@Raddi_On: There are no image data. Only qrcode matrix - i.e. info about rows, columns and cells. You need to use these info (like I do in Elixir example) to get x, y, width and height and color and pass them to Canvas draw and fill functions.
You will export canvas to image - not create canvas from image.
Canvas will allow you to export to more formats than simple png.
Of course nothing stops you from hiding canvas and get base64 string from it after you will done drawing. Then you can add image tag with that base64 string.
you can just use existing Erlang libraries like i.e. 
