From 09bc50a54c0ce5bb0768bef8bbd719af2e58a409 Mon Sep 17 00:00:00 2001
From: be5invis <belleve@typeof.net>
Date: Fri, 29 Oct 2021 21:43:13 -0700
Subject: [PATCH] Make essRatio overridable

---
 README.md                           | 1 +
 font-src/meta/aesthetics.ptl        | 4 ++--
 font-src/support/metric-override.js | 3 ++-
 params/shape-weight.toml            | 6 +++---
 4 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/README.md b/README.md
index b5d1e1425..0769fc823 100644
--- a/README.md
+++ b/README.md
@@ -3040,6 +3040,7 @@ Subsection `metric-override` provides ability to override certain metric values,
 | `powerlineScaleX`, `powerlineScaleY` | (*ratio*) | 1 | X and Y scale of Powerline glyphs. |
 | `powerlineShiftX`, `powerlineShiftY` | emu | 0 | X and Y shift of Powerline glyphs. |
 | `onumZeroHeightRatio` | (*ratio*) | 1.145 | Ratio of height of `0` under `onum` feature, to the height of `x`. |
+| `essRatio` | (*ratio*) | (*varies, 1.12 for Regular*) | Ratio of the thickness of the neck of `S`/`s`, to the normal stroke width. |
 
 The values of each item could be either a number, or a string representing an expression so that it could be different for different instance fonts, or depending on default values. The syntax of valid expressions are:
 
diff --git a/font-src/meta/aesthetics.ptl b/font-src/meta/aesthetics.ptl
index d6b47fb11..ca7dc7bc6 100644
--- a/font-src/meta/aesthetics.ptl
+++ b/font-src/meta/aesthetics.ptl
@@ -129,8 +129,8 @@ export : define [calculateMetrics para] : begin
 	define WideWidth3 : if (para.spacing >= 3) WideWidth0 Width
 	define WideWidth4 : if (para.spacing >= 4) WideWidth0 Width
 
-	define Ess : Stroke * [fallback para.essx Contrast]
-	define EssQuestion : Stroke * [fallback para.essxq Contrast]
+	define Ess : Stroke * [fallback para.essRatio Contrast]
+	define EssQuestion : Stroke * [fallback para.essRatioq Contrast]
 	define HalfStroke : Stroke / 2
 	define RightSB : Width - SB
 	define Middle : Width / 2
diff --git a/font-src/support/metric-override.js b/font-src/support/metric-override.js
index 3e16fc0be..ce6f64889 100644
--- a/font-src/support/metric-override.js
+++ b/font-src/support/metric-override.js
@@ -42,7 +42,8 @@ const validMetricOverrideFields = new Set([
 	"powerlineScaleX",
 	"powerlineShiftY",
 	"powerlineShiftX",
-	"onumZeroHeightRatio"
+	"onumZeroHeightRatio",
+	"essRatio"
 ]);
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
diff --git a/params/shape-weight.toml b/params/shape-weight.toml
index 4f8279daa..8f7f68ef0 100644
--- a/params/shape-weight.toml
+++ b/params/shape-weight.toml
@@ -6,7 +6,7 @@ canonicalStrokeWidthMax = 108 # sync with 900 entry below
 stroke = 70        # Primary stroke width
 contrast = 1.11    # Stroke width contrast
 sb = 64            # Primary sidebearings
-essx = 1.12        # Proportion of widen of center of "S"
+essRatio = 1.12    # Proportion of widen of center of "S"
 dotSize = 125      # Size of dots
 periodSize = 140   # Size of period
 
@@ -43,7 +43,7 @@ vtipfineSlab = 0.9
 stroke = 18
 contrast = 1.08
 sb = 72
-essx = 1.12
+essRatio = 1.12
 dotSize = 53
 periodSize = 55
 
@@ -83,7 +83,7 @@ stroke = 96
 stroke = 114
 contrast = 1.20
 sb = 56
-essx = 1.05
+essRatio = 1.05
 dotSize = 180
 periodSize = 200