office-ui-fabric-react
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Reusable React components for building experiences for Office 365.
185 lines • 7.51 kB
JavaScript
// Technically this should be shades and tints, but for simplicity we'll call everything a shade.
/* This utility module is used with theming. Given a color to shade, whether the theme is inverted (i.e. is a dark color),
* and the desired shade enum, this will return an appropriate shade of that color.
*/
import { MAX_COLOR_RGBA } from './colors';
import * as Colors from './colors';
import { assign } from '../../Utilities';
// Soften: to get closer to the background color's luminance (softening with a white background would be lightening, with black it'd be darkening)
// Strongen: opposite of soften
// Luminance multiplier constants for generating shades of a given color
var WhiteShadeTableBG = [0.027, 0.043, 0.082, 0.145, 0.184, 0.216, 0.349, 0.537]; // white bg
var BlackTintTableBG = [0.537, 0.45, 0.349, 0.216, 0.184, 0.145, 0.082, 0.043]; // black bg
var WhiteShadeTable = [0.537, 0.349, 0.216, 0.184, 0.145, 0.082, 0.043, 0.027]; // white fg
var BlackTintTable = [0.537, 0.45, 0.349, 0.216, 0.184, 0.145, 0.082, 0.043]; // black fg
var LumTintTable = [0.88, 0.77, 0.66, 0.55, 0.44, 0.33, 0.22, 0.11]; // light (strongen all)
var LumShadeTable = [0.11, 0.22, 0.33, 0.44, 0.55, 0.66, 0.77, 0.88]; // dark (soften all)
var ColorTintTable = [0.96, 0.84, 0.7, 0.4, 0.12]; // default soften
var ColorShadeTable = [0.1, 0.24, 0.44]; // default strongen
// If the given shade's luminance is below/above these values, we'll swap to using the White/Black tables above
var LowLuminanceThreshold = 0.2;
var HighLuminanceThreshold = 0.8;
/** Shades of a given color, from softest to strongest. */
export var Shade;
(function (Shade) {
Shade[Shade["Unshaded"] = 0] = "Unshaded";
Shade[Shade["Shade1"] = 1] = "Shade1";
Shade[Shade["Shade2"] = 2] = "Shade2";
Shade[Shade["Shade3"] = 3] = "Shade3";
Shade[Shade["Shade4"] = 4] = "Shade4";
Shade[Shade["Shade5"] = 5] = "Shade5";
Shade[Shade["Shade6"] = 6] = "Shade6";
Shade[Shade["Shade7"] = 7] = "Shade7";
Shade[Shade["Shade8"] = 8] = "Shade8";
// remember to update isValidShade()!
})(Shade || (Shade = {}));
/**
* Returns true if the argument is a valid Shade value
* @param {Shade} shade The Shade value to validate.
*/
export function isValidShade(shade) {
'use strict';
return typeof shade === 'number' && shade >= Shade.Unshaded && shade <= Shade.Shade8;
}
function _isBlack(color) {
return color.r === 0 && color.g === 0 && color.b === 0;
}
function _isWhite(color) {
return color.r === MAX_COLOR_RGBA && color.g === MAX_COLOR_RGBA && color.b === MAX_COLOR_RGBA;
}
function _darken(hsv, factor) {
return {
h: hsv.h,
s: hsv.s,
v: _clamp(hsv.v - hsv.v * factor, 0, 100)
};
}
function _lighten(hsv, factor) {
return {
h: hsv.h,
s: _clamp(hsv.s - hsv.s * factor, 0, 100),
v: _clamp(hsv.v + (100 - hsv.v) * factor, 0, 100)
};
}
function _clamp(n, min, max) {
return n; // Math.max(min, Math.min(n, max));
}
export function isDark(color) {
return Colors.hsv2hsl(color.h, color.s, color.v).l < 50;
}
/**
* Given a color and a shade specification, generates the requested shade of the color.
