1 use super::{FontData, FontFamily, FontStyle, LayoutBox};
2 
3 #[derive(Debug, Clone)]
4 pub struct FontError;
5 
6 impl std::fmt::Display for FontError {
fmt(&self, fmt: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error>7     fn fmt(&self, fmt: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
8         write!(fmt, "General Error")?;
9         Ok(())
10     }
11 }
12 
13 impl std::error::Error for FontError {}
14 
15 #[derive(Clone)]
16 pub struct FontDataInternal(String, String);
17 
18 impl FontData for FontDataInternal {
19     type ErrorType = FontError;
new(family: FontFamily, style: FontStyle) -> Result<Self, FontError>20     fn new(family: FontFamily, style: FontStyle) -> Result<Self, FontError> {
21         Ok(FontDataInternal(
22             family.as_str().into(),
23             style.as_str().into(),
24         ))
25     }
26 
27     /// Note: This is only a crude estimatation, since for some backend such as SVG, we have no way to
28     /// know the real size of the text anyway. Thus using font-kit is an overkill and doesn't helps
29     /// the layout.
estimate_layout(&self, size: f64, text: &str) -> Result<LayoutBox, Self::ErrorType>30     fn estimate_layout(&self, size: f64, text: &str) -> Result<LayoutBox, Self::ErrorType> {
31         let em = size / 1.24 / 1.24;
32         Ok((
33             (0, -em.round() as i32),
34             (
35                 (em * 0.7 * text.len() as f64).round() as i32,
36                 (em * 0.24).round() as i32,
37             ),
38         ))
39     }
40 }
41