Description Hernan Gonzalez 2011-10-22 16:35:22 EDT

Build Identifier: 

I believe some clarification about basic GA properties, in docs and/or Javadocs is  much needed. 

1. Location (X,Y) 
 - Are these coordinates relative to... what? The parent GA ? I think so, but I'm not absolutely sure.
(More basically: has a GA always a parent GA? (except for the diagram's GA)

 - What does the GA location exactly represent? 
 I'm not being pedantic, I don't think this is clear. For rectangles it represents the upper/left corner coordinate (let's use the standard axis convention), and in general it seems to be assumed as the upper-left corner of the bounding box. Is this true? 

An issue arose recently, related to this http://www.eclipse.org/forums/index.php/t/244953/

Suppose I create a triangle (Graphiti.getGaService().createPolygon()) with points :

p1 = (100, 100)  p2 = (100, 120) p3 =(120, 100)

(its center is about (110,110) and I set the "Location" of this 
gaService.setLocation(polygon, 300, 300);

The triangle then would be (relative to the parent GA) around position (410,410)
Which is its bounding box (and its width)? Would it extend to 300 or not?
What does the fact GA.X = 300 means here?

Would the above be equivalent or not to using

p1 = (0, 0)  p2 = (0, 20) p3 =(20, 0)

and  gaService.setLocation(polygon, 400, 400) ?

Another example: what if some of the points coordinates are negative?

2- Width/Height 
 Every GA has Location (X/Y) and Size (Width/Height), it's not very clear when this is computed internally by Graphiti and when it's specified by the user. It also not clear if every GA must have a weel defined Size, if this is equivalent to the concept of the "bounding box". See the example above.
Also, dcouemtn what happens when the size of a children GA exceeds the parent.







Reproducible: Always