Relative positioning

[Urs H. <ur...@an...>]

Hi

Is it possible to place patches at relative positions? For example,
placing a patch at 40% from the left and 40% from the top. Using the
parameters x and y, I have to provide the position of the patch in
pixels. But I don't know the size of the images, I know only the
relative positions. Is it possible to use nx and ny to do such a
relative positioning? (I don't really get what is written in the
documentation. Perhaps using nz=1, nx and ny between -1 and 1 would
work? Right now I don't have the patience to do some experiments
myself, sorry.)
Of course, I also could use image:size() to get the size of a side or a
patch ...

Do you think the following has a chance to work?
I render my patches with Povray using the partial rendering options
StartColumn, StartRow, EndColumn, EndRow by giving relative coordinates
(i.e. numbers between 0 and 1). Then I crop the images with
ImageMagick, again giving relative coordinates. At the end, I place the
patch in Pipmak using relative coordinates.
I fear that this is doomed to result in ugly artifacts.