fzf sixel support on Windows

[FallenGameR]

Checklist

• [x] I have read through the manual page (man fzf)
• [x] I have searched through the existing issues
• [x] For bug reports, I have checked if the bug is reproducible in the latest version of fzf

Output of fzf --version

0.62.0 (d226d841)

OS

• [ ] Linux
• [ ] macOS
• [x] Windows
• [ ] Etc.

Shell

• [ ] bash
• [ ] zsh
• [ ] fish

Problem / Steps to reproduce

I think this is the same bug as https://github.com/junegunn/fzf/issues/3682, but I can add more context and it is not really related to Wezterm / bash. Looks like it is just the way how fzf processes sixels on Windows. And there is a working go code that can do it =)

Repro in pwsh 7.5.1, WindowsTerminal 1.22.11141:

# no sixels
".\wallpapersden.com_curse-by-wlof_1920x1080.jpg" | fzf --preview "chafa {}"

# with sixels
".\wallpapersden.com_curse-by-wlof_1920x1080.jpg" | fzf --preview "chafa {} -f sixel --passthrough auto"

# Chafa sixels work
chafa .\wallpapersden.com_curse-by-wlof_1920x1080.jpg -f sixel --passthrough auto

What makes it interesting is that another TUI tool written in Go actually can render sixels on Windows. https://github.com/gokcehan/lf

» bat C:\Users\alexk\AppData\Local\lf\lfrc
───────┬─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
       │ File: C:\Users\alexk\AppData\Local\lf\lfrc
───────┼─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
   1   │ set previewer C:\\Users\\alexk\\Documents\\Powershell\\Data\\Winget\\preview.bat
   2   │ set sixel
───────┴─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
» bat C:\Users\alexk\Documents\Powershell\Data\Winget\preview.bat
───────┬─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
       │ File: C:\Users\alexk\Documents\Powershell\Data\Winget\preview.bat
───────┼─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
   1   │ @chafa.exe -f sixel --passthrough auto %*
───────┴─────────────────────────────────────────────────────────────────────────────────────────
» lf

[georgejean]

Related to issue #3995. As a workaround, you can specify the --height option with fzf and adjust the --view-size parameter for chafa. For instance, use --preview='chafa --view-size=18 -f sixel input.jpg'.

[junegunn]

Thanks @georgejean for linking the issue.

So we can either fix #3799 in LightRenderer and drop the tcell renderer, or extend the tcell renderer to support image rendering. Since I'm not a Windows user and lack expertise in the platform, I probably won't be working on either, but pull requests are welcome.

[FallenGameR]

Thanks! @georgejean, turns out using fzf --height (that forces using LightRenderer) is enough, no need to specify --view-size in chafa:

[DanSM-5]

I've been previewing images with chafa in windows terminal since I learned about it supports sixels protocol. The final command I came up with is this:

$height = $env:FZF_PREVIEW_LINES
$width = $env:FZF_PREVIEW_COLUMNS
chafa -f sixels --colors=full --polite=on --animate=off -s "${width}x${height}" ./path/to/image