paper.js how to set up multiple canvases using only javascript

Question

I\'m trying to use paper.js in a webapp, but I\'ve been unable to get it to work with multiple canvases. It\'s like the scopes are getting mixed up between the canvases, so when

Answer 1

I think I found the solution: I expanded the fiddle from @freejosh to also work with callbacks (e.g. resize): The trick is to re-fetch the correct scope inside the callback function:

http://jsfiddle.net/rassoh/mx9n3vsf/7/

var mypapers = [];

initPaper(0, $("#canvas1")[0]);
initPaper(1, $("#canvas2")[0]);

function initPaper(id, canvasElement) {
    var mousePosition = new paper.Point(0,0);
    mypapers[id] = new paper.PaperScope();
    paper = mypapers[id];
    paper.setup(canvasElement);
    var myCircle;

    createCircle = function() {
        if( "undefined" !== typeof myCircle) {
            myCircle.remove();
        }
        // this function is called on resize, so we have to re-fetch the scope!
        paper = mypapers[id];
        myCircle = new paper.Path.Circle(30, 30, 20);
        var lightRed = new paper.Color(1, 0.5, 0.5);
        var lightBlue = new paper.Color(0.5, 0.5, 1);
        myCircle.style = {
            fillColor: id === 0 ? lightRed : lightBlue,
            strokeColor: "black"
        };
    }
    createCircle();

    var tool = new paper.Tool();
    tool.onMouseMove = function(event) {
        mousePosition = event.lastPoint;
    };
    paper.view.onFrame = function() {
        if( "undefined" === typeof myCircle) {
            return;
        }
        var dist = mousePosition.subtract( myCircle.position );
        dist = dist.divide( 3 );
        myCircle.position = myCircle.position.add( dist );
    };
    paper.view.onResize = function() {
        createCircle();
    };
}

$(window).resize(function() {
    var width = $(".container").width() / 2;
    var height = $(".container").height();
    // this automatically triggeres paper's onResize event registered above
    mypapers[0].view.viewSize = new paper.Size( width, height );
    mypapers[1].view.viewSize = new paper.Size( width, height );
});

Please note that I also included a simple interaction with the circles, to also test for correct behaviour there.