How to trim a layer to the non-transparent area?

[Starbase1]

Hello All,

I have a very large image with lots of large layers, (over 100), they were all rendered in my CGI application to a standard scale, as 32 bit PNG, regardless of the size actually occupied by the subject. I'm now combining them into one image, and lining them up.

In many cases the layers are 90% or more 100% transparent. But to select with a click and drag, I have to go around all the blank bits I cannot see, which is messy and prone to errors.

Can anyone please tell me of a quick way to crop down to the part in a layer that actually has useful non-blank pixels in it? I suspect that this would also release a LOT of memory, and make working with this image more pleasant in general!

Thank You,

Nick

[walt.farrell]

It woud help to have one or two of your PNG layer files to experiment with.

[Starbase1]

Thanks for the response.

Sample attached! I dragged and dropped the files into the picture, to get all the elements in layers.

If possible I'd rather not start again, (I suspect if I had moved them into the same file with copy / paste that might have done it...)

[Pšenda]

Rasterize & Trim. 

[walt.farrell]

Rasterize & Trim... (from the right-click menu in the Layers panel, or from the Layer menu) is a good way to go, as Pšenda suggests.

 

[carl123]

Document > Clip Canvas

in APhoto

[Starbase1]

Thanks to those who suggested it, Rasterise and trim did what I needed. It's now MUCH easier to select the layers I want with click and drag.

Though I was a little surprised on saving that the file was about 50% larger...