Change image size & transform tool

[Michael Thaler]

On Thursday 23 June 2005 13:09, Casper Boemann wrote:

> Not really, no. It's basically just the scaling with an offset.

I thought about this a little more. Shearing an image is basically trivial. 
You just shift a row in x- or y-direction. If you shift by non-integer 
values, you have to interpolate, but it is still more or less trivial.

Scaling on the other hand is more complicated because the number of pixels 
change and you have to interpolate somehow so that even pictures which are 
enlarged or shrinked by a huge factor look good.

By combining shearing (rotating) and scaling, you basically add a trivial case 
to the scaling code (that is, scaling 1:1) and on the same time you add an 
offset for each row. On the other hand, you cannot use precalculations 
anymore (I did not check, Casper said so), which should slow down scaling 
(but I really don't how much speed gain these precalculations offer).

So I am still not convinced how much sense it makes to combine shearing and 
scaling because shearing is more or less trivial anyway. On the other hand, I 
am really no expert with respect to this stuff and maybe it really makes 
sense to combine the two operations?

Greetings,
Michael