From 34516bcec3a998051ef2cdff4bf355a107721d6f Mon Sep 17 00:00:00 2001
From: Calixte Denizet <calixte.denizet@gmail.com>
Date: Sat, 20 Jun 2026 18:06:14 +0200
Subject: [PATCH] Vertically center the glyphs in comb text fields

---
 src/core/annotation.js       | 15 ++++++++-------
 test/unit/annotation_spec.js |  4 ++--
 2 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/src/core/annotation.js b/src/core/annotation.js
index 0fd275c74..13318bb0a 100644
--- a/src/core/annotation.js
+++ b/src/core/annotation.js
@@ -2574,9 +2574,6 @@ class WidgetAnnotation extends Annotation {
         fontSize,
         totalWidth,
         totalHeight,
-        defaultVPadding,
-        descent,
-        lineHeight,
         alignment,
         bidi(lines[0]).dir === "rtl",
         annotationStorage
@@ -2938,9 +2935,6 @@ class TextWidgetAnnotation extends WidgetAnnotation {
     fontSize,
     width,
     height,
-    vPadding,
-    descent,
-    lineHeight,
     alignment,
     isRTL,
     annotationStorage
@@ -2977,11 +2971,18 @@ class TextWidgetAnnotation extends WidgetAnnotation {
       previousWidth = glyphWidth;
     }
     const renderedComb = buf.join(" ");
+
+    // Vertically center the glyphs within the field: comb fields are mostly
+    // filled with uppercase letters and/or digits, hence we use the cap height
+    // (with a fallback on the ascent or the font size) to center them.
+    const vShift =
+      (height - (font.capHeight || font.ascent || 1) * fontSize) / 2;
+
     return (
       `/Tx BMC q ${colors}BT ` +
       defaultAppearance +
       ` 1 0 0 1 ${numberToString(hShift)} ${numberToString(
-        vPadding + descent
+        vShift
       )} Tm ${renderedComb}` +
       " ET Q EMC"
     );
diff --git a/test/unit/annotation_spec.js b/test/unit/annotation_spec.js
index 99fe01e78..3d87279e7 100644
--- a/test/unit/annotation_spec.js
+++ b/test/unit/annotation_spec.js
@@ -2054,7 +2054,7 @@ describe("annotation", function () {
         annotationStorage
       );
       expect(appearance).toEqual(
-        "/Tx BMC q BT /Helv 5 Tf 1 0 0 1 0 3.07 Tm" +
+        "/Tx BMC q BT /Helv 5 Tf 1 0 0 1 0 3.21 Tm" +
           " 2.61 0 Td (a) Tj 8 0 Td (a) Tj 8.56 0 Td (\\() Tj" +
           " 7.44 0 Td (a) Tj 8 0 Td (a) Tj" +
           " 8.56 0 Td (\\)) Tj 7.44 0 Td (a) Tj" +
@@ -2095,7 +2095,7 @@ describe("annotation", function () {
         annotationStorage
       );
       expect(appearance).toEqual(
-        "/Tx BMC q BT /Goth 5 Tf 1 0 0 1 0 3.07 Tm" +
+        "/Tx BMC q BT /Goth 5 Tf 1 0 0 1 0 2.5 Tm" +
           " 1.5 0 Td (\x30\x53) Tj 8 0 Td (\x30\x93) Tj 8 0 Td (\x30\x6b) Tj" +
           " 8 0 Td (\x30\x61) Tj 8 0 Td (\x30\x6f) Tj" +
           " 8 0 Td (\x4e\x16) Tj 8 0 Td (\x75\x4c) Tj" +