Re: [Gimp-user] why no difference of gaussians on layer masks? gimp 2.7.5

[Gary Aitken]

Hi Seth,

Thanks for the perspective.  I was thinking if my world ever settled 
down (won't happen for a few months at best) I might try to gnaw on that 
a bit.  Thanks again,


Gary

On 1/21/2012 4:05 PM, Seth Burgess wrote:

Hi Gary,

edge_dog isn't the most elegant of plug-ins, and behaves more like a
script than most C plug-ins; it creates temporary layers, and to do so,
uses gimp_layer_copy.  (see
http://git.gnome.org/browse/gimp/tree/plug-ins/common/edge-dog.c line
471).  So it inserts a check that the drawable is a layer before it does
anything else.

I expect that careful checks and alternate code paths could alleviate
the issue (copying masks to new layers), or it could be rewritten to do
its operations in a more self-contained way.  I'm not volunteering here,
but it doesn't seem like an insurmountable amount of work for someone
motivated.

HTH,

Seth Burgess



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Re: [Gimp-user] why no difference of gaussians on layer masks? gimp 2.7.5

[Seth Burgess]

Hi Gary,

edge_dog isn't the most elegant of plug-ins, and behaves more like a script
than most C plug-ins; it creates temporary layers, and to do so, uses
gimp_layer_copy.  (see
http://git.gnome.org/browse/gimp/tree/plug-ins/common/edge-dog.c line
471).  So it inserts a check that the drawable is a layer before it does
anything else.

I expect that careful checks and alternate code paths could alleviate the
issue (copying masks to new layers), or it could be rewritten to do its
operations in a more self-contained way.  I'm not volunteering here, but it
doesn't seem like an insurmountable amount of work for someone motivated.

HTH,

Seth Burgess






On Sat, Jan 21, 2012 at 3:20 PM, Gary Aitken  wrote:

> Hi Alexandre,
>
> Yes, I'm aware that I can work around it as you mention, and have been
> doing so.  But it is a pain in the rear, and unless there is some
> over-riding reason for not allowing one to do this operation, it seems the
> gimp should allow it.
>
> My main reason for posting was to see if it is a known issue and decided
> to be left as-is.  I don't see an open bug for it.  I suspect it may be a
> relic of implementation difficulties and so a capability which may be
> desirable but a bit awkward to implement.
>
> Thanks,
>
> Gary
>
>
> On 1/21/2012 12:39 PM, Alexandre Prokoudine wrote:
>
>> On Fri, Jan 20, 2012 at 11:02 PM, Gary Aitken wrote:
>>
>>> Hello all,
>>>
>>> gimp 2.7.5 on winXP, unfortunately.  New hardware problems on my freebsd
>>> system.  grr.  Anyway...
>>>
>>> Why won't the gimp allow me to use a difference of gaussians on a layer
>>> mask?  This seems like a perfectly fine thing to do for edge detection,
>>> and
>>> indeed, other edge-detect algorithms work:
>>>
>>> For example:
>>>  New layer mask, from grayscale copy of layer
>>>  Filters / edge-detect / difference of gaussians says:
>>>Execution error for 'Difference of Gaussians':
>>>Can operate on layers only (but was called on channel or mask).
>>> but
>>>  Filters / edge-detect / Edge...
>>>works fine
>>>
>>> Is this a bug, or am I missing something?
>>> Any insights would be appreciated,
>>>
>>
>> Hi Gary,
>>
>> Not sure about the technical side of this, but you should be able to
>> perfectly work around that.
>>
>> 1. Enable display of the mask via right-click menu so that the mask is
>> displayed instead of the layers's contents.
>> 2. Layers>  New from Visible.
>> 3. Apply your filter to that layer.
>> 4. Copy all of the layer's contents and paste it into the mask.
>> 5. Remove or disable the extra layer you created.
>>
>> Alexandre Prokoudine
>> http://libregraphicsworld.org
>> __**_
>> gimp-user-list mailing list
>> gimp-user-list@gnome.org
>> http://mail.gnome.org/mailman/**listinfo/gimp-user-list
>>
>>
>>
>>
>>
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>
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Re: [Gimp-user] why no difference of gaussians on layer masks? gimp 2.7.5

[Gary Aitken]

Hi Alexandre,

Yes, I'm aware that I can work around it as you mention, and have been 
doing so.  But it is a pain in the rear, and unless there is some 
over-riding reason for not allowing one to do this operation, it seems 
the gimp should allow it.


My main reason for posting was to see if it is a known issue and decided 
to be left as-is.  I don't see an open bug for it.  I suspect it may be 
a relic of implementation difficulties and so a capability which may be 
desirable but a bit awkward to implement.


Thanks,

Gary

On 1/21/2012 12:39 PM, Alexandre Prokoudine wrote:

On Fri, Jan 20, 2012 at 11:02 PM, Gary Aitken wrote:

Hello all,

gimp 2.7.5 on winXP, unfortunately.  New hardware problems on my freebsd
system.  grr.  Anyway...

Why won't the gimp allow me to use a difference of gaussians on a layer
mask?  This seems like a perfectly fine thing to do for edge detection, and
indeed, other edge-detect algorithms work:

For example:
  New layer mask, from grayscale copy of layer
  Filters / edge-detect / difference of gaussians says:
Execution error for 'Difference of Gaussians':
Can operate on layers only (but was called on channel or mask).
but
  Filters / edge-detect / Edge...
works fine

Is this a bug, or am I missing something?
Any insights would be appreciated,


Hi Gary,

Not sure about the technical side of this, but you should be able to
perfectly work around that.

1. Enable display of the mask via right-click menu so that the mask is
displayed instead of the layers's contents.
2. Layers>  New from Visible.
3. Apply your filter to that layer.
4. Copy all of the layer's contents and paste it into the mask.
5. Remove or disable the extra layer you created.

Alexandre Prokoudine
http://libregraphicsworld.org
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Re: [Gimp-user] why no difference of gaussians on layer masks? gimp 2.7.5

[Alexandre Prokoudine]

On Fri, Jan 20, 2012 at 11:02 PM, Gary Aitken wrote:
> Hello all,
>
> gimp 2.7.5 on winXP, unfortunately.  New hardware problems on my freebsd
> system.  grr.  Anyway...
>
> Why won't the gimp allow me to use a difference of gaussians on a layer
> mask?  This seems like a perfectly fine thing to do for edge detection, and
> indeed, other edge-detect algorithms work:
>
> For example:
>  New layer mask, from grayscale copy of layer
>  Filters / edge-detect / difference of gaussians says:
>    Execution error for 'Difference of Gaussians':
>    Can operate on layers only (but was called on channel or mask).
> but
>  Filters / edge-detect / Edge...
>    works fine
>
> Is this a bug, or am I missing something?
> Any insights would be appreciated,

Hi Gary,

Not sure about the technical side of this, but you should be able to
perfectly work around that.

1. Enable display of the mask via right-click menu so that the mask is
displayed instead of the layers's contents.
2. Layers > New from Visible.
3. Apply your filter to that layer.
4. Copy all of the layer's contents and paste it into the mask.
5. Remove or disable the extra layer you created.

Alexandre Prokoudine
http://libregraphicsworld.org
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