
    fn to_degrees(&self) -> Degrees {
	Degrees(self.0.to_degrees())
    }
}

////////// INTERSECTION ////////////////////////////////////////////////////////

#[derive(Debug)]
pub enum Intersection {
    Point(Point<f64>),
    //Line(Point<f64>, Point<f64>), // TODO: overlapping collinear
    None,
}

impl Intersection {
    pub fn lines(p1: Point<f64>, p2: Point<f64>, p3: Point<f64>, p4: Point<f64>) -> Intersection {
	let s1 = p2 - p1;
	let s2 = p4 - p3;

	let denomimator = -s2.x * s1.y + s1.x * s2.y;
	if denomimator != 0.0 {
	    let s = (-s1.y * (p1.x - p3.x) + s1.x * (p1.y - p3.y)) / denomimator;
	    let t = ( s2.x * (p1.y - p3.y) - s2.y * (p1.x - p3.x)) / denomimator;

	    if s >= 0.0 && s <= 1.0 && t >= 0.0 && t <= 1.0 {
		return Intersection::Point(p1 + (s1 * t))
	    }
	}

	Intersection::None
    }
}

////////// DIMENSION ///////////////////////////////////////////////////////////

#[macro_export]
macro_rules! dimen {
    ( $w:expr, $h:expr ) => {
        Dimension { width: $w, height: $h }
    };
}

#[derive(Debug, Default, Copy, Clone, PartialEq)]
pub struct Dimension<T> {
    pub width: T,
    pub height: T,
}

impl<T: Mul<Output = T> + Copy> Dimension<T> {
    #[allow(dead_code)]
    pub fn area(&self) -> T {
        self.width * self.height
    }
}

impl<T> From<(T, T)> for Dimension<T> {
    fn from(item: (T, T)) -> Self {
        Dimension {
            width: item.0,
            height: item.1,
        }
    }
}

impl<T> From<Dimension<T>> for (T, T) {
    fn from(item: Dimension<T>) -> Self {
        (item.width, item.height)
    }
}

////////////////////////////////////////////////////////////////////////////////

#[allow(dead_code)]
pub fn supercover_line_int(p1: Point<isize>, p2: Point<isize>) -> Vec<Point<isize>> {
    let d = p2 - p1;
    let n = point!(d.x.abs(), d.y.abs());
    let step = point!(
	if d.x > 0 { 1 } else { -1 },
	if d.y > 0 { 1 } else { -1 }
    );

    let mut p = p1.clone();
    let mut points = vec!(point!(p.x as isize, p.y as isize));
    let mut i = point!(0, 0);
    while i.x < n.x || i.y < n.y {
        let decision = (1 + 2 * i.x) * n.y - (1 + 2 * i.y) * n.x;
        if decision == 0 { // next step is diagonal
            p.x += step.x;
            p.y += step.y;
            i.x += 1;
            i.y += 1;
        } else if decision < 0 { // next step is horizontal
            p.x += step.x;
	    i.x += 1;
        } else { // next step is vertical
            p.y += step.y;
            i.y += 1;
        }
        points.push(point!(p.x as isize, p.y as isize));
    }

    points
}

/// Calculates all points a line crosses, unlike Bresenham's line algorithm.
/// There might be room for a lot of improvement here.
pub fn supercover_line(mut p1: Point<f64>, mut p2: Point<f64>) -> Vec<Point<isize>> {
    let mut delta = p2 - p1;
    if (delta.x.abs() > delta.y.abs() && delta.x.is_sign_negative()) || (delta.x.abs() <= delta.y.abs() && delta.y.is_sign_negative()) {
	std::mem::swap(&mut p1, &mut p2);
	delta = -delta;
    }

    let mut last = point!(p1.x as isize, p1.y as isize);
    let mut coords: Vec<Point<isize>> = vec!();
    coords.push(last);

