mini-colors.txt

*mini.colors* Tweak and save any color scheme
*MiniColors*

MIT License Copyright (c) 2023 Evgeni Chasnovski

==============================================================================

Features:
- Create colorscheme object: either manually (|MiniColors.as_colorscheme()|)
  or by querying present color schemes (including currently active one; see
  |MiniColors.get_colorscheme()|).

- Infer data about color scheme and/or modify based on it:
    - Add transparency by removing background color (requires transparency
      in terminal emulator).
    - Infer cterm attributes (|cterm-colors|) based on gui colors making it
      compatible with 'notermguicolors'.
    - Resolve highlight group links (|:highlight-link|).
    - Compress by removing redundant highlight groups.
    - Extract palette of used colors and/or infer terminal colors
      (|terminal-config|) based on it.

- Modify colors to better fit your taste and/or goals (see more in
  |MiniColors-colorscheme-methods|):
    - Apply any function to color hex string.
    - Update channels (like lightness, saturation, hue, temperature, red,
      green, blue, etc.; see more in |MiniColors-channels|).
      Use either own function or one of the implemented methods:
        - Add value to channel or multiply it by coefficient. Like "add 10
          to saturation of every color" or "multiply saturation by 2" to
          make colors more saturated (less gray).
        - Invert. Like "invert lightness" to convert between dark/light theme.
        - Set to one or more values (picks closest to current one). Like
          "set to one or two hues" to make mono- or dichromatic color scheme.
        - Repel from certain source(s) with stronger effect for closer values.
          Like "repel from hue 30" to remove red color from color scheme.
          Repel hue (how much is removed) is configurable.
    - Simulate color vision deficiency.

- Once color scheme is ready, either apply it to see effects right away or
  write it into a Lua file as a fully functioning separate color scheme.

- Experiment interactively with a feedback (|MiniColors.interactive()|).

- Animate transition between color schemes either with |MiniColors.animate()|
  or with |:Colorscheme| user command.

- Convert within supported color spaces (|MiniColors.convert()|):
    - Hex string.
    - 8-bit number (terminal colors).
    - RGB.
    - Oklab, Oklch, Okhsl (https://bottosson.github.io/posts/oklab/).

Notes:
- There is a collection of |MiniColors-recipes| with code snippets for some
  common tasks.
- There is no goal to support as many color spaces as possible, only the
  already present ones.

Tweak quick start ~

- Execute `:lua require('mini.colors').interactive()`.

- Experiment by writing calls to exposed color scheme methods and applying
  them with `<M-a>`. For more information, see |MiniColors-colorscheme-methods|
  and |MiniColors-recipes|.

- If you are happy with result, write color scheme with `<M-w>`. If not,
  reset to initial color scheme with `<M-r>`.

- If only some highlight groups can be made better, adjust them manually
  inside written color scheme file.

# Setup ~

This module doesn't need setup, but it can be done to improve usability.
Setup with `require('mini.colors').setup({})` (replace `{}` with your
`config` table). It will create global Lua table `MiniColors` which you can
use for scripting or manually (with `:lua MiniColors.*`).

See |MiniColors.config| for `config` structure and default values.

This module doesn't have runtime options, so using `vim.b.minicolors_config`
will have no effect here.

# Comparisons ~

- 'rktjmp/lush.nvim':
    - Oriented towards tweaking separate highlight groups, while 'mini.colors'
      is more designed to work with color scheme as a whole.
    - Uses HSL and HSLuv color spaces, while 'mini.colors' uses Oklab, Oklch,
      and Okhsl which have slightly better perceptual uniformity properties.
    - Doesn't have functionality to infer and repair missing data in color
      scheme (like cterm attributes, terminal colors, transparency, etc.),
      while 'mini.colors' does.
    - Doesn't implement animation of color scheme transition, while
      'mini.colors' does.
- 'lifepillar/vim-colortemplate':
    - Comparisons are similar to that of 'rktjmp/lush.nvim'.
- 'tjdevries/colorbuddy.nvim':
    - Comparisons are similar to that of 'rktjmp/lush.nvim'.

------------------------------------------------------------------------------
                                                            *MiniColors-recipes*
Recipes for common tasks ~

All following code snippets assume to be executed inside interactive buffer
(|MiniColors.interactively()|). They are directly copy-pasteable.

