Fix thin strokes on macOS

Remove the `font.use_thin_strokes` config, which only did anything on
macOS and only prior to Big Sur. Instead, we will enable or disable
"font smoothing" on macOS based on the `AppleFontSmoothing` user
default.

These changes let users get the "thin strokes" behavior by setting
`AppleFontSmoothing` to 0 with:

```sh
$ defaults write -g AppleFontSmoothing -int 0
```

(Or replace `-g` with `org.alacritty` to apply this setting only to
Alacritty.app, rather than the whole system.)

Add a `removed` config attribute to show helpful warnings to users
who are using config options that don't do anything anymore, and apply
this attribute to `font.use_thin_strokes`.

Bump `crossfont` to 0.5.0 to pick up the new font smoothing behavior.
This release also includes a fix for a crash when trying to load a
disabled font.

Fixes #4616.
Fixes #6108.

4 files changed, 13 insertions, 11 deletions

diff --git a/alacritty/src/config/font.rs b/alacritty/src/config/font.rs
index cdd84ff9..d3431171 100644
--- a/alacritty/src/config/font.rs
+++ b/alacritty/src/config/font.rs
@@ -22,6 +22,7 @@ pub struct Font {
     /// Glyph offset within character cell.
     pub glyph_offset: Delta<i8>,
 
+    #[config(removed = "set the AppleFontSmoothing user default instead")]
     pub use_thin_strokes: bool,
 
     /// Normal font face.
@@ -79,8 +80,8 @@ impl Default for Font {
     fn default() -> Font {
         Self {
             builtin_box_drawing: true,
-            use_thin_strokes: Default::default(),
             glyph_offset: Default::default(),
+            use_thin_strokes: Default::default(),
             bold_italic: Default::default(),
             italic: Default::default(),
             offset: Default::default(),
diff --git a/alacritty/src/display/mod.rs b/alacritty/src/display/mod.rs
index f1f51ec7..79e57307 100644
--- a/alacritty/src/display/mod.rs
+++ b/alacritty/src/display/mod.rs
@@ -411,7 +411,7 @@ impl Display {
         // Guess the target window dimensions.
         debug!("Loading \"{}\" font", &config.font.normal().family);
         let font = &config.font;
-        let rasterizer = Rasterizer::new(estimated_scale_factor as f32, font.use_thin_strokes)?;
+        let rasterizer = Rasterizer::new(estimated_scale_factor as f32)?;
         let mut glyph_cache = GlyphCache::new(rasterizer, font)?;
         let metrics = glyph_cache.font_metrics();
         let (cell_width, cell_height) = compute_cell_size(config, &metrics);
@@ -488,10 +488,6 @@ impl Display {
         let background_color = config.colors.primary.background;
         renderer.clear(background_color, config.window_opacity());
 
-        // Set subpixel anti-aliasing.
-        #[cfg(target_os = "macos")]
-        crossfont::set_font_smoothing(config.font.use_thin_strokes);
-
         // Disable shadows for transparent windows on macOS.
         #[cfg(target_os = "macos")]
         window.set_has_shadow(config.window_opacity() >= 1.0);
diff --git a/alacritty/src/renderer/text/builtin_font.rs b/alacritty/src/renderer/text/builtin_font.rs
index 36d1ccdc..a4bf65e3 100644
--- a/alacritty/src/renderer/text/builtin_font.rs
+++ b/alacritty/src/renderer/text/builtin_font.rs
@@ -90,6 +90,7 @@ fn box_drawing(character: char, metrics: &Metrics, offset: &Delta<i8>) -> Raster
                 left: 0,
                 height: height as i32,
                 width: width as i32,
+                advance: (0, 0),
                 buffer,
             };
         },
@@ -479,7 +480,15 @@ fn box_drawing(character: char, metrics: &Metrics, offset: &Delta<i8>) -> Raster
 
     let top = height as i32 + metrics.descent as i32;
     let buffer = BitmapBuffer::Rgb(canvas.into_raw());
-    RasterizedGlyph { character, top, left: 0, height: height as i32, width: width as i32, buffer }
+    RasterizedGlyph {
+        character,
+        top,
+        left: 0,
+        height: height as i32,
+        width: width as i32,
+        advance: (0, 0),
+        buffer,
+    }
 }
 
 #[repr(packed)]
diff --git a/alacritty/src/window_context.rs b/alacritty/src/window_context.rs
index a45b9404..7fe33fd0 100644
--- a/alacritty/src/window_context.rs
+++ b/alacritty/src/window_context.rs
@@ -210,10 +210,6 @@ impl WindowContext {
             self.display.window.set_title(config.window.identity.title.clone());
         }
 
-        // Set subpixel anti-aliasing.
-        #[cfg(target_os = "macos")]
-        crossfont::set_font_smoothing(config.font.use_thin_strokes);
-
         // Disable shadows for transparent windows on macOS.
         #[cfg(target_os = "macos")]
         self.display.window.set_has_shadow(config.window_opacity() >= 1.0);