tracking.js页面人脸识别插件使用方法

var video = document.getElementById('video');
var canvas = document.getElementById('canvas');
var context = canvas.getContext('2d');
var tracker = new tracking.ObjectTracker('face');
 tracker.setInitialScale(4);
 tracker.setStepSize(2);
 tracker.setEdgesDensity(0.1);

 tracking.track('#video', tracker, { camera: true });

 tracker.on('track', function(event) {
 context.clearRect(0, 0, canvas.width, canvas.height);

 event.data.forEach(function(rect) {
 context.strokeStyle = '#a64ceb';
 context.strokeRect(rect.x, rect.y, rect.width, rect.height);
 context.font = '11px Helvetica';
 context.fillStyle = "#fff";
 context.fillText('x: ' + rect.x + 'px', rect.x + rect.width + 5, rect.y + 11);
 context.fillText('y: ' + rect.y + 'px', rect.x + rect.width + 5, rect.y + 22);
 });
 });`

var canvas = $('canvas'),
 context = canvas.getContext('2d'),
 video = $('video');
context.drawImage(video, 0, 0, 200, 150);
var snapData = canvas.toDataURL('image/png'),
var imgSrc = "data:image/png;" + snapData;