iPhone 6 Plus Display Zoom Rendering

Ole Begemann on iPhone 6 Plus display zoom feature:

“With Display Zoom enabled, an iPhone 6 Plus effectively behaves as if it had the same logical resolution as the iPhone 6 (375 × 667 points). Output is first rendered into a 1125 × 2001 pixel backing store (at 3× scale) and finally downsampled to fit the 1080 × 1920 pixel screen resolution.”

After a series of tests with OpenGL and 1080p video:

“My tests show that activating Display Zoom on the 6 Plus has no discernible negative or positive effect on output quality.”