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contrast-stretch

Posted: 2009-03-05T06:50:49-07:00
by coulon
I'm trying out the -contrast_stretch option like this:
convert paysage3.jpg -contrast-stretch 15%x60% paysage4.jpg

The result is indeed a more contrasted image, but I always obtain the same image when I change the percentages. I've tried out all sorts of absurd and extreme pairs of percentages.

I'm using version 6.4.9-8 on XP. What am I doing wrong?

Re: contrast-stretch

Posted: 2009-03-05T12:23:41-07:00
by Bonzo
I am not sure but I think you will need to escape the % on windows with another %

Try:

Code: Select all

convert paysage3.jpg -contrast-stretch 15%%x60%% paysage4.jpg
I can not find the relavent section on Anthony's site at the moment.

Re: contrast-stretch

Posted: 2009-03-05T13:39:03-07:00
by fmw42
Bonzo wrote:I am not sure but I think you will need to escape the % on windows with another %

Try:

Code: Select all

convert paysage3.jpg -contrast-stretch 15%%x60%% paysage4.jpg
I can not find the relavent section on Anthony's site at the moment.

see http://www.imagemagick.org/Usage/api/#windows

Re: contrast-stretch

Posted: 2009-03-05T20:17:29-07:00
by coulon
This works fine with %%. Thanks.

But if this is not documented, imagemagick should at least display an error
message when I type something wrong!

Re: contrast-stretch

Posted: 2009-03-05T21:05:18-07:00
by anthony
Im is not seeing anything wrong. DOS is screwing it up before IM sees it!