Re: [Gimp-gui] Make the selected tool default to the Color Picker instead of the last tool used

[Jehan <jehan girinstud io>]

Hi,

On 2015-11-08 22:05, Elle Stone wrote:
> On 11/08/2015 11:40 AM, Jehan wrote:
> > Hi,
> >
> > Le 6 nov. 2015 à 08:18, Elle Stone <ellestone ninedegreesbelow com> a
> > écrit :
>
> > > A generic "other editing operation" icon/cursor might be a nice thing
> > > to display when the selected editing operation doesn't have an
> > > editing-operation-specific" icon/cursor.
> > >
> > > What is the defining difference between a filter and a tool, other
> > > than the place they show up in the menu and whether they can be put 
> > > in
> > > the toolbox?
> >
> > Filters are basically plugins/scripts made to edit pixels (though
> > nowadays they have mostly been re-implemented as GEGL operations
> > instead), and as such they have a very limited interaction with GIMP 
> > GUI
> > as of today (limited by the API GIMP provides).
>
> Thanks! That makes sense. So GEGL operations under "Tools" are also 
> filters?

They are different from the old-style filters in the implementation 
perspective, but we can say they are the same conceptually, i.e. 
basically some "operations" which transform an input image into another. 
Nowadays we are trying to get rid of old-style filters (upstream at 
least. I think third-party dev would still be able to create old-style 
filters without making a GEGL op, even though these are not upstream 
preferences anymore).

> > As far as I know, GIMP
> > has no API to change the cursor to be used over the main canvas.
> > Moreover you can perfectly run several plugins at once (which in many
> > cases — in particular for these plugins which actually edit pixels —
> > would not be wise), so how would this be dealt with anyway?
>
> Hmm, I think I've accidentally run more than one filter at a time, and
> it doesn't seem like a good idea, I think I might even have crashed
> GIMP once or twice doing that. Is there any advantage to keeping this
> option?

It's less an "option" than a lack in our API. Also some plugins are not 
meant to edit the image (they are not really filters). For instance the 
animation plugin could run for a very long time alongside other filters 
and not be much of a problem. Well it's not entirely true currently (for 
instance removing a layer in particular can be a problem), but it should 
be. This is a preview plugin which should be able to run while you 
modify your image.

In any case, these are just daily proofs that our API is still too 
limited.
Because you are right: a plugin which modifies deeply an image should be 
able to advertize to GIMP it cannot run alongside another similar 
plugin. And plugins should be able to receive "updates" from GIMP about 
modified images, and so on.

Jehan

> > Tools are hard-coded in GIMP, not through plugins, and you can only
> > select one tool at a time. Being hard coded in GIMP core, they have
> > access to any part of a GUI that you are willing to implement. But 
> > users
> > are not able to create their own tools without going through the 
> > normal
> > upstream validation.
>
> Thanks! That's a very clear explanation.
>
> Best,
> Elle