How to avoid extra band with Sixels - Githubissues

hpjansson / chafa

📺🗿 Terminal graphics for the 21st century.

https://hpjansson.org/chafa/

GNU Lesser General Public License v3.0

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How to avoid extra band with Sixels #222

Open AmaruCoder opened 1 month ago

AmaruCoder commented 1 month ago

Using the option -s, I keep getting a band at one edge of the image. Is this a feature of using Sixels or is it there an option I am missing? See the examples below:

See the green band at the bottom (using -s 50x20):

example1

See the white band on the right (using -s 50x19):

example2

hpjansson commented 1 month ago

What does chafa --version say? We've had a bit of back and forth on sixel transparency, since different terminals handle this differently. I think we finally got it right in version 1.14.3.

AmaruCoder commented 1 month ago

It says:

Chafa version 1.14.4

Loaders:  GIF JPEG PNG QOI SVG TIFF WebP XWD
Features: mmx sse4.1 popcnt avx2
Applying: mmx sse4.1 popcnt avx2

Copyright (C) 2018-2023 Hans Petter Jansson et al.
Incl. libnsgif copyright (C) 2004 Richard Wilson, copyright (C) 2008 Sean Fox
Incl. LodePNG copyright (C) 2005-2018 Lode Vandevenne
Incl. QOI decoder copyright (C) 2021 Dominic Szablewski

This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE

hpjansson commented 1 month ago

Looks like a persistent bug, then. Have you tried -t .01 as a workaround?

hpjansson commented 1 month ago

Also, which terminal are you on?

AmaruCoder commented 1 month ago

Thank you. I tried -t .01 but got the same band. I am using iTerm2 Build 3.5.5.

hpjansson commented 1 month ago

Thanks. I think this is likely specific to iTerm2 output.

AmaruCoder commented 1 month ago

Thank you. My workaround for now is to set the background to black in iTerm2, and use -t 1.0 in Chafa.

hpjansson commented 1 month ago

Ok. This works fine on the terminals I have access to on Linux/Windows, and unfortunately I don't have Mac hardware to test with, but I'll look into getting it installed in a VM. I have a few other things to attend to first, though.

In the meantime I have two questions for you:

Do transparent sixels from other programs display fine? E.g. lsix, convert with an image with an alpha channel.
Does your test case display correctly in other terminals you have access to, if any? E.g. Wezterm.

AmaruCoder commented 3 weeks ago

Thank you for the followup. I don't h ave lsix or convert installed, but I have tested it in Wezterm and it works well. In fact Chafa doesn't need sixel in Weztermn.