cn_font_split/pre_subset/
fvar.rs

1use opentype::tables::FontVariations;
2use opentype::truetype::q32;
3use opentype::Font;
4use std::io::Cursor;
5
6#[derive(Default, Clone)]
7pub struct FvarTable {
8    pub vf_weight: String,
9    pub vf_default_weight: String,
10}
11/// 解析 fvar table 可以得知可变字体的信息
12pub fn analyze_fvar_table(
13    font: &Font,
14    font_file: &mut Cursor<&Vec<u8>>,
15) -> Option<FvarTable> {
16    let data: Option<FontVariations> = font.take(font_file).unwrap();
17    if data.is_none() {
18        return None;
19    }
20
21    let mut vf = FvarTable::default();
22    data.unwrap().axis_records.iter().for_each(|x| {
23        let tag = x.tag.as_str().unwrap_or("");
24        if tag == "wght".to_string() {
25            let max = q32_to_int_truncate(x.max_value);
26            let min = q32_to_int_truncate(x.min_value);
27            let font_weight = format!("{} {}", min, max).clone();
28            vf.vf_weight = font_weight;
29            vf.vf_default_weight =
30                q32_to_int_truncate(x.default_value).to_string();
31        }
32    });
33    Some(vf)
34}
35pub fn q32_to_int_truncate(input: q32) -> i32 {
36    input.0 >> 16
37}
38#[test]
39fn test_fvar_table() {
40    use cn_font_utils::read_binary_file;
41    let path = "./packages/demo/public/WorkSans-VariableFont_wght.ttf";
42    let file_binary = read_binary_file(&path).expect("Failed to read file");
43    let mut font_file = Cursor::new(&file_binary);
44    let font = Font::read(&mut font_file).expect("TODO: panic message");
45    let data = analyze_fvar_table(&font, &mut font_file).unwrap();
46
47    assert_eq!(data.vf_default_weight, "400");
48    assert_eq!(data.vf_weight, "100 900")
49    // data.table.iter().for_each(|x| {
50    //     println!("{:?}", x);
51    // });
52
53    // assert_eq!()
54}
cn_font_split/pre_subset/fvar.rs

cn_font_split/pre_subset/
fvar.rs