    if delta.x.abs() > delta.y.abs() {
	let k = delta.y / delta.x;
	let m = p1.y as f64 - p1.x as f64 * k;
	for x in (p1.x as isize + 1)..=(p2.x as isize) {
	    let y = (k * x as f64 + m).floor();
	    let next = point!(x as isize - 1, y as isize);
	    if next != last {
		coords.push(next);
	    }
	    let next = point!(x as isize, y as isize);
	    coords.push(next);
	    last = next;
	}
    } else {
	let k = delta.x / delta.y;
	let m = p1.x as f64 - p1.y as f64 * k;
	for y in (p1.y as isize + 1)..=(p2.y as isize) {
	    let x = (k * y as f64 + m).floor();
	    let next = point!(x as isize, y as isize - 1);
	    if next != last {
		coords.push(next);
	    }
	    let next = point!(x as isize, y as isize);
	    coords.push(next);
	    last = next;
	}
    }

    let next = point!(p2.x as isize, p2.y as isize);
    if next != last {
	coords.push(next);
    }

    coords
}

////////// TESTS ///////////////////////////////////////////////////////////////

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn immutable_copy_of_point() {
        let a = point!(0, 0);
        let mut b = a; // Copy
        assert_eq!(a, b); // PartialEq
        b.x = 1;
        assert_ne!(a, b); // PartialEq
    }

    #[test]
    fn add_points() {
        let mut a = point!(1, 0);
        assert_eq!(a + point!(2, 2), point!(3, 2)); // Add
        a += point!(2, 2); // AddAssign
        assert_eq!(a, point!(3, 2));
        assert_eq!(point!(1, 0) + (2, 3), point!(3, 3));
    }

    #[test]
    fn sub_points() {
        let mut a = point!(1, 0);
        assert_eq!(a - point!(2, 2), point!(-1, -2));
        a -= point!(2, 2);
        assert_eq!(a, point!(-1, -2));
        assert_eq!(point!(1, 0) - (2, 3), point!(-1, -3));
    }

    #[test]
    fn mul_points() {
        let mut a = point!(1, 2);
        assert_eq!(a * 2, point!(2, 4));
        assert_eq!(a * point!(2, 3), point!(2, 6));
        a *= 2;
        assert_eq!(a, point!(2, 4));
        a *= point!(3, 1);
        assert_eq!(a, point!(6, 4));
        assert_eq!(point!(1, 0) * (2, 3), point!(2, 0));
    }

    #[test]
    fn div_points() {
        let mut a = point!(4, 8);
        assert_eq!(a / 2, point!(2, 4));
        assert_eq!(a / point!(2, 4), point!(2, 2));
        a /= 2;
        assert_eq!(a, point!(2, 4));
        a /= point!(2, 4);
        assert_eq!(a, point!(1, 1));
        assert_eq!(point!(6, 3) / (2, 3), point!(3, 1));
    }

    #[test]
    fn neg_point() {
        assert_eq!(point!(1, 1), -point!(-1, -1));
    }

    #[test]
    fn angles() {
	assert_eq!(Radians(0.0).to_degrees(), Degrees(0.0));
	assert_eq!(Radians(std::f64::consts::PI).to_degrees(), Degrees(180.0));
	assert_eq!(Degrees(180.0).to_radians(), Radians(std::f64::consts::PI));
	assert!((Point::from(Degrees(90.0)) - point!(0.0, 1.0)).length() < 0.001);
	assert!((Point::from(Radians(std::f64::consts::FRAC_PI_2)) - point!(0.0, 1.0)).length() < 0.001);
    }

    #[test]
    fn area_for_dimension_of_multipliable_type() {
        let r: Dimension<_> = (30, 20).into(); // the Into trait uses the From trait
        assert_eq!(r.area(), 30 * 20);
        // let a = Dimension::from(("a".to_string(), "b".to_string())).area(); // this doesn't work, because area() is not implemented for String
    }

    #[test]
    fn intersection_of_lines() {
        let p1 = point!(0.0, 0.0);
        let p2 = point!(2.0, 2.0);
        let p3 = point!(0.0, 2.0);
        let p4 = point!(2.0, 0.0);
	let r = Intersection::lines(p1, p2, p3, p4);
	if let Intersection::Point(p) = r {
            assert_eq!(p, point!(1.0, 1.0));
	} else {
	    panic!();
	}
    }

    #[test]
    fn some_coordinates_on_line() {
	// horizontally up
	let coords = supercover_line(point!(0.0, 0.0), point!(3.3, 2.2));
	assert_eq!(coords.as_slice(), &[point!(0, 0), point!(1, 0), point!(1, 1), point!(2, 1), point!(2, 2), point!(3, 2)]);

