[Zope] Photo: somes issues and thoughts

J M Cerqueira Esteves jmce@artenumerica.com
Fri, 4 Jan 2002 08:05:25 +0000


* marc lindahl <marc@bowery.com> [2002-01-04 01:54 +0000]:
> > From: J M Cerqueira Esteves <jmce@artenumerica.com>
> 
> > while Photo uses (with integer division, therefore with truncation
> > everywhere):
> > 
> > if hM > h0 * wM / w0:
> >   height = h0 * wM / w0
> >   width = wM
> > else:
> >   height = hM
> >   width =  w0 * hM / h0   [I had a mistake here, /w0 instead of /h0]
> 
> 
> Look at the order of operations - the truncation doesn't hurt anything.

I believe you are mentioning that  

   h0*wM/w0 == (h0*wM)/w0 == int (float(h0*wM) / w0)

instead of the (much worse) h0 * (wM/w0)...  I was aware of that.

The main difference is that Photo defines new dimensions with integer
truncation, while Image Magick rounds each to the nearest integer
(when results of both calculations are different, the aspect ratio is
closer to the original with Image Magick).