How do I convert integer byte values of red, green and blue to a hex string, which can then be assigned to a context for rendering onto a HTML5 canvas?
For example, convert cyan,
var r = 0;
var g = 255;
var b = 255;
To a hex string for assigning to a context fill colour.
this.context.fillStyle = '#00FFFF';
Or is there a better way to do this altogether?
To convert a number to hex, you can use the built-in toString(16) function. Simple code:
function convert(integer) {
var str = Number(integer).toString(16);
return str.length == 1 ? "0" + str : str;
};
function to_rgb(r, g, b) { return "#" + convert(r) + convert(g) + convert(b); }
var color = to_rgb(r, g, b);
Just use the RGB values, like:
this.context.fillStyle = "rgb(0,255,255)";
rgba(...).)
I think, the simplest way is:
var g = 255; g.toString(16); //gives "ff"
Use the feature that gives language.
Convert one integer to a hex byte like:
const g = 255;
gPadded = Number(g).toString(16).padStart(2, "0");
This gets nicer with an array:
const r = 0;
const g = 255;
const b = 255;
const color = [r, g, b];
this.context.fillStyle = "#" + color.map(i=>i.toString(16).padStart(2, "0")).join("");
function pad(number, length) {
var str = '' + number;
while (str.length < length) str = '0' + str;
return str;
}
function toRGBHex(r,g,b) {
return pad(r.toString(16),2) + pad(g.toString(16),2) + pad(b.toString(16),2);
}
To convert your individual RGB values into a hex color, you can use this function, although it makes more sense just to use "rgb("+r+","+g+","+b+")" instead.
function rgbToHex(r,g,b) {
return "#"+("00000"+(r<<16|g<<8|b).toString(16)).slice(-6);
}
You can use .toString(16)
let decimalNumber = 255;
decimalNumber.toString(16)
// Expected output is "FF"
or if you want to convert binary radix
let decimalNumber = 24;
decimalNumber.toString(2)
// Expected output is "1010"
You can write your own method for this conversion -
// function to generate the hex code
function getHex(dec)
{
var hexArray = new Array( "0", "1", "2", "3",
"4", "5", "6", "7",
"8", "9", "A", "B",
"C", "D", "E", "F" );
var code1 = Math.floor(dec / 16);
var code2 = dec - code1 * 16;
var decToHex = hexArray[code2];
return (decToHex);
}
original source - http://programming.top54u.com/post/Javascript-Convert-Decimal-to-Hex.aspx
