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(function(labitrack){
labitrack.utils = {};
labitrack.utils.new_context = function(w, h){
var canvas = document.createElement('canvas');
canvas.width = w;
canvas.height = h;
return canvas.getContext('2d');
};
// Color quantization using Euclidean distance
// https://en.wikipedia.org/wiki/Euclidean_distance
// We don't do any alpha blending for now
labitrack.utils.convert_to_monochrome = function(data){
var p = data.data;
for(var i = 0, l = p.length; i < l; i+=4) {
var v = (p[i+3] === 0 // handle alpha
||
(Math.pow(p[i], 2) + Math.pow(p[i+1], 2) + Math.pow(p[i+2], 2))
>
(Math.pow(255-p[i], 2) + Math.pow(255-p[i+1], 2) + Math.pow(255-p[i+2], 2))
) * 255;
p[i] = p[i+1] = p[i+2] = v;
p[i+3] = 255;
}
};
labitrack.utils.time = function(callback){
var start = Date.now();
var end = start;
callback();
end = Date.now();
return end - start;
};
}(labitrack));
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