Convert the hexadecimal color in css to the rgb format.

Convert the hexadecimal color in css to the rgb format.

 

Function fromHex (color) {/* summary: Convert the css attribute value to an image in rgb format # fff-> 0 xfff length to 4. One character occupies one attribute, 0x10 = 16 (4 to the power of 2, that is, 4 after 1) = 1 0000, then an f is the 1111 placeholder for mask = 1111, used to occupy the last four bits (& used to retain the value of the last four bits). Other High bits are cleared. Each traversal starts from the last four bits, so the B value is obtained first, after the difficulty, move the four digits. After obtaining the g, move the four digits, and get the r, get the B attribute: 0000 1111 1111 1111 0000 & 0000 0000 1111 (only 16 digits are listed here, normally, 32-bit) 0000 0000 0000 1111 B is saved to the variable c 0000 1111 1111 1111> 4,-> 0000 0000 1111 1111 0000 get g attribute 000 0 1111 1111 & 0000 0000 0000 1111 0000 0000 0000 get the value of g, save it to variable c in four places, get the value of r ffffff-> 0 xffffff length is 8, each two characters represents a function 0xff = 1111 1111 each time the last eight digits are obtained, which exactly represents the color value */var t ={}, bits = (color. length = 4 )? 4: 8, // if it is shorthand, # fff, then bits is 4 bits, each representing an attribute, the other values are 8 bits, and each two bits represent an attribute # FFFF00 mask = (1 <bits)-1; // represents a byte placeholder, which shifts four or eight bits to the left, var a = (1 </4)-1-> 10000-1,. toString (2); // 1111, or 8-bit 1111 1111 color = Number (0x + color. substr (1); // # convert ff0000 to hexadecimal 0xff0000; if (isNaN (color) {return null; // Color} [B, g, r]. forEach (function (x) {var c = color & mask; color >>= bits; t [x] = bits = 4? 17 * c: c; // 0 xfff. An f should represent 255. It should be [0-255], divided by 15 equal portions, with an interval of 17. Therefore, the obtained value must be multiplied by 17 to represent the value of 255 in rgb}); t. a = 1; return t; // Color} console. log (fromHex (# 00f) // {r: 0, g: 0, B: 255, a: 1}