Hi,

On Tue, 2008-01-15 at 16:22 -0500, Andy Berdan wrote:

I've been investigating some animation systems for use at work here, and I was wondering about exporting names and locations of layers in the animation.

I am not sure if Wolfgang Hofer, the author of GAP follows this mailing-list. You might have more luck by mailing him directly.

Sven

The information about layer offsets in a frame sequence is not made readily available and a plug-in would need to be written (and, IMO, it would be simpler to write a Script run in batch mode). Also, once an object has been added to a frame sequence, GIMP only knows the offsets and extents of the resulting layer; it does not record whether the object was rotated or otherwise transformed (which would result in altered offsets and extents).

If you added the layers to your animation using the "Move Path" command, you could save the object's placement information for later recall by saving the control points used. There are some limitations to this, though: primarily that a separate file is created for each object; and if you wish to have the specifics of the object's placement for each frame saved (as opposed to keyframe control points) then you need to use the Paths tool to specify that placement (as opposed to manually specifying the control points in the Move Path dialog). Also, there is no way of saving changes made to the objects after their initial placement.

This approach will produce a file with the following parameters for each control point:

x y width height opacity rotation feather_radius (perspective transform factors) (rel_keyframe)

If you need more information on the above approach, it might be better to move the discussion to the Users mailing list, as this wouldn't really contribute to GIMP development.

Quoting Andy Berdan :

Hi all,

I've been investigating some animation systems for use at work here, and I was wondering about exporting names and locations of layers in the animation.

Hm. That doesn't sound too clear - allow me to illustrate with an example.

Suppose the source animation is a 10-frame animation, with a hand and a ball, both moving (and animating) independently, I'd eventually want something like this:

animation-frame-0: hand-frame-1 x=0,y=0 animation-frame-0: ball-frame-1 x=5,y=5 animation-frame-1: hand-frame-2 x=10,y=10 animation-frame-1: ball-frame-1 x=25,y=25 ... etc ...
animation-frame-9: hand-frame-2 x=100,y=100 animation-frame-9: ball-frame-1 x=520,y=520

(ignore the syntax, the data is presented as such for clarity -- though now, I think a graphical example might have been better)

Obviously, GAP itself has access to this data at some point, but it doesn't seem to be exposed or exportable in any way.

The only idea I can come up with at this point involves iterating over animation files in a directory, scanning each layer for frame information, and dumping the data to a file... and I'm not 100% sure if that's do-able, though it seems that that is something script/python-fu should have access to.

BTW, the intent is to use this animation data (not actual video output) in a game engine for layer-based animations, if you're wondering why I'm asking for this somewhat strange feature.