On Wednesday 11 August 2004 8:12 pm, Rodrigo Gonçalves wrote:

> I'm developing a Project subclass which will need to have its main area
> scrollable. I've been trying to make its the Project "world" (a
> PasteUpMorph) scrollable with the TwoWayScrollPane without success.
>
> Any ideas on how could that be done?

If you look at my Connectors package, you'll see a Morph with a scrollable 
pasteup morph. But it isn't a world.

I believe that the range of the arguments given to some of the BitBlt routines 
is limited to a SmallInteger (and very possibly more limited than that); make 
sure that that isn't a problem.

For a really quick way to scroll a world, you can just move all of its morphs 
by the same amount.

You could also subclass PasteUpMorph and override drawSubmorphsOn:. This way 
you could also add scaling. Or, equivalently, you could answer a translated 
Canvas when asked for your canvas to draw the world on.

However, there may be code that assumes that the origin of the World is at 0 at 0 
and that the World's extent is the same as the Display.

I'd try just translating all the morphs first. Turn on deferred updates while 
doing the moves.

I've attached a quick demo of a JoystickMorph moving a World's submorphs.

-- 
Ned Konz
http://bike-nomad.com

-------------- next part --------------
'From Squeak3.7gamma of ''17 July 2004'' [latest update: #5976] on 11 August 2004 at 11:34:36 pm'!
JoystickMorph subclass: #WorldShifter
	instanceVariableNames: 'lastPosition'
	classVariableNames: ''
	poolDictionaries: ''
	category: 'Demo'!
!WorldShifter commentStamp: '<historical>' prior: 0!
A quickie demo of how one might scroll a World.!


!WorldShifter methodsFor: 'initialization' stamp: 'nk 8/11/2004 23:33'!
initialize

	super initialize.
	xScale _ 10.0.
	yScale _ 10.0.
	radiusScale _ 1.0.
	lastAngle _ 0.0.
	autoCenter _ false.
	lastPosition _ 0 at 0.! !


!WorldShifter methodsFor: 'stepping and presenter' stamp: 'nk 8/11/2004 23:33'!
step
	| currentPosition delta morphsToMove |
	self owner isNil
		ifTrue: [^ self].
	currentPosition := self leftRight @ self upDown negated.
	delta := currentPosition - lastPosition.
	delta isZero
		ifFalse: [morphsToMove := self owner submorphs
						reject: [:m | m == self
								or: [m isFlapOrTab]].
			morphsToMove
				do: [:m | m
						position: (m position translateBy: delta)]].
	lastPosition := currentPosition! !