Re: RGSG - GNOMEprint and Icons

[Bowie Poag <bjp primenet com>]

> 
> I don't think requiring several icon sizes is a good idea.  It puts
> too much work on the icon designer.  If icons look bad when scaled up
> or down, then it is a bug in the scaling algorithm used for icons.
> The scaling algorithm should be changed, not the icons.

I hate to step in here, Federico, but this is patently false. No matter
what scaling algorithm you use, you ARE going to see the code generate an
ugly icon. Its not a mark against the algorithm; its just how the
mathematics work out. When going from 64x64 to some non-even number, for
example. The image is going to be fractured, because its simply a
mathematical property of what youre doing. 64x64 bumps down to 32x32
really well -- All the scaling engine is doing is averaging every two
horizontal and every teo vertical, and spitting out the result.. But what
happens when you've got some odd number? SOME pairs of lines are averaged,
while others are not -- Result: crappy output.

True, however, better algorithms minimize the amount of "crappyness"
exhibited by scaled-down icons. But its still there. Its not a bug in the
scaling algorthm -- I cant tell you how many times i've had to explain
this to coders, who think that shoddy engine output is the fault of the
programmer who wrote the scaling engine--It aint. :)

The crappyness factor can be minimized by drawing icons that are
bilaterally symmetric, and dont have any sharply defined diagonal
features.

> So far I think imlib does an acceptable job of scaling the icons that
> are used throughout GNOME, although it could certainly be better
> (i.e. averaging for downscaling, subsampling for upscaling).  Patches
> to do this are welcome.
> 
>   Federico

Everything from Photoshop to high-end image processing gear does the same
thing -- Scale-downs will distort if the destination image's size is not a
factor, or a median of two factors of the original image.

Bowie