ysbcc.github.io/can.html at master · ysbcc/ysbcc.github.io · GitHub

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<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta http-equiv="content-type" content="text/html;charset=utf-8" />
<meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1,maximum-scale=1,user-scalable=no,minimal-ui" />

<title>人脸识别 & canvas应用</title>
<head>
<style>
img {width:200px;}
div {margin:10px;}
.notice {
	padding:5px;
border: dotted 2px #999999;
width: 300px;
background: #eeeeee;
}
.face {
            position: absolute;
            border: 2px solid #FFF;
        }
</style>
</head>
<body>
	<div class="notice">
		该demo包括：
		<ul style="margin:0px">
			<li>读取本地图片base64信息</li>
			<li>读取图片Exif信息，自动旋转图片</li>
			<li>人脸识别，找出图片中的脸部区域</li>
			<li>将多个图片绘制进canvas</li>
			<li>将canvas输出到图片</li>
		</ul>
	</div>
	<div>
		选择照片：<input type="file" id="file" />
	</div>
	<div>
		<img id="logo" src="/images/font.png" />
	</div>
	<div id="tips" style="color: #666666;"></div>
	<div>
        <canvas width=300 height=276 id="thecanvas" style="border: 1px #999999 solid;"></canvas>
    </div>
	<div>
		<canvas width=1200 height=1200 id="precanvas" style="border: 1px #999999 solid;"></canvas>
	</div>
	<div>
		<button id="saveImageBtn">Save Image</button>
        <button id="downloadImageBtn">Download Image</button>
    </div>
	<div>
		<pre id="imgExif">
		</pre>
	</div>
	<div>
		<img src id="can2img" alt="canvas to image" />
	</div>


</body>
<script src="http://libs.baidu.com/jquery/2.0.0/jquery.js"></script>
<script src="./javascripts/exif.js"></script>
<script src="/javascripts/jquery.facedetection.js"></script>
<script>
	var $e = function (a){
		return "string"==typeof a ? document.getElementById(a) : a;
	}

	var canvas = $e("thecanvas");
	var ctx = canvas.getContext("2d");
	window.onerror = function (msg,url,l){
		var txt = "Error: " + msg + "\n";
		txt+="URL: " + url + "\n";
		txt+="Line: " + l + "\n\n";
		txt+="Click OK to continue.\n\n";
		//alert(txt);
		window.a = new Image();
		a.src = "/?err=" + txt;
		return true;
	}

	window.onload = function() {

		if (!window.FileReader){
			alert("not support window.FileReader!");
		}

		draw();
		var saveButton = $e("saveImageBtn");
		bindButtonEvent(saveButton, "click", saveImageInfo);

		var dlButton = $e("downloadImageBtn");
		bindButtonEvent(dlButton, "click", saveAsLocalImage);

		$("#file").on("change", function(e){
			if (this.files.length){
				$e("tips").innerHTML = "正在读取照片并识别人脸..";

				getFileUrl(this.files[0], function(url){
					startRender(url);
				});
			}
		});
	};

	function startRender(url){
		var bottom = new Image();
		bottom.src = url;

		bottom.onload = function(){

			readExif(bottom, function(){

				ctx.clearRect(0,0,canvas.width,canvas.height);
				var otn = EXIF.getTag(bottom, 'Orientation') || 1;

				var degree = fixOrientation(otn);

				var pre_can = $e("precanvas");
				var pre_ctx = pre_can.getContext("2d");

				if (bottom.naturalWidth < pre_can.width){
					pre_can.width = bottom.naturalWidth;
				}
				//pre_can = bottom.naturalWidth;
				pre_can.height = bottom.naturalHeight * pre_can.width / bottom.naturalWidth;

				//设置旋转点到画布中心
				pre_ctx.translate(pre_can.width/2,pre_can.height/2);

				//旋转画布，为了修正图片方向
				pre_ctx.rotate(degree);

				pre_ctx.drawImage(bottom, -pre_can.width/2, -pre_can.height/2, pre_can.width, pre_can.height);

				//再切换回来
				pre_ctx.rotate(-degree);
				pre_ctx.translate(-pre_can.width/2,-pre_can.height/2);

				//人脸识别
				$(pre_can).faceDetection({
					interval: 1,
					complete: function (faces) {
						console.log(faces);
						//console.log(faces.length);

						$('.face').remove();

