Re: [Gimp-user] Off-canvas editing

[Burnie West <west ieee org>]

On 06/09/2013 11:14 AM, Steve Kinney wrote:
> On 06/09/2013 12:11 PM, Eduard Braun wrote:
> > Hello everybody,
> >
> > I don't now if this is just a stupid question or if this is a
> > software limitation or if there is even a setting for it I haven't
> > found yet but why are we not able to edit layers outside the canvas?
> >
> > I often create images were the canvas size is fixed (e.g. display
> > resolution). I then add layers to it that are often larger than the
> > canvas. I would now want to select the superfluous parts of the just
> > added images (e.g. to make them transparent), but I can't select
> > parts of the layers that are not on canvas!
> >
> > I also can not see any layer content that is off-canvas. A workflow
> > I'd prefer would be copy everything somewhere (not necessarily
> > inside the canvas) and then align it layer by layer, which is hard
> > when one can not see the content of the off-canvas layers.
> >
> > I hope my question is clear and am looking for your answers!
> Hey Eduard,
>
> I don't think we can do much other than apply a layer-wide filter,
> to edit image content that is off the canvas.
>
> In situations where I need to work with things that are off the
> canvas, I make the canvas large enough to hold everything that
> extends past the intended "final" dimensions of the image, then crop
> the image or restore the original canvas dimensions later.
>
> To keep track of the original canvas boundaries, add guides by doing
> control-a (select all), followed by image > guides > new guides from
> selection, followed with control-shift-a (select none) and image >
> fit canvas to layers.
>
> The guides mark the boundaries of the original and/or final canvas,
> and make it easy to crop the image to those dimensions.  Or, select
> the area marked by the guides and do Image > Fit Canvas To Selection
> to restore the original canvas dimensions and preserve the
> off-canvas content.
Another method I've used is to create a new layer the required canvas size 
named, e.g. TargetCanvas, filled with anything you want. This layer simply sits 
behind the background, and is made invisible until you need to trim the canvas 
for export.

Then, as Steve suggested, create a larger canvas big enough for all you need to 
do. Do all the manipulating you want, and when you're done, then save the xcf 
file so you can go back where you were in the editing phase and fix it if it 
turned out wrong.

Then, make the TargetCanvas layer visible and active, Select All, crop to 
selection, turn off the TargetCanvas layer, and export (e.g. to png or jpg). At 
this point, don't save (to the xcf file) because if you now save this working 
version your oversize work canvas will be lost.

I find this workflow quite comfortable.

  -- Burnie


The workflow is reasonably clean, and