Sent: 2011-08-28 06:47:16 UTC (9 months ago)

From: Thomas Baruchel

Difference between c2g from Gimp and from Gegl command line

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Hi, I am new to GEGL but I would be interested by writing XML
scripts in order to perform some complex actions from the command
line. I managed to make c2g work with XML scripts, but obviously
the output is not the same than what I get from Gimp.

Here are the two ways I found for making c2g work:

gegl -o - -x "38410231.811file.png" | display -

gegl -o - -x "38410231.811" | display -

As you can see, I use here the default settings from Gimp (except for "samples" where I tried with 10 both in Gimp and here). However this single operation
performed on a picture doesn't give the same output. Do you have an
explanation for that?

By the way, what is the most convenient way for having the input file from
the standard input rather than setting its path in the XML file?
There is such an example on http://gegl.org but I couldn't manage to get it
work and I couldn't find what I had to change in my own command lines above
to do it.

Best regards,

Thomas Baruchel

Sent: 2011-08-28 11:16:17 UTC (9 months ago)

From: Jon Nordby

Difference between c2g from Gimp and from Gegl command line

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On 28 August 2011 08:47, Thomas Baruchel wrote:
> Hi, I am new to GEGL but I would be interested by writing XML
> scripts in order to perform some complex actions from the command
> line. I managed to make c2g work with XML scripts, but obviously
> the output is not the same than what I get from Gimp.
>
> Here are the two ways I found for making c2g work:
>
> gegl -o - -x "38410231.811file.png" | display -
>
>
> gegl -o - -x "38410231.811" | display -
>
> As you can see, I use here the default settings from Gimp (except for "samples" where I tried with 10 both in Gimp and here). However this single operation
> performed on a picture doesn't give the same output. Do you have an
> explanation for that?

You are using the "GEGL operation" tool for this in GIMP, right?
I'm seeing the same behavior here, tested with your examples and with
the color-temperature operation. If there is no bug filed for this
issue, please file one.

> By the way, what is the most convenient way for having the input file from
> the standard input rather than setting its path in the XML file?
> There is such an example on http://gegl.org but I couldn't manage to get it
> work and I couldn't find what I had to change in my own command lines above
> to do it.
Using path = "-" on a load operation is meant to work for this
purpose. If it does not, that is a regression and is worth a bug
report.

> Best regards,
>
> --
> Thomas Baruchel
> _______________________________________________
> Gegl-developer mailing list
> Gegl-developer@lists.XCF.Berkeley.EDU
> https://lists.XCF.Berkeley.EDU/mailman/listinfo/gegl-developer
>

Jon Nordby - www.jonnor.com

Sent: 2011-08-28 11:37:52 UTC (9 months ago)

From: Thomas Baruchel

[Newbie] A few more questions

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On Sun, 28 Aug 2011, Jon Nordby wrote:
> Using path = "-" on a load operation is meant to work for this
> purpose. If it does not, that is a regression and is worth a bug
> report.

Thank you for your very quick answer. I have some other questions. First,
I couldn't manage to get it work with the standard input. I tried
with - with '-' and with "-" like that:

cat Dimocarpus_longan_fruits.jpg | gegl -o - -x "3843231.811-" | display -

cat Dimocarpus_longan_fruits.jpg | gegl -o - -x "3843231.811'-'" | display -

cat Dimocarpus_longan_fruits.jpg | gegl -o - -x "3843231.811\"-\"" | display -

Another question: is there a way to blend layers by combining the HSV or HSL
values (ie. take hue and saturation from one layer and light from the
other one)? ImageMagick calls these modes: Luminize or Colorize; Gimp calls
them Color or Value:
http://www.imagemagick.org/Usage/compose/#hue
http://www.linuxtopia.org/online_books/graphics_tools/gimp_advanced_guide/gimp_guide_node55_004.html

Thank you by advance,
best regards,

Thomas Baruchel

Sent: 2011-08-28 12:14:29 UTC (9 months ago)

From: Jon Nordby

[Newbie] A few more questions

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On 28 August 2011 13:37, Thomas Baruchel wrote:
> On Sun, 28 Aug 2011, Jon Nordby wrote:
>> Using path = "-" on a load operation is meant to work for this
>> purpose. If it does not, that is a regression and is worth a bug
>> report.
>
> Thank you for your very quick answer. I have some other questions. First,
> I couldn't manage to get it work with the standard input. I tried
> with - with '-' and with "-" like that:
I tested it now and it does indeed not work in latest gegl.
Will you file a bugreport for this issue and the previous one
(previous issue should probably be filed against GIMP)?

> Another question: is there a way to blend layers by combining the HSV or HSL
> values (ie. take hue and saturation from one layer and light from the
> other one)? ImageMagick calls these modes: Luminize or Colorize; Gimp calls
> them Color or Value:
> http://www.imagemagick.org/Usage/compose/#hue
> http://www.linuxtopia.org/online_books/graphics_tools/gimp_advanced_guide/gimp_guide_node55_004.html

I do not think there are such operations available at the moment (they
should have been in the "compositors" category of the operation
index[1]).
Implementing such an operation can be done by subclassing
GeglOperationPointComposer, and using BABL to convert between HSV and
RGB.

We want to have such operations in GEGL, contributions very welcomed!

1. http://gegl.org/operations.html#Categories

Jon Nordby - www.jonnor.com