No transparent background in sixel

[niksingh710]

General description of bug:

• What happened: if using sixel to show image then it is rendering a black background instead of transparent one
• What should happen: should render a transparent background
• Where did you get the binary: Arch linux (Aur)

in the image the first one is with --logo that is using symbols.

I can confirm that rendering sixel using chafa renders transparent background in terminal but in fastfetch it renders black bg.

[CarterLi]

sixel doesn't seem to support transparent pixels. There are opening PRs in the fork repo but never got merged.

You should try other image protocols

[niksingh710]

don't know why but for me

if using chafa with sixel the bg is transparent. terminal i am using is foot and tmux as multiplexer and Arch linux is the distro.

[CarterLi]

Try changing the terminal background now?

[niksingh710]

@CarterLi

[CarterLi]

Please paste the result of chafa -f sixels out.png > out.sixel here

I can confirm the behavior with foot, but not konsole and iterm...

[niksingh710]

Please paste the result of chafa -f sixels out.png > out.sixel here

I can confirm the behavior with foot, but not konsole and iterm...

yep maybe the foot implementation of sixel includes patches for the bg transparency.
i am just unsure why fastfetch is rendering background is there any way that can be avoided?

[CarterLi]

Chafa uses its own sixel image convertion implementation, while fastfetch uses imagemagick. Imagemagick doesn't support transparent background for sixel and simply convert transparent pixels to black.

It's possible for fastfetch to use chafa for sixel image generation, but it seems that a lot of terminals don't support transparent backgrounds for sixel image and render a weird bg color. I don't think it's the time of switching.

It's still possible to use transparent background logos:

$ chafa -s WxH out.png > out.sixel
$ fastfetch --raw out.sixel --logo-width W --logo-height H --logo-padding-top 2 # There is a bug that makes fastfetch crash if --logo-padding-top is not set

[niksingh710]

this hack works......

[emilrueh]

no matter what I do. the command $ fastfetch --raw out.sixel --logo-width W --logo-height H --logo-padding-top 2 # There is a bug that makes fastfetch crash if --logo-padding-top is not set does set the logo and it is in-fact transparent but alway in a size that essentially covers the entire terminal.

Neither setting the width and height in the command, nor in the config changes anything about it.

Also changing the image size to something smaller and re-running it through chafa changes anything, except for it now being massive and in rendered in terrible resolution.

[Bloody-Omen]

no matter what I do. the command $ fastfetch --raw out.sixel --logo-width W --logo-height H --logo-padding-top 2 # There is a bug that makes fastfetch crash if --logo-padding-top is not set does set the logo and it is in-fact transparent but alway in a size that essentially covers the entire terminal.

Neither setting the width and height in the command, nor in the config changes anything about it.

Also changing the image size to something smaller and re-running it through chafa changes anything, except for it now being massive and in rendered in terrible resolution.

did you find any solution for it later on? having the same issue

[emilrueh]

I don't think I have and just went with ascii instead :)

[j4james]

If you're using --raw out.sixel, note that the size of the image is controlled entirely by the tool that created that out.sixel file. For example chafa -f sixel -s 40x20 out.png > out.sixel should create an image no wider than 40 columns, and no taller than 20 rows. If you leave off the > out.sixel you can see exactly what it's going to look like before trying to integrate it in fastfetch.

Once you've got chafa producing the image at the right size, you'll also then need to pass the image dimensions to fastfetch so it can correctly position the text relative to that image. For example, if your image is exactly 40x20, then you'd use something like fastfetch --raw out.sixel --logo-width 40 --logo-height 20.

However, be aware that the image produced by chafa may not exactly match the dimensions you requested in the -s parameter, since it tries to to maintain the aspect ratio. So you may still need to tweak the --logo-width and --logo-height parameters if the text ends up in the wrong place.

If you can't even get chafa to produce an image at the right size, then that's not a fastfetch problem. That may be an issue with your terminal or OS. Also make sure you're using the most recent version of chafa.