Per aspera ad cross-platform. Porting a WPF app to Avalonia

Since 2017, we have been developing the WPF Lunacy vector editor, and there was a task to move to the Windows + macOS + Linux cross-platform. We've chosen Avalonia. The port took half a year. It was a serious test. I'll tell you how to make a port step by step, which pitfalls are on the way, and how to get around them. Is Avalonia production-ready? We'll touch on the problems of publishing applications, including stores and the limitations of the WebAssembly platform.