在进行移动端手机照片上传时,iOS手机上传竖拍照片逆时针旋转90度,横排则无此问题;安卓手机则没这个问题。

因此解决这个问题的思路是:获取到照片拍摄的方向角,对非横拍的iOS照片进行角度旋转修正。

利用exif.js读取照片的拍摄信息,详见:http://code.ciaoca.com/javascript/exif-js/

主要代码如下:

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <meta name="viewport" content="initial-scale=1.0, maximum-scale=1.0, user-scalable=no" />
    <title>图片上传</title>
    <script type="text/javascript" src="js/jquery-1.8.3.js"></script>
    <script type="text/javascript" src="js/exif.js" ></script>
</head>
<body>
    <div style="height: 50px; line-height: 50px;text-align: center;border-bottom: 1px solid #171E28;">
		上传图片:
		<input type="file" accept="image/*" id="uploadImage" capture="camera" onchange="selectFileImage(this);" />    //调取手机摄像头的属性
	</div>
	<div style="margin-top: 10px;">
		<img alt="preview" src="" id="myImage" width="180" />
	</div>
</body>
</html>
<script>

$('#uploadImage').on('change',function(){
	selectFileImage(this);
});

function selectFileImage(fileObj) {
	var file = fileObj.files['0'];
	//图片方向角 added by lzk
	var Orientation = null;

	if (file) {
		console.log("正在上传,请稍后...");
		var rFilter = /^(image\/jpeg|image\/png)$/i; // 检查图片格式
		if (!rFilter.test(file.type)) {
			console.log("请选择jpeg、png格式的图片");
			return;
		}
		//获取照片方向角属性,用户旋转控制
		EXIF.getData(file, function() {
			// alert(EXIF.pretty(this));
			EXIF.getAllTags(this);
			//alert(EXIF.getTag(this, 'Orientation'));
			Orientation = EXIF.getTag(this, 'Orientation');
			//return;
		});

		var oReader = new FileReader();
		oReader.onload = function(e) {
			var image = new Image();
			image.src = e.target.result;
			image.onload = function() {
				var expectWidth = this.naturalWidth;
				var expectHeight = this.naturalHeight;
				if (this.naturalWidth > this.naturalHeight && this.naturalWidth > 800) {
					expectWidth = 800;
					expectHeight = expectWidth * this.naturalHeight / this.naturalWidth;
				} else if (this.naturalHeight > this.naturalWidth && this.naturalHeight > 1200) {
					expectHeight = 1200;
					expectWidth = expectHeight * this.naturalWidth / this.naturalHeight;
				}
				var canvas = document.createElement("canvas");
				var ctx = canvas.getContext("2d");
				canvas.width = expectWidth;
				canvas.height = expectHeight;
				ctx.drawImage(this, 0, 0, expectWidth, expectHeight);
				var base64 = null;

				//如果方向角不为1
				if(Orientation != "" && Orientation != 1){
					console.log('旋转处理');
					switch(Orientation){
						case 6://需要顺时针(向左)90度旋转
							console.log('需要顺时针(向左)90度旋转');
							rotateImg(this,'left',canvas);
							break;
						case 8://需要逆时针(向右)90度旋转
							console.log('需要顺时针(向右)90度旋转');
							rotateImg(this,'right',canvas);
							break;
						case 3://需要180度旋转
							console.log('需要180度旋转');
							rotateImg(this,'right',canvas);
							rotateImg(this,'right',canvas);
							break;
					}
				}
				base64 = canvas.toDataURL("image/jpeg", 0.8);
				$("#myImage").attr("src", base64);
				console.log("上传完成,请稍后...");
			};
		};
		oReader.readAsDataURL(file);
	}
}

//对图片旋转处理
function rotateImg(img, direction,canvas) {
	//最小与最大旋转方向,图片旋转4次后回到原方向
	var min_step = 0;
	var max_step = 3;
	if (img == null)return;
	var height = img.height;
	var width = img.width;
	var step = 2;
	if (step == null) {
		step = min_step;
	}
	if (direction == 'right') {
		step++;
		//旋转到原位置,即超过最大值
		step > max_step && (step = min_step);
	} else {
		step--;
		step < min_step && (step = max_step);
	}
	//旋转角度以弧度值为参数
	var degree = step * 90 * Math.PI / 180;
	var ctx = canvas.getContext('2d');
	switch (step) {
		case 0:
			canvas.width = width;
			canvas.height = height;
			ctx.drawImage(img, 0, 0);
			break;
		case 1:
			canvas.width = height;
			canvas.height = width;
			ctx.rotate(degree);
			ctx.drawImage(img, 0, -height);
			break;
		case 2:
			canvas.width = width;
			canvas.height = height;
			ctx.rotate(degree);
			ctx.drawImage(img, -width, -height);
			break;
		case 3:
			canvas.width = height;
			canvas.height = width;
			ctx.rotate(degree);
			ctx.drawImage(img, -width, 0);
			break;
	}
}
</script>

  

12-30 06:11