iOS Swift first app having UI and primary window exhibiting manually generated buffer (not a picture)

I’m a beginner to iOS Swift improvement and need to write an utility that has UI and exhibits buffers of manually generated photos. Take into consideration medical utility having UI and displaying photos generated some other place on the identical machine.

The place can I discover some code pattern for related job demonstrating

1. primary rendering window definition
2. definition of rendering thread (with manually triggered replace)
3. pushing the calculated buffer (“bitblit”-ing) to primary rendering window?

I’m skilled in C++ and OpenCL, have some expertise in graphics (OpenGL), making an attempt to construct my first iOS Swift utility for medical functions.