	// horizontally down
	let coords = supercover_line(point!(0.0, 5.0), point!(3.3, 2.2));
	assert_eq!(coords.as_slice(), &[point!(0, 5), point!(0, 4), point!(1, 4), point!(1, 3), point!(2, 3), point!(2, 2), point!(3, 2)]);

	// vertically right
	let coords = supercover_line(point!(0.0, 0.0), point!(2.2, 3.3));
	assert_eq!(coords.as_slice(), &[point!(0, 0), point!(0, 1), point!(1, 1), point!(1, 2), point!(2, 2), point!(2, 3)]);

	// vertically left
	let coords = supercover_line(point!(5.0, 0.0), point!(3.0, 3.0));
	assert_eq!(coords.as_slice(), &[point!(5, 0), point!(4, 0), point!(4, 1), point!(3, 1), point!(3, 2), point!(3, 3)]);

	// negative
	let coords = supercover_line(point!(0.0, 0.0), point!(-3.0, -2.0));
	assert_eq!(coords.as_slice(), &[point!(-3, -2), point!(-2, -2), point!(-2, -1), point!(-1, -1), point!(-1, 0), point!(0, 0)]);

	// 
	let coords = supercover_line(point!(0.0, 0.0), point!(2.3, 1.1));
	assert_eq!(coords.as_slice(), &[point!(0, 0), point!(1, 0), point!(2, 0), point!(2, 1)]);
    }
}
Commit	Line	Data
2836f506	1	use std::ops::{Add, AddAssign, Sub, SubAssign, Mul, MulAssign, Div, DivAssign, Neg};
296187ca	2
60058b91 TW	3	////////// POINT ///////////////////////////////////////////////////////////////
60058b91 TW	4
787dbfb4	5	#[macro_export]
296187ca	6	macro_rules! point {
6ba7aef1	7	( $x:expr, $y:expr ) => {
e570927a	8	Point { x: $x, y: $y }
6ba7aef1	9	};
296187ca TW	10	}
296187ca TW	11
b0566120	12	#[derive(Debug, Default, Copy, Clone, PartialEq)]
e570927a	13	pub struct Point<T> {
296187ca TW	14	pub x: T,
	15	pub y: T,
	16	}
	17
e570927a	18	impl Point<f64> {
eca25591	19	pub fn length(&self) -> f64 {
296187ca TW	20	((self.x * self.x) + (self.y * self.y)).sqrt()
296187ca TW	21	}
bf7b5671	22
93fc5734	23	pub fn normalized(&self) -> Self {
eca25591 TW	24	let l = self.length();
	25	Self {
	26	x: self.x / l,
	27	y: self.y / l,
	28	}
	29	}
	30
ee533e13	31	pub fn to_radians(&self) -> Radians {
eca25591 TW	32	Radians(self.y.atan2(self.x))
	33	}
	34
ee533e13 TW	35	pub fn to_degrees(&self) -> Degrees {
ee533e13 TW	36	self.to_radians().to_degrees()
eca25591 TW	37	}
eca25591 TW	38
e570927a TW	39	pub fn to_i32(self) -> Point<i32> {
e570927a TW	40	Point {
bf7b5671 TW	41	x: self.x as i32,
	42	y: self.y as i32,
	43	}
	44	}
296187ca TW	45	}
296187ca TW	46
6cd86b94 TW	47	macro_rules! point_op {
6cd86b94 TW	48	($op:tt, $trait:ident($fn:ident), $trait_assign:ident($fn_assign:ident), $rhs:ident = $Rhs:ty => $x:expr, $y:expr) => {
e570927a	49	impl<T: $trait<Output = T>> $trait<$Rhs> for Point<T> {
6cd86b94 TW	50	type Output = Self;
	51
	52	fn $fn(self, $rhs: $Rhs) -> Self {
	53	Self {
	54	x: self.x $op $x,
	55	y: self.y $op $y,
	56	}
	57	}
2836f506	58	}
2836f506	59
e570927a	60	impl<T: $trait<Output = T> + Copy> $trait_assign<$Rhs> for Point<T> {
6cd86b94 TW	61	fn $fn_assign(&mut self, $rhs: $Rhs) {
	62	*self = Self {
	63	x: self.x $op $x,
	64	y: self.y $op $y,
	65	}
	66	}
2836f506 TW	67	}
	68	}
	69	}
	70
