On Sun, 17 Oct 2010 11:02:03 -0400 Phillip Jones <pjone...@gmail.com> wrote:
> Mainly because that has been the standard at least since Televisions > were invented. The beam in a CRT scans from left-to-right, > top-to-bottom. It's codified in the NTSC standard. So (x,y)=(0,0) is > the upper left corner. Why are CRT's like this? Probably because words > in books are also oriented left-to-right, top-to-bottom. Maybe if the > television had been invented in the middle-east it would be different. > I've got several digital image processing books on my shelf, the > oldest is from 1972. Every one of them defines (x,y)=(0,0) as the > upper left corner of an image. y as positive down, and x as positive > right is simply the de-facto standard in digital image processing. I think that is why X11 has its coordinate system as is; and that is why PCB developers went that way. But a CAD tool is not about CRT display or image processing. I think we should change it; it looks very awkward for a new user, who doesn't know the story. Just my EUR0.02 Levente -- Levente Kovacs http://levente.logonex.eu _______________________________________________ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user