| *dev_theme.txt* Nvim | |
| NVIM REFERENCE MANUAL | |
| Nvim colorscheme guidelines *dev-theme* | |
| Style guidelines for developing Nvim's default colorscheme. | |
| License: CC-By 3.0 https://creativecommons.org/licenses/by/3.0/ | |
| Type |gO| to see the table of contents. | |
| ============================================================================== | |
| Design | |
| - Be "Neovim branded", i.e. have mostly "green-blue" feel plus one or two | |
| colors reserved for very occasional user attention. | |
| - Be oriented for 'termguicolors' (true colors) while being extra minimal for | |
| 'notermguicolors' (16 colors) as fallback. | |
| - Be accessible, i.e. have high enough contrast ratio (as defined in | |
| https://www.w3.org/TR/2008/REC-WCAG20-20081211/#contrast-ratiodef). | |
| This means to have value at least 7 for |hl-Normal| and 4.5 for some common | |
| cases (|hl-Visual|, `Comment` with set 'cursorline', colored syntax, `Diff*`, | |
| |hl-Search|). | |
| - Be suitable for dark and light backgrounds via exchange of dark and light | |
| palettes. | |
| - Be usable, i.e. provide enough visual feedback for common objects. | |
| ============================================================================== | |
| Palettes | |
| - There are two separate palettes: dark and light. They all contain the same | |
| set of colors exported as `NvimDark*` and `NvimLight*` colors respectively. | |
| - The dark palette is used for background in the dark color scheme and for | |
| foreground in the light color scheme; and vice versa. This introduces | |
| recognizable visual system without too standing out. | |
| - Actual computation of palettes should be done in a perceptually uniform | |
| color space. Oklch is a good choice. | |
| - Each palette has the following colors (descriptions are for dark background; | |
| reverse for light one): | |
| - Four shades of colored "cold" greys for general UI. | |
| - Dark ones (from darkest to lightest) are reserved as background for | |
| |hl-NormalFloat| (considered as "black"), |hl-Normal| (background), | |
| |hl-CursorLine|, |hl-Visual|. | |
| - Light ones (also from darkest to lightest) are reserved for | |
| `Comment`, |hl-StatusLine|/|hl-TabLine|, |hl-Normal| (foreground), | |
| and color considered as "white". | |
| - Six colors to provide enough terminal colors: red, yellow, green, cyan, | |
| blue, magenta. | |
| They should have (reasonably) similar lightness and chroma to make them | |
| visually coherent. Lightness should be as equal to the palette's basic grey | |
| (which is used for |hl-Normal|) as possible. They should have (reasonably) | |
| different hues to make them visually separable. | |
| - For 16 colors: | |
| - Greys are not used and are replaced with the foreground and background | |
| colors of the terminal emulator. | |
| - Non-grey colors fall back to terminal colors as ordered in ANSI codes | |
| (https://en.wikipedia.org/wiki/ANSI_escape_code#3-bit_and_4-bit), | |
| that is red (1, 9), green (2, 10), yellow (3, 11), blue (4, 12), | |
| magenta (5, 13), cyan (6, 14). | |
| To increase contrast, colors 1-6 are used for light background and 9-14 | |
| for dark background. | |
| ============================================================================== | |
| Highlight groups | |
| Use: | |
| - Grey shades for general UI according to their design. | |
| - Bold text for keywords (`Statement` highlight group). This is an important | |
| choice to increase accessibility for people with color deficiencies, as it | |
| doesn't rely on actual color. | |
| - Green for strings, |hl-DiffAdd| (as background), |hl-DiagnosticOk|, and some | |
| minor text UI elements. | |
| - Cyan as main syntax color, i.e. for function usage (`Function` highlight | |
| group), |hl-DiffText|, |hl-DiagnosticInfo|, and some minor text UI elements. | |
| - Red to generally mean high user attention, i.e. errors; in particular for | |
| |hl-ErrorMsg|, |hl-DiffDelete|, |hl-DiagnosticError|. | |
| - Yellow very sparingly to mean mild user attention, i.e. warnings. That is, | |
| |hl-DiagnosticWarn| and |hl-WarningMsg|. | |
| - Blue very sparingly as |hl-DiagnosticHint| and some additional important | |
| syntax group (like `Identifier`). | |
| - Magenta very carefully (if at all). | |
| In case of 16 colors: | |
| - Rely on the assumption "Background color can be used as background; other | |
| colors can be used as foreground". This means that in any | |
| foreground/background combination there should be background and one | |
| non-background color. | |
| - Use 0 (black) or 15 (bright white) as foreground for non-grey background, | |
| depending on whether normal background is light or dark. | |
| vim:tw=78:ts=8:et:ft=help:norl: | |