To apply single method to current color scheme, use >
  :lua MiniColors.get_colorscheme():<method goes here>:apply().

Recipes:
- Tweak lightness: >

  -- Invert dark/light color scheme to be light/dark
  chan_invert('lightness', { gamut_clip = 'cusp' })

  -- Ensure constant contrast ratio
  chan_set('lightness', 15, { filter = 'bg' })
  chan_set('lightness', 85, { filter = 'fg' })

- Tweak saturation: >

  -- Make background colors less saturated and foreground - more
  chan_add('saturation', -20, { filter = 'bg' })
  chan_add('saturation', 20,  { filter = 'fg' })

  -- Convert to grayscale
  chan_set('saturation', 0)

- Tweak hue: >

  -- Create monochromatic variant (this uses green color)
  chan_set('hue', 135)

  -- Create dichromatic variant (this uses Neovim-themed hues)
  chan_set('hue', { 140, 245 })

- Tweak temperature: >

  -- Invert temperature (make cold theme become warm and vice versa)
  chan_invert('temperature')

  -- Make background colors colder and foreground warmer
  chan_add('temperature', -40, { filter = 'bg' })
  chan_add('temperature', 40,  { filter = 'fg' })

- Counter color vision deficiency (try combinations of these to see which
  one works best for you):

    - Improve text saturation contrast (usually the best starting approach): >

      chan_set('saturation', { 10, 90 }, { filter = 'fg' })
<
    - Remove certain hues from all colors (use 30 for red, 90 for yellow,
      135 for green, 270 for blue): >

      -- Repel red color
      chan_repel('hue', 30, 45)
<
    - Force equally spaced palette (remove ones with which you know you
      have trouble): >

      -- Might be a good choice for red-green color blindness
      chan_set('hue', { 90, 180, 270})

      -- Might be a good choice for blue-yellow color blindness
      chan_set('hue', { 0, 90, 180 })
<
    - Inverting temperature or pressure can sometimes improve readability: >

      chan_invert('temperature')
      chan_invert('pressure')
<
    - If all hope is lost, hue random generation might help if you are lucky: >

      chan_modify('hue', function() return math.random(0, 359) end)
<
- For color scheme creators use |MiniColors-colorscheme:simulate_cvd()| to
  simulate various color vision deficiency types to see how color scheme
  would look in the eyes of color blind person.

------------------------------------------------------------------------------
                                                       *MiniColors-color-spaces*
Color space is a way to quantitatively describe a color. In this module
color spaces are used both as source for |MiniColors-channels| and inputs
for |MiniColors.convert()|

List of supported color spaces (along with their id in parenthesis):
- 8-bit (`8-bit`) - integer between 16 and 255. Usually values 0-15 are also
  supported, but they depend on terminal emulator theme which is not reliable.
  See https://en.wikipedia.org/wiki/ANSI_escape_code#8-bit .

- Hex (`hex`) - string of the form "#xxxxxx" where `x` is a hexadecimal number.

- RGB (`rgb`) - table with numeric fields `r` (red), `g` (green), `b` (blue).
  Visible range is from 0 to 255.

- Oklab (`oklab`) - table with fields `l` (lightness; numeric in [0; 100]),
  `a`, `b` (both are unbounded numeric; visible range is usually between
  -30 to 30). Field `l` describes how light is color; `a` - how "green-red" it is;
  `b` - how "blue-yellow" it is.

- Oklch (`oklch`) - table with fields `l` (same as in Oklab),
  `c` (chroma; positive numeric, visible range usually lower than 32),
  `h` (`nil` for grays or periodic numeric in [0, 360)). Field `c` describes how
  colorful a color is; `h` is a value of "true color" on color circle/wheel.
  NOTE: gray colors, being achromatic by nature, don't have hue.

- Okhsl (`okhsl`) - Oklch but with `c` replaced by `s` (saturation; numeric
  in [0; 100]). Field `s` describes a percent of chroma relative to maximum
  visible chroma for the particular lightness and hue combination. Note,
  that mathematical model used to compute maximum visible chroma is
  approximate which might lead to inaccuracies for highly saturated colors
  with relatively low or high lightness.

Sources for Oklab/Oklch/Okhsl:
- https://bottosson.github.io/posts/oklab/ - initial derivation and
  introduction of Oklab and Oklch.
- https://bottosson.github.io/misc/colorpicker - interactive color picker.
  Great way for a hands-on introduction to concepts of lightness, chroma,
  saturation, and hue.

