Scale all fonts based on device-pixel-ratio

Rather than use DPI from config, use device-pixel-ratio from winit. This
is computed using the display DPI anyhow, so it should have the same
effect.

8 files changed, 11 insertions, 72 deletions

diff --git a/README.md b/README.md
index a84a97d6..e2b81e24 100644
--- a/README.md
+++ b/README.md
@@ -246,9 +246,9 @@ run. On most systems this often defaults to
 `$HOME/.config/alacritty/alacritty.yml`.
 
 Many configuration options will take effect immediately upon saving changes to
-the config file. The only exception is the `font`, `dimensions` and `dpi`
-sections which requires Alacritty to be restarted. For further explanation of
-the config file, please consult the comments in the default config file.
+the config file. The only exception is the `font` and `dimensions` sections
+which requires Alacritty to be restarted. For further explanation of the config
+file, please consult the comments in the default config file.
 
 ## Issues (known, unknown, feature requests, etc)
 
diff --git a/alacritty.yml b/alacritty.yml
index e4080a8c..fb498fda 100644
--- a/alacritty.yml
+++ b/alacritty.yml
@@ -27,12 +27,6 @@ padding:
   x: 2
   y: 2
 
-# The FreeType rasterizer needs to know the device DPI for best results
-# (changes require restart)
-dpi:
-  x: 96.0
-  y: 96.0
-
 # Display tabs using this many cells (changes require restart)
 tabspaces: 8
 
diff --git a/alacritty_macos.yml b/alacritty_macos.yml
index 78bbfb92..1a16a8c9 100644
--- a/alacritty_macos.yml
+++ b/alacritty_macos.yml
@@ -26,12 +26,6 @@ padding:
   x: 2
   y: 2
 
-# The FreeType rasterizer needs to know the device DPI for best results
-# (changes require restart)
-dpi:
-  x: 96.0
-  y: 96.0
-
 # Display tabs using this many cells (changes require restart)
 tabspaces: 8
 
diff --git a/font/src/darwin/mod.rs b/font/src/darwin/mod.rs
index 45423123..70b9e1f3 100644
--- a/font/src/darwin/mod.rs
+++ b/font/src/darwin/mod.rs
@@ -130,7 +130,7 @@ impl ::std::fmt::Display for Error {
 impl ::Rasterize for Rasterizer {
     type Err = Error;
 
-    fn new(_dpi_x: f32, _dpi_y: f32, device_pixel_ratio: f32, use_thin_strokes: bool) -> Result<Rasterizer, Error> {
+    fn new(device_pixel_ratio: f32, use_thin_strokes: bool) -> Result<Rasterizer, Error> {
         info!("device_pixel_ratio: {}", device_pixel_ratio);
         Ok(Rasterizer {
             fonts: HashMap::new(),
diff --git a/font/src/ft/mod.rs b/font/src/ft/mod.rs
index f37a500e..42134a88 100644
--- a/font/src/ft/mod.rs
+++ b/font/src/ft/mod.rs
@@ -63,9 +63,7 @@ pub struct FreeTypeRasterizer {
     faces: HashMap<FontKey, Face>,
     library: Library,
     keys: HashMap<PathBuf, FontKey>,
-    dpi_x: u32,
-    dpi_y: u32,
-    dpr: f32,
+    device_pixel_ratio: f32,
 }
 
 #[inline]
@@ -76,16 +74,14 @@ fn to_freetype_26_6(f: f32) -> isize {
 impl ::Rasterize for FreeTypeRasterizer {
     type Err = Error;
 
-    fn new(dpi_x: f32, dpi_y: f32, device_pixel_ratio: f32, _: bool) -> Result<FreeTypeRasterizer, Error> {
+    fn new(device_pixel_ratio: f32, _: bool) -> Result<FreeTypeRasterizer, Error> {
         let library = Library::init()?;
 
         Ok(FreeTypeRasterizer {
             faces: HashMap::new(),
             keys: HashMap::new(),
             library: library,
-            dpi_x: dpi_x as u32,
-            dpi_y: dpi_y as u32,
-            dpr: device_pixel_ratio,
+            device_pixel_ratio: device_pixel_ratio,
         })
     }
 
