Class new title: ScrollBar
	subclassof: Object
	fields: 'rect bitstr owner position'
	declare: 'JumpCursor UpCursor DownCursor '

boxPosition_ t1 
	[position moveto: rect origin + (9  (4 + ([t1 < 0.0  [0.0]
	t1 > 1.0  [1.0]
	t1] * (rect height - 16))))]

classInit 
	[UpCursor _ Cursor new fromtext: '
1000000000000000
1100000000000000
1110000000000000
1111000000000000
1111100000000000
1111110000000000
1100000000000000
1100000000000000
1100000000000000
1100000000000000
1100000000000000
1100000000000000
1100000000000000
1100000000000000
1100000000000000
1100000000000000'.
	DownCursor _ Cursor new fromtext: '
1100000000000000
1100000000000000
1100000000000000
1100000000000000
1100000000000000
1100000000000000
1100000000000000
1100000000000000
1100000000000000
1100000000000000
1111110000000000
1111100000000000
1111000000000000
1110000000000000
1100000000000000
1000000000000000'.
	JumpCursor _ Cursor new fromtext: '
0111000000000000
1111100000000000
1111100000000000
0111000000000000
0000000000000000
0000000000000000
0000000000000000
0000000000000000
0000000000000000
0000000000000000
0000000000000000
0000000000000000
0000000000000000
0000000000000000
0000000000000000
0000000000000000' offset: 2  1]

close 
	[owner _ nil]

eachtime | t1 t2 t3 
	[t1 _ user mp.
	rect has: t1 
		[t2 _ rect center x - 2.
		t1 x < t2 
			[t3 _ Rectangle new origin: rect origin corner: t2  rect maxY.
			DownCursor showwhile 
				[while [t1 _ user mp.
				t3 has: t1] do
					[self slide: t1  [owner scrollTo: (position minY - rect minY - 4) asFloat / (rect height - 12)]
					user redbug  [self reposition [owner scrollUp: rect origin y - t1 y]]].
				nil]]
		t3 _ Rectangle new origin: t2  rect minY corner: rect corner.
		UpCursor showwhile 
			[while [t1 _ user mp.
			t3 has: t1] do
				[self slide: t1  [owner scrollTo: (position minY - rect minY - 4) asFloat / (rect height - 12)]
				user redbug  [self reposition [owner scrollUp: t1 y - rect origin y]]].
			nil]]
	false]

firsttime 
	[rect has: user mp]

hide 
	[bitstr  nil  [user notify: 'Attempt to hide unshown scrollbar']
	rect bitsFromString: bitstr.
	bitstr _ nil]

hidewhile t1 | t2 
	[self hide.
	t2 _ t1 eval.
	self show.
	t2]

lasttime

on: t1 from: t2 
	[self on: t1 from: t2 at: t2 scrollPos]

on: t1 from: t2 at: t3 
	[owner _ t2.
	rect _ Rectangle new origin: t1 origin - (32  2) extent: 32  (t1 height + 4).
	position _ Rectangle new origin: rect origin + (9  4) extent: 16  8.
	self boxPosition_ t3]

reposition t1 
	[self reshow 
		[t1 eval.
		self boxPosition_ owner scrollPos]]

reshow t1 | t2 
	[t2 _ position inset: 2.
	t1 eval.
	t2 clear: white.
	position outline]

show 
	[bitstr _ rect bitsIntoString.
	rect clear: black.
	(rect inset: 2  2 and: 1  2) clear: white.
	position outline]

slide: t1 | t2 
	[position has: t1 
		[JumpCursor showwhile 
			[t2 _ false.
			while ((position has: user mp) and t2  false) do
				[user redbug 
					[t2 _ true.
					while user redbug do
						[self reshow [position moveto: position origin x  ((user mp y max: rect origin y + 4) min: rect corner y - 12)]]]].
			nil].
		t2]
	false]