resolves #2326 don't include bottom margin when computing heading height if heading-min-height-after theme key is empty (PR #2327)

3 files changed, 24 insertions, 5 deletions

diff --git a/CHANGELOG.adoc b/CHANGELOG.adoc
index c2f52a5c..cd9b1f70 100644
--- a/CHANGELOG.adoc
+++ b/CHANGELOG.adoc
@@ -19,6 +19,10 @@ Enhancements::
 * rename `kbd-separator` theme key to `kbd-separator-content` to make its consistent with other content keys; remap old key and warn
 * preserve em and rem units on numerator in calc operation in theme (#2314)
 
+Improvements::
+
+* don't include bottom margin when computing heading height if `heading-min-height-after` theme key is empty (#2326)
+
 Bug Fixes::
 
 * keep caret between items in menu macro with previous item if items wrap
diff --git a/lib/asciidoctor/pdf/converter.rb b/lib/asciidoctor/pdf/converter.rb
index 21574349..b8ee8c01 100644
--- a/lib/asciidoctor/pdf/converter.rb
+++ b/lib/asciidoctor/pdf/converter.rb
@@ -2862,13 +2862,13 @@ module Asciidoctor
           advance_page if orphaned
         else
           theme_font :heading, level: (hlevel = opts[:level]) do
+            if (space_below = ::Numeric === min_height_after ? min_height_after : 0) > 0 && (node.context == :section ? node.blocks? : !node.last_child?)
+              space_below += @theme[%(heading_h#{hlevel}_margin_bottom)] || @theme.heading_margin_bottom
+            end
             h_padding_t, h_padding_r, h_padding_b, h_padding_l = expand_padding_value @theme[%(heading_h#{hlevel}_padding)]
             h_fits = indent h_padding_l, h_padding_r do
-              heading_h = (height_of_typeset_text title, inline_format: true, text_transform: @text_transform) +
-                (@theme[%(heading_h#{hlevel}_margin_top)] || @theme.heading_margin_top) +
-                (@theme[%(heading_h#{hlevel}_margin_bottom)] || @theme.heading_margin_bottom) + h_padding_t + h_padding_b
-              heading_h += min_height_after if min_height_after && (node.context == :section ? node.blocks? : !node.last_child?)
-              cursor >= heading_h
+              cursor >= (height_of_typeset_text title, inline_format: true, text_transform: @text_transform) +
+                h_padding_t + h_padding_b + (@theme[%(heading_h#{hlevel}_margin_top)] || @theme.heading_margin_top) + space_below
             end
             advance_page unless h_fits
           end
diff --git a/spec/section_spec.rb b/spec/section_spec.rb
index 42ff43c9..2c7d7cbb 100644
--- a/spec/section_spec.rb
+++ b/spec/section_spec.rb
@@ -1101,6 +1101,21 @@ describe 'Asciidoctor::PDF::Converter - Section' do
     (expect heading_texts.map {|it| it[:page_number] }.uniq).to eql [2]
   end
 
+  it 'should not require space for bottom margin between section title and bottom of page if min-height-after is 0' do
+    pdf = with_content_spacer 10, 710 do |spacer_path|
+      to_pdf <<~EOS, pdf_theme: { heading_min_height_after: 0, heading_font_color: 'AA0000' }, analyze: true
+      image::#{spacer_path}[]
+
+      == Heading Fits
+
+      content
+      EOS
+    end
+
+    heading_text = pdf.find_unique_text font_color: 'AA0000'
+    (expect heading_text[:page_number]).to eql 1
+  end
+
   it 'should force section title with text transform to next page to keep with first line of section content' do
     pdf = to_pdf <<~EOS, pdf_theme: { heading_text_transform: 'uppercase' }, analyze: true
     image::tall.svg[pdfwidth=80mm]