canvas - 如何将二进制的canvas元素发送到dart中的服务器

Question

如何在不使用base64加密的情况下使用Dart将canvas元素发送到服务器？

Answer 1

此代码将canvas元素转换为dart的二进制格式:

import 'dart:html';
import 'dart:core';
import 'dart:typed_data';

/*** possible values for imagetype: 'image/jpeg', 'image/png', 'image/webp' 
 *** see https://developer.mozilla.org/en-US/docs/Web/API/HTMLCanvasElement
 ***/
Uint8List toUploadData(CanvasElement canvas, String imagetype, num quality) =>
  new Uint8List.fromList(window.atob(canvas.toDataUrl(imagetype,
      quality).split(",")[1]).codeUnits);

然后可以按以下方式上传:

UploadImageData(Uint8List imagedata) =>
    HttpRequest.request('myserverscript.php',
        method:"POST",
        sendData: imagedata);