解决ios横屏拍照图片自动旋转90度问题

<!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 src="https://cdn.bootcss.com/exif-js/2.3.0/exif.min.js"></script>
    <style>
        * {
            margin: 0;
            padding: 0;
        }
        #app,body,html {
            height: 100%
        }
        body {
            font-size: 12px;
            -webkit-tap-highlight-color: transparent;
            font-family: Helvetica, Arial, sans-serif;
        }
    </style>
</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/png, image/jpeg, image/jpg" id="uploadImage" onchange="selectFileImage(this);" />  
    </div>  
    <img style="width:100%;" id="myImage"/ alt="preview" src="">  
    
    <!-- 微信SDK -->
    <script src="https://res.wx.qq.com/open/js/jweixin-1.2.0.js"></script>
    <!-- 引入zepto -->
    <script src="https://cdn.bootcss.com/zepto/1.2.0/zepto.min.js"></script>
    <script>
                
        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)) {  
                    //showMyTips("请选择jpeg、png格式的图片", false);  
                    return;  
                }  
                // var URL = URL || webkitURL;  
                //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 blob = URL.createObjectURL(file);  
                    //_compress(blob, file, basePath);  
                    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;  
                        //修复ios  
                        if (navigator.userAgent.match(/iphone/i)) {  
                            console.log('iphone');  
                            //alert(expectWidth + ',' + expectHeight);  
                            //如果方向角不为1,都需要进行旋转 added by lzk  
                            if(Orientation != "" && Orientation != 1){  
                                alert('旋转处理');  
                                switch(Orientation){  
                                    case 6://需要顺时针(向左)90度旋转  
                                        alert('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  
                                        alert('需要顺时针(向右)90度旋转');  
                                        rotateImg(this,'right',canvas);  
                                        break;  
                                    case 3://需要180度旋转  
                                        alert('需要180度旋转');  
                                        rotateImg(this,'right',canvas);//转两次  
                                        rotateImg(this,'right',canvas);  
                                        break;  
                                }         
                            }  
                            base64 = canvas.toDataURL("image/jpeg", 0.8);  
                        }else if (navigator.userAgent.match(/Android/i)) {// 修复android  
                            var encoder = new JPEGEncoder();  
                            base64 = encoder.encode(ctx.getImageData(0, 0, expectWidth, expectHeight), 80);  
                        }else{  
                            //alert(Orientation);  
                            if(Orientation != "" && Orientation != 1){  
                                //alert('旋转处理');  
                                switch(Orientation){  
                                    case 6://需要顺时针(向左)90度旋转  
                                        alert('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  
                                        alert('需要顺时针(向右)90度旋转');  
                                        rotateImg(this,'right',canvas);  
                                        break;  
                                    case 3://需要180度旋转  
                                        alert('需要180度旋转');  
                                        rotateImg(this,'right',canvas);//转两次  
                                        rotateImg(this,'right',canvas);  
                                        break;  
                                }         
                            }  
                            base64 = canvas.toDataURL("image/jpeg", 0.8);  
                        }  
                        //uploadImage(base64);  
                        document.getElementById('myImage').src = base64
                    };  
                };  
                oReader.readAsDataURL(file);  
            }  
        }  
        
        //对图片旋转处理 added by lzk  
        function rotateImg(img, direction,canvas) {    
            //alert(img);  
            //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;    
            //var img = document.getElementById(pid);    
            if (img == null)return;    
            //img的高度和宽度不能在img元素隐藏后获取,否则会出错    
            var height = img.height;    
            var width = img.width;    
            //var step = img.getAttribute('step');    
            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);    
            }    
            //img.setAttribute('step', step);    
            /*var canvas = document.getElementById('pic_' + pid);   
            if (canvas == null) {   
                img.style.display = 'none';   
                canvas = document.createElement('canvas');   
                canvas.setAttribute('id', 'pic_' + pid);   
                img.parentNode.appendChild(canvas);   
            }  */  
            //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>
</body>  

</html>  

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转载自www.cnblogs.com/lanshengzhong/p/9008562.html