Reuse Rasterizer in Display::new

Instead of creating a `Rasterizer` to guess the window dimensions,
dropping it and then creating a new one for the glyph cache, reuse the
same `Rasterizer`.

This prevents the font from being loaded twice during startup.

alacritty/src/display/mod.rs

@@ -232,7 +232,8 @@ impl Display {
  };
 
  // Guess the target window dimensions.
- let metrics = GlyphCache::static_metrics(config.font.clone(), estimated_dpr)?;
+ let mut rasterizer = Rasterizer::new(estimated_dpr as f32, config.font.use_thin_strokes)?;
+ let metrics = GlyphCache::static_metrics(&mut rasterizer, config.font.clone())?;
  let (cell_width, cell_height) = compute_cell_size(config, &metrics);
 
  // Guess the target window size if the user has specified the number of lines/columns.
@@ -256,12 +257,13 @@ impl Display {
  )?;
 
  info!("Device pixel ratio: {}", window.dpr);
+ rasterizer.update_dpr(window.dpr as f32);
 
  // Create renderer.
  let mut renderer = QuadRenderer::new()?;
 
  let (glyph_cache, cell_width, cell_height) =
- Self::new_glyph_cache(window.dpr, &mut renderer, config)?;
+ Self::new_glyph_cache(rasterizer, &mut renderer, config)?;
 
  if let Some(dimensions) = dimensions {
  if (estimated_dpr - window.dpr).abs() < f64::EPSILON {
@@ -361,12 +363,11 @@ impl Display {
  }
 
  fn new_glyph_cache(
- dpr: f64,
+ rasterizer: Rasterizer,
  renderer: &mut QuadRenderer,
  config: &UiConfig,
  ) -> Result<(GlyphCache, f32, f32), Error> {
  let font = config.font.clone();
- let rasterizer = Rasterizer::new(dpr as f32, config.font.use_thin_strokes)?;
 
  // Initialize glyph cache.
  let glyph_cache = {

alacritty/src/renderer/mod.rs

@@ -404,10 +404,12 @@ impl GlyphCache {
  }
 
  /// Calculate font metrics without access to a glyph cache.
- pub fn static_metrics(font: Font, dpr: f64) -> Result<crossfont::Metrics, crossfont::Error> {
- let mut rasterizer = crossfont::Rasterizer::new(dpr as f32, font.use_thin_strokes)?;
+ pub fn static_metrics(
+ rasterizer: &mut crossfont::Rasterizer,
+ font: Font,
+ ) -> Result<crossfont::Metrics, crossfont::Error> {
  let regular_desc = GlyphCache::make_desc(font.normal(), Slant::Normal, Weight::Normal);
- let regular = Self::load_regular_font(&mut rasterizer, &regular_desc, font.size())?;
+ let regular = Self::load_regular_font(rasterizer, &regular_desc, font.size())?;
  rasterizer.get_glyph(GlyphKey { font_key: regular, character: 'm', size: font.size() })?;
 
  rasterizer.metrics(regular, font.size())