Add progress option to Vtracer

[zamazan4ik]

Hi!

I found that Vtracer performs conversion too slowly on this sample: https://sample-videos.com/download-sample-jpg-image.php , 30 Mib image with the following command: vtracer --input input_30mib.jpg --output output.svg. Vtracer is built locally with cargo build --release with Rust 1.74 on the latest master branch, commit 74f2a04a17d8c246d80c439fb162780160a7c3e9. It took 2341.102 s [User: 2291.374 s, System: 42.931 s] to convert the image (according to Hyperfine) even on my quite good AMD Ryzen 5900x with 48 Gib RAM (no swapping) I guess it's not an internal bug - just the input image is quite large to convert.

From the user perspective, it would be nice to have an option to track the conversion progress somehow. So I will be able to estimate the finish time and check that Vtracker doesn't stuck and works properly.

[tyt2y3]

What's the resolution of the image? The pipeline is not parallelized, so it is bound to 1 CPU core.

[zamazan4ik]

The image resolution is 13583  x  5417 (quite large, yeah). Yes, I see that Vtracer is bound to 1 CPU. I am not complaining a lot about the conversion speed (however having a faster conversion is always better) - I just want to have the ability to track the progress of the conversion process.

[tyt2y3]

73MP is not that bad. If you tile the image, it can easily be parallalized. The web GUI has a progress bar, may be you can take a look into how it calculates the progress and port the bits into the CLI.