"Thorsten Froehlich" wrote:
> The function is evaluated as if (actually is) an image
> was generated from it. Thus the evaluation takes place
> in the image space, not the scene space.

Image space doesn't have to be the same for all image types. For most image
types the origin is defined as being in the upper right corner. Because this
is a standard in those image types, the user can be sure that up will always
remain up and down will remain down. What corner of the image is the origin
doesn't really matter, but one corner had to be chosen so that the user can
count on the alignment always being the same.

Now, when choosing what corner should be the origin in the function image
type, one should choose the best solution for *this* image type, not just
use the same as for all the other image types. So what is the best solution
for the pattern image type?

Well, naturally it is to use the same coordinate definition as used
everywhere else in POV-Ray, i.e. the corner being in the lower right corner.
That is what users expect both logically and intuitively.

It's important for me to point out that what you call "image space" can be
whatever you make it to, so you have to choose the image space that is the
*best* solution. I have argued that having the origin in the lower left
corner is the image space that is easiest to understand for users. What is
your argument for using a different image space)?

To me it seems like you keep assuming that there is only one possible
definition of image space and that is the one the other image types use.

Rune
--
3D images and anims, include files, tutorials and more:
Rune's World:  http://rsj.mobilixnet.dk (updated Mar 19)
POV-Ray Users: http://rsj.mobilixnet.dk/povrayusers/
POV-Ray Ring:  http://webring.povray.co.uk

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