* Logic:
* if white
* darken via tables defined above
* if black
* lighten
* if light
* strongen
* if dark
* soften
* else default
* soften or strongen depending on shade#
* @param {IColor} color The base color whose shade is to be computed
* @param {Shade} shade The shade of the base color to compute
* @param {Boolean} isInverted Default false. Whether the given theme is inverted (reverse strongen/soften logic)
*/
export function getShade(color, shade, isInverted) {
'use strict';
if (isInverted === void 0) { isInverted = false; }
if (!color) {
return null;
}
if (shade === Shade.Unshaded || !isValidShade(shade)) {
return color;
}
var hsl = Colors.hsv2hsl(color.h, color.s, color.v);
var hsv = { h: color.h, s: color.s, v: color.v };
var tableIndex = shade - 1;
var _soften = _lighten;
var _strongen = _darken;
if (isInverted) {
_soften = _darken;
_strongen = _lighten;
}
if (_isWhite(color)) {
// white
hsv = _darken(hsv, WhiteShadeTable[tableIndex]);
}
else if (_isBlack(color)) {
// black
hsv = _lighten(hsv, BlackTintTable[tableIndex]);
}
else if (hsl.l / 100 > HighLuminanceThreshold) {
// light
hsv = _strongen(hsv, LumShadeTable[tableIndex]);
}
else if (hsl.l / 100 < LowLuminanceThreshold) {
// dark
hsv = _soften(hsv, LumTintTable[tableIndex]);
}
else {
// default
if (tableIndex < ColorTintTable.length) {
hsv = _soften(hsv, ColorTintTable[tableIndex]);
}
else {
hsv = _strongen(hsv, ColorShadeTable[tableIndex - ColorTintTable.length]);
}
}
return Colors.getColorFromRGBA(assign(Colors.hsv2rgb(hsv.h, hsv.s, hsv.v), { a: color.a }));
}
// Background shades/tints are generated differently. The provided color will be guaranteed
// to be the darkest or lightest one. If it is <50% luminance, it will always be the darkest,
// otherwise it will always be the lightest.
export function getBackgroundShade(color, shade, isInverted) {
'use strict';
if (isInverted === void 0) { isInverted = false; }
if (!color) {
return null;
}
if (shade === Shade.Unshaded || !isValidShade(shade)) {
return color;
}
var hsv = { h: color.h, s: color.s, v: color.v };
var tableIndex = shade - 1;
if (!isInverted) {
// lightish
hsv = _darken(hsv, WhiteShadeTableBG[tableIndex]);
}
else {
// default: if (hsl.l / 100 < .5) { // darkish
hsv = _lighten(hsv, BlackTintTableBG[BlackTintTable.length - 1 - tableIndex]);
}
return Colors.getColorFromRGBA(assign(Colors.hsv2rgb(hsv.h, hsv.s, hsv.v), { a: color.a }));
}
/* Calculates the contrast ratio between two colors. Used for verifying
* color pairs meet minimum accessibility requirements.
* See: https://www.w3.org/TR/WCAG20/ section 1.4.3
*/
export function getContrastRatio(color1, color2) {
// Formula defined by: http://www.w3.org/TR/UNDERSTANDING-WCAG20/visual-audio-contrast-contrast.html#contrast-ratiodef
// relative luminance: http://www.w3.org/TR/2008/REC-WCAG20-20081211/#relativeluminancedef
/* calculate the intermediate value needed to calculating relative luminance */
function _getThing(x) {
if (x <= 0.03928) {
return x / 12.92;
}
else {
return Math.pow((x + 0.055) / 1.055, 2.4);
}
}
var r1 = _getThing(color1.r / MAX_COLOR_RGBA);
var g1 = _getThing(color1.g / MAX_COLOR_RGBA);
var b1 = _getThing(color1.b / MAX_COLOR_RGBA);
var L1 = 0.2126 * r1 + 0.7152 * g1 + 0.0722 * b1; // relative luminance of first color
L1 += 0.05;
var r2 = _getThing(color2.r / MAX_COLOR_RGBA);
var g2 = _getThing(color2.g / MAX_COLOR_RGBA);
var b2 = _getThing(color2.b / MAX_COLOR_RGBA);
var L2 = 0.2126 * r2 + 0.7152 * g2 + 0.0722 * b2; // relative luminance of second color
L2 += 0.05;
// return the lighter color divided by darker
return L1 / L2 > 1 ? L1 / L2 : L2 / L1;
}
//# sourceMappingURL=shades.js.map