Question

I am just getting started with Backbone.js, but it looks really interesting…

Right now, I am redoing a previous project that draws various objects (2-3 different model types) into a single HTML5 canvas.

Each object is clickable. There is a event handler for the canvas that gets the location of the click (local to the canvas object) and then searches the objects for one that could produce a hit.

Is there a particular way or best practice that I should use when doing this for a click event on a Backbone.js view?

Thanks!

Update: found fabric.js which seems to handle the idea of objects within a canvas element, but doesn’t provide the MVC style framework as backbone.js.

Also, I took a look at knockout.js. It seems even more tied to HTML elements (not canvas) than backbone.js.

Answer 1

I came across this question because I’m working on a Backbone-based framework for working with canvas, so I grappled with this myself. The answer I eventually came to was: Forget about using Backbone.View with canvas. If it can’t be represented by a DOM element, then it doesn’t make sense to use Backbone.View for it; its properties just don’t map to canvas “elements.”

You could use Backbone.View to represent a single canvas DOM element just fine, mind you, but that’s not the scenario you’re describing. What you need is a custom view class that can represent your in-canvas objects and handle their events.