Recognize stave ending with repeat-begin

by carrying over the repeat to the next stave.

Author: newlandsvalley

examples/display-tests/src/Main.purs

@@ -40,6 +40,7 @@ abcContext (Tuple x y) keySignature staveNo =
   , isNewTimeSignature : false
   , maxWidth : round $ (toNumber canvasWidth / scale)
   , pendingGraceKeys : []
+  , pendingRepeatBegin: false
   }
 
 -- | we give each test it's own stave.  The downside is that subsequent staves

src/VexFlow/Abc/BarEnd.purs

@@ -1,6 +1,7 @@
 module VexFlow.Abc.BarEnd
   ( repositionBarEndRepeats
   , fillStaveLine
+  , staveEndsWithRepeatBegin
   , staveWidth) where
 
 -- | Routines to handle the disparity between the manner in which ABC descibes
@@ -11,7 +12,7 @@ module VexFlow.Abc.BarEnd
 -- | (only attached to the end barline).
 
 import Prelude
-import Data.Maybe (Maybe(..))
+import Data.Maybe (Maybe(..), maybe)
 import Data.Array ((:), last, reverse, snoc)
 import Data.Foldable (foldM)
 import Control.Monad.State (State, evalState, get, put)
@@ -25,6 +26,7 @@ type BarState = State Boolean (Array BarSpec)
 -- | move any bar end repeat marker to the previous bar
 -- | i.e. a bar end should belong to the bar it ends not the next one
 -- | that it introduces.
+-- | remember we're processing the bars backwards
 shiftBarEnd :: Array BarSpec -> BarSpec -> BarState
 shiftBarEnd  acc barSpec = do
   lastEndBar <- get
@@ -94,14 +96,21 @@ fillStaveLine maxWidth bs =
     Nothing ->
       bs
 
+-- | does the stave end with a begin repeat marker?
+-- | (to be carried over to the next stave).
+staveEndsWithRepeatBegin :: Array BarSpec -> Boolean
+staveEndsWithRepeatBegin bs =
+  let
+    isBeginVolta b =
+       ((b.startLine.repeat == Just Begin) ||
+        (b.startLine.repeat == Just BeginAndEnd))
+  in
+    maybe false isBeginVolta (last bs)
+
 -- | the current width of the stave's Stave Bars
 staveWidth :: Array BarSpec -> Int
 staveWidth bs =
-  case (last bs) of
-    Just b ->
-      b.xOffset + b.width
-    Nothing ->
-      0
+  maybe 0 (\b -> b.xOffset + b.width) (last bs)
 
 simpleBarType :: BarType
 simpleBarType =

src/VexFlow/Abc/TranslateStateful.purs

@@ -23,14 +23,15 @@ import Data.Newtype (unwrap)
 import Data.Array ((..), zip)
 import Data.Array (length) as Array
 import Data.Traversable (traverse)
-import Data.Abc (Bar, BodyPart(..), Music(..))
+import Data.Abc (Bar, BarType, BodyPart(..), Music(..), Repeat(..))
 import Data.Abc.Metadata (isEmptyStave)
 import VexFlow.Abc.Utils (applyContextChanges, nextStaveNo, updateAbcContext
                          ,beatsPerBeam, isEmptyMusicSpec)
 import VexFlow.Types (AbcContext, BarSpec, MusicSpec(..), StaveSpec
       ,staveIndentation)
 import VexFlow.Abc.TickableContext (NoteCount, TickableContext(..), estimateBarWidth)
-import VexFlow.Abc.BarEnd (repositionBarEndRepeats, fillStaveLine, staveWidth)
+import VexFlow.Abc.BarEnd (repositionBarEndRepeats, fillStaveLine, staveWidth,
+         staveEndsWithRepeatBegin)
 import VexFlow.Abc.Volta (startVolta, isMidVolta)
 
 type Translation a = ExceptT String (State AbcContext) a
@@ -81,16 +82,15 @@ bodyPart bp =
                              })
         -- then translate the bars
         staveBars <- bars staveNo bs
+        -- reget the state after processing the bars
+        abcContext' <- get
         let
-          {-}
-          -- find the overall width
-          accumulatedStaveWidth = staveWidth staveBars
-          -- fill the stave to the end with an empty staveline
-          filledStaveLine = fillStaveLine abcContext.maxWidth $ repositionBarEndRepeats staveBars
-          -}
+          pendingRepeatBegin = staveEndsWithRepeatBegin staveBars
           normalisedStaveBars = repositionBarEndRepeats staveBars
           accumulatedStaveWidth = staveWidth normalisedStaveBars
           filledStaveLine = fillStaveLine abcContext.maxWidth normalisedStaveBars
+        -- save to state whether we need to carry over a Begin Volta from the last stave
+        _ <- put (abcContext' { pendingRepeatBegin = pendingRepeatBegin })
         -- return the stave specification
         pure $ Just { staveNo : staveNo
                     , staveWidth : accumulatedStaveWidth
@@ -137,7 +137,7 @@ bar staveNumber barNumber abcBar =
         { barNumber : barNumber
         , width : width
         , xOffset : abcContext.accumulatedStaveWidth
-        , startLine : abcBar.startLine
+        , startLine : modifiedStartLine abcContext.pendingRepeatBegin abcBar.startLine
         , hasEndLine : true
         , endLineRepeat : false
         , volta : startVolta abcBar.startLine isEmptyBar abcContext.isMidVolta
@@ -154,6 +154,7 @@ bar staveNumber barNumber abcBar =
       newAbcContext = abcContext { accumulatedStaveWidth = newWidth
                                  , isMidVolta = newIsMidVolta
                                  , isNewTimeSignature = false
+                                 , pendingRepeatBegin = false
                                  }
     _ <- put newAbcContext
     withExceptT (\err -> err <> ": bar " <> show barNumber) $ pure barSpec
@@ -205,3 +206,12 @@ music tickablePosition noteIndex m =
           newContext = applyContextChanges abcContext spec
         _ <- put newContext {pendingGraceKeys = []}
         either throwError pure spec
+
+-- | carry over any pending Repeat Begin marker that may have ended the last stave
+modifiedStartLine :: Boolean -> BarType -> BarType
+modifiedStartLine isPendingRepeatbegin barType =
+  if isPendingRepeatbegin
+    then
+      barType { repeat = Just Begin }
+    else
+      barType

src/VexFlow/Abc/Utils.purs

@@ -137,6 +137,7 @@ initialAbcContext tune config =
     , maxWidth : Int.round $
         (Int.toNumber (config.canvasWidth - staveIndentation)) / config.scale
     , pendingGraceKeys : []
+    , pendingRepeatBegin : false
     }
 
 

src/VexFlow/Types.purs

@@ -46,7 +46,8 @@ type AbcContext =
   , isMidVolta :: Boolean            -- we've started but not finished a volta
   , isNewTimeSignature :: Boolean    -- we need to display a changed time signature
   , maxWidth :: Int
-  , pendingGraceKeys :: Array String -- grace notes to be apended to next note
+  , pendingGraceKeys :: Array String -- grace notes to be appended to next note
+  , pendingRepeatBegin :: Boolean    -- begin repeat to be appended to next stave
   }
 
 type NoteSpec =

test/Samples.purs

@@ -22,6 +22,7 @@ startAbcContext (Tuple x y) =
   , isNewTimeSignature : false
   , maxWidth : 1200
   , pendingGraceKeys : []
+  , pendingRepeatBegin: false
   }
 
 c :: Int -> Music