						//人脸识别可能有误判，因此获取最大的那张脸
						var biggest = 0;
						for (var i = 0; i < faces.length; i++) {
                            $('<div>', {
                                'class':'face',
                                'css': {
                                    'position': 'absolute',
                                    'left':     faces[i].offsetX + 'px',
                                    'top':      faces[i].offsetY + 'px',
                                    'width':    faces[i].width  + 'px',
                                    'height':   faces[i].height + 'px'
                                }
                            })
                            .insertAfter(this);

							if (i && faces[biggest].width < faces[i].width){
								biggest = i;
							}
                        }

						if (faces.length){
							var msg = "识别出" + faces.length + "张人脸";
							if (faces.length > 1){
								msg = msg + ",取脸最大的那张";
							}

							$e("tips").innerHTML = msg;
							ctx.drawImage(pre_can, Math.floor(faces[biggest].x), Math.floor(faces[biggest].y),
							Math.floor(faces[biggest].width*1.1), Math.floor(faces[biggest].height*1.3),
							170, 95, 65, 82);
						}
						else{
							//没有识别出人脸
							$e("tips").innerHTML = "oops, 没识别出人脸";
							ctx.drawImage(pre_can, 0, 0, canvas.width,
							bottom.naturalHeight * canvas.width / bottom.naturalWidth);
						}

						//ctx.clearRect(0,240,canvas.width, canvas.height - 240);

						var font = $e("logo");
						var font_height = font.naturalHeight * canvas.width/font.naturalWidth;
						ctx.drawImage($e("logo"), 0, 0, canvas.width, font_height);
					},
					error:function (code, message) {
						//alert('Error: ' + message);
						$e("tips").innerHTML = code + " 脸部识别出错：" + message;
					}
				});

			});

		};
	}

	//调整图片方向
	function fixOrientation(otn){
		//参考 http://blog.csdn.net/ouyangtianhan/article/details/29825885
		var degree = 90 * Math.PI / 180;
		switch(otn){
			case 1:
				degree = 0;
				break;
			case 3:
				degree *= -1;
				break;
			case 5:
				degree *= 1;
				break;
			case 6:
				degree *= 1;
				break;
			case 7:
				degree *= 1;
				break;
			case 8:
				degree *= -1;
				break;
			default:
				degree = 0;
				break;
		};

		return degree;
	}

	function readExif(img, cb){
		//参考 http://code.ciaoca.com/javascript/exif-js/

		EXIF.getData(img, function(){
			$("#imgExif").html("图片Exif信息：\r\n" + EXIF.pretty(this));
			cb();
			//
			//EXIF.getTag(this, 'Orientation');
		});
	}


	/**
	* 从 file 域获取 本地图片 url
	*/
	function getFileUrl(img, cb) {
		var url;

		/* 安卓不支持
		if (navigator.userAgent.indexOf("MSIE")>=1) { // IE
			url = img.value;
		}
		else {
			url = window.URL.createObjectURL(img.files.item(0));
		}
		return url;
		*/

		var reader = new FileReader();
		reader.onload = function(e){
			cb(e.target.result);
		};
		reader.readAsDataURL(img);
	}


	function draw(){
		/*
		ctx.fillStyle = "rgba(125, 46, 138, 0.5)";
		ctx.fillRect(25,25,100,100);
		ctx.fillStyle = "rgba( 0, 146, 38, 0.5)";
		ctx.fillRect(58, 74, 125, 100);
		ctx.fillStyle = "rgba( 0, 0, 0, 1)"; // black color
		*/
		ctx.fillText("画图区域", 120, 140);
	}

	function bindButtonEvent(element, type, handler)
	{
		   if(element.addEventListener) {
			  element.addEventListener(type, handler, false);
		   } else {
			  element.attachEvent('on'+type, handler);
		   }
	}

	function saveImageInfo ()
	{
		var mycanvas = $e("thecanvas");
		var image    = mycanvas.toDataURL("image/png");

		var can2img = $e("can2img");
		can2img.src=image;
		var w=window.open('about:blank','image from canvas');
		w.document.write("<img src='"+image+"' alt='from canvas'/>");
	}

	function saveAsLocalImage () {
		var myCanvas = $e("thecanvas");
		// here is the most important part because if you dont replace you will get a DOM 18 exception.
		// var image = myCanvas.toDataURL("image/png").replace("image/png", "image/octet-stream;Content-Disposition: attachment;filename=foobar.png");
		var image = myCanvas.toDataURL("image/png").replace("image/png", "image/octet-stream");
		window.location.href=image; // it will save locally
	}
</script>
</html>