If you have set your design resolution and content scale right then you will not have scaling issues in retina devices.
Design resolution is the base resolution for which you have designed your app.
eg: if i want my apps to run on 2 devices say 480X320 and 960X640, then i will design my entire app for one of them ie., let’s say 480X320. So this will be my design resolution.
Now i can set my content scale based on this i.e, for devices with 480X320 my content scale will be (480/designWidth) or (320/designHeight) i.e 1.
and for retina devices it will be (960/designWidth) = 2.
It does not matter what your design resolution is just select one and stick with it. Just dont randomize design resolution based on your current Window width and height.
and what kresolutionborder is?
kresolutionBorder is used by the framework to determine whether images must be stretched to fit the screen or not. it works exactly as mention in the wiki -
Exact fitThe entire application is visible in the specified area without trying to preserve the original aspect ratio. Distortion can occur, and the application may appear stretched or compressed.
No borderThe entire application fills the specified area, without distortion but possibly with some cropping, while maintaining the original aspect ratio of the application.
Show allThe entire application is visible in the specified area without distortion while maintaining the original aspect ratio of the application. Borders can appear on two sides of the application.