I'd like to generate images in a bit of asm.js code running on a web worker. And I'd like to regularly posite the latest state of that putation onto a user-visible 2d canvas, together with some other content. Currently I have code which

1. constructs an ImageData object using its constructor, based on a portion of the array buffer used by the asm.js code,
2. calls createImageBitmap to turn the ImageData into an ImageBitmap,
3. transfers that image bitmap from the worker to the GUI thread and
4. uses that ImageBitmap as an argument to CanvasRenderingContext2D.drawImage.

Things work nicely in recent Chrome and Firefox, but Safari 9.1.3 apparently has no createImageBitmap function. How would I do something like the above in a way that works on Safari?

Is there some low-cost encoding of images, short of creating a data:image/png… for it? Is there some other way to turn a byte array into something you can feed to drawImage?

By the way: / currently doesn't list this feature. There is a feature request which you can