From 4415c30c05dab911c592dfcbcfed8d3b46b8d87c Mon Sep 17 00:00:00 2001
From: Jaro <jaro@argonaut-constellation.org>
Date: Wed, 10 May 2023 21:39:27 +0200
Subject: [PATCH] Test soft breaking on box spacing.

---
 .../ParagraphLayout/Rich/ParagraphData.hs     | 20 +++++++
 test/Data/Text/ParagraphLayout/RichSpec.hs    | 53 +++++++++++++++++++
 2 files changed, 73 insertions(+)

diff --git a/test/Data/Text/ParagraphLayout/Rich/ParagraphData.hs b/test/Data/Text/ParagraphLayout/Rich/ParagraphData.hs
index 63e69c1..2886877 100644
--- a/test/Data/Text/ParagraphLayout/Rich/ParagraphData.hs
+++ b/test/Data/Text/ParagraphLayout/Rich/ParagraphData.hs
@@ -4,9 +4,11 @@ module Data.Text.ParagraphLayout.Rich.ParagraphData
     , loremIpsumParagraph
     , mixedSizesParagraph
     , nestedBoxesParagraph
+    , softBreakParagraph
     )
 where
 
+import Data.Int (Int32)
 import Data.Text (pack)
 import Data.Text.Glyphize (Direction (DirLTR, DirRTL), Font)
 
@@ -121,3 +123,21 @@ nestedBoxesParagraph font = constructParagraph
     (pack "suffix")
     where
         t = tLTR { textFont = font, textLanguage = "en" }
+
+softBreakParagraph :: Int32 -> Font -> ParagraphOptions -> Paragraph String
+softBreakParagraph spacing font = constructParagraph
+    (pack "prefix")
+    (rootBox t
+        [ text "text1" "Lorem "
+        , text "text2" "ipsum "
+        , box "box2" b t
+            [ text "text3" "dolor "
+            , text "text4" "sit "
+            , text "text5" "amet,"
+            ]
+        ]
+    )
+    (pack "suffix")
+    where
+        b = b_ { boxSpacing = BoxSpacingLeftRight spacing spacing }
+        t = tLTR { textFont = font, textLanguage = "en" }
diff --git a/test/Data/Text/ParagraphLayout/RichSpec.hs b/test/Data/Text/ParagraphLayout/RichSpec.hs
index 9f8cfdc..c76ec89 100644
--- a/test/Data/Text/ParagraphLayout/RichSpec.hs
+++ b/test/Data/Text/ParagraphLayout/RichSpec.hs
@@ -1,5 +1,7 @@
 module Data.Text.ParagraphLayout.RichSpec (spec) where
 
+import Data.Int (Int32)
+
 import Test.Hspec
 import System.FilePath ((</>))
 import Data.Text.ParagraphLayout
@@ -7,9 +9,14 @@ import Data.Text.ParagraphLayout.FontLoader
 import Data.Text.ParagraphLayout.Internal.Paginable (paginateAll)
 import Data.Text.ParagraphLayout.PrettyShow
 import Data.Text.ParagraphLayout.PrettyShow.Golden
+import Data.Text.ParagraphLayout.Rect
 import Data.Text.ParagraphLayout.Rich
 import Data.Text.ParagraphLayout.Rich.ParagraphData
 
+fragmentRects :: ParagraphLayout d -> [(d, Rect Int32)]
+fragmentRects p = map toItem $ paragraphFragments p
+    where toItem (Fragment { fragmentUserData = d, fragmentRect = r }) = (d, r)
+
 spec :: Spec
 spec = do
 
@@ -46,6 +53,52 @@ spec = do
                 let result = layoutRich input
                 result `shouldBeGolden` "hardBoxBreakLTR"
 
+            it "breaks line early if box spacing does not fit" $ do
+                let lineH = -1121
+                let lineY n = lineH * (n - 1)
+                let wordAdvancesWithSpace = [3134, 2954, 2659, 1332, 2601]
+                let spaceAdvance = 231
+                let wordW n = wordAdvancesWithSpace !! (n - 1)
+                let wordW_ n = wordW n - spaceAdvance
+                let originX = 0
+                let wordX n =
+                        originX + (sum $ take (n - 1) wordAdvancesWithSpace)
+                let endX = originX + (sum wordAdvancesWithSpace)
+                -- A paragraph exactly wide enough to fit the whole text.
+                let opts = defaultParagraphOptions { paragraphMaxWidth = endX }
+                -- Small spacing that should push one word onto the next line.
+                let s = 5
+                -- Large spacing that should push two words onto the next line.
+                let s' = wordW 5 + spaceAdvance + 1
+                let inputNoSpacing = softBreakParagraph 0 font opts
+                let inputSmallSpacing = softBreakParagraph s font opts
+                let inputLargeSpacing = softBreakParagraph s' font opts
+                let resultNoSpacing = layoutRich inputNoSpacing
+                let resultSmallSpacing = layoutRich inputSmallSpacing
+                let resultLargeSpacing = layoutRich inputLargeSpacing
+                fragmentRects resultNoSpacing `shouldBe`
+                    [ ("text1", Rect (wordX 1) (lineY 1) (wordW 1) lineH)
+                    , ("text2", Rect (wordX 2) (lineY 1) (wordW 2) lineH)
+                    , ("text3", Rect (wordX 3) (lineY 1) (wordW 3) lineH)
+                    , ("text4", Rect (wordX 4) (lineY 1) (wordW 4) lineH)
+                    , ("text5", Rect (wordX 5) (lineY 1) (wordW 5) lineH)
+                    ]
+                fragmentRects resultSmallSpacing `shouldBe`
+                    [ ("text1", Rect (wordX 1) (lineY 1) (wordW 1) lineH)
+                    , ("text2", Rect (wordX 2) (lineY 1) (wordW 2) lineH)
+                    , ("text3", Rect (wordX 3 + s) (lineY 1) (wordW 3) lineH)
+                    , ("text4", Rect (wordX 4 + s) (lineY 1) (wordW_ 4) lineH)
+                    , ("text5", Rect originX (lineY 2) (wordW 5) lineH)
+                    ]
+                fragmentRects resultLargeSpacing `shouldBe`
+                    [ ("text1", Rect (wordX 1) (lineY 1) (wordW 1) lineH)
+                    , ("text2", Rect (wordX 2) (lineY 1) (wordW 2) lineH)
+                    , ("text3", Rect (wordX 3 + s') (lineY 1) (wordW_ 3) lineH)
+                    , ("text4", Rect originX (lineY 2) (wordW 4) lineH)
+                    , ("text5",
+                        Rect (originX + wordW 4) (lineY 2) (wordW 5) lineH)
+                    ]
+
         describe "with Arabic font" $ do
             font <- runIO $ loadFont arabicFont 0 testingOptions
 
-- 
2.30.2