In the decade I spent working on RenderMan at Pixar, I learned just how immensely useful it was to have an image viewer running in a separate process talking to

In the decade I spent working on RenderMan at Pixar, I learned just how immensely useful it was to have an image viewer running in a separate process talking to the renderer over a socket or pipe. (The Image Tool, or "It" is RenderMan's viewer.) Having it stay up even if you kill the render or it crashes for some reason and being able to flip back and forth to easily compare test renders across recompiles is game changing. If I were to start writing a new renderer, the first thing I'd do is to hook it up to an external image viewer over some protocol. These days, I find myself liking TEV (https://github.com/Tom94/tev https://github.com/Tom94/tev) a lot as a simple open-source image viewer that supports this and most other basic features that I'd want. See the links in the README for Python and Rust implementations of its protocol.