From 3573cd906bafa46069b64c68e97ea69e62d1c03b Mon Sep 17 00:00:00 2001
From: Simon Cozens <simon@simon-cozens.org>
Date: Mon, 30 Oct 2023 10:11:31 +0000
Subject: [PATCH 1/2] Recalc avgcharwidth after instancing

---
 Lib/fontTools/varLib/instancer/__init__.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Lib/fontTools/varLib/instancer/__init__.py b/Lib/fontTools/varLib/instancer/__init__.py
index a8663ec42..29cfc4260 100644
--- a/Lib/fontTools/varLib/instancer/__init__.py
+++ b/Lib/fontTools/varLib/instancer/__init__.py
@@ -1273,6 +1273,9 @@ def instantiateVariableFont(
                     ignoreErrors=(overlap == OverlapMode.REMOVE_AND_IGNORE_ERRORS),
                 )
 
+    if "OS/2" in varfont:
+        varfont["OS/2"].recalcAvgCharWidth(varfont)
+
     varLib.set_default_weight_width_slant(
         varfont, location=axisLimits.defaultLocation()
     )

From 71e991b87fe770f3a59addaaef86a19630079c09 Mon Sep 17 00:00:00 2001
From: Simon Cozens <simon@simon-cozens.org>
Date: Thu, 2 Nov 2023 17:28:13 +0000
Subject: [PATCH 2/2] Fixup expectations

---
 .../test_results/PartialInstancerTest2-VF-instance-100,100.ttx  | 2 +-
 .../test_results/PartialInstancerTest2-VF-instance-100,62.5.ttx | 2 +-
 .../test_results/PartialInstancerTest2-VF-instance-400,100.ttx  | 2 +-
 .../test_results/PartialInstancerTest2-VF-instance-400,62.5.ttx | 2 +-
 .../test_results/PartialInstancerTest2-VF-instance-900,100.ttx  | 2 +-
 .../test_results/PartialInstancerTest2-VF-instance-900,62.5.ttx | 2 +-
 6 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/Tests/varLib/instancer/data/test_results/PartialInstancerTest2-VF-instance-100,100.ttx b/Tests/varLib/instancer/data/test_results/PartialInstancerTest2-VF-instance-100,100.ttx
index 776a92f18..c89949c25 100644
--- a/Tests/varLib/instancer/data/test_results/PartialInstancerTest2-VF-instance-100,100.ttx
+++ b/Tests/varLib/instancer/data/test_results/PartialInstancerTest2-VF-instance-100,100.ttx
@@ -74,7 +74,7 @@
     <!-- The fields 'usFirstCharIndex' and 'usLastCharIndex'
          will be recalculated by the compiler -->
     <version value="4"/>
-    <xAvgCharWidth value="577"/>
+    <xAvgCharWidth value="502"/>
     <usWeightClass value="100"/>
     <usWidthClass value="5"/>
     <fsType value="00000000 00000000"/>
diff --git a/Tests/varLib/instancer/data/test_results/PartialInstancerTest2-VF-instance-100,62.5.ttx b/Tests/varLib/instancer/data/test_results/PartialInstancerTest2-VF-instance-100,62.5.ttx
index 61bc41cc3..a78019f83 100644
--- a/Tests/varLib/instancer/data/test_results/PartialInstancerTest2-VF-instance-100,62.5.ttx
+++ b/Tests/varLib/instancer/data/test_results/PartialInstancerTest2-VF-instance-100,62.5.ttx
@@ -74,7 +74,7 @@
     <!-- The fields 'usFirstCharIndex' and 'usLastCharIndex'
          will be recalculated by the compiler -->
     <version value="4"/>
-    <xAvgCharWidth value="577"/>
+    <xAvgCharWidth value="383"/>
     <usWeightClass value="100"/>
     <usWidthClass value="2"/>
     <fsType value="00000000 00000000"/>
diff --git a/Tests/varLib/instancer/data/test_results/PartialInstancerTest2-VF-instance-400,100.ttx b/Tests/varLib/instancer/data/test_results/PartialInstancerTest2-VF-instance-400,100.ttx
index c2d205715..635acd719 100644
--- a/Tests/varLib/instancer/data/test_results/PartialInstancerTest2-VF-instance-400,100.ttx
+++ b/Tests/varLib/instancer/data/test_results/PartialInstancerTest2-VF-instance-400,100.ttx
@@ -74,7 +74,7 @@
     <!-- The fields 'usFirstCharIndex' and 'usLastCharIndex'
          will be recalculated by the compiler -->
     <version value="4"/>
-    <xAvgCharWidth value="577"/>
+    <xAvgCharWidth value="543"/>
     <usWeightClass value="400"/>
     <usWidthClass value="5"/>
     <fsType value="00000000 00000000"/>
diff --git a/Tests/varLib/instancer/data/test_results/PartialInstancerTest2-VF-instance-400,62.5.ttx b/Tests/varLib/instancer/data/test_results/PartialInstancerTest2-VF-instance-400,62.5.ttx
index 63eeb0e7f..fcafe91c0 100644
--- a/Tests/varLib/instancer/data/test_results/PartialInstancerTest2-VF-instance-400,62.5.ttx
+++ b/Tests/varLib/instancer/data/test_results/PartialInstancerTest2-VF-instance-400,62.5.ttx
@@ -74,7 +74,7 @@
     <!-- The fields 'usFirstCharIndex' and 'usLastCharIndex'
          will be recalculated by the compiler -->
     <version value="4"/>
-    <xAvgCharWidth value="577"/>
+    <xAvgCharWidth value="428"/>
     <usWeightClass value="400"/>
     <usWidthClass value="2"/>
     <fsType value="00000000 00000000"/>
diff --git a/Tests/varLib/instancer/data/test_results/PartialInstancerTest2-VF-instance-900,100.ttx b/Tests/varLib/instancer/data/test_results/PartialInstancerTest2-VF-instance-900,100.ttx
index 013ba1e73..61c3b2bb9 100644
--- a/Tests/varLib/instancer/data/test_results/PartialInstancerTest2-VF-instance-900,100.ttx
+++ b/Tests/varLib/instancer/data/test_results/PartialInstancerTest2-VF-instance-900,100.ttx
@@ -74,7 +74,7 @@
     <!-- The fields 'usFirstCharIndex' and 'usLastCharIndex'
          will be recalculated by the compiler -->
     <version value="4"/>
-    <xAvgCharWidth value="577"/>
+    <xAvgCharWidth value="609"/>
     <usWeightClass value="900"/>
     <usWidthClass value="5"/>
     <fsType value="00000000 00000000"/>
diff --git a/Tests/varLib/instancer/data/test_results/PartialInstancerTest2-VF-instance-900,62.5.ttx b/Tests/varLib/instancer/data/test_results/PartialInstancerTest2-VF-instance-900,62.5.ttx
index 45e34cbf7..fa31886a6 100644
--- a/Tests/varLib/instancer/data/test_results/PartialInstancerTest2-VF-instance-900,62.5.ttx
+++ b/Tests/varLib/instancer/data/test_results/PartialInstancerTest2-VF-instance-900,62.5.ttx
@@ -74,7 +74,7 @@
     <!-- The fields 'usFirstCharIndex' and 'usLastCharIndex'
          will be recalculated by the compiler -->
     <version value="4"/>
-    <xAvgCharWidth value="577"/>
+    <xAvgCharWidth value="506"/>
     <usWeightClass value="900"/>
     <usWidthClass value="2"/>
     <fsType value="00000000 00000000"/>