Apple is known for using odd screen resolutions for it’s iPhone screens, save for the first generation which debuted with a 3.5″ display with 320 x 480 pixels resolution.
An Xcode 6 SDK file alleged to be belonging to the upcoming iPhone 6 has revealed the device will have a 828 x 1472 pixels screen. So the physical 4.7″ size will work out with the above to get us at a 360 PPI.
The Apple iPhone 5s, iPhone 5c and their predecessor, the iPhone 5, all employed 640 x 1136 pixels displays, and that’s quite different from the resolutions on most flagship smartphones at their time.
Take for example, the Samsung Galaxy S5, the Galaxy S4 and the Galaxy Note 3 all had 1080 x 1920 pixels. The next wave of updates saw the LG G3 coming out a screen that measure 1440 x 2560 pixels and the Samsung Galaxy S5 LTE-A and (coming soon) Note 4 followed suit.
Most phones in the smartphone ecosystem (especially on Android) bear qVGA (320×240), WVGA (480×800 ) , FWVGA (480×854), qHD (540×960), HD (720×1280), FullHD (1080×1920) or QHD (1440×2560) screens.
However, Apple doesn’t ‘obey’ the rules because apps for Apple smartphones are developed exclusively for iOS devices and thus does not share compatibility with other phones’ displays.