diff options
Diffstat (limited to 'font/src/ft/mod.rs')
| -rw-r--r-- | font/src/ft/mod.rs | 133 |
1 files changed, 90 insertions, 43 deletions
diff --git a/font/src/ft/mod.rs b/font/src/ft/mod.rs index c9abd693..8e653816 100644 --- a/font/src/ft/mod.rs +++ b/font/src/ft/mod.rs @@ -15,9 +15,7 @@ //! Rasterization powered by FreeType and FontConfig use std::collections::HashMap; -use freetype::Library; -use freetype::Face; -use freetype; +use freetype::{self, Library, Face}; mod list_fonts; @@ -25,7 +23,7 @@ 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 { +pub struct FreeTypeRasterizer { faces: HashMap<FontKey, Face<'static>>, library: Library, system_fonts: HashMap<String, Family>, @@ -40,16 +38,13 @@ 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 ::Rasterize for FreeTypeRasterizer { + type Err = Error; -impl Rasterizer { - pub fn new(dpi_x: f32, dpi_y: f32, device_pixel_ratio: f32) -> Rasterizer { - let library = Library::init().unwrap(); + fn new(dpi_x: f32, dpi_y: f32, device_pixel_ratio: f32) -> Result<FreeTypeRasterizer, Error> { + let library = Library::init()?; - Rasterizer { + Ok(FreeTypeRasterizer { system_fonts: get_font_families(), faces: HashMap::new(), keys: HashMap::new(), @@ -57,11 +52,13 @@ impl Rasterizer { 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(); + fn metrics(&self, key: FontKey, size: Size) -> Result<Metrics, Error> { + let face = self.faces + .get(&key) + .ok_or(Error::FontNotLoaded)?; let scale_size = self.dpr as f64 * size.as_f32_pts() as f64; @@ -72,48 +69,36 @@ impl Rasterizer { let w_scale = w * scale_size / em_size; let h_scale = h * scale_size / em_size; - Metrics { + Ok(Metrics { average_advance: w_scale, line_height: h_scale, - } + }) } - pub fn load_font(&mut self, desc: &FontDesc, _size: Size) -> Option<FontKey> { + fn load_font(&mut self, desc: &FontDesc, _size: Size) -> Result<FontKey, Error> { self.keys .get(&desc.to_owned()) - .map(|k| *k) - .or_else(|| { - 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") + .map(|k| Ok(*k)) + .unwrap_or_else(|| { + let face = self.get_face(desc)?; + let key = FontKey::next(); + self.faces.insert(key, face); + Ok(key) }) } - pub fn get_glyph(&mut self, glyph_key: &GlyphKey) -> RasterizedGlyph { + fn get_glyph(&mut self, glyph_key: &GlyphKey) -> Result<RasterizedGlyph, Error> { let face = self.faces .get(&glyph_key.font_key) - .expect("TODO handle get_face error"); + .ok_or(Error::FontNotLoaded)?; 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(); + face.set_char_size(to_freetype_26_6(size), 0, self.dpi_x, self.dpi_y)?; + face.load_char(c as usize, freetype::face::TARGET_LIGHT)?; let glyph = face.glyph(); - glyph.render_glyph(freetype::render_mode::RenderMode::Lcd).unwrap(); + glyph.render_glyph(freetype::render_mode::RenderMode::Lcd)?; unsafe { let ft_lib = self.library.raw(); @@ -134,18 +119,80 @@ impl Rasterizer { packed.extend_from_slice(&buf[start..stop]); } - RasterizedGlyph { + Ok(RasterizedGlyph { c: c, top: glyph.bitmap_top(), left: glyph.bitmap_left(), width: glyph.bitmap().width() / 3, height: glyph.bitmap().rows(), buf: packed, + }) + } +} + +impl FreeTypeRasterizer { + fn get_face(&mut self, desc: &FontDesc) -> Result<Face<'static>, Error> { + self.system_fonts + .get(&desc.name[..]) + .and_then(|font| font.variants().get(&desc.style[..])) + .ok_or_else(|| Error::MissingFont(desc.to_owned())) + .and_then(|variant| Ok(self.library.new_face(variant.path(), variant.index())?)) + } +} + +/// Errors occurring when using the freetype rasterizer +#[derive(Debug)] +pub enum Error { + /// Error occurred within the FreeType library + FreeType(freetype::Error), + + /// Couldn't find font matching description + MissingFont(FontDesc), + + /// Requested an operation with a FontKey that isn't known to the rasterizer + FontNotLoaded, +} + +impl ::std::error::Error for Error { + fn cause(&self) -> Option<&::std::error::Error> { + match *self { + Error::FreeType(ref err) => Some(err), + _ => None, + } + } + + fn description(&self) -> &str { + match *self { + Error::FreeType(ref err) => err.description(), + Error::MissingFont(ref _desc) => "couldn't find the requested font", + Error::FontNotLoaded => "tried to operate on font that hasn't been loaded", + } + } +} + +impl ::std::fmt::Display for Error { + fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result { + match *self { + Error::FreeType(ref err) => { + err.fmt(f) + }, + Error::MissingFont(ref desc) => { + write!(f, "Couldn't find a font with {}", desc) + }, + Error::FontNotLoaded => { + f.write_str("Tried to use a font that hasn't been loaded") + } } } } -unsafe impl Send for Rasterizer {} +impl From<freetype::Error> for Error { + fn from(val: freetype::Error) -> Error { + Error::FreeType(val) + } +} + +unsafe impl Send for FreeTypeRasterizer {} #[cfg(test)] mod tests { |