What is the unit for the screensize returned by Appium

Hello guys,

I am using Appium’s JavaScript client to write tests.

I tried to use driver.getWindowSize() to determine the screen size of the device.

On Android for example Nexus 6P, it returns 1440 for the width which is pixel and it is correct.
On iOS for example iPhone 6s Plus, however, it returns 414 for the width which dose not seem to be pixel as iPhone 6s Plus is 1080 pixel for the width.

Any ideas how could I get the screen size of the device under test?