backport fix for #2463 consider inherited styles when analyzing glyph…

…s for fallback font support

CHANGELOG.adoc

@@ -11,6 +11,7 @@ Bug Fixes::
 
 * show dot leaders in TOC entry if toclevels is increased for a given section (#2441)
 * decouple tests from path of PWD (#2444)
+* consider inherited styles when analyzing glyphs for fallback font support (#2463)
 * add fallback character for placeholder character when using AFM font (#2453)
 
 == 2.3.9 (2023-06-28) - @mojavelinux

lib/asciidoctor/pdf/ext/prawn/formatted_text/box.rb

@@ -32,21 +32,26 @@ def draw_fragment_overlay_styles fragment
     end
   end
 
-  # TODO: remove when upgrading to prawn-2.5.0
+  # help Prawn correctly resolve which font to analyze, including the font style
   def analyze_glyphs_for_fallback_font_support fragment_hash
     fragment_font = fragment_hash[:font] || (original_font = @document.font.family)
+    effective_font_styles = @document.font_styles
+    fragment_font_opts = {}
     if (fragment_font_styles = fragment_hash[:styles])
-      if fragment_font_styles.include? :bold
-        fragment_font_opts = { style: (fragment_font_styles.include? :italic) ? :bold_italic : :bold }
-      elsif fragment_font_styles.include? :italic
-        fragment_font_opts = { style: :italic }
+      effective_font_styles.merge fragment_font_styles
+      if effective_font_styles.include? :bold
+        fragment_font_opts[:style] = (effective_font_styles.include? :italic) ? :bold_italic : :bold
+      elsif effective_font_styles.include? :italic
+        fragment_font_opts[:style] = :italic
       end
+    elsif !effective_font_styles.empty?
+      fragment_font_opts[:style] = @document.resolve_font_style effective_font_styles
     end
     fallback_fonts = @fallback_fonts.drop 0
     font_glyph_pairs = []
     @document.save_font do
       fragment_hash[:text].each_char do |char|
-        font_glyph_pairs << [(find_font_for_this_glyph char, fragment_font, fragment_font_opts || {}, (fallback_fonts.drop 0)), char]
+        font_glyph_pairs << [(find_font_for_this_glyph char, fragment_font, fragment_font_opts, (fallback_fonts.drop 0)), char]
       end
     end
     # NOTE: don't add a :font to fragment if it wasn't there originally

spec/fixtures/glyph-font-test.adoc

@@ -18,6 +18,8 @@ To ∞!
 // circled numbers
 `①` to `⑳`
 `❶` to `⓴`
+// ballot boxes
+☐ ☑
 // greek
 Α to Ω
 // cyrillic
@@ -38,6 +40,8 @@ fast‑approaching
 ifeval::["{pdf-theme}"=="default-with-font-fallbacks"]
 // check mark
 ✓ done
+// bold ballot boxes
+*☐ ☑*
 // upside down e
 upsidə down
 // extended monospace punctuation

spec/font_spec.rb

@@ -37,6 +37,20 @@
       (expect to_file).to visually_match 'font-glyph-fallback-only.pdf'
     end
 
+    it 'should resolve glyph in fallback font when styles are inherited', visual: true do
+      input = <<~'END'
+      |===
+      |&#x2611; For | &#x2610; Against
+
+      |Tastes great
+      |High in sugar
+      |===
+      END
+
+      to_file = to_pdf_file input, 'fallback-font-inherited-styles.pdf', attribute_overrides: { 'pdf-theme' => 'default-with-font-fallbacks' }
+      (expect to_file).to visually_match 'fallback-font-inherited-styles.pdf'
+    end
+
     it 'should use notdef from original font of glyph not found in any fallback font', visual: true do
       input = ?\u0278 * 10
       to_file = to_pdf_file input, 'font-notdef-glyph.pdf', attribute_overrides: { 'pdf-theme' => 'default-with-font-fallbacks' }