@@ -152,8 +148,7 @@ impl FreeTypeRasterizer {
     /// Load a font face accoring to `FontDesc`
     fn get_face(&mut self, desc: &FontDesc, size: Size) -> Result<Face, Error> {
         // Adjust for DPI
-        let scale = self.dpi_x as f32 / 72.;
-        let size = Size::new(size.as_f32_pts() * scale);
+        let size = Size::new(size.as_f32_pts() * self.device_pixel_ratio * 96. / 72.);
 
         match desc.style {
             Style::Description { slant, weight } => {
@@ -278,7 +273,7 @@ impl FreeTypeRasterizer {
 
         let size = face.non_scalable.as_ref()
             .map(|v| v.pixelsize as f32)
-            .unwrap_or_else(|| glyph_key.size.as_f32_pts() * self.dpi_x as f32 / 72.);
+            .unwrap_or_else(|| glyph_key.size.as_f32_pts() * self.device_pixel_ratio * 96. / 72.);
 
         face.ft_face.set_char_size(to_freetype_26_6(size), 0, 0, 0)?;
 
diff --git a/font/src/lib.rs b/font/src/lib.rs
index f02df436..181fd88c 100644
--- a/font/src/lib.rs
+++ b/font/src/lib.rs
@@ -229,7 +229,7 @@ pub trait Rasterize {
     type Err: ::std::error::Error + Send + Sync + 'static;
 
     /// Create a new Rasterize
-    fn new(dpi_x: f32, dpi_y: f32, device_pixel_ratio: f32, use_thin_strokes: bool) -> Result<Self, Self::Err>
+    fn new(device_pixel_ratio: f32, use_thin_strokes: bool) -> Result<Self, Self::Err>
         where Self: Sized;
 
     /// Get `Metrics` for the given `FontKey`
diff --git a/src/config.rs b/src/config.rs
index cef4d22a..d49caae8 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -222,10 +222,6 @@ pub struct Config {
     #[serde(default="default_padding")]
     padding: Delta,
 
-    /// Pixels per inch
-    #[serde(default)]
-    dpi: Dpi,
-
     /// Font configuration
     #[serde(default)]
     font: Font,
@@ -318,7 +314,6 @@ impl Default for Config {
         Config {
             draw_bold_text_with_bright_colors: true,
             dimensions: Default::default(),
-            dpi: Default::default(),
             font: Default::default(),
             render_timer: Default::default(),
             custom_cursor_colors: false,
@@ -1133,12 +1128,6 @@ impl Config {
         self.dimensions
     }
 
-    /// Get dpi config
-    #[inline]
-    pub fn dpi(&self) -> &Dpi {
-        &self.dpi
-    }
-
     /// Get visual bell config
     #[inline]
     pub fn visual_bell(&self) -> &VisualBellConfig {
@@ -1248,38 +1237,6 @@ impl Dimensions {
     }
 }
 
-/// Pixels per inch
-///
-/// This is only used on `FreeType` systems
-#[derive(Debug, Deserialize)]
-pub struct Dpi {
-    /// Horizontal dpi
-    x: f32,
-
-    /// Vertical dpi
-    y: f32,
-}
-
-impl Default for Dpi {
-    fn default() -> Dpi {
-        Dpi { x: 96.0, y: 96.0 }
-    }
-}
-
-impl Dpi {
-    /// Get horizontal dpi
-    #[inline]
-    pub fn x(&self) -> f32 {
-        self.x
-    }
-
-    /// Get vertical dpi
-    #[inline]
-    pub fn y(&self) -> f32 {
-        self.y
-    }
-}
-
 /// A delta for a point in a 2 dimensional plane
 #[derive(Clone, Copy, Debug, Deserialize)]
 pub struct Delta {
diff --git a/src/display.rs b/src/display.rs
index 012d803b..cb5cf8c9 100644
--- a/src/display.rs
+++ b/src/display.rs
@@ -134,7 +134,6 @@ impl Display {
     ) -> Result<Display, Error> {
         // Extract some properties from config
         let font = config.font();
-        let dpi = config.dpi();
         let render_timer = config.render_timer();
 
         // Create the window where Alacritty will be displayed
@@ -147,7 +146,7 @@ impl Display {
 
         info!("device_pixel_ratio: {}", dpr);
 
-        let rasterizer = font::Rasterizer::new(dpi.x(), dpi.y(), dpr, config.use_thin_strokes())?;
+        let rasterizer = font::Rasterizer::new(dpr, config.use_thin_strokes())?;
 
         // Create renderer
         let mut renderer = QuadRenderer::new(&config, size)?;