I run a test with my setup. And I found mixed results.
With the MBPr 15.4-inch LCD set as a
mirror to a 27-inch 4K UHD display: letter boxing
- If the mirror is optimized to the 15.4 inch panel, I do get vertical letterboxing on the 27-inch display.
- If the mirror is optimized to the 27-inch display, I do get horizontal letterboxing on the 15.4-inch display.
With the 27-inch panel set as an
extended display (
not a mirror): no letter boxing.
I just do not understand how that works, then, as the virtual space (programmer's space) has a 16:10 aspect ratio, and I did get letter boxing when mirroring.
Maybe you can explain. Thanks.