                                                         *MiniColors-gamut-clip*
Gamut clip ~

In Neovim highlight group colors are usually specified by their red, green,
and blue values from 0 to 255 in the form of HEX string (see |gui-colors|).
Although plenty, these are not all possible colors.

When performing color manipulation using |MiniColors-colorscheme-methods|,
it is possible to end up with "impossible" color (which can't be directly
converted to HEX string). For example, inverting lightness of color "#fce094"
will lead to a color `{ l = 10, c = 10, h = 90 }` in Oklch space, i.e.
"dark yellow" which is impossible to show in HEX.

**Gamut clipping** is an action of converting color outside of visible gamut
(colors representable with HEX string) to be inside it while preserving
certain perceptual characteristics as much as possible.

Gamut clipping in this module is done inside Oklch color space. The goal is to
preserve hue as much as possible while manipulating lightness and/or chroma.

List of supported gamut clip methods (along with their id in parenthesis):
- Clip chroma (`'chroma'`) - reduce chroma while preserving lightness until
  color is inside visible gamut. Default method.

- Clip lightness (`'lightness'`) - reduce lightness while preserving chroma
  until color is inside visible gamut.

- Clip according to "cusp" (`'cusp'`) - reduce both lightness and chroma in
  a compromise way depending on hue.
  Cusp is a color with the highest chroma inside slice of visible gamut
  with the same hue (hue leaf). It is called that way because the slice has
  a roughly triangular shape with points at (0, 0) - (0, 100) - "cusp" in
  (chroma, lightness) coordinates.
  Gamut clipping using "cusp" as reference is done by changing color towards
  (0, cusp_lightness) point (gray with lightness equal to that of a current
  cusp) until color is inside visible gamut.

In short:
- Usually `'chroma'` is enough.
- If colors are too desaturated - try `'cusp'`.
- If still not colorful enough - try `'lightness'`.

Notes:
- Currently implemented formulas are approximate (by design; to reduce code
  complexity) so there might be problems for highly saturated colors with
  relatively low or high lightness.

------------------------------------------------------------------------------
                                                           *MiniColors-channels*
A color channel is a number describing one particular aspect of a color.
It is usually direct or modified coordinate of a color space. See
|MiniColors-color-spaces| for information on color spaces.

List of supported channels (along with their id in parenthesis):
- Lightness (`lightness`) - corrected `l` component of Oklch. Describes how
  light is a color. Ranges from 0 (black dark) to 100 (white light).

- Chroma (`chroma`) - `c` component of Oklch. Describes how colorful is
  a color in absolute units. Ranges from 0 (gray) to infinity (more like
  around 30 in practice).

- Saturation (`saturation`) - `s` component of Okhsl. Describes how colorful
  is color in relative units. Ranges from 0 (gray) to 100 (maximum saturation
  for a given lightness-hue pair).

- Hue (`hue`) - `h` component of Oklch. Describes "true color value" (like
  red/green/blue) as a number. It is a periodic value from 0 (included) to
  360 (not included). Best perceived as a degree on a color circle/wheel.

  Approximate values for common color names:
    - 0   - pink.
    - 30  - red.
    - 60  - orange.
    - 90  - yellow.
    - 135 - green.
    - 180 - cyan.
    - 225 - light blue.
    - 270 - blue.
    - 315 - magenta/purple.

- Temperature (`temperature`) - circular distance from current hue to hue 270
  angle (blue). Ranges from 0 (cool) to 180 (hot) anchored at hues 270 (blue)
  and 90 (yellow). Similar to `b` channel but tries to preserve chroma.

- Pressure (`pressure`) - circular distance from current hue to hue 180.
  Ranges from 0 (low; green-ish) to 180 (high; red-ish) anchored at hues
  180 and 0. Similar to `a` channel but tries to preserve chroma.
  Not widely used; added to have something similar to temperature.

- a (`a`) - `a` component of Oklab. Describes how "green-red" a color is.
  Can have any value. Negative values are "green-ish", positive - "red-ish".

- b (`b`) - `b` component of Oklab. Describes how "blue-yellow" a color is.
  Can have any value. Negative values are "blue-ish", positive - "yellow-ish".

