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首先引入exif.js文件，可通过 npm install exif-js --save 下载
<body>
<label>照相机</label>
<input type="file" accept="image/*" onchange="selectFileImage(this);" />
<img src="" id="img" width="200px">
</body>
<script src="exif.js" type="text/javascript" charset="utf-8"></script>
<script type="text/javascript">
var file = document.querySelector('input');
var img_show = document.getElementById('img');
var box = document.getElementById('box');
function selectFileImage(fileObj) {
var file = fileObj.files['0'];
//图片方向角 added by lzk
var Orientation = null;
if (file) {
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;
}
//获取照片方向角属性，用户旋转控制
EXIF.getData(file, function() {
EXIF.getAllTags(this);
Orientation = EXIF.getTag(this, 'Orientation');
});
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;
//修复ios
if (navigator.userAgent.match(/iphone/i)) {
//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 {
console.log(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);
}
img_show.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;
//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 = 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);
}
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>
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