How to display images on DLP using HDMI for 3D printing?
Q1: Printrun is 3D printer host software written in Python with limited DLP support. You can checkout how it display layers.
NanoDLP directly talk to GPU through Dispmanx which makes it Raspberry Pi only. 

Q2: Printrun supports SVG. To convert SVG (multi-layer) to PNG you can use ImageMagick cli tools, you should consider your projector resolution too.