resolves #2528 position foreground image correctly when page layout c…

…hanges (PR #2529)

CHANGELOG.adoc

@@ -53,6 +53,7 @@ Bug Fixes::
 * prevent special character substitution from interfering with callouts in plain verbatim block (#2390)
 * remove deprecated, undocumented `svg-font-family` theme key (the correct key is `svg-fallback-font-family`)
 * major improvement to OTF support following release of ttfunk 1.8.0 (automatic transitive dependency of prawn)
+* position foreground image correctly when page layout changes (#2528)
 
 == 2.3.17 (2024-06-01) - @mojavelinux
 

lib/asciidoctor/pdf/converter.rb

@@ -4428,14 +4428,17 @@ def stamp_foreground_image doc, has_front_cover
         if (first_page = (has_front_cover ? (pages.drop 1) : pages).find {|it| !it.imported_page? }) &&
             (first_page_num = (pages.index first_page) + 1) &&
             (fg_image = resolve_background_image doc, @theme, 'page-foreground-image') && fg_image[0]
-          go_to_page first_page_num
-          create_stamp 'foreground-image' do
-            canvas { image fg_image[0], ({ position: :center, vposition: :center }.merge fg_image[1]) }
-          end
-          stamp 'foreground-image'
-          (first_page_num.next..page_count).each do |num|
+          stamps = ::Set.new
+          (first_page_num..page_count).each do |num|
             go_to_page num
-            stamp 'foreground-image' unless page.imported_page?
+            next if page.imported_page?
+            unless stamps.include? (stamp_name = %(foreground-image-#{page.layout}))
+              create_stamp stamp_name do
+                canvas { image fg_image[0], ({ position: :center, vposition: :center }.merge fg_image[1]) }
+              end
+              stamps << stamp_name
+            end
+            stamp stamp_name
           end
         end
       end

spec/page_spec.rb

@@ -1826,6 +1826,12 @@
 
       <<<
 
+      [.text-left]
+      #{['lots of rambling'] * 150 * ?\n}
+
+      [page-layout=landscape]
+      <<<
+
       [.text-left]
       #{['lots of rambling'] * 150 * ?\n}
       END