Compressing base64 data uri images

Question

Problem

I\'m creating multiple charts that are then sent to the server to create a PDF. This data can get large.

Question

Answer 1

I finally got this working with fairly large files.

To do it, I used lz-string, as shown above.

There is one issue though, which is that sending UTF-16 data via ajax is deprecated, so.. it doesn't work. The fix is to convert to and from UTF-16 and UTF-8.

Here's the conversion code I'm using. I'm not sure what the standard endian is, btw:

var UTF = {};

UTF.U16to8 = function(convertMe) {
var out = "";
  for(var i = 0; i < convertMe.length; i++) {
      var charCode = convertMe.charCodeAt(i);
      out += String.fromCharCode(~~(charCode/256));
      out += String.fromCharCode(charCode%256);
    }
  return out;
}

UTF.U8to16 = function(convertMe) {
  var out = ""
  for(var i = 0; i < convertMe.length; i += 2) {
    var charCode = convertMe.charCodeAt(i)*256;
    charCode += convertMe.charCodeAt(i+1);
    out += String.fromCharCode(charCode)
  }
  return out;
}

If you're using Node.js, this code works on both sides. If not, you'll have to write your own version of these converters for the server side.

Phew! What a day this was.