backport fix for #1858 deduplicate inline image fragments that have been split up

4 files changed, 19 insertions, 1 deletions

diff --git a/CHANGELOG.adoc b/CHANGELOG.adoc
index ece3c97c..29d6e9ae 100644
--- a/CHANGELOG.adoc
+++ b/CHANGELOG.adoc
@@ -12,6 +12,7 @@ Bug Fixes::
 * restore compatiblity with Asciidoctor 2.0.12 when using Pygments (#1846)
 * fix numeric assertions in test suite (#1542)
 * keep caption with image when image is scaled down to fit page (#1803)
+* prevent inline image from rendering multiple times if fallback font is used for alt text (#1858)
 * disable cache tests if open-uri-cache gem is not available
 * disable hyphen tests if text-hyphen gem is not available
 * compensate for change in how character_spacing is applied in FontMetricCache#width_of after Prawn 2.2.2
diff --git a/lib/asciidoctor/pdf/formatted_text/inline_image_arranger.rb b/lib/asciidoctor/pdf/formatted_text/inline_image_arranger.rb
index 32a16fd1..7637eb00 100644
--- a/lib/asciidoctor/pdf/formatted_text/inline_image_arranger.rb
+++ b/lib/asciidoctor/pdf/formatted_text/inline_image_arranger.rb
@@ -39,8 +39,14 @@ module Asciidoctor::PDF::FormattedText
       scratch = doc.scratch?
       available_w = doc.bounds.width
       available_h = doc.page.empty? ? doc.cursor : doc.bounds.height
+      last_fragment = {}
       raw_image_fragments.each do |fragment|
-        drop = scratch
+        if fragment[:object_id] == last_fragment[:object_id]
+          fragments.delete fragment
+          next
+        else
+          drop = scratch
+        end
         begin
           image_path = fragment[:image_path]
 
@@ -125,6 +131,7 @@ module Asciidoctor::PDF::FormattedText
             # NOTE retain key to indicate we've visited fragment already
             fragment[:image_obj] = nil
           end
+          last_fragment = fragment
         end
       end
     end
diff --git a/lib/asciidoctor/pdf/formatted_text/transform.rb b/lib/asciidoctor/pdf/formatted_text/transform.rb
index a2d0ca24..bba1c0f5 100644
--- a/lib/asciidoctor/pdf/formatted_text/transform.rb
+++ b/lib/asciidoctor/pdf/formatted_text/transform.rb
@@ -175,6 +175,7 @@ module Asciidoctor
                     # NOTE: add enclosing square brackets here to avoid errors in parsing
                     text: %([#{attributes[:alt].delete ZeroWidthSpace}]),
                     callback: [InlineImageRenderer],
+                    object_id: node.object_id, # used to deduplicate if fragment gets split up
                   }
                   if inherited && (link = inherited[:link])
                     fragment[:link] = link
diff --git a/spec/image_spec.rb b/spec/image_spec.rb
index cc91ce53..88ffcc5a 100644
--- a/spec/image_spec.rb
+++ b/spec/image_spec.rb
@@ -788,6 +788,15 @@ describe 'Asciidoctor::PDF::Converter - Image' do
       end).to log_message severity: :WARN, message: '~image to embed not found or not readable'
     end
 
+    it 'should only render inline image once if alt text is chunked to apply a fallback font' do
+      pdf = to_pdf <<~'EOS', attribute_overrides: { 'imagesdir' => examples_dir, 'pdf-theme' => 'default-with-fallback-font' }, analyze: :image
+      How many wolpertingers do you see? +
+      image:wolpertinger.jpg[チのデータレプリケーションです。]
+      EOS
+
+      (expect pdf.images).to have_size 1
+    end
+
     it 'should warn instead of crash if inline image is unreadable' do
       image_file = fixture_file 'logo.png'
       old_mode = (File.stat image_file).mode