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// Copyright 2016 Joe Wilm, The Alacritty Project Contributors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//! Rasterization powered by FreeType and FontConfig
use std::collections::HashMap;
use freetype::Library;
use freetype::Face;
use freetype;
mod list_fonts;
use self::list_fonts::{Family, get_font_families};
use super::{FontDesc, RasterizedGlyph, Metrics, Size, FontKey, GlyphKey};
/// Rasterizes glyphs for a single font face.
pub struct Rasterizer {
faces: HashMap<FontKey, Face<'static>>,
library: Library,
system_fonts: HashMap<String, 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
}
// #[inline]
// fn freetype_26_6_to_float(val: i64) -> f64 {
// val as f64 / (1i64 << 6) as f64
// }
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 metrics(&self, key: FontKey, size: Size) -> Metrics {
let face = self.faces.get(&key).unwrap();
let scale_size = self.dpr as f64 * size.as_f32_pts() as f64;
let em_size = face.em_size() as f64;
let w = face.max_advance_width() as f64;
let h = (face.ascender() - face.descender() + face.height()) as f64;
let w_scale = w * scale_size / em_size;
let h_scale = h * scale_size / em_size;
Metrics {
average_advance: w_scale,
line_height: h_scale,
}
}
pub fn load_font(&mut self, desc: &FontDesc, _size: Size) -> Option<FontKey> {
self.get_face(desc)
.map(|face| {
let key = FontKey::next();
self.faces.insert(key, face);
key
})
}
fn get_face(&mut self, desc: &FontDesc) -> Option<Face<'static>> {
self.system_fonts
.get(&desc.name[..])
.and_then(|font| font.variants().get(&desc.style[..]))
.map(|variant| {
self.library.new_face(variant.path(), variant.index())
.expect("TODO handle new_face error")
})
}
pub fn get_glyph(&mut self, glyph_key: &GlyphKey) -> RasterizedGlyph {
let face = self.faces
.get(&glyph_key.font_key)
.expect("TODO handle get_face error");
let size = glyph_key.size.as_f32_pts() * self.dpr;
let c = glyph_key.c;
face.set_char_size(to_freetype_26_6(size), 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 {
c: c,
top: glyph.bitmap_top(),
left: glyph.bitmap_left(),
width: glyph.bitmap().width() / 3,
height: glyph.bitmap().rows(),
buf: packed,
}
}
}
unsafe impl Send for Rasterizer {}
#[cfg(test)]
mod tests {
use ::FontDesc;
fn font_desc() -> FontDesc {
FontDesc::new("Ubuntu Mono", "Regular")
}
}
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