Re: How do I get the offset result from "-trim"?

On Tue, 8 Sep 2020, Adam Richter wrote:

> Hi, Bob.
>
> I have found the "-trim -fuzz ..." discrepancy between ImageMagick and
> GraphicsMagick.
>
> I suspect that this was a change that someone put into ImageMagic, and
> I recommend you follow this one.  In particular, in color.c, in
> FuzzyColorMatch(), I recommend that you multiply fuzz_squared by 3.0,
> which ImageMagick does.  Basically, fuzz is supposed to be a value

Interesting.  I have not updated this function significantly since 
2008 when an optimization was added.  The function is used in many 
(22!) places.

Looking closer, it seems that there is ample opportunity for possible 
speed-up as well.

Unless the user knows what they are doing (unlikely), the results of 
the distance vector are not likely to be very useful because they are 
performed in an inadequate color-space.  In many cases the user can 
not "fix" FuzzyColorMatch() without breaking something else because it 
is called deep in the bowels of other algorithms.

> If you would prefer I generate a proposed patch and email it to you
> (or submit it my whatever other mechanism you prefer, such a merge
> request, etc.), please just let me know.  I am happy to do so.

A simple emailed text patch would be great.  If there is a SourceForge 
problem report, then a text patch attached to the problem report will 
work as well.

Bob
-- 
Bob Friesenhahn
[email protected], http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/
Public Key,     http://www.simplesystems.org/users/bfriesen/public-key.txt