Re: gEDA-user: coordinate systems [was: pcb crooked traces]

[Stefan Salewski <mail@xxxxxxxxxxxx>]

On Fri, 2010-10-15 at 23:15 +0200, Stefan Salewski wrote:
> On Fri, 2010-10-15 at 11:54 -0700, Andrew Poelstra wrote:
> 
> > 
> > The reason for it is that this is generally how drawing canvases work,
> > so from a programmer's perspective, it is simpler to have y pointing down.
> > 
> 
> WHY?
> 
> And of course, we had that discussion some months ago:
> 
> http://archives.seul.org/geda/user/Aug-2010/msg00406.html
> 

For cairo two statements fix the default system:

CR.translate(0, y) # translate y==0 to bottom    
CR.scale(1, -1)    # flip y direction

May be similar for OpenGL.




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