Good i3blocks Powerline: good_i3blocks_powerline.png
Bad i3blocks Powerline: bad_i3blocks_powerline.png (not mine)
Notice in the bad one, the entire bar has like a 3px margin on top and bottom, which is very uncool. My hack removes that margin so it's a proper Powerline.
You'll obviously need pango formatting for this to work. In your i3blocks.conf change/add these lines at the top of the file:
markup=pango
full_text="<span font-family='Source Code Pro' size='16000'> </span>"
separator=false
separator_block_width=0Then add [separator] in every place that you want to show a separator.
Change the font-family too:
If you're using a patched font for the entire bar i think it'll work if you set the same font for this.
If the font isn't patched you'll have to find a patched font with the same size as the one in your i3bar config. For bitmap fonts there's Tamzen and Terminus, and for vector fonts there's a zillion Nerd Fonts
Note : I found Terminus to work with any font size, so, try that one first if you're going with bitmap fonts, and just keep trying to adjust the size parameter until you find something that works. For example, for ProFont size 8 i put size='14000'
It's also possible to patch the font by yourself but it's hardd
Eye candy
To make eye candy, you can just copy the full_text variable after any [separator] and change the things you want like fgcolor or bgcolor. See Pango Markup manual
[separator]
full_text="<span font-family='Terminus' bgcolor='#0000FF' fgcolor='#00FF00' size='16000'></span>"Lastly to remove the 1px margin add this: (put in the top to apply globally)
background="#FF0000"
border="#0000FF"
border_top=30
border_bottom=30
border_right=0
border_left=0Tadaaa.png (the red line is i3 border)
Credits to Rebbit user riiskyy for enlightening me on the global setting