如何以编程方式在smalltalk80（吱吱声）中创建箭头变形？

Question

I need to draw an arrow morph from center of one given morph to center of another given morph.

Any help would be appreciated.

Answer 1

Assuming a and b are your morphs:

arrow := (LineMorph from: a center to: b center color: Color red width: 2) makeForwardArrow.
arrow openInWorld.

If you want to update the position after the morphs move, do this:

arrow setVertices: {a center. b center}