I've left the SPECTRE_CONSOLE_DEBUG env var in there because I found it easier to visualize the dimensions of the sixel data and how they lined up to character cells positioning. When you set that it will render a canvas checkerboard overtop of the sixel data.

I used cursor-right control codes to simulate transparent pixels in the canvas which breaks the snapshot tests for canvas rendering. Using those characters could be only under sixel rendering circumstances but I'm not sure how @patriksvensson wanted to reorganize this so they're still broken atm.

I'll take a look at this asap

I think there might be opportunities for some interesting use cases for the Sixel output independent of ImageSharp. Might be cool if the parsing and building of the ansi was part of Spectre.Console itself with the code to convert an ImageSharp frame being the only code with dependencies on ImageSharp.

@phil-scott-78 Yes, that was my initial idea as well, but quickly realized that it's a pretty daunting task without a library behind it. Open to refactor it out later, and make it available without the ImageSharp library, but for now I think it's ok.