- Red (`red`) - `r` component of RGB. Describes how much red a color has.
  Ranges from 0 (no red) to 255 (full red).

- Green (`green`) - `g` component of RGB. Describes how much green a color has.
  Ranges from 0 (no green) to 255 (full green).

- Blue (`blue`) - `b` component of RGB. Describes how much blue a color has.
  Ranges from 0 (no blue) to 255 (full blue).

------------------------------------------------------------------------------
                                                        *MiniColors-colorscheme*
Colorscheme object is a central structure of this module. It contains all
data relevant to colors in fields and provides methods to modify it.

Create colorscheme object manually with |MiniColors.as_colorscheme()|: >

  MiniColors.as_colorscheme({
    name = 'my_cs',
    groups = {
      Normal   = { fg = '#dddddd', bg = '#222222' },
      SpellBad = { sp = '#dd2222', undercurl = true },
    },
    terminal = { [0] = '#222222', [1] = '#dd2222' },
  })

Get any registered color scheme (including currently active) as colorscheme
object with |MiniColors.get_colorscheme()|: >

  -- Get current color scheme
  MiniColors.get_colorscheme()

  -- Get registered color scheme by name
  MiniColors.get_colorscheme('minischeme', { new_name = 'maxischeme' })

Class ~
{Colorscheme}

                                                 *MiniColors-colorscheme-fields*

Fields ~
{name} `(string|nil)` Name of the color scheme (as in |g:colors_name|).

{groups} `(table|nil)` Table with highlight groups data. Keys are group
  names appropriate for `name` argument of |nvim_set_hl()|, values - tables
  appropriate for its `val` argument. Note: gui colors are accepted only in
  short form (`fg`, `bg`, `sp`).

{terminal} `(table|nil)` Table with terminal colors data (|terminal-config|).
  Keys are numbers from 0 to 15, values - strings representing color (hex
  string or plain color name; see |nvim_get_color_by_name()|).

                                                *MiniColors-colorscheme-methods*
Notes about all methods:
- They never modify underlying colorscheme object instead returning deep
  copy with modified fields.
- They accept `self` colorscheme object as first argument meaning they should be
  called with `:` notation (like `cs:method()`).

Example calling methods: >

  -- Get current color scheme, set hue of colors to 135, infer cterm
  -- attributes and apply
  local cs = MiniColors.get_colorscheme()
  cs:chan_set('hue', 135):add_cterm_attributes():apply()
<
                                 *MiniColors-colorscheme:add_cterm_attributes()*
Infer |cterm-colors| based on present |gui-colors|. It updates `ctermbg`/`ctermfg`
based on `fg`/`bg` by approximating in perceptually uniform distance in Oklab
space (|MiniColors-color-spaces|).

Parameters ~
{opts} `(table|nil)` Options. Possible fields:
  - <force> `(boolean)` - Whether to replace already present cterm attributes
    with inferred ones. Default: `true`.

                                  *MiniColors-colorscheme:add_terminal_colors()*
Infer terminal colors (|terminal-config|) based on colorscheme palette
(see |MiniColors-colorscheme:get_palette()|). It updates `terminal` field
based on color scheme's palette by picking the most appropriate entry to
represent terminal color. Colors from 0 to 7 are attempted to be black,
red, green, yellow, blue, magenta, cyan, white. Colors from 8 to 15 are
the same as from 0 to 7.

Parameters ~
{opts} `(table|nil)` Options. Possible fields:
  - <force> `(boolean)` - Whether to replace already present terminal colors
    with inferred ones. Default: `true`.
  - <palette_args> `(table)` - |MiniColors-colorscheme:get_palette()| arguments.

                                     *MiniColors-colorscheme:add_transparency()*
Add transparency by removing background from a certain highlight groups.
Requires actual transparency from terminal emulator to experience visible
transparency.

Parameters ~
{opts} `(table|nil)` Options. Possible fields can be used to configure which
  sets of highlight groups to update:
  - <general> `(boolean)` - general groups (like `Normal`). Default: `true`.
  - <float> `(boolean)` - built-in groups for floating windows. Default: `false`.
  - <statuscolumn> `(boolean)` - groups related to 'statuscolumn' (signcolumn,
    numbercolumn, foldcolumn). Also updates groups for all currently
    defined signs. Default: `false`.
  - <statusline> `(boolean)` - built-in groups for 'statusline'. Default: `false`.
  - <tabline> `(boolean)` - built-in groups for 'tabline'. Default: `false`.
  - <winbar> `(boolean)` - built-in groups for 'winbar'. Default: `false`.

