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This commit adds the default theme used in Emacs' terminal emulator modes (such as `ansi-term`) when running GUI Emacs without any configuration. The colour palette of this theme traces back through a long lineage, starting with the original `rgb.txt` distributed with X11 after its development at MIT. The exact names of who picked which colours here are unknown (people didn't spend as much time on version control 41 years ago), so I have attributed it to Jim Gettys (original X11 developer) & co. In Emacs source code, the colurs can be found in `lisp/term/tty-colors.el`, and are mapped to ANSI colours from there in `lisp/ansi-color.el`. I had to convert them from 16-bit colour space to the 8-bit colour space used by Alacritty (ironic, considering the relative age of the programs!). This was done using some Lisp and Python code which mapped the 16-bit RGB to LAB colour space, and back to 8-bit RGB. I experimented with multiple ways of doing this, and simple rounding or bit-shifting yielded visually unpleasing results, whereas the LAB-match is pretty accurate.
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For comparison (didn't want to put this in the commit message itself), here is a screenshot of the theme in actual Emacs, using the 16-bit colour space:
Versus the Alacritty version:
As you can see, the conversion worked pretty well. |
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But it didn't… Those are clearly different colors, trivially verified by just looking at the images. I'm confused why you went through so much trouble when you can just get the rgb color codes from the images directly. Yellow for example is #cdcd00 in Emacs while being #c0c000 in your theme. |
chrisduerr
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Jul 4, 2025
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This commit adds the default theme used in Emacs' terminal emulator modes (such as
ansi-term) when running GUI Emacs without any configuration.The colour palette of this theme traces back through a long lineage, starting with the original
rgb.txtdistributed with X11 after its development at MIT. The exact names of who picked which colours here are unknown (people didn't spend as much time on version control 41 years ago), so I have attributed it to Jim Gettys (original X11 developer) & co.In Emacs source code, the colurs can be found in
lisp/term/tty-colors.el, and are mapped to ANSI colours from there inlisp/ansi-color.el.I had to convert them from 16-bit colour space to the 8-bit colour space used by Alacritty (ironic, considering the relative age of the programs!).
This was done using some Lisp and Python code which mapped the 16-bit RGB to LAB colour space, and back to 8-bit RGB. I experimented with multiple ways of doing this, and simple rounding or bit-shifting yielded visually unpleasing results, whereas the LAB-match is pretty accurate.