e570927a TW	71	point_op!(+, Add(add), AddAssign(add_assign), rhs = Point<T> => rhs.x, rhs.y);
	72	point_op!(-, Sub(sub), SubAssign(sub_assign), rhs = Point<T> => rhs.x, rhs.y);
	73	point_op!(*, Mul(mul), MulAssign(mul_assign), rhs = Point<T> => rhs.x, rhs.y);
	74	point_op!(/, Div(div), DivAssign(div_assign), rhs = Point<T> => rhs.x, rhs.y);
6cd86b94 TW	75	point_op!(+, Add(add), AddAssign(add_assign), rhs = (T, T) => rhs.0, rhs.1);
	76	point_op!(-, Sub(sub), SubAssign(sub_assign), rhs = (T, T) => rhs.0, rhs.1);
	77	point_op!(*, Mul(mul), MulAssign(mul_assign), rhs = (T, T) => rhs.0, rhs.1);
	78	point_op!(/, Div(div), DivAssign(div_assign), rhs = (T, T) => rhs.0, rhs.1);
2836f506 TW	79
2836f506 TW	80	////////// multiply point with scalar //////////////////////////////////////////
e570927a	81	impl<T: Mul<Output = T> + Copy> Mul<T> for Point<T> {
2836f506 TW	82	type Output = Self;
	83
	84	fn mul(self, rhs: T) -> Self {
	85	Self {
	86	x: self.x * rhs,
	87	y: self.y * rhs,
	88	}
	89	}
	90	}
	91
e570927a	92	impl<T: Mul<Output = T> + Copy> MulAssign<T> for Point<T> {
2836f506 TW	93	fn mul_assign(&mut self, rhs: T) {
	94	*self = Self {
	95	x: self.x * rhs,
	96	y: self.y * rhs,
	97	}
	98	}
	99	}
	100
2836f506	101	////////// divide point with scalar ////////////////////////////////////////////
e570927a	102	impl<T: Div<Output = T> + Copy> Div<T> for Point<T> {
2836f506 TW	103	type Output = Self;
	104
	105	fn div(self, rhs: T) -> Self {
	106	Self {
	107	x: self.x / rhs,
	108	y: self.y / rhs,
	109	}
	110	}
	111	}
	112
e570927a	113	impl<T: Div<Output = T> + Copy> DivAssign<T> for Point<T> {
2836f506 TW	114	fn div_assign(&mut self, rhs: T) {
	115	*self = Self {
	116	x: self.x / rhs,
	117	y: self.y / rhs,
	118	}
	119	}
	120	}
	121
e570927a	122	impl<T: Neg<Output = T>> Neg for Point<T> {
2836f506 TW	123	type Output = Self;
	124
	125	fn neg(self) -> Self {
	126	Self {
	127	x: -self.x,
	128	y: -self.y,
	129	}
296187ca TW	130	}
	131	}
	132
e570927a	133	impl<T> From<(T, T)> for Point<T> {
b0566120	134	fn from(item: (T, T)) -> Self {
e570927a	135	Point {
b0566120 TW	136	x: item.0,
	137	y: item.1,
	138	}
	139	}
	140	}
	141
e570927a TW	142	impl<T> From<Point<T>> for (T, T) {
e570927a TW	143	fn from(item: Point<T>) -> Self {
bf7b5671 TW	144	(item.x, item.y)
	145	}
	146	}
	147
e570927a	148	impl From<Degrees> for Point<f64> {
e58a1769	149	fn from(item: Degrees) -> Self {
ee533e13	150	let r = item.0.to_radians();
e570927a	151	Point {
ee533e13 TW	152	x: r.cos(),
ee533e13 TW	153	y: r.sin(),
e58a1769 TW	154	}
	155	}
	156	}
	157
e570927a	158	impl From<Radians> for Point<f64> {
e58a1769	159	fn from(item: Radians) -> Self {
e570927a	160	Point {
e58a1769 TW	161	x: item.0.cos(),
	162	y: item.0.sin(),
	163	}
	164	}
	165	}
	166
bf7b5671 TW	167	#[derive(Debug, Default, PartialEq, Clone, Copy)]
	168	pub struct Degrees(pub f64);
	169	#[derive(Debug, Default, PartialEq, Clone, Copy)]
	170	pub struct Radians(pub f64);
e58a1769 TW	171
e58a1769 TW	172	impl Degrees {
bf7b5671	173	#[allow(dead_code)]
