You may want to look into http://snapsvg.io/. I haven't used it yet but I've heard good things. ;)

(This uses SVGs instead of canvas if that matters, otherwise check out http://www.graphicsjs.org/)

Don't ask wrong questions based on implementations, ask right questions based on use case, business model, requirements. What are you trying to do?

Do you need to build a some kind of simple online banner creator/editor where user can:

1. Upload BG photo
2. Type text
3. Format text
4. Upload icons?

Or do you just need to do the same without 1.step from your code/CLI?

You also may look into SVG solution since it is better for banners.