reify convert handler for STEM blocks

4 files changed, 80 insertions, 13 deletions

diff --git a/CHANGELOG.adoc b/CHANGELOG.adoc
index 069be6a7..18425e58 100644
--- a/CHANGELOG.adoc
+++ b/CHANGELOG.adoc
@@ -20,6 +20,7 @@ Improvements::
 
 * configure spacing around thematic break using `thematic-break-padding` key instead of margin top and bottom (#2164)
 * rename `convert_listing_or_literal` to `convert_code` and alias old name
+* reify convert handler for STEM blocks (`convert_stem`)
 
 Bug Fixes::
 
diff --git a/lib/asciidoctor/pdf/converter.rb b/lib/asciidoctor/pdf/converter.rb
index 19572dd8..d2c9f6ae 100644
--- a/lib/asciidoctor/pdf/converter.rb
+++ b/lib/asciidoctor/pdf/converter.rb
@@ -1917,7 +1917,20 @@ module Asciidoctor
         node.instance_variable_set :@subs, prev_subs
       end
 
-      alias convert_stem convert_code
+      def convert_stem node
+        arrange_block node do |extent|
+          add_dest_for_block node if node.id
+          tare_first_page_content_stream { theme_fill_and_stroke_block :code, extent, caption_node: node }
+          pad_box @theme.code_padding, node do
+            theme_font :code do
+              typeset_formatted_text [text: (guard_indentation node.content), color: @font_color],
+                (calc_line_metrics @base_line_height),
+                bottom_gutter: @bottom_gutters[-1][node]
+            end
+          end
+        end
+        theme_margin :block, :bottom, (next_enclosed_block node)
+      end
 
       # Extract callout marks from string, indexed by 0-based line number
       # Return an Array with the processed string as the first argument
diff --git a/spec/pass_spec.rb b/spec/pass_spec.rb
index e7ed91d8..02a14a1a 100644
--- a/spec/pass_spec.rb
+++ b/spec/pass_spec.rb
@@ -30,16 +30,4 @@ describe 'Asciidoctor::PDF::Converter - Pass' do
     margin_bottom = pass_text[:y] - (para_text[:y] + para_text[:font_size])
     (expect margin_bottom).to be > 12
   end
-
-  it 'should render stem as code block if stem extension not present' do
-    pdf = to_pdf <<~'EOS', analyze: true
-    [stem]
-    ++++
-    sig = enc(H(D), s)
-    ++++
-    EOS
-
-    equation_text = (pdf.find_text 'sig = enc(H(D), s)')[0]
-    (expect equation_text[:font_name]).to eql 'mplus1mn-regular'
-  end
 end
diff --git a/spec/stem_spec.rb b/spec/stem_spec.rb
new file mode 100644
index 00000000..ae46141e
--- /dev/null
+++ b/spec/stem_spec.rb
@@ -0,0 +1,65 @@
+# frozen_string_literal: true
+
+require_relative 'spec_helper'
+
+describe 'Asciidoctor::PDF::Converter - STEM' do
+  it 'should render stem as code block if stem extension not present' do
+    pdf = to_pdf <<~'EOS', analyze: true
+    [stem]
+    ++++
+    sig = enc(H(D), s)
+    ++++
+
+    after
+    EOS
+
+    equation_text = (pdf.find_text 'sig = enc(H(D), s)')[0]
+    (expect equation_text[:font_name]).to eql 'mplus1mn-regular'
+    after_text = pdf.find_unique_text 'after'
+    (expect equation_text[:y] - after_text[:y]).to be > 36
+  end
+
+  it 'should preserve indentation in stem block' do
+    pdf = to_pdf <<~'EOS', pdf_theme: { page_margin: 36, code_padding: 10 }, analyze: true
+    [stem]
+    ++++
+    M = \left[
+      \begin{array}{ c c }
+       1 & 2 \\
+       3 & 4
+      \end{array} \right]
+    ++++
+    EOS
+
+    pdf.text.each {|text| (expect text[:font_name]).to eql 'mplus1mn-regular' }
+    lhs_text = pdf.find_unique_text %r/^M/
+    (expect lhs_text[:x]).to eql 46.0
+    begin_text = pdf.find_unique_text %r/begin/
+    (expect begin_text[:x]).to eql 46.0
+    (expect begin_text[:string]).to start_with %(\u00a0 )
+  end
+
+  it 'should show caption and anchor above block if specified' do
+    input = <<~'EOS'
+    // listing-caption is not used in this case
+    :listing-caption: Listing
+
+    .A basic matrix
+    [stem#matrix]
+    ++++
+    M = \left[
+      \begin{array}{ c c }
+       1 & 2 \\
+       3 & 4
+      \end{array} \right]
+    ++++
+    EOS
+
+    pdf = to_pdf input, analyze: true
+    caption_text = pdf.find_unique_text 'A basic matrix'
+    (expect caption_text[:font_name]).to eql 'NotoSerif-Italic'
+    lhs_text = pdf.find_unique_text %r/^M/
+    (expect caption_text[:y]).to be > lhs_text[:y]
+    (expect get_names (to_pdf input)).to have_key 'matrix'
+  end
+end