e58a1769	174	fn to_radians(&self) -> Radians {
ee533e13	175	Radians(self.0.to_radians())
e58a1769 TW	176	}
	177	}
	178
	179	impl Radians {
bf7b5671	180	#[allow(dead_code)]
e58a1769	181	fn to_degrees(&self) -> Degrees {
ee533e13	182	Degrees(self.0.to_degrees())
e58a1769 TW	183	}
	184	}
	185
60058b91 TW	186	////////// INTERSECTION ////////////////////////////////////////////////////////
	187
	188	#[derive(Debug)]
	189	pub enum Intersection {
	190	Point(Point<f64>),
	191	//Line(Point<f64>, Point<f64>), // TODO: overlapping collinear
	192	None,
	193	}
	194
	195	impl Intersection {
	196	pub fn lines(p1: Point<f64>, p2: Point<f64>, p3: Point<f64>, p4: Point<f64>) -> Intersection {
	197	let s1 = p2 - p1;
	198	let s2 = p4 - p3;
	199
	200	let denomimator = -s2.x * s1.y + s1.x * s2.y;
	201	if denomimator != 0.0 {
	202	let s = (-s1.y * (p1.x - p3.x) + s1.x * (p1.y - p3.y)) / denomimator;
	203	let t = ( s2.x * (p1.y - p3.y) - s2.y * (p1.x - p3.x)) / denomimator;
	204
	205	if s >= 0.0 && s <= 1.0 && t >= 0.0 && t <= 1.0 {
	206	return Intersection::Point(p1 + (s1 * t))
	207	}
	208	}
	209
	210	Intersection::None
	211	}
	212	}
	213
	214	////////// DIMENSION ///////////////////////////////////////////////////////////
	215
0b5024d1	216	#[macro_export]
1f42d724 TW	217	macro_rules! dimen {
	218	( $w:expr, $h:expr ) => {
	219	Dimension { width: $w, height: $h }
0b5024d1 TW	220	};
	221	}
	222
8012f86b	223	#[derive(Debug, Default, Copy, Clone, PartialEq)]
1f42d724	224	pub struct Dimension<T> {
6edafdc0 TW	225	pub width: T,
	226	pub height: T,
	227	}
	228
1f42d724	229	impl<T: Mul<Output = T> + Copy> Dimension<T> {
6edafdc0 TW	230	#[allow(dead_code)]
6edafdc0 TW	231	pub fn area(&self) -> T {
6ba7aef1	232	self.width * self.height
6edafdc0 TW	233	}
	234	}
	235
1f42d724	236	impl<T> From<(T, T)> for Dimension<T> {
6edafdc0	237	fn from(item: (T, T)) -> Self {
1f42d724	238	Dimension {
6ba7aef1 TW	239	width: item.0,
	240	height: item.1,
	241	}
6edafdc0 TW	242	}
	243	}
	244
8012f86b TW	245	impl<T> From<Dimension<T>> for (T, T) {
	246	fn from(item: Dimension<T>) -> Self {
	247	(item.width, item.height)
	248	}
	249	}
	250
	251	////////////////////////////////////////////////////////////////////////////////
	252
	253	#[allow(dead_code)]
	254	pub fn supercover_line_int(p1: Point<isize>, p2: Point<isize>) -> Vec<Point<isize>> {
	255	let d = p2 - p1;
	256	let n = point!(d.x.abs(), d.y.abs());
	257	let step = point!(
	258	if d.x > 0 { 1 } else { -1 },
	259	if d.y > 0 { 1 } else { -1 }
	260	);
	261
	262	let mut p = p1.clone();
	263	let mut points = vec!(point!(p.x as isize, p.y as isize));
	264	let mut i = point!(0, 0);
	265	while i.x < n.x \|\| i.y < n.y {
	266	let decision = (1 + 2 * i.x) * n.y - (1 + 2 * i.y) * n.x;
	267	if decision == 0 { // next step is diagonal
	268	p.x += step.x;
	269	p.y += step.y;
	270	i.x += 1;
	271	i.y += 1;
	272	} else if decision < 0 { // next step is horizontal
	273	p.x += step.x;
	274	i.x += 1;
	275	} else { // next step is vertical
	276	p.y += step.y;
	277	i.y += 1;
