Any way to get touch co-ordinates in Ionic?

This is my markup:

<canvas id="canvas" on-tap="onTap($event)"></canvas>

and this is my angularJS code:

angular.module('ionicApp', ['ionic'])
.controller("wallControl", ['$scope', '$interval', function($scope, $interval) {
    $scope.onTap = function(event) {
    $(".score").text(ionic.tap.pointerCoord(event).x);
};

However, it always returns 0. Am I doing something wrong?

Thanks.