Hey there, I tried my best to make a ruler stencil for the s10+ I just got this week. I was just eyeballing it, so it may not be perfect. It looked like an image was displayed on the s10+ a bit differently sometimes.
This image is made to account for the corners that don’t get seen in full screen.
This cutout should be pretty close. About one pixel off of showing a white sliver on the edges, and showing one pixel of the cutout pill shape.
The pixel resolution is 1440 x 3040. Make a rectangle that size and place it in the center. Then give it a 110px corner radius, what you see is what gets displayed. The pill-shaped rectangle is 248 x 107px.
Place it at coordinates x: 1116px y: 34px. Then give it a corner radius of 52px.
I made this for people who like to customize their phone wallpapers. If you find a more exact measurement, let me know and I’ll post your suggestions. Thanks, I hope this is helpful if you found it.