	278	}
	279	points.push(point!(p.x as isize, p.y as isize));
	280	}
	281
	282	points
	283	}
	284
	285	/// Calculates all points a line crosses, unlike Bresenham's line algorithm.
	286	/// There might be room for a lot of improvement here.
	287	pub fn supercover_line(mut p1: Point<f64>, mut p2: Point<f64>) -> Vec<Point<isize>> {
	288	let mut delta = p2 - p1;
	289	if (delta.x.abs() > delta.y.abs() && delta.x.is_sign_negative()) \|\| (delta.x.abs() <= delta.y.abs() && delta.y.is_sign_negative()) {
	290	std::mem::swap(&mut p1, &mut p2);
	291	delta = -delta;
	292	}
	293
	294	let mut last = point!(p1.x as isize, p1.y as isize);
	295	let mut coords: Vec<Point<isize>> = vec!();
	296	coords.push(last);
	297
	298	if delta.x.abs() > delta.y.abs() {
	299	let k = delta.y / delta.x;
	300	let m = p1.y as f64 - p1.x as f64 * k;
	301	for x in (p1.x as isize + 1)..=(p2.x as isize) {
	302	let y = (k * x as f64 + m).floor();
	303	let next = point!(x as isize - 1, y as isize);
	304	if next != last {
	305	coords.push(next);
	306	}
	307	let next = point!(x as isize, y as isize);
	308	coords.push(next);
309	last = next;
310	}
311	} else {
312	let k = delta.x / delta.y;
313	let m = p1.x as f64 - p1.y as f64 * k;
314	for y in (p1.y as isize + 1)..=(p2.y as isize) {
315	let x = (k * y as f64 + m).floor();
316	let next = point!(x as isize, y as isize - 1);
317	if next != last {
318	coords.push(next);
319	}
320	let next = point!(x as isize, y as isize);
321	coords.push(next);
322	last = next;
323	}
324	}
325
326	let next = point!(p2.x as isize, p2.y as isize);
327	if next != last {
328	coords.push(next);
329	}
330
331	coords
332	}
333
60058b91	334	////////// TESTS ///////////////////////////////////////////////////////////////
249d43ea	335
296187ca TW	336	#[cfg(test)]
	337	mod tests {
	338	use super::*;
	339
	340	#[test]
	341	fn immutable_copy_of_point() {
	342	let a = point!(0, 0);
	343	let mut b = a; // Copy
	344	assert_eq!(a, b); // PartialEq
	345	b.x = 1;
	346	assert_ne!(a, b); // PartialEq
	347	}
	348
	349	#[test]
	350	fn add_points() {
	351	let mut a = point!(1, 0);
	352	assert_eq!(a + point!(2, 2), point!(3, 2)); // Add
	353	a += point!(2, 2); // AddAssign
	354	assert_eq!(a, point!(3, 2));
2836f506 TW	355	assert_eq!(point!(1, 0) + (2, 3), point!(3, 3));
	356	}
	357
	358	#[test]
	359	fn sub_points() {
	360	let mut a = point!(1, 0);
	361	assert_eq!(a - point!(2, 2), point!(-1, -2));
	362	a -= point!(2, 2);
	363	assert_eq!(a, point!(-1, -2));
6cd86b94	364	assert_eq!(point!(1, 0) - (2, 3), point!(-1, -3));
2836f506 TW	365	}
	366
	367	#[test]
	368	fn mul_points() {
	369	let mut a = point!(1, 2);
	370	assert_eq!(a * 2, point!(2, 4));
	371	assert_eq!(a * point!(2, 3), point!(2, 6));
	372	a *= 2;
	373	assert_eq!(a, point!(2, 4));
	374	a *= point!(3, 1);
	375	assert_eq!(a, point!(6, 4));
6cd86b94	376	assert_eq!(point!(1, 0) * (2, 3), point!(2, 0));
2836f506 TW	377	}
	378
	379	#[test]
	380	fn div_points() {
	381	let mut a = point!(4, 8);
	382	assert_eq!(a / 2, point!(2, 4));
