What should be the dimensions of the design layout for the iphone?

Question

iOS

Good afternoon. I want to clarify, if you make a design for iphone 5-7 models, you need to make an artboard 320x568px for 5 and export to 2x = 640x1136px. For 6,6s and 7ki 375x667px and export to 2x and 3x= 750x1334px. For 6s, 6s plus360x640px=1080x1920px. Those. It turns out 3 separate layouts. I understood correctly. And if you made one layout in one resolution of 750x1334px, will the developers adjust the dimensions themselves with the code?

Answer 1

You just need to take into account the multiplicity and draw in a resolution that is more comfortable.
Then you export it to the sizes the developers need. They usually say for themselves what they will sharpen and in what form they will give it.
At the output, you give psd to understand fonts, colors and sizes, and export graphics to svg.
Directly ask the developers for what devices they will make.

Answer 2

viewport and ppi apparently need to google