Re: [Gimp-user] Point Guides aka guide points aka Anchors

[Jehan Pagès <jehan marmottard gmail com>]

Hi,

On Sun, Aug 20, 2017 at 7:34 AM, Gimp-Monkey <forums gimpusers com> wrote:
> I know someone must have been wanting or even working on this.  I would like to
> make a plugin or extension that is basically guide point.  Like the current
> Guides (h and v line) it would be a point.  These are good for snapping image
> parts together: think sprites that have multiple parts.  If this concept if
> taken to its conclusion they could also be like simple bines allowing /
> restricting rotation, offset amounts.

"Guide points" are definitely an interesting feature.

> As a part of this all Guides could be assignable to the image or individual
> layers / groups.  Currently of course guides are associated with an image.
>
> I have already written gui driven plugin for this, however it does not actually
> display or restrict  or snap.  It simple serves as a method for storing
> important points associated with an image or its drawables.

Alexandre's comment seems to imply you have your code somewhere
accessible online. But unless I am blind, I don't see any link
anywhere…
And yes, please work off of master git: https://git.gnome.org/browse/gimp/
Do not work from a tarball from older releases or from code based out
of other branches.

> Now the question... is anyone already doing this?  If so can I help?

I don't think anyone is doing this. Actually I don't think this was
every proposed (though I don't know all our bug requests). So feel
free to propose patches. We will review thoroughly, may ask you to
change stuff, improve code quality (if needed), fix stuffs, but
personally I would vouch for such a feature. And I think others will
as well.

> If not anyone have suggestions for how to implement a small and simple anchor
> icon that is not part of pixel data?  Any suggestions how to have the cursor
> snap to these points?

There is a feature called "Sample points" which is actually not well
known. To create a sample point, you can ctrl-click the rulers (this
usage makes it kind of a "friend" of guides then, even though AFAIK it
doesn't share code) on the side and drag onto the canvas. It will
create numbered points on the canvas. Its main usage though is with
the dock named "Sample Points" to get color information under the
point.
It may be interesting to enhance this feature to make it usable for
other things, like snapping. The "visual" part is already there,
though you seem to propose various visuals (squares, circles,
triangles…). I must say I'm not sure about this part of your proposal.
At least not at first.

Of course some could argue that it may be better to create a separate
feature, but I'm not sure it would be better.

Also in our code, sample points seem to be an independent structure.
IMO it could be a good idea to make guide and sample points as both
children of a common parent class for such features.

> Also some paint programs offer guides (lines) that are any angle, not just h and
> v.  I realize these are not often that useful but there are many times I have
> wished for these to help especially when doing transformations.

Free-angle guides would be definitely useful. As much as I haven't
seen a feature request for guide points until now, we are regularly
asked for free-angle guides, and we have a bug report, even with a
tentative patch by a contributor:
https://bugzilla.gnome.org/show_bug.cgi?id=344109
I have myself several times considered to look into implementing this
(but always had other priorities).
So you are more than welcome to look at current implementation and
propose a patch for this.

As a general rules, our guides are currently quite basic and would
deserve to improve. We also have a lot of requests around better guide
management too. For instance:
https://bugzilla.gnome.org/show_bug.cgi?id=754515
In any case, propositions and patches welcome.

Jehan

> Live long and may your gimp prosper.
>
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> Gimp-Monkey (via www.gimpusers.com/forums)
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