I've been researching about canvas and I know security protocol denies outputting/saving the canvas if it has been tainted.
what I can't seem to get an explanation on is what precisely triggers it to be tainted on my end.
I have a div with a background and some draggable content, and want to save the user-created layout as a .png on my server. However, it keeps blocking it due to the tainted canvas security. All of the images within the div (and page) are housed on my site.
Is there some kind of header permission I need to grant to work around this (without permitting others to use my images cross-source on their canvas, etc)?