我尝试使用以下功能在运行于iOS 8的Cordova / hybrid应用程序上将JPEG的base64字符串转换为blob b64toBlob。
b64toBlob = function(b64, onsuccess, onerror) {
var img = new Image();
img.onerror = onerror;
img.onload = function onload() {
var canvas = document.createElement('canvas');
canvas.width = img.width;
canvas.height = img.height;
var ctx = canvas.getContext('2d');
ctx.drawImage(img, 0, 0, canvas.width, canvas.height);
canvas.toBlob(onsuccess);
};
img.src = b64;
}
但是它给出了一个错误
Uncaught Error: TypeError: undefined is not a function (evaluating 'canvas.toBlob(onsuccess)')
当我们做
var imageData = "data:image/jpeg;base64," + imageData
b64toBlob(imageData,
function(imageBlob) {
uploadBlob(imageBlob)
}, function(error) {
console.log(error)
});
如何解决此错误？
试试看 请注意，dataURI假定包含base64前缀。（例如："data:image/jpeg;base64,"）
function b64toBlob(dataURI) {
var byteString = atob(dataURI.split(',')[1]);
var ab = new ArrayBuffer(byteString.length);
var ia = new Uint8Array(ab);
for (var i = 0; i < byteString.length; i++) {
ia[i] = byteString.charCodeAt(i);
}
return new Blob([ab], { type: 'image/jpeg' });
}
用法：
...
var blob = b64toBlob(imageData);
var formData = new FormData();
formData.append("source", blob);
...
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我来说两句