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

use crate::glyph::{Contour, Glyph, Segment};
use crate::{Number, Offset};

pub struct Builder {
    contour: Contour,
    glyph: Glyph,

    offset: Offset,
    scale: (Number, Number, Number, Number),
}

impl Builder {
    pub fn flush(&mut self) {
        if self.contour.is_empty() {
            return;
        }
        self.glyph.contours.push(std::mem::take(&mut self.contour));
    }

    pub fn nest<T, U, V, F>(&mut self, offset: T, scale: (U, U, U, U), build: F) -> V
    where
        T: Into<Offset>,
        U: Into<Number>,
        F: Fn(&mut Builder) -> V,
    {
        macro_rules! multiply(
            ($product:expr, $left:expr, $right:expr) => (
                $product.0 = $left.0 * $right.0 + $left.1 * $right.2;
                $product.1 = $left.0 * $right.1 + $left.1 * $right.3;
                $product.2 = $left.2 * $right.0 + $left.3 * $right.2;
                $product.3 = $left.2 * $right.1 + $left.3 * $right.3;
            )
        );

        let offset = offset.into();
        let scale = (
            scale.0.into(),
            scale.1.into(),
            scale.2.into(),
            scale.3.into(),
        );
        let previous_offset = self.offset;
        let previous_scale = self.scale;
        self.offset += offset;
        multiply!(self.scale, scale, self.scale);
        let result = build(self);
        self.scale = previous_scale;
        self.offset = previous_offset;
        result
    }

    #[inline]
    pub fn transform<T: Into<Offset>>(&self, value: T) -> Offset {
        macro_rules! multiply(
            ($product:expr, $left:expr, $right:expr) => (
                $product.0 = $left.0 * $right.0 + $left.1 * $right.1;
                $product.1 = $left.2 * $right.0 + $left.3 * $right.1;
            )
        );

        let mut value = value.into();
        multiply!(value, self.scale, value);
        value
    }
}

impl Builder {
    pub fn move_absolute<T: Into<Offset>>(&mut self, a: T) {
        let last_position = match self.glyph.len() {
            0 => Offset::default(),
            count => self.glyph[count - 1].position,
        };
        let a = self.offset + self.transform(a);
        self.contour.offset = a - last_position;
        self.contour.position = a;
    }

    pub fn move_relative<T: Into<Offset>>(&mut self, a: T) {
        let a = self.transform(a);
        self.contour.offset += a;
        self.contour.position += a;
    }

    pub fn move_control<T: Into<Offset>>(&mut self, a: T) {
        let a = self.transform(a);
        let b = match self.contour.segments.get_mut(0) {
            Some(&mut Segment::Quadratic(ref mut b, _)) => b,
            Some(&mut Segment::Cubic(ref mut b, _, _)) => b,
            _ => unreachable!(),
        };
        *b = a;
    }
}

impl Builder {
    pub fn add_linear<T: Into<Offset>>(&mut self, a: T) {
        self.contour
            .segments
            .push(Segment::Linear(self.transform(a)));
    }

    pub fn add_quadratic<T: Into<Offset>>(&mut self, a: T, b: T) {
        self.contour
            .segments
            .push(Segment::Quadratic(self.transform(a), self.transform(b)));
    }

    pub fn add_cubic<T: Into<Offset>>(&mut self, a: T, b: T, c: T) {
        self.contour.segments.push(Segment::Cubic(
            self.transform(a),
            self.transform(b),
            self.transform(c),
        ));
    }
}

impl Builder {
    #[inline]
    pub fn set_bounding_box<T: Into<Number>>(
        &mut self,
        (min_x, min_y, max_x, max_y): (T, T, T, T),
    ) {
        self.glyph.bounding_box = (min_x.into(), min_y.into(), max_x.into(), max_y.into());
    }

    #[inline]
    pub fn set_horizontal_metrics(&mut self, (advance_width, left_side_bearing): (Number, Number)) {
        self.glyph.advance_width = advance_width;
        self.glyph.side_bearings.0 = left_side_bearing;
    }
}

impl Default for Builder {
    #[inline]
    fn default() -> Self {
        Self {
            contour: Default::default(),
            glyph: Default::default(),

            offset: Default::default(),
            scale: (1.0, 0.0, 0.0, 1.0),
        }
    }
}

impl From<Builder> for Glyph {
    fn from(builder: Builder) -> Glyph {
        let Builder { mut glyph, .. } = builder;
        let width = glyph.bounding_box.2 - glyph.bounding_box.0;
        glyph.side_bearings.1 = glyph.advance_width - (glyph.side_bearings.0 + width);
        glyph
    }
}