[Q][Drag&Drop] Event handling, PolygonMorph, line drawing questions

Bob Arning arning at charm.net
Mon Apr 24 04:24:49 UTC 2000


On Mon, 24 Apr 2000 04:47:23 +0200 Stephan Rudlof <sr at evolgo.de> wrote:
>I'm trying to use PolygonMorph (or a similar subclass) to visualize
>drag&drop operations.
>I want to have a line from the drag start point following the hand while
>dragging a Morph to the drop position.

Stephan,

Here's a simpler one.

Cheers,
Bob

===== code snippet follows =====
'From Squeak2.8alpha of 13 January 2000 [latest update: #2005] on 24 April 2000 at 12:23:59 am'!
"Change Set:		draglines
Date:			24 April 2000
Author:			Bob Arning

A simple morph which, when picked up by the hand, draws a line between its original position and its current position"!

RectangleMorph subclass: #LineDrawingMorph
	instanceVariableNames: 'positionWhenPickedUp myPolygon '
	classVariableNames: ''
	poolDictionaries: ''
	category: 'Test-DragAndDrop'!

!LineDrawingMorph methodsFor: 'as yet unclassified' stamp: 'RAA 4/23/2000 23:38'!
aboutToBeGrabbedBy: aHand

	myPolygon _ PolygonMorph
		vertices: {self position. self bounds corner} 
		color: Color red 
		borderWidth: 1 
		borderColor: Color blue.
	World addMorphFront: myPolygon.! !

!LineDrawingMorph methodsFor: 'as yet unclassified' stamp: 'RAA 4/24/2000 00:04'!
justDroppedInto: aMorph event: anEvent

	myPolygon ifNotNil: [myPolygon delete. myPolygon _ nil].
	self changed.! !

!LineDrawingMorph methodsFor: 'as yet unclassified' stamp: 'RAA 4/24/2000 00:18'!
privateMoveBy: delta

	super privateMoveBy: delta.
	myPolygon ifNil: [^self].
	myPolygon vertices at: 2 put: self position.
	myPolygon computeBounds.
! !






More information about the Squeak-dev mailing list