Force a pasted selection to not overwrite transparent sections?

[blearnyey]

I'm trying to make an image with 2 layers: one is a circle that I'm using as a background (and everything outside the circle is transparent) and the other is a selection that I've copied that I want to paste over the background. Is there a way to make it such that the selection I'm pasting will only cover the background image and if any parts of the selection that I'm pasting go outside the background image into the transparent parts of the image that the transparent section will remain transparent?

I've been doing it an ad hoc way of just erasing parts of the layer that I'm using to paste and checking for transparency underneath but that's pretty time consuming. I assume there's a better way?

edit: also, vice versa: is there a way so that if I have a selection that has transparent sections that I paste over a background, that the selection I'm pasting will have it's transparent sections not overwrite none transparent sections of the background? I mean, outside of using magic wand to select everything except the transparent sections and just pasting the parts I selected using magic wand over.

Edited June 9, 2012 by blearnyey

[jim100361]

At the very moment you paste your image on a separate layer over your background, there are nubs on the corners (little circles) and at each mid point (horizontally and vertically) between those corner nubs. These permit you to resize so you can have the image fit to the size you desire. Hold the "Shift" key while clicking and dragging the nubs to keep the proportion of the image.

The image above shows the "nubs" that I was referring to.

[pdnnoob]

Plugin needed: Alpha mask

Duplicate the layer with the transparency setting you like and name the new layer "mask"

Use brightness/contrast to turn everything on the mask layer completely black

Select the entire mask layer and copy it (ctrl+c)

You now have what is called an alpha mask in your clipboard. Whenever you want to cut things that enter the transparent area, just run the alpha mask plugin with "paste from clipboard" checked.

[minners71]

I personally would use the method described above but if you do not have the alphamask plugin you can use the magic wand.

to make the image only show on the circle and not the transparent area.

1.Paste your image into a new layer

2.Select the background layer and using the magic wand tool click on the transparency area.

3.Now re-select your pasted in layer and hit ctrl+X

To do it the opposite way so that the pasted in image only shows on the transparent areas and not the circle just move the pasted in layer down below the circle layer.

Or do the 3 steps above but after you re-select your pasted in layer hit ctrl+I ( this inverts your selection ) then ctrl+X

Note the magic wand tool will only select all the transparent pixels if they are connected, so if you had a ring instead of a circle hold down the shift key when you click with the magic wand this will then select the transparent pixels outside the ring as well as inside.