You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
51 lines
1.3 KiB
51 lines
1.3 KiB
import { single as validate } from "validate.js";
|
|
|
|
export function validateValue(value: string, constraints: any) {
|
|
return <string>(validate(value || null, constraints) ?? [""])[0];
|
|
}
|
|
|
|
export function getAverageRgb(imgEl: HTMLImageElement) {
|
|
|
|
var blockSize = 5, // only visit every 5 pixels
|
|
defaultRGB = {r:0,g:0,b:0}, // for non-supporting envs
|
|
canvas = document.createElement('canvas'),
|
|
context = canvas.getContext && canvas.getContext('2d'),
|
|
data, width, height,
|
|
i = -4,
|
|
length,
|
|
rgb = {r:0,g:0,b:0},
|
|
count = 0;
|
|
|
|
if (!context) {
|
|
return defaultRGB;
|
|
}
|
|
|
|
height = canvas.height = imgEl.naturalHeight || imgEl.offsetHeight || imgEl.height;
|
|
width = canvas.width = imgEl.naturalWidth || imgEl.offsetWidth || imgEl.width;
|
|
|
|
context.drawImage(imgEl, 0, 0);
|
|
|
|
try {
|
|
data = context.getImageData(0, 0, width, height);
|
|
} catch(e) {
|
|
/* security error, img on diff domain */alert('x');
|
|
return defaultRGB;
|
|
}
|
|
|
|
length = data.data.length;
|
|
|
|
while ( (i += blockSize * 4) < length ) {
|
|
++count;
|
|
rgb.r += data.data[i];
|
|
rgb.g += data.data[i+1];
|
|
rgb.b += data.data[i+2];
|
|
}
|
|
|
|
// ~~ used to floor values
|
|
rgb.r = ~~(rgb.r/count);
|
|
rgb.g = ~~(rgb.g/count);
|
|
rgb.b = ~~(rgb.b/count);
|
|
|
|
return rgb;
|
|
|
|
}
|