History of "Improved Image Resizing"

[Wilhelm Sanke]

The "engine change log" of version 2.8 had announced an improved image 
resizing algorithm as a new feature:

> Improved Image Resizing
> ~~~~~~~~~~~~~~~~~~~~~~~
>   There are now three levels of image resize quality:
>     - normal: uses a 'nearest' filter - i.e. no interpolation
>     - good: uses a 'bilinear' filter - i.e. interpolation is done 
> between the four nearest pixels using bilinearity
>     - best: uses a 'bicubic' filter - i.e. interpolation is done using 
> cubic approximation from near pixels" etc.



Just found out while experimenting with enlarging and resizing images 
that this feature goes back to 2004 and was introduced with Revolution 
2.2 (engine version 2.6), but was curiously never documented.

I find this "resizequality" feature to be very powerful when the 
resizequality is set to "best", e.g. you could blow up the images of my 
"Preview Gallery" for the Imagedata Toolkit 3

<http://www.sanke.org/MetaMedia/PreviewToolkit3.htm>

from their decreased size of 400x300 to full screensize (1280x960 in my 
case) with little loss of detail - of course inside Revolution or other 
photo tools that also use cubic approximation.

I will rewrite the script of button "stretch", menu option "enlarge --> 
choose segment" incorporating the resizequality feature. I amm not sure 
if I can manage it to put it into the announced version 3.
On the other hand, my present algorithms for enlargement of 1/4, 2/3, or 
3/4 of the area of the image to be enlarged are not too bad either. The 
scripts can be inspected.

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