/statictext superclass
 /scroll_width
//OLScrollW 4 add cvi def

/textarea_width {
	% -- int
	w margin2 sub scroll_width sub cvi
} def

/boxarea_width {
	% -- int
	w scroll_width sub cvi
} def

/set_top_line {
	% int --
	dup display_top_line eq {pop} {
		/do_set_top_line [3 -1 roll] gexeca
		/@scroll promoted {
			[display_top_line] /changevalue
			/@scroll Send
		} if
	} ifelse
} def

/do_set_top_line {
	% int --
	dup 0 ge {
		dup total_display_lines le
	} false ifelse
	{
		total_display_lines 0 2 index
		max_display_lines add 1 sub max min dup
		display_top_line lt true {
			1 index display_bottom_line gt
		} ifelse
		{
			exch /display_top_line exch promote
			/display_bottom_line exch promote
			/paint_text_from_line [
			display_top_line] gexeca
		} {
			textfont fontheight line_gap add cvi
			2 index display_top_line lt {
				margin 2 index ypos_from_line
				textarea_width 4 index
				display_top_line sub 1 add 4 index mul
				rectpath 0 3 index display_top_line sub
				3 -1 roll mul copyarea
				display_top_line 3 -1 roll
				/display_top_line exch promote exch
				/display_bottom_line exch promote
				display_top_line exch 1 sub
				paint_text_from_line_to
			} {
				margin display_bottom_line
				ypos_from_line textarea_width
				display_bottom_line 0 7 index 1 sub max
				sub 4 index mul rectpath 0 3 index
				display_top_line sub 3 -1 roll mul
				copyarea exch /display_top_line exch
				promote display_bottom_line exch
				/display_bottom_line exch promote 1 add
				paint_text_from_line
			} ifelse
		} ifelse
	} {pop} ifelse
} def

/scroll_up_line {
	% --
	display_top_line 0 gt {
		display_top_line 1 sub set_top_line
	} if
} def

/scroll_down_line {
	% --
	display_top_line total_display_lines lt {
		display_top_line 1 add set_top_line
	} if
} def

/scroll_up_page {
	% --
	display_top_line max_display_lines sub 1
	add 0 max set_top_line
} def

/scroll_down_page {
	% --
	display_top_line max_display_lines add 1
	sub total_display_lines min set_top_line
} def

/scroll_to_top {
	% --
	0 set_top_line
} def

/scroll_to_bottom {
	% --
	0 total_display_lines max set_top_line
} def

/create_scrollbar {
	% --
	/olscrollbar newmember /@scroll /rename
	2 index send
	pop //nullstring (/Preview {\n       [exch] /set_top_line @parent Send } def\n\t\t\t    /Action /pop load def )
	/setscript 3 index send
	pop null 0 0 0 /setposition 5 index send
	/map exch send
} def

/OnInit {
	% --
	//OnInit exec /@scroll promoted not {
		create_scrollbar} if
} def

/compute_display_map_from {
	% int int string --
	//compute_display_map_from exec [
	display_top_line max_display_lines
	total_display_lines] /setparameters
	/@scroll Send
} def

/compute_display_map {
	% --
	value length 0 eq {
		/display_top_line 0 promote
		/display_bottom_line 0 promote
		/total_display_lines 0 promote [0 0]
		/display_map exch promote [
		display_top_line max_display_lines
		total_display_lines] /setparameters
		/@scroll Send
	} {
		0 0 value compute_display_map_from
	} ifelse
} def

/minwidth {
	% -- float
	//minwidth exec scroll_width add
} def