union two or more layers without duplication?

[Human3]

I have searched around and only found how to union selection on the same layer, how do you do it on different layers without duplicating the layers, if you understand me?   

Im using tiles to create a larger image and overlapping the layers where they match.  Im new to this, so there is probably a better way to do this.  But for now this is it.  After i match up the layers, i want to combine them without the image becoming more opaque/darker where they overlap.  

Thank you

[Blighty]

(08-12-2019, 11:51 PM)Human3 Wrote: After i match up the layers, i want to combine them without the image becoming more opaque/darker where they overlap.

Some questions:
1) Is the layer mode set to Normal or something else?
2) Is the layer opacity set to 100% or a lower value?
3) Do the layers have semi-transparency in them?

[Human3]

1. yes normal
2. 100% opacity
3. When i overlap the one on top of the other, i can see that it is darker in the 'transparent' areas.  Which leads me to believe they are semi transparent between the solid, colored (gray) areas.  The image im using is from a brush, stamped once, in each layer up, and moved to match each others boundary, easy on the first row, now on the second i must overlap them on that first row, thus i only want one copy when done?    Perhaps gimp doesnt have a way to do that between layers?  I know my silhouette software can do the union and i thought gimp would be able to also.  Not sure if Inkscape can.

[Blighty]

(08-13-2019, 06:18 AM)Human3 Wrote: Which leads me to believe they are semi transparent between the solid, colored (gray) areas.

Yes, I agree. Those areas would not get darker if they were completely transparent. You can check it with the Pointer  Windows > Dockable Dialogues > Pointer

I can't quite visualize what you are doing. Could you attach the brush and/or a sample xcf file. My first impression is to create a seamless pattern. Then just bucket fill with the pattern, no need to do any alignment. But need to see if this is feasible in your case.

[rich2005]

Same as Blighty, not sure what is required and sample(s) will be a great help.

The mention of silhouettes and maybe using layer masks is a possibility, although if the brush is not pure black/white ie. any grey parts will be semi-transparent.

[Ofnuts]

(08-12-2019, 11:51 PM)Human3 Wrote: After i match up the layers, i want to combine them without the image becoming more opaque/darker where they overlap.

But what does that mean...Is the result just the more opaque or more transparent of the two? or a normal blend of the two, set to the opacity of the most opaque? For the latter:

* extract the alpha channels of both layers to a new image (add a layer mask on each layer, init to "Transfer alpha channel" and copy/paste the masks as layers in another image). "Undo" to remove the masks.
* merge the two layers in the initial image
* in the "masks" image, set the top layer to "darken only"
* Edit>Copy visible
* Add  mask to the merged layers in the initial image, initialize to "Transfer alpha channel"
* Paste+Anchor the "computed alpha channel": Ctrl-V+Ctrl-H

[Human3]

Thank you will get a pic to show you.  Ofnuts, im lost there maybe when i get back i can read it and understand.  If i overlap two images matching the area where they are the same, then i want them to become one without duplication where they are the same.

thank you all for your help.  have to run. ok i did a full edit here and attached the file but then got an error connection lost so yeah.. this is an older file, lost the newest one that was in gray when gimp and win crashed.  I was playing.  this one is white, ignore the names of the layers they mean nothing. i will try again

Ok i dont know whats happening it fails upload every time at 36 % ill have to upload it someplace else and put the link in later today.

[Human3]

https://drive.google.com/open?id=1U0VNCq...9mQdE0_j76

[rich2005]

Well you can mess around with merging selections forevermore,  if you want, or as here I blanked out overlapping sections using layer masks.



or you can make a repeating pattern as attached. Which I think is favourite.

https://www.dropbox.com/s/4jrkgj0ei8egpk...n.png?dl=0 1.7 MB

[Ofnuts]

The background layer is fully opaque? What are you trying to do really? Looks like an XY problem...