Size and power ratio of backpattern images

[Wilhelm Sanke]

On Sun Oct 8, Kevin Miller <kevin at runrev.com> in a mutilated response 
to an unknown request with subject "no subject" wrote:

> Pattern images can be color or black-and-white. To be used on Mac OS
> systems, patterns must be 128x128 pixels or less, and both its height and
> width must be a power of 2. To be used on Windows and Unix systems, height
> and width must be divisible by 8.
>
> Does that explain it?
>
> Kevin


At first I thought Kevin was somehow referring to icons (?), but the 
docs state the same for images as backpatterns:

> Cross-platform note:  To be used as a pattern on Mac OS systems, an 
> image must be 128x128 pixels or less, and both its height and width 
> must be a power of 2. To be used on Windows and Unix systems, height 
> and width must be divisible by 8. To be used as a fully cross-platform 
> pattern, both an image's dimensions should be one of 8, 16, 32, 64, or 
> 128.


Well, seems to me that an obsolete state of things is being described here.

Presently I am experimenting with an add-on to my "Imagedata Toolkit" 
that creates "seamless tiles" of various sizes and 3 different 
algorithms (with 5 options each for the overlapping areas) to create the 
tiles. A test button shows the resulting pattern in whole-screen preview.

I experience no limitations so far on MacOS and on Windows concerning 
the size of the images or constraints of divisibility. Backpattern 
images can be of a size of 500X300 pixels - or *any* other size - on 
MacOS and Windows and can have indivisible ratios for example of 151 X 259!

So I am wondering to what Kevin is referring?

Regards,

Wilhelm Sanke
<http://www.sanke.org/MetaMedia>