From bb6ef2fda49c191de4e171bd1c29554ed0aabee3 Mon Sep 17 00:00:00 2001
From: Jaro <jaro@argonaut-constellation.org>
Date: Sat, 18 Mar 2023 15:38:13 +0100
Subject: [PATCH] Add internal functions for "shaped runs" output.

---
 .../Text/ParagraphLayout/Internal/Fragment.hs | 19 ++++++++++++++++++-
 .../ParagraphLayout/Internal/Paragraph.hs     | 11 +++++++++++
 .../Text/ParagraphLayout/Internal/Span.hs     |  7 ++++++-
 3 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/src/Data/Text/ParagraphLayout/Internal/Fragment.hs b/src/Data/Text/ParagraphLayout/Internal/Fragment.hs
index c306dfc..b16991a 100644
--- a/src/Data/Text/ParagraphLayout/Internal/Fragment.hs
+++ b/src/Data/Text/ParagraphLayout/Internal/Fragment.hs
@@ -1,4 +1,7 @@
-module Data.Text.ParagraphLayout.Internal.Fragment (Fragment(..))
+module Data.Text.ParagraphLayout.Internal.Fragment
+    (Fragment(..)
+    ,ShapedRun
+    ,shapedRun)
 where
 
 import Data.Int (Int32)
@@ -41,3 +44,17 @@ data Fragment = Fragment
 
     }
     deriving (Eq, Read, Show)
+
+-- | A simplified representation of a box fragment, suitable for passing to a
+-- text drawing library but lacking detailed size information.
+type ShapedRun = (Int32, Int32, [(GlyphInfo, GlyphPos)])
+
+-- | Convert a `Fragment` to a `ShapedRun`.
+shapedRun :: Fragment -> ShapedRun
+shapedRun f = (x, y, g)
+    where
+        x = x_origin r + px
+        y = y_origin r + py
+        g = fragmentGlyphs f
+        (px, py) = fragmentPen f
+        r = fragmentRect f
diff --git a/src/Data/Text/ParagraphLayout/Internal/Paragraph.hs b/src/Data/Text/ParagraphLayout/Internal/Paragraph.hs
index 34fa076..4f9c42e 100644
--- a/src/Data/Text/ParagraphLayout/Internal/Paragraph.hs
+++ b/src/Data/Text/ParagraphLayout/Internal/Paragraph.hs
@@ -6,6 +6,7 @@ module Data.Text.ParagraphLayout.Internal.Paragraph
     ,paragraphOriginX
     ,paragraphOriginY
     ,paragraphSpanBounds
+    ,shapedRuns
     )
 where
 
@@ -15,6 +16,7 @@ import qualified Data.List.NonEmpty as NonEmpty
 import Data.Text.Array (Array)
 import Data.Text.Glyphize (Font)
 
+import Data.Text.ParagraphLayout.Internal.Fragment
 import Data.Text.ParagraphLayout.Internal.LineHeight
 import Data.Text.ParagraphLayout.Internal.Rect
 import Data.Text.ParagraphLayout.Internal.Span
@@ -115,3 +117,12 @@ containRects = foldr union empty
 paragraphLayout :: [SpanLayout] -> ParagraphLayout
 paragraphLayout sls = ParagraphLayout pRect sls
     where pRect = containRects $ concat $ map spanRects sls
+
+-- | Return all fragments of shaped text in one flat list,
+-- discarding information about their associated spans.
+paragraphFragments :: ParagraphLayout -> [Fragment]
+paragraphFragments pl = concat $ map spanFragments $ spanLayouts pl
+
+-- | Return all shaped runs in the paragraph.
+shapedRuns :: ParagraphLayout -> [ShapedRun]
+shapedRuns pl = map shapedRun $ paragraphFragments pl
diff --git a/src/Data/Text/ParagraphLayout/Internal/Span.hs b/src/Data/Text/ParagraphLayout/Internal/Span.hs
index b8750b1..564313c 100644
--- a/src/Data/Text/ParagraphLayout/Internal/Span.hs
+++ b/src/Data/Text/ParagraphLayout/Internal/Span.hs
@@ -2,6 +2,7 @@ module Data.Text.ParagraphLayout.Internal.Span
     (Span(..)
     ,SpanLayout(..)
     ,SpanOptions(..)
+    ,spanFragments
     ,spanRects
     )
 where
@@ -46,5 +47,9 @@ data SpanLayout = SpanLayout [Fragment]
     -- TODO: Consider merging fragments created by script changes.
     deriving (Eq, Read, Show)
 
+-- | Return all fragments of shaped text from the given span.
+spanFragments :: SpanLayout -> [Fragment]
+spanFragments (SpanLayout frags) = frags
+
 spanRects :: SpanLayout -> [Rect Int32]
-spanRects (SpanLayout frags) = map fragmentRect frags
+spanRects sl = map fragmentRect $ spanFragments sl
-- 
2.30.2