From 7d43e7d9a61f3ed60203e43ce63c9ba16d404e10 Mon Sep 17 00:00:00 2001
From: Alexander Mankuta <alex@pointless.one>
Date: Mon, 22 Jan 2024 17:46:50 +0200
Subject: [PATCH] Fix missing glyph width.

Prawn correctly used width of missing glyphs to layout text but didn't
encode the widths correctly in subset fonts. The resulted in characters
with missing glyphs to have 0 width. And even though Prawn drawn
Replacement Character glyphs they were stacking on top of each other
because their widths were wrong.
---
 lib/prawn/fonts/ttf.rb    | 12 ++++++------
 spec/prawn_manual_spec.rb |  4 ++--
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/lib/prawn/fonts/ttf.rb b/lib/prawn/fonts/ttf.rb
index 5e55220f9..779234de8 100644
--- a/lib/prawn/fonts/ttf.rb
+++ b/lib/prawn/fonts/ttf.rb
@@ -393,18 +393,18 @@ def embed_simple_font(reference, font, unicode_mapping)
           XHeight: x_height
         )
 
-        first_char = font.cmap.tables.first.code_map.index { |gid| !gid.zero? }
-        last_char = font.cmap.tables.first.code_map.rindex { |gid| !gid.zero? }
+        first_char, last_char = unicode_mapping.keys.minmax
         hmtx = font.horizontal_metrics
         widths =
-          font.cmap.tables.first.code_map[first_char..last_char].map do |gid|
-            if gid.zero?
+          (first_char..last_char).map do |code|
+            if unicode_mapping.key?(code)
+              gid = font.cmap.tables.first.code_map[code]
+              Integer(hmtx.widths[gid] * scale_factor)
+            else
               # These characters are not in the document so we don't ever use
               # these values but we need to encode them so let's use as little
               # sapce as possible.
               0
-            else
-              Integer(hmtx.widths[gid] * scale_factor)
             end
           end
 
diff --git a/spec/prawn_manual_spec.rb b/spec/prawn_manual_spec.rb
index b92c55441..105016409 100644
--- a/spec/prawn_manual_spec.rb
+++ b/spec/prawn_manual_spec.rb
@@ -6,9 +6,9 @@
 MANUAL_HASH =
   case RUBY_ENGINE
   when 'ruby'
-    '8ace5f35f945e5994647cefc2cf7bc369d131e0646d91eb8aeb94e58f72de18d8e7bf82f58fc45406110c4adad239dcbe834059580d29fec2b2a039db67db04c'
+    '7991e4f72e944140840e1c26f0fff331029846eaab148de8483d06491c7808bc4963e8e7376a514e855037f1f1b4197877a31f2df44f511f4f7f5e0ce5df3170'
   when 'jruby'
-    'b77a740d3290192360c4c083018ca61ccc88d42e7c6a152c7bc394d751f5f08d85aec613549f6660713644b00518561cc0f9c947701f01e8c25632c9db81201a'
+    '29b8f8cb00910426805ce226fb47c59d6409683f35f0d2c056a6cf837ba086ca5c763ff89266cfc8e11b1d92af60c9974822b12ad761cdbdf520adb005a98750'
   end
 
 RSpec.describe Prawn do