-module(gleam_community@colour@accessibility).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).
-define(FILEPATH, "src/gleam_community/colour/accessibility.gleam").
-export([luminance/1, contrast_ratio/2, maximum_contrast/2]).
-if(?OTP_RELEASE >= 27).
-define(MODULEDOC(Str), -moduledoc(Str)).
-define(DOC(Str), -doc(Str)).
-else.
-define(MODULEDOC(Str), -compile([])).
-define(DOC(Str), -compile([])).
-endif.
?MODULEDOC(
" \n"
" - **Accessibility**\n"
" - [`luminance`](#luminance)\n"
" - [`contrast_ratio`](#contrast_ratio)\n"
" - [`maximum_contrast`](#maximum_contrast)\n"
"\n"
" ---\n"
"\n"
" This package was heavily inspired by the `elm-color-extra` module.\n"
" The original source code can be found\n"
" here.\n"
"\n"
" \n"
" The license of that package is produced below:
\n"
" \n"
" \n"
" > MIT License\n"
"\n"
" > Copyright (c) 2016 Andreas Köberle\n"
"\n"
" > Permission is hereby granted, free of charge, to any person obtaining a copy\n"
" of this software and associated documentation files (the \"Software\"), to deal\n"
" in the Software without restriction, including without limitation the rights\n"
" to use, copy, modify, merge, publish, distribute, sublicense, and/or sell\n"
" copies of the Software, and to permit persons to whom the Software is\n"
" furnished to do so, subject to the following conditions:\n"
"\n"
" > The above copyright notice and this permission notice shall be included in all\n"
" copies or substantial portions of the Software.\n"
"\n"
" > THE SOFTWARE IS PROVIDED \"AS IS\", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR\n"
" IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,\n"
" FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE\n"
" AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER\n"
" LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,\n"
" OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE\n"
" SOFTWARE.\n"
"\n"
" \n"
"\n"
).
-file("src/gleam_community/colour/accessibility.gleam", 56).
-spec intensity(float()) -> float().
intensity(Colour_value) ->
case true of
_ when Colour_value =< 0.03928 ->
Colour_value / 12.92;
_ ->
I@1 = case gleam@float:power((Colour_value + 0.055) / 1.055, 2.4) of
{ok, I} -> I;
_assert_fail ->
erlang:error(#{gleam_error => let_assert,
message => <<"Pattern match failed, no pattern matched the value."/utf8>>,
file => <>,
module => <<"gleam_community/colour/accessibility"/utf8>>,
function => <<"intensity"/utf8>>,
line => 62,
value => _assert_fail,
start => 2399,
'end' => 2470,
pattern_start => 2410,
pattern_end => 2415})
end,
I@1
end.
-file("src/gleam_community/colour/accessibility.gleam", 92).
?DOC(
" Returns the relative brightness of the given `Colour` as a `Float` between\n"
" 0.0, and 1.0 with 0.0 being the darkest possible colour and 1.0 being the lightest.\n"
"\n"
" \n"
" Example:
\n"
"\n"
" ```gleam\n"
" fn example() {\n"
" luminance(colour.white) // 1.0\n"
" }\n"
" ```\n"
" \n"
"\n"
" \n"
).
-spec luminance(gleam_community@colour:colour()) -> float().
luminance(Colour) ->
{R, G, B, _} = gleam_community@colour:to_rgba(Colour),
R_intensity = intensity(R),
G_intensity = intensity(G),
B_intensity = intensity(B),
((0.2126 * R_intensity) + (0.7152 * G_intensity)) + (0.0722 * B_intensity).
-file("src/gleam_community/colour/accessibility.gleam", 125).
?DOC(
" Returns the contrast between two `Colour` values as a `Float` between 1.0,\n"
" and 21.0 with 1.0 being no contrast and, 21.0 being the highest possible contrast.\n"
"\n"
" \n"
" Example:
\n"
"\n"
" ```gleam\n"
" fn example() {\n"
" contrast_ratio(between: colour.white, and: colour.black) // 21.0\n"
" }\n"
" ```\n"
" \n"
"\n"
" \n"
).
-spec contrast_ratio(
gleam_community@colour:colour(),
gleam_community@colour:colour()
) -> float().
contrast_ratio(Colour_a, Colour_b) ->
Luminance_a = luminance(Colour_a) + 0.05,
Luminance_b = luminance(Colour_b) + 0.05,
case Luminance_a > Luminance_b of
true ->
case Luminance_b of
+0.0 -> +0.0;
-0.0 -> -0.0;
Gleam@denominator -> Luminance_a / Gleam@denominator
end;
false ->
case Luminance_a of
+0.0 -> +0.0;
-0.0 -> -0.0;
Gleam@denominator@1 -> Luminance_b / Gleam@denominator@1
end
end.
-file("src/gleam_community/colour/accessibility.gleam", 161).
?DOC(
" Returns the `Colour` with the highest contrast between the base `Colour`,\n"
" and and the other provided `Colour` values.\n"
"\n"
" \n"
" Example:
\n"
"\n"
" ```gleam\n"
" fn example() {\n"
" maximum_contrast(\n"
" colour.yellow,\n"
" [colour.white, colour.dark_blue, colour.green],\n"
" )\n"
" }\n"
" ```\n"
" \n"
"\n"
" \n"
).
-spec maximum_contrast(
gleam_community@colour:colour(),
list(gleam_community@colour:colour())
) -> {ok, gleam_community@colour:colour()} | {error, nil}.
maximum_contrast(Base, Colours) ->
_pipe = Colours,
_pipe@1 = gleam@list:sort(
_pipe,
fun(Colour_a, Colour_b) ->
Contrast_a = contrast_ratio(Base, Colour_a),
Contrast_b = contrast_ratio(Base, Colour_b),
gleam@float:compare(Contrast_b, Contrast_a)
end
),
gleam@list:first(_pipe@1).