JSFiddle - React, Tailwind, and code Playground
by vfportero
HTML
<canvas id="myCanvas">
Your browser does not support the canvas element.
</canvas>
<button onclick="paintItBlack()">Paint it black!</button>
JavaScript
/**
*
* Javascript color conversion
* http://www.webtoolkit.info/
*
**/
function HSV(h, s, v) {
if (h <= 0) { h = 0; }
if (s <= 0) { s = 0; }
if (v <= 0) { v = 0; }
if (h > 360) { h = 360; }
if (s > 100) { s = 100; }
if (v > 100) { v = 100; }
this.h = h;
this.s = s;
this.v = v;
}
function RGB(r, g, b) {
if (r <= 0) { r = 0; }
if (g <= 0) { g = 0; }
if (b <= 0) { b = 0; }
if (r > 255) { r = 255; }
if (g > 255) { g = 255; }
if (b > 255) { b = 255; }
this.r = r;
this.g = g;
this.b = b;
}
function CMYK(c, m, y, k) {
if (c <= 0) { c = 0; }
if (m <= 0) { m = 0; }
if (y <= 0) { y = 0; }
if (k <= 0) { k = 0; }
if (c > 100) { c = 100; }
if (m > 100) { m = 100; }
if (y > 100) { y = 100; }
if (k > 100) { k = 100; }
this.c = c;
this.m = m;
this.y = y;
this.k = k;
}
var ColorConverter = {
_RGBtoHSV : function (RGB) {
var result = new HSV(0, 0, 0);
r = RGB.r / 255;
g = RGB.g / 255;
b = RGB.b / 255;
var minVal = Math.min(r, g, b);
var maxVal = Math.max(r, g, b);
var delta = maxVal - minVal;
result.v = maxVal;
if (delta == 0) {
result.h = 0;
result.s = 0;
} else {
result.s = delta / maxVal;
var del_R = (((maxVal - r) / 6) + (delta / 2)) / delta;
var del_G = (((maxVal - g) / 6) + (delta / 2)) / delta;
var del_B = (((maxVal - b) / 6) + (delta / 2)) / delta;
if (r == maxVal) { result.h = del_B - del_G; }
else if (g == maxVal) { result.h = (1 / 3) + del_R - del_B; }
else if (b == maxVal) { result.h = (2 / 3) + del_G - del_R; }
if (result.h < 0) { result.h += 1; }
if (result.h > 1) { result.h -= 1; }
}
result.h = Math.round(result.h * 360);
result.s = Math.round(result.s * 100);
...