ixy 0.5.7

A minimal, no-std compatible crate for 2D integer geometry
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158

//! Line operations.

use crate::{Pos, int::Int};

/// Calculates positions along a line using a fast 2D vector algorithm.
///
/// The resulting iterator is exclusive of the end position; use [`inclusive`][] to include it.
///
/// [`inclusive`]: VectorIter::inclusive
///
/// Considered less "pixel-perfect" than Bresenham's line algorithm, but faster and simpler.
///
/// ## Examples
///
/// ```rust
/// use ixy::{Pos, ops::line};
///
/// let start = Pos::new(0, 0);
/// let end = Pos::new(2, 2);
/// let mut iter = line::vector(start, end);
/// assert_eq!(iter.next(), Some(Pos::new(0, 0)));
/// assert_eq!(iter.next(), Some(Pos::new(1, 1)));
/// assert_eq!(iter.next(), None);
/// ```
pub fn vector<T: Int>(start: Pos<T>, end: Pos<T>) -> VectorIter<T> {
    let dxy = (end - start).normalized_approx();
    VectorIter {
        pos: start,
        end,
        dxy,
    }
}

pub struct VectorIter<T>
where
    T: Int,
{
    pos: Pos<T>,
    end: Pos<T>,
    dxy: Pos<T>,
}

impl<T> VectorIter<T>
where
    T: Int,
{
    /// Removes a single step from the iterator, making it inclusive of the end position.
    #[must_use]
    pub fn inclusive(self) -> Self {
        Self {
            pos: self.pos,
            end: self.end + self.dxy,
            dxy: self.dxy,
        }
    }
}

impl<T> Iterator for VectorIter<T>
where
    T: Int,
{
    type Item = Pos<T>;

    fn next(&mut self) -> Option<Self::Item> {
        if self.pos == self.end {
            None
        } else {
            let current = self.pos;
            self.pos += self.dxy;
            Some(current)
        }
    }
}

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

    #[test]
    fn vector_iter_blank() {
        let start = Pos::new(0, 0);
        let end = Pos::new(0, 0);
        let mut iter = vector(start, end);
        assert_eq!(iter.next(), None);
    }

    #[test]
    fn vector_iter_horizontal() {
        let start = Pos::new(0, 0);
        let end = Pos::new(5, 0);
        let mut iter = vector(start, end);
        assert_eq!(iter.next(), Some(Pos::new(0, 0)));
        assert_eq!(iter.next(), Some(Pos::new(1, 0)));
        assert_eq!(iter.next(), Some(Pos::new(2, 0)));
        assert_eq!(iter.next(), Some(Pos::new(3, 0)));
        assert_eq!(iter.next(), Some(Pos::new(4, 0)));
        assert_eq!(iter.next(), None);
    }

    #[test]
    fn vector_iter_inclusive() {
        let start = Pos::new(0, 0);
        let end = Pos::new(5, 0);
        let mut iter = vector(start, end).inclusive();
        assert_eq!(iter.next(), Some(Pos::new(0, 0)));
        assert_eq!(iter.next(), Some(Pos::new(1, 0)));
        assert_eq!(iter.next(), Some(Pos::new(2, 0)));
        assert_eq!(iter.next(), Some(Pos::new(3, 0)));
        assert_eq!(iter.next(), Some(Pos::new(4, 0)));
        assert_eq!(iter.next(), Some(Pos::new(5, 0)));
        assert_eq!(iter.next(), None);
    }

    #[test]
    fn vector_iter_vertical() {
        let start = Pos::new(0, 0);
        let end = Pos::new(0, 5);
        let mut iter = vector(start, end);
        assert_eq!(iter.next(), Some(Pos::new(0, 0)));
        assert_eq!(iter.next(), Some(Pos::new(0, 1)));
        assert_eq!(iter.next(), Some(Pos::new(0, 2)));
        assert_eq!(iter.next(), Some(Pos::new(0, 3)));
        assert_eq!(iter.next(), Some(Pos::new(0, 4)));
        assert_eq!(iter.next(), None);
    }

    #[test]
    fn vector_iter_diagonal() {
        let start = Pos::new(0, 0);
        let end = Pos::new(3, 3);
        let mut iter = vector(start, end);
        assert_eq!(iter.next(), Some(Pos::new(0, 0)));
        assert_eq!(iter.next(), Some(Pos::new(1, 1)));
        assert_eq!(iter.next(), Some(Pos::new(2, 2)));
        assert_eq!(iter.next(), None);
    }

    #[test]
    fn vector_iter_negative() {
        let start = Pos::new(0, 0);
        let end = Pos::new(-3, -3);
        let mut iter = vector(start, end);
        assert_eq!(iter.next(), Some(Pos::new(0, 0)));
        assert_eq!(iter.next(), Some(Pos::new(-1, -1)));
        assert_eq!(iter.next(), Some(Pos::new(-2, -2)));
        assert_eq!(iter.next(), None);
    }

    #[test]
    fn vector_iter_jagged() {
        let start = Pos::new(0, 0);
        let end = Pos::new(6, 4);
        let mut iter = vector(start, end);
        assert_eq!(iter.next(), Some(Pos::new(0, 0)));
        assert_eq!(iter.next(), Some(Pos::new(3, 2)));
        assert_eq!(iter.next(), None);
    }
}