resolves #2291 allow theme to control vertical alignment of footnotes block (PR #2292)

4 files changed, 44 insertions, 5 deletions

diff --git a/CHANGELOG.adoc b/CHANGELOG.adoc
index 37c818b0..ae390df2 100644
--- a/CHANGELOG.adoc
+++ b/CHANGELOG.adoc
@@ -7,6 +7,10 @@ For a detailed view of what has changed, refer to the {url-repo}/commits/main[co
 
 == Unreleased
 
+Enhancements::
+
+* Allow footnotes to be placed directly below last block of content if `footnotes_margin_top` theme key is 0 (#2291)
+
 Bug Fixes::
 
 * apply text transform and formatting when checking height of heading for orphan prevention
diff --git a/docs/modules/theme/pages/footnotes.adoc b/docs/modules/theme/pages/footnotes.adoc
index 75781338..35b4cbfc 100644
--- a/docs/modules/theme/pages/footnotes.adoc
+++ b/docs/modules/theme/pages/footnotes.adoc
@@ -41,11 +41,11 @@ footnotes:
   item-spacing: 5
 
 |margin-top
-|xref:measurement-units.adoc[Measurement] +
-(default: `0`)
+|xref:measurement-units.adoc[Measurement] {vbar} `auto` +
+(default: `auto`)
 |[source]
 footnotes:
-  margin-top: 2
+  margin-top: 0
 
 |text-transform
 |xref:text.adoc#transform[Text transform] +
diff --git a/lib/asciidoctor/pdf/converter.rb b/lib/asciidoctor/pdf/converter.rb
index 3df0e3e8..b75a34c3 100644
--- a/lib/asciidoctor/pdf/converter.rb
+++ b/lib/asciidoctor/pdf/converter.rb
@@ -578,6 +578,7 @@ module Asciidoctor
         theme.code_linenum_font_color ||= '999999'
         theme.callout_list_margin_top_after_code ||= 0
         theme.role_unresolved_font_color ||= 'FF0000'
+        theme.footnotes_margin_top ||= 'auto'
         theme.footnotes_item_spacing ||= 0
         theme.index_columns ||= 2
         theme.index_column_gap ||= theme.base_font_size
@@ -3164,9 +3165,9 @@ module Asciidoctor
       def ink_footnotes node
         return if (fns = (doc = node.document).footnotes - @rendered_footnotes).empty?
         theme_margin :block, :bottom if node.context == :document || node == node.document.last_child
-        theme_margin :footnotes, :top
+        theme_margin :footnotes, :top unless (valign_bottom = @theme.footnotes_margin_top == 'auto')
         with_dry_run do |extent|
-          if (single_page_height = extent&.single_page_height) && (delta = cursor - single_page_height - 0.0001) > 0
+          if valign_bottom && (single_page_height = extent&.single_page_height) && (delta = cursor - single_page_height - 0.0001) > 0
             move_down delta
           end
           theme_font :footnotes do
diff --git a/spec/footnote_spec.rb b/spec/footnote_spec.rb
index af1d3d95..43294455 100644
--- a/spec/footnote_spec.rb
+++ b/spec/footnote_spec.rb
@@ -165,6 +165,40 @@ describe 'Asciidoctor::PDF::Converter - Footnote' do
     (expect first_footnote[:y]).to be < (footnotes_height + 50)
   end
 
+  it 'should put footnotes directly below last block if footnotes_margin_top is 0' do
+    pdf_theme = { footnotes_margin_top: 0 }
+    input = <<~'EOS'
+    About this thing.footnote:[More about this thing.]
+
+    ****
+    sidebar
+    ****
+    EOS
+
+    pdf = to_pdf input, pdf_theme: pdf_theme, analyze: true
+    horizontal_lines = (to_pdf input, pdf_theme: pdf_theme, analyze: :line).lines
+      .select {|it| it[:from][:y] == it[:to][:y] }.sort_by {|it| -it[:from][:y] }
+    (expect pdf.pages).to have_size 1
+    footnote_text = pdf.find_unique_text %r/More about /
+    footnote_text_top = footnote_text[:y] + footnote_text[:font_size]
+    content_bottom_y = horizontal_lines[-1][:from][:y]
+    (expect content_bottom_y - footnote_text_top).to be > 12.0
+    (expect content_bottom_y - footnote_text_top).to be < 14.0
+  end
+
+  it 'should push footnotes to bottom of page if footnotes_margin_top is auto' do
+    pdf_theme = { page_margin: 36, footnotes_margin_top: 'auto', footnotes_item_spacing: 0 }
+    input = <<~'EOS'
+    About this thing.footnote:[More about this thing.]
+
+    more content
+    EOS
+
+    pdf = to_pdf input, pdf_theme: pdf_theme, analyze: true
+    footnote_text = pdf.find_unique_text %r/More about /
+    (expect footnote_text[:y]).to (be_within 3).of 36
+  end
+
   it 'should put footnotes beyond margin below last block of content' do
     pdf_theme = { sidebar_background_color: 'transparent' }
     input = <<~'EOS'