                                                *MiniColors-colorscheme:apply()*
Apply colorscheme:
- Set |g:colors_name| to a `name` field.
- Apply highlight groups in a `groups` field.
- Set terminal colors from a `terminal` field.

Parameters ~
{opts} `(table|nil)` Options. Possible fields:
  - <clear> `(boolean)` - whether to execute |:hi-clear| first. Default: `true`.

                                             *MiniColors-colorscheme:chan_add()*
Add value to a channel (see |MiniColors-channels|).

Parameters ~
{channel} `(string)` One of supported |MiniColors-channels|.
{value} `(number)` Number to add (can be negative).
{opts} `(table|nil)` Options. Possible fields:
  - <filter> `(function|string)` - filter colors to update. Possible values:
      - String representing target attributes. One of `'fg'`, `'bg'`, `'sp'`,
        `'term'` (only terminal colors).
      - Callable with signature as in |MiniColors-colorscheme:color_modify()|.
    Default: `nil` to update all colors.
  - <gamut_clip> `(string)` - gamut clipping method. One of `'chroma'`,
    `'lightness'`, `'cusp'`. See |MiniColors-gamut-clip|. Default: `'chroma'`.


                                          *MiniColors-colorscheme:chan_invert()*
Invert value in a channel (see |MiniColors-channels|).

Notes:
- Most Oklab/Oklch inversions are not exactly invertible: applying it twice
  might lead to slightly different colors depending on gamut clip method
  (|MiniColors-gamut-clip|) like smaller chroma with default `'chroma'` method.

Parameters ~
{channel} `(string)` One of supported |MiniColors-channels|.
{opts} `(table|nil)` Options. Possible fields:
  - <filter> `(function|string)` - filter colors to update. Possible values:
      - String representing target attributes. One of `'fg'`, `'bg'`, `'sp'`,
        `'term'` (only terminal colors).
      - Callable with signature as in |MiniColors-colorscheme:color_modify()|.
    Default: `nil` to update all colors.
  - <gamut_clip> `(string)` - gamut clipping method. One of `'chroma'`,
    `'lightness'`, `'cusp'`. See |MiniColors-gamut-clip|. Default: `'chroma'`.

                                          *MiniColors-colorscheme:chan_modify()*
Modify channel with a callable.

Parameters ~
{channel} `(string)` One of supported |MiniColors-channels|.
{f} `(function)` - callable which defines modification. Should take current
  value of a channel and return a new one.
{opts} `(table|nil)` Options. Possible fields:
  - <filter> `(function|string)` - filter colors to update. Possible values:
      - String representing target attributes. One of `'fg'`, `'bg'`, `'sp'`,
        `'term'` (only terminal colors).
      - Callable with signature as in |MiniColors-colorscheme:color_modify()|.
    Default: `nil` to update all colors.
  - <gamut_clip> `(string)` - gamut clipping method. One of `'chroma'`,
    `'lightness'`, `'cusp'`. See |MiniColors-gamut-clip|. Default: `'chroma'`.

                                        *MiniColors-colorscheme:chan_multiply()*
Multiply value of a channel (see |MiniColors-channels|).

Parameters ~
{channel} `(string)` One of supported |MiniColors-channels|.
{coef} `(number)` Number to multiply with (can be negative).
{opts} `(table|nil)` Options. Possible fields:
  - <filter> `(function|string)` - filter colors to update. Possible values:
      - String representing target attributes. One of `'fg'`, `'bg'`, `'sp'`,
        `'term'` (only terminal colors).
      - Callable with signature as in |MiniColors-colorscheme:color_modify()|.
    Default: `nil` to update all colors.
  - <gamut_clip> `(string)` - gamut clipping method. One of `'chroma'`,
    `'lightness'`, `'cusp'`. See |MiniColors-gamut-clip|. Default: `'chroma'`.

                                           *MiniColors-colorscheme:chan_repel()*
Repel from certain sources.

