scroll-to-position

Scrolls the editor so that a given position is visible.

Scrolling is disallowed when the editor is internally locked for reflowing (see also Locks).

The system may scroll the editor without calling this method.

• (send a-text scroll-to-position start at-eol? end bias) -> boolean
      start : exact non-negative integer
      at-eol? = #f : boolean
      end = 'same : exact non-negative integer or 'same
      bias = 'none : symbol in '(start end none)

  If end is 'same or equal to start, then position start is made visible. See End of Line for a discussion of at-eol?.

  If end is not 'same and not the same as start, then the range start to end is made visible and at-eol? is ignored.

  When the specified range cannot fit in the visible area, bias indicates which end of the range to display. When bias is 'same, then the start of the range is displayed. When bias is 'end, then the end of the range is displayed. Otherwise, bias must be 'none.

  If the editor is scrolled, then the editor is redrawn and the return value is #t; otherwise, the return value is #f.