Returns a data URI containing a representation of the image in the format specified by type (defaults to 'image/png').
Data Uri format is as follow data:[<MIME-type>][;charset=<encoding>][;base64],<data>
Optional parameter quality
in the range of 0.0 and 1.0 can be used when requesting type
'image/jpeg' or 'image/webp'. If quality
is not passed the default value is used. Note: the default value varies by browser.
If the height or width of this canvas element is 0, then 'data:' is returned, representing no data.
If the type requested is not 'image/png', and the returned value is 'data:image/png', then the requested type is not supported.
Example usage:
CanvasElement canvas = new CanvasElement(); var ctx = canvas.context2D ..fillStyle = "rgb(200,0,0)" ..fillRect(10, 10, 55, 50); var dataUrl = canvas.toDataUrl("image/jpeg", 0.95); // The Data Uri would look similar to // 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUA // AAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO // 9TXL0Y4OHwAAAABJRU5ErkJggg==' //Create a new image element from the data URI. var img = new ImageElement(); img.src = dataUrl; document.body.children.add(img);
See also:
Data URI Scheme from Wikipedia.
HTMLCanvasElement from MDN.
toDataUrl from W3C.
String toDataUrl([String type = 'image/png', num quality]) => _toDataUrl(type, quality);
© 2012 the Dart project authors
Licensed under the Creative Commons Attribution-ShareAlike License v4.0.
https://api.dartlang.org/stable/2.0.0/dart-html/CanvasElement/toDataUrl.html