Function backgroundMask

kinetic.js:4730–4752

(idata, threshold)

	}

	function backgroundMask(idata, threshold) {
		var rgbv_no = pixelAt(idata, 0, 0);
		var rgbv_ne = pixelAt(idata, idata.width - 1, 0);
		var rgbv_so = pixelAt(idata, 0, idata.height - 1);
		var rgbv_se = pixelAt(idata, idata.width - 1, idata.height - 1);


		var thres = threshold || 10;
		if (rgbDistance(rgbv_no, rgbv_ne) < thres && rgbDistance(rgbv_ne, rgbv_se) < thres && rgbDistance(rgbv_se, rgbv_so) < thres && rgbDistance(rgbv_so, rgbv_no) < thres) {

			// Mean color
			var mean = rgbMean([rgbv_ne, rgbv_no, rgbv_se, rgbv_so]);

			// Mask based on color distance
			var mask = [];
			for (var i = 0; i < idata.width * idata.height; i++) {
				var d = rgbDistance(mean, [idata.data[i * 4], idata.data[i * 4 + 1], idata.data[i * 4 + 2]]);
				mask[i] = (d < thres) ? 0 : 255;
			}

			return mask;
		}
	}

	function applyMask(idata, mask) {
		for (var i = 0; i < idata.width * idata.height; i++) {