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use std::collections::HashMap;
use list_fonts::get_font_families;
use freetype::Library;
use freetype::Face;
use freetype;
/// Rasterizes glyphs for a single font face.
pub struct Rasterizer {
faces: HashMap<FontDesc, Face<'static>>,
library: Library,
system_fonts: HashMap<String, ::list_fonts::Family>,
dpi_x: u32,
dpi_y: u32,
dpr: f32,
}
#[inline]
fn to_freetype_26_6(f: f32) -> isize {
((1i32 << 6) as f32 * f) as isize
}
#[derive(Clone, PartialEq, Eq, Hash)]
pub struct FontDesc {
name: String,
style: String,
}
impl FontDesc {
pub fn new<S>(name: S, style: S) -> FontDesc
where S: Into<String>
{
FontDesc {
name: name.into(),
style: style.into()
}
}
}
impl Rasterizer {
pub fn new(dpi_x: f32, dpi_y: f32, device_pixel_ratio: f32) -> Rasterizer {
let library = Library::init().unwrap();
Rasterizer {
system_fonts: get_font_families(),
faces: HashMap::new(),
library: library,
dpi_x: dpi_x as u32,
dpi_y: dpi_y as u32,
dpr: device_pixel_ratio,
}
}
pub fn box_size_for_font(&mut self, desc: &FontDesc, size: f32) -> (u32, u32) {
let face = self.get_face(&desc).unwrap();
let scale_size = self.dpr * size;
let em_size = face.em_size() as f32;
let w = face.max_advance_width() as f32;
let h = face.height() as f32;
let w_scale = w / em_size;
let h_scale = h / em_size;
((w_scale * scale_size) as u32, (h_scale * scale_size) as u32)
}
pub fn get_face(&mut self, desc: &FontDesc) -> Option<Face<'static>> {
if let Some(face) = self.faces.get(desc) {
return Some(face.clone());
}
if let Some(font) = self.system_fonts.get(&desc.name[..]) {
if let Some(variant) = font.variants().get(&desc.style[..]) {
let face = self.library.new_face(variant.path(), variant.index())
.expect("TODO handle new_face error");
self.faces.insert(desc.to_owned(), face);
return Some(self.faces.get(desc).unwrap().clone());
}
}
None
}
pub fn get_glyph(&mut self, desc: &FontDesc, size: f32, c: char) -> RasterizedGlyph {
let face = self.get_face(desc).expect("TODO handle get_face error");
face.set_char_size(to_freetype_26_6(size * self.dpr), 0, self.dpi_x, self.dpi_y).unwrap();
face.load_char(c as usize, freetype::face::TARGET_LIGHT).unwrap();
let glyph = face.glyph();
glyph.render_glyph(freetype::render_mode::RenderMode::Lcd).unwrap();
unsafe {
let ft_lib = self.library.raw();
freetype::ffi::FT_Library_SetLcdFilter(ft_lib, freetype::ffi::FT_LCD_FILTER_DEFAULT);
}
let bitmap = glyph.bitmap();
let buf = bitmap.buffer();
let pitch = bitmap.pitch() as usize;
let mut packed = Vec::with_capacity((bitmap.rows() * bitmap.width()) as usize);
for i in 0..bitmap.rows() {
let start = (i as usize) * pitch;
let stop = start + bitmap.width() as usize;
packed.extend_from_slice(&buf[start..stop]);
}
RasterizedGlyph {
top: glyph.bitmap_top() as usize,
left: glyph.bitmap_left() as usize,
width: glyph.bitmap().width() as usize / 3,
height: glyph.bitmap().rows() as usize,
buf: packed,
}
}
}
#[derive(Debug)]
pub struct RasterizedGlyph {
pub width: usize,
pub height: usize,
pub top: usize,
pub left: usize,
pub buf: Vec<u8>,
}
#[cfg(test)]
mod tests {
use super::{Rasterizer, FontDesc};
#[cfg(target_os = "linux")]
fn font_desc() -> FontDesc {
FontDesc::new("Ubuntu Mono", "Regular")
}
}
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