office-ui-fabric-react
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Reusable React components for building experiences for Office 365.
176 lines • 7.17 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 = [.973, .957, .918, .855, .816, .784, .651, .463]; // white bg
var BlackTintTableBG = [.463, .55, .651, .784, .816, .855, .918, .957]; // black bg
var WhiteShadeTable = [.463, .651, .784, .816, .855, .918, .957, .973]; // white fg
var BlackTintTable = [.463, .55, .651, .784, .816, .855, .918, .957]; // black fg
var LumTintTable = [.12, .23, .34, .45, .56, .67, .78, .89]; // light (strongen all)
var LumShadeTable = [.89, .78, .67, .56, .45, .34, .23, .12]; // dark (soften all)
var ColorTintTable = [.07, .18, .436, .751, .956]; // default soften
var ColorShadeTable = [.90, .64, .550]; // 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(hsl, factor) {
return {
h: hsl.h,
s: hsl.s,
l: hsl.l * factor
};
}
function _lighten(hsl, factor) {
return {
h: hsl.h,
s: hsl.s,
l: hsl.l * factor + (100 * (1 - factor))
};
}
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 tableIndex = shade - 1;
var _soften = _lighten;
var _strongen = _darken;
if (isInverted) {
// tableIndex = LumTintTable.length - 1 - tableIndex;
_soften = _darken;
_strongen = _lighten;
}
if (_isWhite(color)) {
hsl = _darken(hsl, WhiteShadeTable[tableIndex]);
}
else if (_isBlack(color)) {
hsl = _lighten(hsl, BlackTintTable[tableIndex]);
}
else if (hsl.l / 100 > HighLuminanceThreshold) {
hsl = _strongen(hsl, LumShadeTable[tableIndex]);
}
else if (hsl.l / 100 < LowLuminanceThreshold) {
hsl = _soften(hsl, LumTintTable[tableIndex]);
}
else {
if (tableIndex < ColorTintTable.length) {
hsl = _soften(hsl, ColorTintTable[tableIndex]);
}
else {
hsl = _strongen(hsl, ColorShadeTable[tableIndex - ColorTintTable.length]);
}
}
return Colors.getColorFromRGBA(assign(Colors.hsl2rgb(hsl.h, hsl.s, hsl.l), { 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 hsl = Colors.hsv2hsl(color.h, color.s, color.v);
var tableIndex = shade - 1;
if (!isInverted) {
hsl = _darken(hsl, WhiteShadeTableBG[tableIndex]);
}
else {
hsl = _lighten(hsl, BlackTintTableBG[BlackTintTable.length - 1 - tableIndex]);
}
return Colors.getColorFromRGBA(assign(Colors.hsl2rgb(hsl.h, hsl.s, hsl.l), { 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 <= .03928) {
return x / 12.92;
}
else {
return Math.pow((x + .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 = (.2126 * r1) + (.7152 * g1) + (.0722 * b1); // relative luminance of first color
L1 += .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 = (.2126 * r2) + (.7152 * g2) + (.0722 * b2); // relative luminance of second color
L2 += .05;
// return the lighter color divided by darker
return L1 / L2 > 1 ?
L1 / L2 : L2 / L1;
}
//# sourceMappingURL=shades.js.map