Re: A simple question

• To: Ricardo Ivan Mantilla G <mantilla@xxxxxxxxxxxxxxxxxxxxxxx>
• Subject: Re: A simple question
• From: "From: Bill Hibbard <hibbard@xxxxxxxxxxxxxxxxx>" <billh@xxxxxxxxxxxxx>
• Date: Mon, 19 Jun 2000 16:48:25 -0500 (CDT)

Hi Ricardo,

> I have a simple question about coordinate systems conversion.   I want
> to know how to convert a window X coordinate into graphic display
> coordinates.  I spent some time looking for the answer but I couldn't
> find it.

Given window coordinates x and y, you can do something like this:

  DisplayImpl display = . . .
  DisplayRenderer dr = display.getDisplayRenderer();
  MouseBehavior mouse = dr.getMouseBehavior();
  VisADRay ray = mouse.findRay(x, y);

In a 2-D display, the x and y graphics coordinates are
just ray.position[0] and ray.position[1].  In a 3-D display
it is more complex - the ray position and vector define
a ray that generally runs obliquely through the 3-D
graphics coordinate system.  Note that you'll need a new
copy of VisAD to use the DisplayRenderer.getMouseBehavior()
method.

Cheers,
Bill
----------------------------------------------------------
Bill Hibbard, SSEC, 1225 W. Dayton St., Madison, WI  53706
hibbard@xxxxxxxxxxxxxxxxx  608-263-4427  fax: 608-263-6738
http://www.ssec.wisc.edu/~billh/vis.html

• References:
  • A simple question
    • From: Ricardo Ivan Mantilla G