从Base64字符串转换为PNG文件 [英] Convert from Base64 String to PNG File

问题描述

我正在尝试使用以下方法将base64编码的字符串转换为图像对象。

I am trying to convert a base64 encoded string to an image object using the method below.

function gotFileWriter(writer) {
    console.log('Starting gotFileWriter');
    writer.onwrite = function (evt) {
        console.log("write success");
    };

    $.mobile.showPageLoadingMsg();
    //        console.log('height: ' + cb_canvas.height);
    //        console.log('width: ' + cb_canvas.width);
    Signaturebase64 = cb_canvas.toDataURL();

    //I need to save the base64 string to a PNG image on the Phone here.  
    writer.write(Signaturebase64 );

    $.mobile.hidePageLoadingMsg();
    $.mobile.changePage("#MyJob");
    console.log('Finished gotFileWriter');
}

行：

Signaturebase64 = cb_canvas.toDataURL();

按预期工作并返回我的base64字符串。

Works as expected and gives me back my base64 string.

我现在想做的是将它转换为手机持久存储上的图像文件。

What I would like to do now is to convert it to an image file on the phone's persistent storage.

以下行是将base64字符串写入存储，但我想要它将其保存为PNG文件：

The following line is writing the base64 string to the storage but what I want it to do is save it as a PNG file instead:

writer.write(filedata);

推荐答案

你不能使用PhoneGap FileWriter写二进制文件数据。您需要编写一个插件来将base64编码数据发送到本机端，将其编码为二进制文件，然后使用本机代码编写它。

You can't use the PhoneGap FileWriter to write binary data. You'd need to write a plugin to send your base64 encoded data to the native side, encode it into binary then write it using native code.

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