Given an array of repel centers (`sources`) and repel degree (`coef`) add to
current channel value some amount ("nudge") with the following properties:
- Nudges from several sources are added together.
- Nudge is directly proportional to `coef`: bigger `coef` means bigger nudge.
- Nudge is inversely proportional to the distance between current value and
  source: for positive `coef` bigger distance means smaller nudge, i.e.
  repel effect weakens with distance.
- With positive `coef` nudges close to source are computed in a way to remove
  whole `[source - coef; source + coef]` range.
- Negative `coef` results into attraction to source. Nudges in
  `[source - coef; source + coef]` range are computed to completely collapse it
  into `source`.

Examples: >

  -- Repel hue from red color removing hue in range from 20 to 40
  chan_repel('hue', 30, 10)

  -- Attract hue to red color collapsing [20; 40] range into 30.
  chan_repel('hue', 30, -10)

Parameters ~
{channel} `(string)` One of supported |MiniColors-channels|.
{sources} `(table|number)` Single or multiple source from which to repel.
{coef} `(number)` Repel degree (can be negative to attract).
{opts} `(table|nil)` Options. Possible fields:
  - <filter> `(function|string)` - filter colors to update. Possible values:
      - String representing target attributes. One of `'fg'`, `'bg'`, `'sp'`,
        `'term'` (only terminal colors).
      - Callable with signature as in |MiniColors-colorscheme:color_modify()|.
    Default: `nil` to update all colors.
  - <gamut_clip> `(string)` - gamut clipping method. One of `'chroma'`,
    `'lightness'`, `'cusp'`. See |MiniColors-gamut-clip|. Default: `'chroma'`.

                                             *MiniColors-colorscheme:chan_set()*
Set channel to certain value(s). This can be used to ensure that channel has
value(s) only within supplied set. If more than one is supplied, closest
element to current value is used.

Parameters ~
{channel} `(string)` One of supported |MiniColors-channels|.
{values} `(table|number)` Single or multiple values to set.
{opts} `(table|nil)` Options. Possible fields:
  - <filter> `(function|string)` - filter colors to update. Possible values:
      - String representing target attributes. One of `'fg'`, `'bg'`, `'sp'`,
        `'term'` (only terminal colors).
      - Callable with signature as in |MiniColors-colorscheme:color_modify()|.
    Default: `nil` to update all colors.
  - <gamut_clip> `(string)` - gamut clipping method. One of `'chroma'`,
    `'lightness'`, `'cusp'`. See |MiniColors-gamut-clip|. Default: `'chroma'`.

                                         *MiniColors-colorscheme:color_modify()*
Modify all colors with a callable. It should return new color value (hex
string or `nil` to remove attribute) base on the following input:
- Current color as hex string.
- Data about the color: a table with fields:
    - <attr> - one of `'fg'`, `'bg'`, `'sp'`, and `'term'` for terminal color.
    - <name> - name of color source. Either a name of highlight group or
      string of the form `terminal_color_x` for terminal color (as in
      |terminal-config|).

Example: >

  -- Set to '#dd2222' all foreground colors for groups starting with "N"
  color_modify(function(hex, data)
    if data.attr == 'fg' and data.name:find('^N') then
      return '#dd2222'
    end
    return hex
  end)

Parameters ~
{f} `(function)` Callable returning new color value.

                                             *MiniColors-colorscheme:compress()*
Remove redundant highlight groups. These are one of the two kinds:
- Having values identical to ones after |:hi-clear| (meaning they usually
  don't add new information).
- Coming from a curated list of plugins with highlight groups usually not
  worth keeping around. Current list of such plugins:
    - 'nvim-tree/nvim-web-devicons'
    - 'norcalli/nvim-colorizer.lua'

This method is useful to reduce size of color scheme before writing into
the file with |MiniColors-colorscheme:write()|.

Parameters ~
{opts} `(table|nil)` Options. Possible fields:
  - <plugins> `(boolean)` - whether to remove highlight groups from a curated
    list of plugins. Default: `true`.

                                          *MiniColors-colorscheme:get_palette()*
Get commonly used colors. This basically counts number of all color
occurrences and filter out rare ones.

It is usually a good idea to apply both |MiniColors-colorscheme:compress()|
and |MiniColors-colorscheme:resolve_links()| before applying this.

Parameters ~
{opts} `(table|nil)` Options. Possible fields:
  - <threshold> `(number)` - relative threshold for groups to keep. A group
    is not included in output if it has less than this many occurrences
    relative to a total number of colors. Default: 0.01.

