[Gimp-developer] selecting multiple layers (feature request)

[Bogdan Butnaru <bogdanb gmail com>]

Hello everyone,

I'd like to (probably re-)start the discussion about adding the "feature"  of selecting multiple layers in the GIMP, and of course manipulating such selections. I've seen a few people asking about this, and the only answer I found other than "you can't" was "why?" So here's why I (and, I believe, many others) need that feature.

By "selecting layers" I mean picking more than one layer at a time in the layers panel, not selecting pixels from multiple layers, though the later also has uses. But the important stuff is manipulating layers as a whole.

Why would one select several layers? Well, right now I'm working with creating animations out of video, which means I start with dozens or hundreds of layers, which I need to show, hide, rearange (i.e., move above/below one another), or delete, etc.

Layer groups would do pretty much all of that. But since you can't select layers, you need to create an empty layer group and move layers one by one inside it. So, if I needed, say, move the bottom two dozen layers above all others, groups don't help at all. I'd need to create an empty group, move the layers in that group one by one, then move the group. Want to delete a dozen consecutive layers? I need at a minimum a dozen clicks *and* a dozen keystrokes, instead of just click (on the first layer), shift-click (on the last, thus selecting the range), keystroke (to delete all of them). Need to hide (or show) all but one layer? That means two clicks per layer.

The *minimum* solution to this feature would be to allow selecting several layers (and/or groups) and have a "create layer group from selection" option (say, in the right-click menu). Ideally it should be possible to do all layer-group operations (reorder, hide/show, delete/copy, merge) directly on the selection, as if it were a "temporary group" (it could be slightly more complex because a selection can be discontinuous).

While we're on the subject, I don't see why you can't do *any* operation that works on one individual layer apply at the same time to several ones, by applying it in turn on each layer. You can't do that even with a group today. For example, I just tried applying the "Invert colors" option on a layer group and got an error, though conceptually it's quite obvious what it would mean and what it would do. I didn't look at GIMP's plugin architecture, but I can imagine it might prevent it being that easy. But GIMP has a lot of operations---pretty much everything under the 'layer' and 'colors' menus---that's are included out of the box, and most of those would be easy to apply to several layers in turn; the only ones I can think of that would be tricky are dialogs that allow setting an option by looking at a layer (e.g., the auto-level option), though it wouldn't be unreasonable to simply disable those buttons if more than one layer is selected.

— Bogdan Butnaru