CODEWITHSUNDEEP
flashactionscript
simo
simo

Reputation: 24580

How to translate local point of DisplayObject?

There are some scenarios where we need to translate a local point in a displayObject to its parent. When the displayObject is not rotated or scaled, the result is calculated easily:

var xAtParent:Number= displayObject.x+ localX; 
var yAtParent:Number= displayObject.y+ localY;
// where localX& localY are with respect to displayObject

But, when the displayObject is rotated or scaled, its not directly calculated, so the question is, Is there out of the box solution in action script 3 to solve this issue?

Upvotes: 0

Views: 38

Answers (1)

Jeff Ward
Jeff Ward

Reputation: 19136

Because it's built on a display list with affine (Matrix) transforms, Flash provides easy-to-use coordinate space transformation functions. To go from src coordinate system to dst coordinate system (assuming both src and dst are DisplayObjects on the stage):

var p:Point = new Point(src_local_x, src_local_y);
p = src.localToGlobal(p);
p = dst.globalToLocal(p);
// p.x is dst_local_x
// p.y is dst_local_y

You can also easily get the bounds of any src object in the local coordinate space of any other dst object:

var dst_local_bounds:Rectangle = src.getBounds(dst);

Upvotes: 1

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