How to get UI coordinate in WorldSpace?

[Shifty Geezer]

I'm wanting to measure the worldspace distance between a transform and a dragged NGUI widget.

1.         void OnDragStart(){
2.                 if(CanBeDragged){
3.                         dragPos = transform.localPosition;
4.                         isDragging = true;
5.                 }
6.         }
7.  
8.         void OnDrag (Vector2 delta){
9.                 if(isDragging){
10.                         dragPos += (Vector3)(delta*uiRoot.pixelSizeAdjustment);
11.                         dragWorldPos = Camera.main.ScreenToWorldPoint (dragPos);
12.                         print ("dragpos "+dragPos+"  worldposs  "+dragWorldPos+"    transpos "+targetTrans.position+"   mag "+(targetTrans.position - dragWorldPos).sqrMagnitude);
13.                 }
14.         }
15.  

sqrMagnitude should decrease towards zero as the widget is dragged over towards the target object, but there's an offset. dragWorldPos isn't the correct world coordinates.

[devomage]

try using something like this:
(i use this to calculate the distance of a row in a grid/table)

1. Vector2 size = NGUIMath.CalculateRelativeWidgetBounds(t, true).size;
2.  
3. Vector3 point = scrollview.transform.InverseTransformPoint(t.FindChild("Sprite").position);
4.  
5. float amount = Mathf.Round(point.y - scrollview.panel.localCorners[0].y - size.y - table.padding.y * 2);
6.  

[Shifty Geezer]

Isn't that working in screen space coordinates?

My specific requirement is to see if a drag is within range (world space) of a gameObject's skill, and to cap the distance from the gameObject of the widget based on skill range.

[ArenMook]

Check UIScrollView.Drag(). A plane is created, a ray is cast into it using the screen point's position. This gets you a 3D position on the plane of the widget.