javascript - Canvas.toDataUrl sometimes truncated in Chrome/Firefox -

in html5 version of libgdx game, sometimes canvas.todataurl("image/png") returns truncated string yielding black image.

canvaselement canvas = ((gwtapplication)gdx.app).getcanvaselement(); string dataurl = canvas.todataurl("image/png"); window.open(dataurl, "_blank", ""); 

the odd part works. when work ~100kib image expected, , new window opens address bar saying "data:". can send webservice , translate base64 bytes of proper png , osx preview shows fine too.

when doesn't work new window shows black image of correct dimensions, , address bar base64-encoded data in (starting data:image/png;base64,ivborw0kggoaaaan...), ending in elipsis appears rendered browser ui rather 3 periods in actual data string. data in case ~31kib. when try transcoding via webservice, same black rectangle.

i see happen in both chome , firefox.

any ideas? code canvas contents simple, can't see how can doing wrong. i'm thinking either bug in browsers, or kind of timing issue libgdx , rendering?

this caused libgdx not preserving drawing buffer. libgdx guys kindly fixed in nightly build available.

updating latest build of 1.0-snapshot , setting below flag works reliably:

    @override public gwtapplicationconfiguration getconfig () {     if(config == null)     {         config = new gwtapplicationconfiguration(1280, 960);         config.preservedrawingbuffer = true;     }      return config;  }