                                        *MiniColors-colorscheme:resolve_links()*
Resolve links (|:highlight-link|). This makes all highlight groups with `link`
attribute have data from a linked one.

Notes:
- Resolves nested links.
- If some group is linked to a group missing in current colorscheme object,
  it is not resolved.

                                         *MiniColors-colorscheme:simulate_cvd()*
Simulate color vision deficiency (CVD, color blindness). This is basically
a wrapper using |MiniColors.simulate_cvd()| as a part of
call to |MiniColors-colorscheme:color_modify()| method.

Parameters ~
{cvd_type} `(string)` One of `'protan'`, `'deutan'`, `'tritan'`, `'mono'`.
{severity} `(number|nil)` Severity of CVD, number between 0 and 1. Default: 1.

                                                *MiniColors-colorscheme:write()*
Write color scheme to a file. It will be a Lua script readily usable as
a regular color scheme. Useful to both save results of color scheme tweaking
and making local snapshot of some other color scheme.

Sourcing this file on startup usually leads to a better performance that
sourcing initial color scheme, as it is essentially a conditioned
|:hi-clear| call followed by a series of |nvim_set_hl()| calls.

Default writing location is a "colors" directory of your Neovim config
directory (see |base-directories|). After writing, it should be available
for sourcing with |:colorscheme| or |:Colorscheme|.

Name of the file by default is taken from `name` field (`'mini_colors'` is
used if it is `nil`). If color scheme with this name already exists, it
appends prefix based on current time to make it unique.

Notes:
- If colors were updated, it is usually a good idea to infer cterm attributes
  with |MiniColors-colorscheme:add_cterm_attributes()| prior to writing.

Parameters ~
{opts} `(table|nil)` Options. Possible fields:
  - <compress> `(boolean)` - whether to call |MiniColors-colorscheme:compress()|
    prior to writing. Default: `true`.
  - <name> `(string|nil)` - basename of written file. Default: `nil` to infer
    from `name` field.
  - <directory> `(string)` - directory to where file should be saved.
    Default: "colors" subdirectory of Neovim home config (`stdpath("config")`).

------------------------------------------------------------------------------
                                                            *MiniColors.setup()*
                          `MiniColors.setup`({config})
Module setup

                                                                  *:Colorscheme*
Calling this function creates a `:Colorscheme` user command. It takes one or
more registered color scheme names and performs animated transition between
them (starting from currently active color scheme).
It uses |MiniColors.animte()| with default options.

Parameters ~
{config} `(table|nil)` Module config table. See |MiniColors.config|.

Usage ~
`require('mini.colors').setup({})` (replace `{}` with your `config` table)

------------------------------------------------------------------------------
                                                             *MiniColors.config*
                              `MiniColors.config`
Module config

Default values:
>lua
  MiniColors.config = {}
<
------------------------------------------------------------------------------
                                                   *MiniColors.as_colorscheme()*
                        `MiniColors.as_colorscheme`({x})
Create colorscheme object

Parameters ~
{x} `(table)` Table to be transformed into |MiniColors-colorscheme| object.

Return ~
`(table)` Copy of `x` transformed into a colorscheme object.

------------------------------------------------------------------------------
                                                  *MiniColors.get_colorscheme()*
                  `MiniColors.get_colorscheme`({name}, {opts})
Get colorscheme object from registered color scheme

Parameters ~
{name} `(string|nil)` Name of color scheme to use. If `nil` (default) creates
 colorscheme object based on currently active data (|g:colors_name|,
 highlight groups, terminal colors). If string, converts color scheme with
 that name to a colorscheme object.
{opts} `(table|nil)` Options. Possible fields:
  - <new_name> `(string|nil)` - new name of colorscheme object.

Return ~
`(table)` Colorscheme object |(MiniColors-colorscheme|).

------------------------------------------------------------------------------
                                                      *MiniColors.interactive()*
                        `MiniColors.interactive`({opts})
Start interactive experiments

Create a special buffer in which user can write plain Lua code to tweak
color scheme and apply to get visual feedback.

General principles ~
- Initial colorscheme object is fixed to interactive buffer on its creation.

- There are special buffer convenience mappings:
    - Apply (source) current buffer content.
    - Reset color scheme (make initial colorscheme the current one).
    - Write to a file the result of applying current buffer content.
      This sources current content and calls |MiniColors-colorscheme:write()|.
    - Quit interactive buffer.

