问题描述
我正在尝试使用FileSaver.js下载从我的快递应用程序提供的PNG文件。这些文件是作为base64编码的字符串发送的,但是当我尝试使用FileSaver.js来保存它们时,它们就会被破坏。
I'm trying to use FileSaver.js to download PNG files that are being served from my express app. The files are being sent as base64 encoded strings, but when I try to use FileSaver.js to save them they become corrupted.
这就是我想要的方式保存它们:
This is the way I'm trying to save them:
var blob = new Blob([base64encodedString], {type: "data:image/png;base64"});
saveAs(blob, "image.png");
我也使用这种保存图像的方法,但是如果base64encodedString它不起作用变得太大了:
I've also used this method of saving the images, but it doesn't work if the base64encodedString becomes too large:
var download = document.createElement('a');
download.href = 'data:image/png;base64,' + base64encodedString;
download.download = 'reddot.png';
download.click();
FileSaver.js我做错了什么?
What am I doing wrong with the FileSaver.js?
推荐答案
我发现你可能想先将它写入Canvas。
I've found that you'll probably want to write it to a Canvas first.
base_image = new Image();
base_image.src = Base64String
canvas in blob
canvas into a blob
var canvas = document.getElementById('YourCanvas');
context = canvas.getContext('2d');
// Draw image within
context.drawImage(base_image, 0,0);
然后你可以使用FileSaver.js保存它
then you can use FileSaver.js to save it
最后保存它
x_canvas.toBlob(function(blob) {
saveAs(blob, "screenshot.png");
}, "image/png");
在帖子中也创建了一个很好的小提琴
A nice fiddle was also created for this in that post Click Here For Fiddle
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