PPTX writer: keep tables and surrounding text on same slide (#11411)

Previously, when a slide contained bullet points before and after a
table, content would be split across multiple slides or use a two-column
layout that didn't preserve the source order.

This change:

1. Modified `splitBlocks'` in Presentation.hs to continue accumulating
   content after tables instead of immediately splitting to a new slide.

2. When a slide has a table with surrounding text, use ContentSlide
   (single column) instead of ContentWithCaptionSlide (two columns)
   to preserve content order.

3. Added vertical stacking in Output.hs (shapesToElementsStacked) to
   properly position multiple shapes (tables + text) within a content
   area. Space is allocated proportionally based on content size
   (paragraphs and table rows).

Closes #11433.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: Chris Callison-Burch <ccb+github@upenn.edu>

test/Tests/Writers/Powerpoint.hs

@@ -78,6 +78,10 @@ tests = let
       def
       "pptx/tables/input.native"
       "pptx/tables/output.pptx"
+    , pptxTests "table with surrounding content stays on same slide"
+      def
+      "pptx/table-with-surrounding-content/input.native"
+      "pptx/table-with-surrounding-content/output.pptx"
     , pptxTests "table of contents"
       def{ writerTableOfContents = True }
       "pptx/slide-breaks/input.native"

test/command/pptx-table-content-same-slide.md

@@ -0,0 +1,121 @@
+Test that content after a table stays on the same slide.
+
+```
+% pandoc -t native
+## Slide with Bullets and Table
+
+- First bullet before table
+- Second bullet before table
+
+| A | B |
+|---|---|
+| 1 | 2 |
+
+- Third bullet after table
+- Fourth bullet after table
+^D
+[ Header
+    2
+    ( "slide-with-bullets-and-table" , [] , [] )
+    [ Str "Slide"
+    , Space
+    , Str "with"
+    , Space
+    , Str "Bullets"
+    , Space
+    , Str "and"
+    , Space
+    , Str "Table"
+    ]
+, BulletList
+    [ [ Plain
+          [ Str "First"
+          , Space
+          , Str "bullet"
+          , Space
+          , Str "before"
+          , Space
+          , Str "table"
+          ]
+      ]
+    , [ Plain
+          [ Str "Second"
+          , Space
+          , Str "bullet"
+          , Space
+          , Str "before"
+          , Space
+          , Str "table"
+          ]
+      ]
+    ]
+, Table
+    ( "" , [] , [] )
+    (Caption Nothing [])
+    [ ( AlignDefault , ColWidthDefault )
+    , ( AlignDefault , ColWidthDefault )
+    ]
+    (TableHead
+       ( "" , [] , [] )
+       [ Row
+           ( "" , [] , [] )
+           [ Cell
+               ( "" , [] , [] )
+               AlignDefault
+               (RowSpan 1)
+               (ColSpan 1)
+               [ Plain [ Str "A" ] ]
+           , Cell
+               ( "" , [] , [] )
+               AlignDefault
+               (RowSpan 1)
+               (ColSpan 1)
+               [ Plain [ Str "B" ] ]
+           ]
+       ])
+    [ TableBody
+        ( "" , [] , [] )
+        (RowHeadColumns 0)
+        []
+        [ Row
+            ( "" , [] , [] )
+            [ Cell
+                ( "" , [] , [] )
+                AlignDefault
+                (RowSpan 1)
+                (ColSpan 1)
+                [ Plain [ Str "1" ] ]
+            , Cell
+                ( "" , [] , [] )
+                AlignDefault
+                (RowSpan 1)
+                (ColSpan 1)
+                [ Plain [ Str "2" ] ]
+            ]
+        ]
+    ]
+    (TableFoot ( "" , [] , [] ) [])
+, BulletList
+    [ [ Plain
+          [ Str "Third"
+          , Space
+          , Str "bullet"
+          , Space
+          , Str "after"
+          , Space
+          , Str "table"
+          ]
+      ]
+    , [ Plain
+          [ Str "Fourth"
+          , Space
+          , Str "bullet"
+          , Space
+          , Str "after"
+          , Space
+          , Str "table"
+          ]
+      ]
+    ]
+]
+```

test/pptx/table-with-surrounding-content/input.native

@@ -0,0 +1,34 @@
+[Header 2 ("slide-with-bullets-and-table",[],[]) [Str "Slide",Space,Str "with",Space,Str "Bullets",Space,Str "and",Space,Str "Table"]
+,BulletList
+ [[Plain [Str "First",Space,Str "bullet",Space,Str "point",Space,Str "before",Space,Str "the",Space,Str "table"]]
+ ,[Plain [Str "Second",Space,Str "bullet",Space,Str "point",Space,Str "before",Space,Str "the",Space,Str "table"]]]
+,Table ("",[],[]) (Caption Nothing [])
+ [(AlignDefault,ColWidthDefault)
+ ,(AlignDefault,ColWidthDefault)]
+ (TableHead ("",[],[])
+ [Row ("",[],[])
+  [Cell ("",[],[]) AlignDefault (RowSpan 1) (ColSpan 1)
+   [Plain [Str "Column",Space,Str "A"]]
+  ,Cell ("",[],[]) AlignDefault (RowSpan 1) (ColSpan 1)
+   [Plain [Str "Column",Space,Str "B"]]]])
+ [(TableBody ("",[],[]) (RowHeadColumns 0)
+  []
+  [Row ("",[],[])
+   [Cell ("",[],[]) AlignDefault (RowSpan 1) (ColSpan 1)
+    [Plain [Str "Value",Space,Str "1"]]
+   ,Cell ("",[],[]) AlignDefault (RowSpan 1) (ColSpan 1)
+    [Plain [Str "Value",Space,Str "2"]]]
+  ,Row ("",[],[])
+   [Cell ("",[],[]) AlignDefault (RowSpan 1) (ColSpan 1)
+    [Plain [Str "Value",Space,Str "3"]]
+   ,Cell ("",[],[]) AlignDefault (RowSpan 1) (ColSpan 1)
+    [Plain [Str "Value",Space,Str "4"]]]])]
+ (TableFoot ("",[],[]) [])
+,BulletList
+ [[Plain [Str "Third",Space,Str "bullet",Space,Str "point",Space,Str "after",Space,Str "the",Space,Str "table"]]
+ ,[Plain [Str "Fourth",Space,Str "bullet",Space,Str "point",Space,Str "after",Space,Str "the",Space,Str "table"]]]
+,Header 2 ("second-slide-for-reference",[],[]) [Str "Second",Space,Str "Slide",Space,Str "for",Space,Str "Reference"]
+,BulletList
+ [[Plain [Str "This",Space,Str "slide",Space,Str "has",Space,Str "just",Space,Str "bullets"]]
+ ,[Plain [Str "No",Space,Str "table",Space,Str "here"]]
+ ,[Plain [Str "Everything",Space,Str "stays",Space,Str "together"]]]]