Re: [Gzz] Re: [Gzz-commits] gzz/doc/pegboard 1008/PEG_1008.rst 1009/PEG_100...

[Tuomas Lukka]

On Mon, Oct 07, 2002 at 08:21:46PM +0200, Benja Fallenstein wrote:
> Tuomas Lukka wrote:
> 
> >Ok, maybe the problem is that you're now thinking of scaling the coordinate
> >system as scaling the image. This not the point here. The point is that
> >coordinate systems give everything coordinates but the rendering code
> >decides what to do with them.
> >
> 
> Ok, I'll try to see it from that perspective.
> 
> But then, in the fisheye case, if I draw a rectangle, why's it 
> *distorted* in the end? I mean, it's just taking four points; they may 
> not yield a rectangle when connected, but the lines should be straight, 
> not distorted? -- Yet, if this is the case, the fisheye doesn't really 
> fulfill its purpose, does it?

No, see, the point is that the fisheye is then transforming the *parent*
coordinate system. I.e. instead of having everything scaled according to
the root coordinate system, we use the fisheye.

> But basically, the point is that we've had these semantics in gl earlier 
> (the scale defines the size of things, esp. boxes), and it was so 
> difficult to work with. I simply don't want to continue working in this 
> system.

The reason it was difficult was that we didn't have all the parts.
The really important part that was missing was a call like

        cs3 = coordsys_at(cs1, cs2, 0.3, 0.3)

which would create a coordsys which is a translation inside cs1, but whose 
center
is always at the point (0.3, 0.3) of cs2. 

This is what I've been trying to explain.

There's something really really important here, I can't explain it fully, but
trust me: this system will work. I'll prove it.

        Tuomas