2 files changed, 14 insertions(+), 1 deletions(-)

M src/Data/Text/ParagraphLayout/Internal/Layout.hs
M src/Data/Text/ParagraphLayout/Internal/ProtoLine.hs

@@ 68,7 68,8 @@ layoutAndAlignLines dir align maxWidth runs = frags
         (_, fragsInLines) = mapAccumL positionLine originY numberedLines
         positionLine = positionLineH dir align maxWidth
         numberedLines = zip [1 ..] canonicalLines
-        canonicalLines = fmap reorderProtoFragments logicalLines
+        canonicalLines = fmap reorderProtoFragments visibleLines
+        visibleLines = filter PL.visible logicalLines
         logicalLines = nonEmptyItems $ layoutLines maxWidth [] runs
         originY = paragraphOriginY
 

@@ 1,6 1,7 @@
 module Data.Text.ParagraphLayout.Internal.ProtoLine
     ( ProtoLine (..)
     , nonEmpty
+    , visible
     , width
     , applyBoxes
     )


@@ 38,6 39,17 @@ nonEmpty (ProtoLine [] _ _) = Nothing
 nonEmpty pl@(ProtoLine { protoFragments = (f : fs) }) =
     Just pl { protoFragments = f :| fs }
 
+-- | `True` if this line should generate a visible line box.
+visible :: Foldable f => ProtoLine f d -> Bool
+visible pl = any visibleProtoFragment $ protoFragments pl
+
+visibleProtoFragment :: WithSpan d ProtoFragment -> Bool
+visibleProtoFragment (WithSpan _ pf) =
+    hasGlyphs || hasHardBreak
+    where
+        hasGlyphs = not $ null $ glyphs pf
+        hasHardBreak = hardBreak pf
+
 -- | Total width of the line (content and spacing).
 width :: (Foldable f, Functor f) => ProtoLine f d -> Int32
 width pl = totalAdvances pl + totalBoxesStart pl + totalBoxesEnd pl