Confession: despite all my other computer skills, I have almost no ability to do anything with images other than cropping/resizing. I’ve never “had to” and so I’ve never learned.
Here’s an example. This is an round image in a square image
I’d basically like to crop that to be just a round image, leaving just a small white border around the outside circle and the white in the center. I know enough to know this means making it a PNG with the “corners” transparent…
I’m guessing this must be a simple thing to do, but I have literally no idea how to start, and trying to google it gives me 1,000 hits that aren’t what I’m looking for, presumably because I’m not looking for the right terms.
I have Pixelmator and Pixelmator Pro from the Mac App Store, and I have an iPad Pro if there’s an iOS tool that’s better for this.
Any pointers would be appreciated.
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Circle select tool, invert selection, and delete should let you save it as a png with transparency outside the circle.
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Exactly.
For clarity, this means you have a square image with a transparent ‘border’.
I use Preview for this.
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For completeness, what app would you do this in?
Any image editing app can do it. I’ve typically used Photoshop, Pixelmator and Affinity Photo. @GraemeS’ tip to use Preview is an excellent one. I didn’t realize it had Invert Selection and had never tried its circle select before. Just tested, and it works well!
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This is easily accomplished with most image editors.
For example, in Pixelmator Pro:
- Switch to Elliptical Selection Tool (Tools > Select > Elliptical Selection)
- Draw a selection circle that encompasses the circular image. Use the Shift key to make the selection a circle and the alignment guides to position the selection in the centre.
- Invert the selection (Edit > Invert Selection)
- Delete the area outside the circle (Edit > Delete)
- Save the image as a PNG (File > Export, Format: PNG)
Mission accomplished!
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Well, thank you all. That worked pretty well.
I had one issue with the shift+drag to keep the circle shape. It seemed that once I let it go from the initial selection, then I could not get it to maintain it’s circle-ness. I was mostly able to free-hand it, but I wondered if there was a trick to doing “fine adjustments” after the initial selection.
You’re welcome, TJ. Good do hear that worked pretty well.
Once you’ve got a circular selection positioned in the centre of the image (with some help from the alignment guides), you could hold down both Option and Shift and adjust the size of the circular selection using the corner drag handles. Option will resize the selection from the centre and Shift will maintain a circular selection. You can also zoom in on the image to get the level of precision you need.
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This was really cool. Had no idea that you could do this in Preview. This stuff is why I like this forum so much:)
In preview it tells you the dimensions whilst resizing, so adjust horizontally and vertically separately if it is easier and use the numbers to match.
To get it centred, I use the little square pickup/adjustment points to know where center is, then nudge left/right with the arrow keys to get the selection in the right place
(I think, from memory).
One trick I like to do in Pixelmator (Pro) that also works in Photoshop is to select the whole image, and then adjust the selection roundness. It removes the corners for you and you can use this on all sorts of weird shapes! Bonus: use the soften feature to have a soft fade from white (or whichever colour) to transparent too.
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