	383	assert_eq!(a / point!(2, 4), point!(2, 2));
	384	a /= 2;
	385	assert_eq!(a, point!(2, 4));
	386	a /= point!(2, 4);
	387	assert_eq!(a, point!(1, 1));
6cd86b94	388	assert_eq!(point!(6, 3) / (2, 3), point!(3, 1));
2836f506 TW	389	}
	390
	391	#[test]
	392	fn neg_point() {
	393	assert_eq!(point!(1, 1), -point!(-1, -1));
296187ca	394	}
6edafdc0 TW	395
6edafdc0 TW	396	#[test]
e58a1769 TW	397	fn angles() {
	398	assert_eq!(Radians(0.0).to_degrees(), Degrees(0.0));
	399	assert_eq!(Radians(std::f64::consts::PI).to_degrees(), Degrees(180.0));
	400	assert_eq!(Degrees(180.0).to_radians(), Radians(std::f64::consts::PI));
e570927a TW	401	assert!((Point::from(Degrees(90.0)) - point!(0.0, 1.0)).length() < 0.001);
e570927a TW	402	assert!((Point::from(Radians(std::f64::consts::FRAC_PI_2)) - point!(0.0, 1.0)).length() < 0.001);
e58a1769 TW	403	}
	404
	405	#[test]
1f42d724 TW	406	fn area_for_dimension_of_multipliable_type() {
1f42d724 TW	407	let r: Dimension<_> = (30, 20).into(); // the Into trait uses the From trait
6ba7aef1	408	assert_eq!(r.area(), 30 * 20);
1f42d724	409	// let a = Dimension::from(("a".to_string(), "b".to_string())).area(); // this doesn't work, because area() is not implemented for String
6edafdc0	410	}
60058b91 TW	411
	412	#[test]
	413	fn intersection_of_lines() {
	414	let p1 = point!(0.0, 0.0);
	415	let p2 = point!(2.0, 2.0);
	416	let p3 = point!(0.0, 2.0);
	417	let p4 = point!(2.0, 0.0);
	418	let r = Intersection::lines(p1, p2, p3, p4);
	419	if let Intersection::Point(p) = r {
	420	assert_eq!(p, point!(1.0, 1.0));
	421	} else {
	422	panic!();
	423	}
	424	}
8012f86b TW	425
	426	#[test]
	427	fn some_coordinates_on_line() {
	428	// horizontally up
	429	let coords = supercover_line(point!(0.0, 0.0), point!(3.3, 2.2));
	430	assert_eq!(coords.as_slice(), &[point!(0, 0), point!(1, 0), point!(1, 1), point!(2, 1), point!(2, 2), point!(3, 2)]);
	431
	432	// horizontally down
	433	let coords = supercover_line(point!(0.0, 5.0), point!(3.3, 2.2));
	434	assert_eq!(coords.as_slice(), &[point!(0, 5), point!(0, 4), point!(1, 4), point!(1, 3), point!(2, 3), point!(2, 2), point!(3, 2)]);
	435
	436	// vertically right
	437	let coords = supercover_line(point!(0.0, 0.0), point!(2.2, 3.3));
	438	assert_eq!(coords.as_slice(), &[point!(0, 0), point!(0, 1), point!(1, 1), point!(1, 2), point!(2, 2), point!(2, 3)]);
	439
	440	// vertically left
	441	let coords = supercover_line(point!(5.0, 0.0), point!(3.0, 3.0));
	442	assert_eq!(coords.as_slice(), &[point!(5, 0), point!(4, 0), point!(4, 1), point!(3, 1), point!(3, 2), point!(3, 3)]);
	443
	444	// negative
	445	let coords = supercover_line(point!(0.0, 0.0), point!(-3.0, -2.0));
	446	assert_eq!(coords.as_slice(), &[point!(-3, -2), point!(-2, -2), point!(-2, -1), point!(-1, -1), point!(-1, 0), point!(0, 0)]);
	447
	448	//
	449	let coords = supercover_line(point!(0.0, 0.0), point!(2.3, 1.1));
	450	assert_eq!(coords.as_slice(), &[point!(0, 0), point!(1, 0), point!(2, 0), point!(2, 1)]);
	451	}
296187ca	452	}