We do this kinda thing with Sketch and iOS for all assets (including app icons). We also do font styling, colors, gradients etc from Sketch to a styling plist.

We do this kinda thing with Sketch and iOS for all assets (including app icons). We also do font styling, colors, gradients etc from Sketch to a styling plist. Kinda annoying to set up, but it's a godsend for styling updates and whitelabeling.