From 1ee70a014638afe550ef18bff1a8928b35d501ca Mon Sep 17 00:00:00 2001
From: Nathan Sobo <nathan@zed.dev>
Date: Wed, 27 Sep 2023 23:05:39 -0600
Subject: [PATCH] Checkpoint

---
 crates/gpui3/src/elements/text.rs |  4 +++-
 crates/gpui3/src/geometry.rs      | 17 +++++++++++++++++
 crates/gpui3/src/style.rs         |  4 +++-
 crates/gpui3/src/text_system.rs   | 16 +++++++---------
 4 files changed, 30 insertions(+), 11 deletions(-)

diff --git a/crates/gpui3/src/elements/text.rs b/crates/gpui3/src/elements/text.rs
index 6530a3c42300527f664729831ef78e8df4b39606..e188370a6f32968828b9929ad3613cd89a98241d 100644
--- a/crates/gpui3/src/elements/text.rs
+++ b/crates/gpui3/src/elements/text.rs
@@ -42,7 +42,9 @@ impl<S: 'static> Element for Text<S> {
         let text_system = cx.text_system().clone();
         let text_style = cx.text_style();
         let font_size = text_style.font_size * cx.rem_size();
-        let line_height = cx.text_system().line_height(font_size);
+        let line_height = text_style
+            .line_height
+            .to_pixels(font_size.into(), cx.rem_size());
         let text = self.text.clone();
         let paint_state = Arc::new(Mutex::new(None));
 
diff --git a/crates/gpui3/src/geometry.rs b/crates/gpui3/src/geometry.rs
index 9b4f04ab3f76de2798d1273eaf4f913bc2bc98c8..c587096e7c0acfb0ed6742998d7dff7196285c95 100644
--- a/crates/gpui3/src/geometry.rs
+++ b/crates/gpui3/src/geometry.rs
@@ -572,6 +572,18 @@ pub enum DefiniteLength {
     Fraction(f32),
 }
 
+impl DefiniteLength {
+    pub fn to_pixels(&self, base_size: AbsoluteLength, rem_size: Pixels) -> Pixels {
+        match self {
+            DefiniteLength::Absolute(size) => size.to_pixels(rem_size),
+            DefiniteLength::Fraction(fraction) => match base_size {
+                AbsoluteLength::Pixels(px) => px * *fraction,
+                AbsoluteLength::Rems(rems) => rems * rem_size * *fraction,
+            },
+        }
+    }
+}
+
 impl Debug for DefiniteLength {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
@@ -625,6 +637,11 @@ pub fn relative(fraction: f32) -> DefiniteLength {
     DefiniteLength::Fraction(fraction).into()
 }
 
+/// Returns the Golden Ratio, i.e. `~(1.0 + sqrt(5.0)) / 2.0`.
+pub fn phi() -> DefiniteLength {
+    relative(1.61803398875)
+}
+
 pub fn rems(rems: f32) -> Rems {
     Rems(rems)
 }
diff --git a/crates/gpui3/src/style.rs b/crates/gpui3/src/style.rs
index 2d1467d6a72bb5047f853bc3f9654c72ec22706f..a8bac7ed782a8a7c931ed5e25730685a4a0fe7e8 100644
--- a/crates/gpui3/src/style.rs
+++ b/crates/gpui3/src/style.rs
@@ -1,5 +1,5 @@
 use crate::{
-    rems, AbsoluteLength, Bounds, Corners, CornersRefinement, DefiniteLength, Edges,
+    phi, rems, AbsoluteLength, Bounds, Corners, CornersRefinement, DefiniteLength, Edges,
     EdgesRefinement, Font, FontFeatures, FontStyle, FontWeight, Hsla, Length, Pixels, Point,
     PointRefinement, Rems, Result, RunStyle, SharedString, Size, SizeRefinement, ViewContext,
     WindowContext,
@@ -100,6 +100,7 @@ pub struct TextStyle {
     pub font_family: SharedString,
     pub font_features: FontFeatures,
     pub font_size: Rems,
+    pub line_height: DefiniteLength,
     pub font_weight: FontWeight,
     pub font_style: FontStyle,
     pub underline: Option<UnderlineStyle>,
@@ -112,6 +113,7 @@ impl Default for TextStyle {
             font_family: SharedString::default(),
             font_features: FontFeatures::default(),
             font_size: rems(1.),
+            line_height: phi(),
             font_weight: FontWeight::default(),
             font_style: FontStyle::default(),
             underline: None,
diff --git a/crates/gpui3/src/text_system.rs b/crates/gpui3/src/text_system.rs
index f33ee9e0360aa807f437cbd195493fb744a654e0..c65331a8da5e0e94df9929c82657a25e9dda3326 100644
--- a/crates/gpui3/src/text_system.rs
+++ b/crates/gpui3/src/text_system.rs
@@ -99,19 +99,13 @@ impl TextSystem {
         let result =
             self.platform_text_system.advance(font_id, glyph_id)? / self.units_per_em(font)? as f32;
 
-        let result = result * font_size;
-        Ok(todo!())
+        Ok(result * font_size)
     }
 
     pub fn units_per_em(&self, font: &Font) -> Result<u32> {
         self.read_metrics(font, |metrics| metrics.units_per_em as u32)
     }
 
-    pub fn line_height(&self, font_size: Pixels) -> Pixels {
-        todo!()
-        // self.font_cache.line_height(font_size)
-    }
-
     pub fn cap_height(&self, font: &Font, font_size: Pixels) -> Result<Pixels> {
         self.read_metrics(font, |metrics| metrics.cap_height(font_size))
     }
@@ -128,8 +122,12 @@ impl TextSystem {
         self.read_metrics(font, |metrics| metrics.descent(font_size))
     }
 
-    pub fn baseline_offset(&self, font: &Font, font_size: Pixels) -> Result<Pixels> {
-        let line_height = self.line_height(font_size);
+    pub fn baseline_offset(
+        &self,
+        font: &Font,
+        font_size: Pixels,
+        line_height: Pixels,
+    ) -> Result<Pixels> {
         let ascent = self.ascent(font, font_size)?;
         let descent = self.descent(font, font_size)?;
         let padding_top = (line_height - ascent - descent) / 2.;