- User is expected to iteratively tweak color scheme by writing general Lua
  code in interactive buffer and applying it using convenience mapping.

- Application of interactive buffer is essentially these steps:
    - Expose `self` as initial colorscheme object on any application.
      It is always the same for every application.
    - Expose initial colorscheme methods as standalone functions. So instead
      of writing `self = self:add_transparency()` user can only write
      `add_transparency()`.
    - Source buffer content as plain Lua code.

Example of interactive buffer content: >

  chan_modify('hue', function() return math.random(0, 359) end)
  simulate_cvd('protan')
  add_cterm_attributes()
  add_terminal_colors()

Parameters ~
{opts} `(table|nil)` Options. Possible fields:
  - <colorscheme> `(table|nil)` - |MiniColors-colorscheme| object to be
    used as initial colorscheme for executed code. By default uses current
    color scheme.
  - <mappings> `table` - buffer mappings for actions. Possible fields:
      - <Apply> `(string)` - apply buffer code. Default: `'<M-a>'`.
      - <Reset> `(string)` - apply initial color scheme as is. Default: `'<M-r>'`.
      - <Quit> `(string)` - close interactive buffer. Default: `'<M-q>'`.
      - <Write> `(string)` - write result of buffer code into a file.
        Prompts for file name with |vim.ui.input()| and then
        uses |MiniColors-colorscheme:write()| with other options being default.
        Default: `'<M-w>'`.

------------------------------------------------------------------------------
                                                          *MiniColors.animate()*
                    `MiniColors.animate`({cs_array}, {opts})
Animate color scheme change

Start from currently active color scheme and loop through `cs_array`.

Powers |:Colorscheme| user command created in |MiniColors.setup()|.

Parameters ~
{cs_array} `(`(table)`)` Array of |MiniColors-colorscheme| objects.
{opts} `(table|nil)` Options. Possible fields:
  - <transition_steps> `(number)` - number of intermediate steps to show
    during transition between two color schemes. Bigger values result in
    smoother visual feedback but require more computational power.
    Default: 25.
  - <transition_duration> `(number)` - number of milliseconds to spend
    showing transition. Default: 1000.
  - <show_duration> `(number)` - number of milliseconds to show intermediate
    color schemes (all but last in `cs_array`). Default: 1000.

------------------------------------------------------------------------------
                                                          *MiniColors.convert()*
                 `MiniColors.convert`({x}, {to_space}, {opts})
Convert between color spaces

For a list of supported colors spaces see |MiniColors-color-spaces|.

Parameters ~
{x} `(table|string|number|nil)` Color to convert from. Its color space is
  inferred automatically.
{to_space} `(string)` Id of allowed color space.
{opts} `(table|nil)` Options. Possible fields:
  - <gamut_clip> `(string)` - method for |MiniColors-gamut-clip|.
    Default: `'chroma'`.

Return ~
`(table|string|number|nil)` Color in space `to_space` or `nil` if input is `nil`.

------------------------------------------------------------------------------
                                                   *MiniColors.modify_channel()*
            `MiniColors.modify_channel`({x}, {channel}, {f}, {opts})
Modify channel

Parameters ~
{x} `(table|string|number|nil)` Color which channel will be modified. Color
  space is inferred automatically.
{channel} `(string)` One of supported |MiniColors-channels|.
{f} `(function)` Callable which defines modification. Should take current
  value of a channel and return a new one.
{opts} `(table|nil)` Options. Possible fields:
  - <gamut_clip> `(string)` - method for |MiniColors-gamut-clip|.
    Default: `'chroma'`.

Return ~
`(string|nil)` Hex string of color with modified channel or `nil` if input is `nil`.

------------------------------------------------------------------------------
                                                     *MiniColors.simulate_cvd()*
             `MiniColors.simulate_cvd`({x}, {cvd_type}, {severity})
Simulate color vision deficiency

Parameters ~
{x} `(table|string|number|nil)` Color to convert from. Its color space is
  inferred automatically.
{cvd_type} `(string)` Type of CVD. One of `'protan'`, `'deutan'`,
or `'mono'` (equivalent to converting to graysacle).
{severity} `(number|nil)` Severity of CVD. A number between 0 and 1 (default).

Return ~
`(string|nil)` Hex string of simulated color or `nil` if input is `nil`.


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