Is there a way to draw partially loaded progressive Image objects (PNG, JPG) into canvas?
Most browsers support progressive loading in the tag, but I can't find how it can be controlled in within canvas.
The answer is no, as per the specification's orders.
If a browser does happen to do this, it is against the spec, which states:
If the image isn't yet fully decoded, then nothing is drawn.
When an img element is in the completely available state and the user agent can decode the media data without errors, then the img element is said to be fully decodable.