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extract a reusable function to calculate the scroll column in different contexts (can be used for a plain string or a LineGap.t; doesn't matter)

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Humza Shahid
2025-09-14 09:22:37 +01:00
parent 428208f9bf
commit b556fc7d63
1 changed files with 12 additions and 3 deletions
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15
fcore/text-scroll.sml
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@@ -2,10 +2,10 @@ structure TextScroll =
struct struct
structure TC = TextConstants structure TC = TextConstants
(* Preqreuisite: move buffer to cursorIdx *) (* calculates new scroll column from integer arguments *)
fun getScrollColumn (buffer, cursorIdx, windowWidth, prevScrollColumn) = fun calculateScrollColumn
(startOfLine, cursorIdx, windowWidth, prevScrollColumn) =
let let
val startOfLine = Cursor.vi0 (buffer, cursorIdx)
val newColumn = cursorIdx - startOfLine val newColumn = cursorIdx - startOfLine
val howManyColumnsCanWeFit = val howManyColumnsCanWeFit =
if windowWidth >= TC.textLineWidth then TC.textLineCount if windowWidth >= TC.textLineWidth then TC.textLineCount
@@ -25,6 +25,15 @@ struct
prevScrollColumn prevScrollColumn
end end
(* Preqreuisite: move buffer to cursorIdx *)
fun getScrollColumn (buffer, cursorIdx, windowWidth, prevScrollColumn) =
let
val startOfLine = Cursor.vi0 (buffer, cursorIdx)
in
calculateScrollColumn
(startOfLine, cursorIdx, windowWidth, prevScrollColumn)
end
fun getStartLine (prevLineNumber, cursorLine, windowHeight) = fun getStartLine (prevLineNumber, cursorLine, windowHeight) =
if cursorLine <= (prevLineNumber + 3) then if cursorLine <= (prevLineNumber + 3) then
(* cursorLine is prior to or same as prevLineNumber, (* cursorLine is prior to or same as prevLineNumber,