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

// https://docs.microsoft.com/en-us/typography/opentype/spec/hhea

use crate::parser::SafeStream;
use crate::Font;

// This is a mandatory table, so we already know that this table exists
// and has a valid size. So we can use SafeStream.

impl<'a> Font<'a> {
    /// Returns font's ascender value.
    #[inline]
    pub fn ascender(&self) -> i16 {
        const ASCENDER_OFFSET: usize = 4;
        SafeStream::read_at(self.hhea, ASCENDER_OFFSET)
    }

    /// Returns font's descender value.
    #[inline]
    pub fn descender(&self) -> i16 {
        const DESCENDER_OFFSET: usize = 6;
        SafeStream::read_at(self.hhea, DESCENDER_OFFSET)
    }

    /// Returns font's height.
    #[inline]
    pub fn height(&self) -> i16 {
        self.ascender() - self.descender()
    }

    /// Returns font's line gap.
    #[inline]
    pub fn line_gap(&self) -> i16 {
        const LINEGAP_OFFSET: usize = 8;
        SafeStream::read_at(self.hhea, LINEGAP_OFFSET)
    }

    #[inline]
    pub(crate) fn number_of_hmetrics(&self) -> u16 {
        const NUMBER_OF_HMETRICS_OFFSET: usize = 34;
        SafeStream::read_at(self.hhea, NUMBER_OF_HMETRICS_OFFSET)
    }
}