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
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173

use std::slice;
use std::marker::PhantomData;
use libc::{ c_short, c_char };
use { ffi, Vector };

#[derive(Copy, Clone)]
pub enum Curve {
    Line(Vector),
    Bezier2(Vector, Vector),
    Bezier3(Vector, Vector, Vector)
}

pub struct Outline<'a> {
    raw: &'a ffi::FT_Outline
}

impl<'a> Outline<'a> {
    pub unsafe fn from_raw(raw: &'a ffi::FT_Outline) -> Self {
        Outline {
            raw: raw
        }
    }

    pub fn points(&self) -> &'a [Vector] {
        unsafe {
            slice::from_raw_parts(self.raw.points, self.raw.n_points as usize)
        }
    }

    pub fn tags(&self) -> &'a [c_char] {
        unsafe {
            slice::from_raw_parts(self.raw.tags, self.raw.n_points as usize)
        }
    }

    pub fn contours(&self) -> &'a [c_short] {
        unsafe {
            slice::from_raw_parts(self.raw.contours, self.raw.n_contours as usize)
        }
    }

    pub fn contours_iter(&self) -> ContourIterator<'a> {
        unsafe {
            ContourIterator::from_raw(self.raw)
        }
    }
}

const TAG_ONCURVE: c_char = 0x01;
const TAG_BEZIER3: c_char = 0x02;

pub struct CurveIterator<'a> {
    start_point: *const Vector,
    start_tag: *const c_char,
    idx: isize,
    length: isize,
    marker: PhantomData<&'a ()>
}

impl<'a> CurveIterator<'a> {
    pub unsafe fn from_raw(outline: &'a ffi::FT_Outline,
                               start_idx: isize,
                               end_idx: isize) -> Self {
        CurveIterator {
            start_point: outline.points.offset(start_idx),
            start_tag: outline.tags.offset(start_idx),
            idx: 0,
            length: end_idx - start_idx + 1,
            marker: PhantomData
        }
    }

    pub fn start(&self) -> &'a Vector {
        unsafe {
            &*self.start_point
        }
    }

    // Retrieves the point at offset i from the current point. Note that contours implicitly repeat their
    // first point at the end.
    unsafe fn pt(&self, i: isize) -> Vector {
        if self.idx + i < self.length {
            *self.start_point.offset(self.idx + i)
        } else {
            *self.start_point
        }
    }

    unsafe fn tg(&self, i: isize) -> c_char {
        if self.idx + i < self.length {
            *self.start_tag.offset(self.idx + i)
        } else {
            *self.start_tag
        }
    }
}

impl<'a> Iterator for CurveIterator<'a> {
    type Item = Curve;

    fn next(&mut self) -> Option<Self::Item> {
        if self.idx >= self.length {
            None
        } else {
            unsafe {
                let tag1 = self.tg(1);

                let (shift, curve) = if (tag1 & TAG_ONCURVE) == TAG_ONCURVE {
                    (1, Curve::Line(self.pt(1)))
                } else if (tag1 & TAG_BEZIER3) == TAG_BEZIER3 {
                    (3, Curve::Bezier3(self.pt(1), self.pt(2), self.pt(3)))
                } else {
                    // We are some kind of quadratic Bezier.
                    // Quadratic Bezier curves have a special treatment in TTF outlines:
                    // as an optimization, curves are often constructed from sequences
                    // of off-curve control points. In this case, there are implied on-curve
                    // points in between each pair of off-curve points.
                    if (self.tg(2) & TAG_ONCURVE) == TAG_ONCURVE {
                        (2, Curve::Bezier2(self.pt(1), self.pt(2)))
                    } else {
                        let pt = ffi::FT_Vector {
                            x: (self.pt(1).x + self.pt(2).x) / 2,
                            y: (self.pt(1).y + self.pt(2).y) / 2,
                        };

                        (1, Curve::Bezier2(self.pt(1), pt))
                    }
                };

                self.idx += shift;
                Some(curve)
            }
        }
    }
}

pub struct ContourIterator<'a> {
    outline: &'a ffi::FT_Outline,
    contour_start: c_short,
    contour_end_idx: *const c_short,
    last_end_idx: *const c_short
}

impl<'a> ContourIterator<'a> {
    pub unsafe fn from_raw(outline: &'a ffi::FT_Outline) -> Self {
        ContourIterator {
            outline: outline,
            contour_start: 0,
            contour_end_idx: outline.contours,
            last_end_idx: outline.contours.offset(outline.n_contours as isize - 1)
        }
    }
}

impl<'a> Iterator for ContourIterator<'a> {
    type Item = CurveIterator<'a>;

    fn next(&mut self) -> Option<Self::Item> {
        if self.contour_end_idx > self.last_end_idx {
            None
        } else {
            unsafe {
                let contour_end = *self.contour_end_idx;
                let curves = CurveIterator::from_raw(self.outline, self.contour_start as isize,
                                                     contour_end as isize);
                self.contour_start = contour_end + 1;
                self.contour_end_idx = self.contour_end_idx.offset(1);

                Some(curves)
            }
        }
    }
}