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

use crate::path::LinePathCommand;
use crate::geometry::{Point, Transform, Transformation};
use crate::internal_iter::{
    ExtendFromInternalIterator, FromInternalIterator, InternalIterator, IntoInternalIterator,
};
use std::iter::Cloned;
use std::slice::Iter;

/// A sequence of commands that defines a set of contours, each of which consists of a sequence of
/// line segments. Each contour is either open or closed.
#[derive(Clone, Debug, Default, PartialEq)]
pub struct LinePath {
    verbs: Vec<Verb>,
    points: Vec<Point>,
}

impl LinePath {
    /// Creates a new empty line path.
    pub fn new() -> LinePath {
        LinePath::default()
    }

    /// Returns a slice of the points that make up `self`.
    pub fn points(&self) -> &[Point] {
        &self.points
    }

    /// Returns an iterator over the commands that make up `self`.
    pub fn commands(&self) -> Commands {
        Commands {
            verbs: self.verbs.iter().cloned(),
            points: self.points.iter().cloned(),
        }
    }

    /// Returns a mutable slice of the points that make up `self`.
    pub fn points_mut(&mut self) -> &mut [Point] {
        &mut self.points
    }

    /// Adds a new contour, starting at the given point.
    pub fn move_to(&mut self, p: Point) {
        self.verbs.push(Verb::MoveTo);
        self.points.push(p);
    }

    /// Adds a line segment to the current contour, starting at the current point.
    pub fn line_to(&mut self, p: Point) {
        self.verbs.push(Verb::LineTo);
        self.points.push(p);
    }

    /// Closes the current contour.
    pub fn close(&mut self) {
        self.verbs.push(Verb::Close);
    }

    /// Clears `self`.
    pub fn clear(&mut self) {
        self.verbs.clear();
        self.points.clear();
    }
}

impl ExtendFromInternalIterator<LinePathCommand> for LinePath {
    fn extend_from_internal_iter<I>(&mut self, internal_iter: I)
    where
        I: IntoInternalIterator<Item = LinePathCommand>,
    {
        internal_iter.into_internal_iter().for_each(&mut |command| {
            match command {
                LinePathCommand::MoveTo(p) => self.move_to(p),
                LinePathCommand::LineTo(p) => self.line_to(p),
                LinePathCommand::Close => self.close(),
            }
            true
        });
    }
}

impl FromInternalIterator<LinePathCommand> for LinePath {
    fn from_internal_iter<I>(internal_iter: I) -> Self
    where
        I: IntoInternalIterator<Item = LinePathCommand>,
    {
        let mut path = LinePath::new();
        path.extend_from_internal_iter(internal_iter);
        path
    }
}

impl Transform for LinePath {
    fn transform<T>(mut self, t: &T) -> LinePath
    where
        T: Transformation,
    {
        self.transform_mut(t);
        self
    }

    fn transform_mut<T>(&mut self, t: &T)
    where
        T: Transformation,
    {
        for point in self.points_mut() {
            point.transform_mut(t);
        }
    }
}

/// An iterator over the commands that make up a line path.
#[derive(Clone, Debug)]
pub struct Commands<'a> {
    verbs: Cloned<Iter<'a, Verb>>,
    points: Cloned<Iter<'a, Point>>,
}

impl<'a> Iterator for Commands<'a> {
    type Item = LinePathCommand;

    fn next(&mut self) -> Option<LinePathCommand> {
        self.verbs.next().map(|verb| match verb {
            Verb::MoveTo => LinePathCommand::MoveTo(self.points.next().unwrap()),
            Verb::LineTo => LinePathCommand::LineTo(self.points.next().unwrap()),
            Verb::Close => LinePathCommand::Close,
        })
    }
}

#[derive(Clone, Debug, Eq, Hash, PartialEq)]
enum Verb {
    MoveTo,
    LineTo,
    Close,
}