read_fonts/tables/
ebdt.rs

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
//! The [EBDT (Embedded Bitmap Data)](https://docs.microsoft.com/en-us/typography/opentype/spec/ebdt) table

use super::bitmap::{BitmapData, BitmapLocation};

include!("../../generated/generated_ebdt.rs");

impl<'a> Ebdt<'a> {
    pub fn data(&self, location: &BitmapLocation) -> Result<BitmapData<'a>, ReadError> {
        super::bitmap::bitmap_data(self.offset_data(), location, false)
    }
}

#[cfg(test)]
mod tests {
    use super::super::bitmap::{
        BigGlyphMetrics, BitmapContent, BitmapData, BitmapDataFormat, BitmapMetrics,
        SmallGlyphMetrics,
    };
    use crate::{
        types::{GlyphId, GlyphId16},
        FontRef, TableProvider,
    };

    impl<'a> BitmapContent<'a> {
        pub(crate) fn extract_data(&self) -> (BitmapDataFormat, &'a [u8]) {
            match self {
                BitmapContent::Data(fmt, data) => (*fmt, *data),
                _ => panic!("expected data content"),
            }
        }
    }

    impl<'a> BitmapData<'a> {
        pub(crate) fn extract_small_metrics(&self) -> &SmallGlyphMetrics {
            match &self.metrics {
                BitmapMetrics::Small(small) => small,
                _ => panic!("expected small glyph metrics"),
            }
        }
    }

    #[test]
    fn read_eblc_3_ebdt_2() {
        let font = FontRef::new(font_test_data::EMBEDDED_BITMAPS).unwrap();
        let eblc = font.eblc().unwrap();
        let ebdt = font.ebdt().unwrap();
        let size = &eblc.bitmap_sizes()[0];
        // Metrics for size at index 0
        assert!(
            size.hori.ascender() == 6
                && size.hori.descender() == 2
                && size.hori.width_max() == 4
                && size.hori.max_before_bl() == 6
                && size.hori.min_after_bl() == -2
                && size.vert.ascender() == 6
                && size.vert.descender() == 2
                && size.start_glyph_index() == GlyphId16::new(1)
                && size.end_glyph_index() == GlyphId16::new(2)
                && size.ppem_x() == 7
                && size.ppem_y() == 7
                && size.bit_depth() == 1
        );
        // Bit aligned formats in this strike:
        let expected: &[(GlyphId, &[u8], SmallGlyphMetrics)] = &[
            (
                GlyphId::new(1),
                &[0xee, 0xae, 0xea],
                SmallGlyphMetrics {
                    height: 8,
                    width: 3,
                    bearing_x: 1.into(),
                    bearing_y: 6.into(),
                    advance: 4,
                },
            ),
            (
                GlyphId::new(2),
                &[0xf0, 0xf0, 0xf0, 0xf0],
                SmallGlyphMetrics {
                    height: 8,
                    width: 4,
                    bearing_x: 0.into(),
                    bearing_y: 6.into(),
                    advance: 4,
                },
            ),
        ];
        for (gid, data, metrics) in expected {
            let location = size.location(eblc.offset_data(), *gid).unwrap();
            assert_eq!(location.format, 2);
            let bitmap_data = ebdt.data(&location).unwrap();
            let (img_fmt, img_data) = bitmap_data.content.extract_data();
            assert_eq!(img_fmt, BitmapDataFormat::BitAligned);
            assert_eq!(img_data, *data);
            assert_eq!(bitmap_data.extract_small_metrics(), metrics);
        }
    }

    #[test]
    fn read_eblc_2_ebdt_5() {
        let font = FontRef::new(font_test_data::EMBEDDED_BITMAPS).unwrap();
        let eblc = font.eblc().unwrap();
        let ebdt = font.ebdt().unwrap();
        let size = &eblc.bitmap_sizes()[1];
        // Metrics for size at index 1
        assert!(
            size.hori.ascender() == 12
                && size.hori.descender() == 5
                && size.hori.width_max() == 9
                && size.hori.max_before_bl() == 12
                && size.hori.min_after_bl() == -5
                && size.vert.ascender() == 12
                && size.vert.descender() == 5
                && size.start_glyph_index() == GlyphId16::new(3)
                && size.end_glyph_index() == GlyphId16::new(3)
                && size.ppem_x() == 15
                && size.ppem_y() == 15
                && size.bit_depth() == 1
        );
        let expected: &[(GlyphId, &[u8])] = &[(
            GlyphId::new(3),
            &[
                0xaa, 0xbb, 0xcc, 0xdd, 0x00, 0x11, 0x22, 0x33, 0xff, 0xee, 0x12, 0x34, 0x42, 0x42,
                0x42, 0xaa, 0x88, 0x99, 0x00, 0x11,
            ],
        )];
        for (gid, data) in expected {
            let location = size.location(eblc.offset_data(), *gid).unwrap();
            // Metrics are in EBLC, so the same for all glyphs
            assert_eq!(
                &location.metrics,
                &Some(BigGlyphMetrics {
                    height: 17,
                    width: 9,
                    hori_bearing_x: 0.into(),
                    hori_bearing_y: 12.into(),
                    hori_advance: 9,
                    vert_bearing_x: (-4).into(),
                    vert_bearing_y: (-9).into(),
                    vert_advance: 0,
                })
            );
            assert_eq!(location.format, 5);
            let bitmap_data = ebdt.data(&location).unwrap();
            let (img_fmt, img_data) = bitmap_data.content.extract_data();
            assert_eq!(img_fmt, BitmapDataFormat::BitAligned);
            assert_eq!(img_data, *data);
        }
    }
}