I have a canvas that shows digits, rising ,until its green color changes to red and stop numbering.
i want to warn me just on time its color changes to red or any time in this period before getting red.please guide me
<canvas id="qrlsa" width="575" height="359" style="width: 575px; height: 359px;"></canvas>
Please see the sample movie on youtube:
My code:
function getAverageRGB(imgEl) {
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;
}
setInterval(function() {
var rgb = getAverageRGB(document.getElementById('qrlsa'));
document.body.style.backgroundColor = 'rgb('+rgb.r+','+rgb.g+','+rgb.b+')';
//if (rgb.r>10) {
//alert(rgb.r+','+rgb.g+','+rgb.b);
//}
}, 1);