23 lines
597 B
Standard ML
23 lines
597 B
Standard ML
structure TextScroll =
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struct
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structure TC = TextConstants
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(* Preqreuisite: move buffer to cursorIdx *)
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fun getScrollColumn (buffer, cursorIdx, windowWidth) =
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let
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val startOfLine = Cursor.vi0 (buffer, cursorIdx)
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val columnDifference = cursorIdx - startOfLine
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in
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if columnDifference = 0 then
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0
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else
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let
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val howManyColumnsCanWeFit =
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if windowWidth >= TC.textLineWidth then TC.textLineCount
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else windowWidth div TC.xSpace
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in
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columnDifference mod howManyColumnsCanWeFit
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end
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end
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end
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