seabird is a Vim and terminal theme based on hue 204 .
- gui (Linux/Windows GVim, MacVim, Neovim) + terminal + true (24-bit) colour
- mathematically derived, incorporating two contrast ratio standards (ISO 'standard' 3:1, W3C 'AA-accessible' 4½:1)
- four variants
seabird variants |
light theme |
dark theme |
high-saturation |
seagull | petrel |
low-saturation |
grey gull | storm petrel |
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Download the desired colourscheme files and place in directory ~/.vim/colors/
(Linux/Mac) or %userprofile%\vimfiles\colors\
(Windows).
For easy management of Vim colour schemes (and other plugins), try a plugin manager. With vim-plug, for instance, just add Plug 'nightsense/seabird'
to the list of plugins in vimrc
, then run PlugUpdate
.
To activate the seagull theme, add colorscheme seagull
to the vimrc
file. Choose from among seagull
, greygull
, petrel
, and stormpetrel
.
For Neovim, add set termguicolors
to enable truecolour support.
To switch automatically between a 'day theme' and 'night theme', try the night-and-day plugin.
In order for seabird to work properly in terminal Vim, set the terminal's colours to match those of the active Vim theme.
As of now, this repository provides the following terminal configuration files:
Xresources
files for xterm and urxvt (Linux)gsettings
'command blocks' for pantheon-terminal (elementary OS).terminal
files for terminal.app (OSX).itermcolors
files for iTerm2 (OSX)
For gnome-terminal, see this repository.
Configuration files for other terminals may be added if requested.
- a sky blue colour was desired
- at 100% saturation and value, hue 204 features 3:1 contrast ratio (the ISO standard) with a white background
The base colours, which are shared by the light and dark versions of seabird, were selected using the hue/saturation/value model of colour definition.
First, all base colours were assigned hue 204.
Second, saturation levels were assigned. The lightest colour, seagrey8, was assigned 0. For the remaining colours, an excerpt of the Fibonacci sequence was applied.
base colour | role | hue ° | saturation % |
---|---|---|---|
seagrey1 | regular background (petrel) | 204 | 55 |
seagrey2 | highlighted background (petrel) | 204 | 34 |
seagrey3 | subdued text (petrel) | 204 | 21 |
seagrey4 | regular text (seagull) | 204 | 13 |
seagrey5 | regular text (petrel) | 204 | 8 |
seagrey6 | subdued text (seagull) | 204 | 5 |
seagrey7 | highlighted background (seagull) | 204 | 3 |
seagrey8 | regular background (seagull) | 204 | 0 |
Third, value levels were assigned. seagrey8 was set to 100% value. The rest were assigned values based on contrast ratios with other base colours.
this colour was assigned... | ...this value... | ...to meet this contrast ratio... | ...with this colour |
---|---|---|---|
seagrey1 | 10 | 18½:1 | seagrey8 |
seagrey2 | 17 | 1⅕:1 | seagrey1 |
seagrey3 | 48 | 3:1 | seagrey2 |
seagrey4 | 49 | 4½:1 | seagrey8 |
seagrey5 | 51 | 4½:1 | seagrey1 |
seagrey6 | 53 | 3:1 | seagrey7 |
seagrey7 | 93 | 1⅕:1 | seagrey8 |
seagrey8 | 100 | - | - |
- the 18½:1 ratio ensures a 10% value background for the dark theme: a "soft black" good for long-term readability
- the 1⅕:1 ratio provides background highlights that stand out clearly from the regular background
- the 3:1 ratio ensures that subdued text on highlighted background is ISO "standard" readable
- the 4½:1 ratio ensures that regular text on regular background is W3C "AA accessible" readable
The resulting colours:
Accent colour hues were selected from around the (30°-divided) colour wheel: hue 204 plus seven companions.
colour | hue ° | contrast level |
---|---|---|
red | 354 | high |
orange | 24 | medium |
yellow | 54 | low |
green | 114 | low |
teal | 174 | low |
blue | 204 | medium |
purple | 264 | high |
pink | 324 | high |
All hues were initially set to 100% saturation and value. Then:
- the low-contrast colours were reduced in value (yellow by ¼, green and teal by ⅓)
- the high-contrast colours were reduced in saturation (red by ¼, purple and pink by ⅓)
- the mid-contrast colours (orange and blue) were left alone
The goal contrast ratio was 3:1 (the ISO standard), prompting a few small hue adjustments.
For grey gull, each seagull accent colour was reduced in saturation by 38.2% (by applying the golden ratio), then reduced in value to a contrast ratio of 3:1.
For petrel, each grey gull accent colour was reduced in value to a contrast ratio of 4½:1 (the W3C AA minimum).
For storm petrel, each petrel accent colour was reduced in saturation by 38.2% (by applying the golden ratio), then reduced in value to a contrast ratio of 4½:1.
The seabird colour scheme files are generated by modifying those of the flattened colour scheme by Romain Lafourcade, which is in turn derived from the Solarized colour scheme by Ethan Schnoonover.
Colour adjustment was performed with the GnuIMP colour selection tool. Contrast ratios were calculated with these formulas.
Actual contrast ratios may be slightly higher than those listed, due to discrete jumps in digital colour values.
Photo credits:
- seagull by Dan Hurt, petrel by Duncan (angrysunbird); both licensed CC BY-SA 2.0.
- 'fair weather sea' by Ali West, 'grey skies sea' by Mary (puzzlement); both licensed CC BY 2.0, both colour-adjusted