On Sunday 15 June 2003 15:31, Liz Quilty wrote:
>Is it possible to rotate an image with gimp 1-2 degrees rather than
> only 90 degree angles?
>I dont appear to be able to find any options anywhere :/

The short answer is no.

The longer answer is that 90 degree rotates are nothing more than byte 
location shuffling.

But a 1 or 2 degree rotate would probably cost half the resolution in 
those sreas of the pix where you'd have to mix the bytes above and 
below to get the value of that one.  Thats on the left-right edges.  
Ditto the byte left and right of that one at the top and bottom of 
the image.  When the angles got up to where you had to go to 
shuffling the whole square of 9 bytes, and reaching into adjacent 9 
byte cells, the time to do the math would rapidly degenerate toward 
infinity.  This would be the situation for the corners of the image.

At some point it would be quicker to degenerate the image into and x 
and y values linked to the current x(color/hue/intensity) on a per 
pixel basis, and then manipulate the x and y values, then redraw the 
image based on that.  And that also needs resolution killing 
anti-aliasing to look good, else the stairsteps get pretty 
noticeable.  That turns such a program into a full fledged, and 3-5 
digit priced graphics rendering thing if it can do a full frame in 
under 10 minutes.  The older amiga Lightwave is I believe in that 
category, since migrated to wintel platforms and heavily used in the 
gfx business yet by those who can afford it.  And I believe that the 
hollywood extended gimp, motion-gimp can also do such things, but 
I've personally never seen it run.  Someone who has some experience 
with it should comment about my probable miss-conceptions right about 

I used to watch an amiga, doing an all gfx 30 second tv spot, with 
frames rendered sometimes only 4 or 5 an hour for complex, real life 
appearing images.  A 30 second at 60 fps spot took several of days to 

As I was in charge of the maintainance on the tape machines that 
recorded that, it was painfull to me to watch them sitting in still 
frame pause wearing out the tape and heads waiting for the next one 
frame edit to be appended.  And we stopped doing that when the real 
costs of doing those animations was totalled up, the advertising 
client soon learned that state of the (then) art was expensive so it 
was self-throttling.  Now we do much of that with non-linear editing 
from disk stored image files, and get results in 5% of the time, 4% 
of which is the artist sitting there deciding if he likes this, or 
that, better.  But without the fancy morphing and such effects except 
in the character overlays.

Cheers, Gene
99.26% setiathome rank, not too shabby for a WV hillbilly
Yahoo.com attornies please note, additions to this message
by Gene Heskett are:
Copyright 2003 by Maurice Eugene Heskett, all rights reserved.

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