So I'm just testing some screenshots through elgato, and when my roku is 1080p, the home screen icons are not 290x218, but come out to 295x223 when I zoom in and find the outline, does anyone see similar?
You sizes are ~2% bigger, i bet that's because of overscan!
Don't know how that's happening between Roku and your capturer, are there any settings in said Elgato? Is this over HDMI?
To test, draw rectangle at the very edge of the screen, (0,0) - (maxX, maxY) - and see if these get clipped in the capture. If my suspicion is right, then ~1% of your programmatic screen is being chopped at each side and image gets zoomed by ~2% to fill in.
How did you measure 290x218?
Sharing my exact methodology would be embarassing, so i won't :P