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/
<script type="text/javascript" src="js/exif.js" ></script>
HTML
<input @change="selectFileImage" class="weui-uploader__input" type="file" accept="image/*" multiple />
JS
/**
* 选择图片
*/
function selectFileImage(e) {
let file = e.target.files[0];
//图片方向角 added by lzk
var Orientation = null;
if (file) {
console.log("正在上传,请稍后...");
console.log("size=" + formatSize(file.size));
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);
html.showTooltips('请选择jpeg、png格式的图片');
return;
}
// var URL = URL || webkitURL;
//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 img_size = file.size;
console.log("img_size=" + img_size);
let quality = 1;
if (img_size <= 1024 * 1024) {
quality = 1.0;
} else if (img_size <= 2048 * 1024) {
quality = 0.8;
} else if (img_size <= 3072 * 1024) {
quality = 0.7;
} else if (img_size <= 4096 * 1024) {
quality = 0.6;
} else if (img_size <= 5125 * 1024) {
quality = 0.5;
} else {
quality = 0.4;
}
console.log("quality=" + quality);
var base64 = null;
//修复ios
if (navigator.userAgent.match(/iphone/i)) {
console.log('iphone');
console.log(expectWidth + ',' + expectHeight);
console.log(Orientation);
//如果方向角不为1,都需要进行旋转 added by lzk
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); //转两次
rotateImg(this, 'right', canvas);
break;
}
}
base64 = canvas.toDataURL("image/jpeg", quality);
} else if (navigator.userAgent.match(/Android/i)) {
// 修复android
//var encoder = new JPEGEncoder();
//base64 = encoder.encode(ctx.getImageData(0, 0, expectWidth, expectHeight), 80);
// base64码
// var base64 = e.target.result; //或e.target都是一样的
base64 = canvas.toDataURL("image/jpeg", quality);
} else {
console.log(Orientation);
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); //转两次
rotateImg(this, 'right', canvas);
break;
}
}
base64 = canvas.toDataURL("image/jpeg", quality);
}
//计算base64文件流大小
var strLength = base64.length;
var fileLength = parseInt(strLength - (strLength / 8) * 2);
// 由字节转换为KB
var size = "";
size = (fileLength / 1024).toFixed(2);
console.log("base64=" + size);
//调用
html.updateShopLogo(base64);
};
};
oReader.readAsDataURL(file);
}
}
/**
* 对图片旋转处理
* @param {Object} img
* @param {Object} direction
* @param {Object} canvas
*/
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 = 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);
}
//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;
}
}
/**
* 图片大小
*/
function formatSize(size, len, units) {
let unit;
units = units || ['B', 'K', 'M', 'G', 'TB'];
while ((unit = units.shift()) && size > 1024) {
size = size / 1024;
}
return (unit === 'B' ? size : size.toFixed(len === undefined ? 2 : len)) + unit;
}