From bd6ded6ba57de4c4ba1367fbf1d781d5f82d4c3a Mon Sep 17 00:00:00 2001
From: Antonio Scandurra <me@as-cii.com>
Date: Mon, 11 Nov 2024 16:51:52 +0100
Subject: [PATCH] Avoid subpixel positioning when scale factor is 1

---
 crates/gpui/src/geometry.rs |  9 +++++++++
 crates/gpui/src/window.rs   | 19 +++++++++++++++----
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/crates/gpui/src/geometry.rs b/crates/gpui/src/geometry.rs
index 9e0b9b90140391..97fac6b87bb040 100644
--- a/crates/gpui/src/geometry.rs
+++ b/crates/gpui/src/geometry.rs
@@ -2572,6 +2572,15 @@ impl ScaledPixels {
         Self(self.0.floor())
     }
 
+    /// Rounds the `ScaledPixels` value to the nearest whole number.
+    ///
+    /// # Returns
+    ///
+    /// Returns a new `ScaledPixels` instance with the rounded value.
+    pub fn round(&self) -> Self {
+        Self(self.0.round())
+    }
+
     /// Rounds the `ScaledPixels` value to the nearest whole number.
     ///
     /// # Returns
diff --git a/crates/gpui/src/window.rs b/crates/gpui/src/window.rs
index dcda69723b5d86..b1fe23bf2cefbe 100644
--- a/crates/gpui/src/window.rs
+++ b/crates/gpui/src/window.rs
@@ -647,6 +647,7 @@ impl Window {
         let modifiers = platform_window.modifiers();
         let content_size = platform_window.content_size();
         let scale_factor = platform_window.scale_factor();
+        log::info!("!!!!!! SCALE FACTOR {:?}", scale_factor);
         let appearance = platform_window.appearance();
         let text_system = Arc::new(WindowTextSystem::new(cx.text_system().clone()));
         let dirty = Rc::new(Cell::new(true));
@@ -1187,6 +1188,7 @@ impl<'a> WindowContext<'a> {
 
     fn bounds_changed(&mut self) {
         self.window.scale_factor = self.window.platform_window.scale_factor();
+        log::info!("!!!!!! SCALE FACTOR {:?}", self.window.scale_factor);
         self.window.viewport_size = self.window.platform_window.content_size();
         self.window.display_id = self
             .window
@@ -2436,9 +2438,13 @@ impl<'a> WindowContext<'a> {
         let element_opacity = self.element_opacity();
         let scale_factor = self.scale_factor();
         let glyph_origin = origin.scale(scale_factor);
-        let subpixel_variant = Point {
-            x: (glyph_origin.x.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
-            y: (glyph_origin.y.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
+        let subpixel_variant = if scale_factor == 1. {
+            Point::default()
+        } else {
+            Point {
+                x: (glyph_origin.x.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
+                y: (glyph_origin.y.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
+            }
         };
         let params = RenderGlyphParams {
             font_id,
@@ -2460,8 +2466,13 @@ impl<'a> WindowContext<'a> {
                     Ok(Some((size, Cow::Owned(bytes))))
                 })?
                 .expect("Callback above only errors or returns Some");
+            let origin = if scale_factor == 1. {
+                glyph_origin.map(|px| px.round())
+            } else {
+                glyph_origin.map(|px| px.floor())
+            };
             let bounds = Bounds {
-                origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
+                origin: origin + raster_bounds.origin.map(Into::into),
                 size: tile.bounds.size.map(Into::into),
             };
             let content_mask = self.content_mask().scale(scale_factor);