'From Squeak2.8 of 13 June 2000 [latest update: #2359] on 31 October 2000 at 1:31:42 am'!

!ScrollPane commentStamp: 'dew 10/31/2000 01:02' prior: 0!
The scroller (a transform) of a scrollPane is driven by the scrollBar.  The scroll values vary from 0.0, meaning zero offset to 1.0 meaning sufficient offset such that the bottom of the scrollable material appears 3/4 of the way down the pane.  The total distance to achieve this range is called the totalScrollRange.!

!ScrollPane methodsFor: 'initialization' stamp: 'dew 10/31/2000 01:28'!
setScrollDeltas
	"Set the ScrollBar deltas, values and interval based on the current scroll pane size, offset and range."
	| range delta |
	self hideOrShowScrollBar.
	scroller hasSubmorphs ifFalse: [scrollBar interval: 1.0.  ^ self].
	range _ self leftoverScrollRange.
	delta _ self scrollDeltaHeight.
	range = 0 ifTrue: [^ scrollBar scrollDelta: 0.02 pageDelta: 0.2; interval: 1.0].

	"Set up for one line (for arrow scrolling), or a full pane less one line (for paging)."
	scrollBar scrollDelta: (delta / range) asFloat 
			pageDelta: ((self innerBounds height - delta) / range) asFloat.
	scrollBar interval: ((self innerBounds height - delta) / self totalScrollRange) asFloat.
	self updateScrollBarValueFromTransform.
! !

!ScrollPane methodsFor: 'geometry' stamp: 'dew 10/31/2000 01:13'!
updateScrollBarValueFromTransform
	"Update the ScrollBar value (0.0 to 1.0) based on the (possibly changed) scroller/transform offset relative to the scroll range.  (This is the inverse of the scrollBarValue: method.)"
	scrollBar value: scroller offset y / self leftoverScrollRange.! !