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define([    'constants',    'components',    'text!templates/spritesheet.tpl'], function(c, components, template) {        var Spritesheet = Backbone.View.extend({        template: _.template(template),        prepared: false,        events: {        },                initialize: function() {            pubsub.on("filereader.loaded", this._changeFile, this);            this.model.bind('change:file', this.render, this);        },        prepareElements: function() {            this.playground = this.$el.find("#playground").get(0);            this.canvas = this.$el.find("#canvas").get(0);            this.context = this.canvas.getContext('2d');            this.cwidth = this.canvas.width;            this.cheight = this.canvas.height;            this.buffer = null;            this.bctx = null;            this.spritesheet = null;            this.prepared = true;        },        render: function() {                        this.$el.html( this.template() );            return this;        },        prepareBuffers: function(file) {            var self = this;            var spritesheet = new Image();            spritesheet.src = file;            spritesheet.onload = function() {                self.cwidth = self.canvas.width = this.width;                self.cheight = self.canvas.height = this.height;                self.buffer = document.createElement('canvas');                self.bctx = self.buffer.getContext('2d');                self.buffer.width = self.cwidth;                self.buffer.height = self.cheight;                self.bctx.drawImage(this, 0, 0);                self._displayFile();            }        },        _changeFile: function(event) {            var file = event.target.result;            this.model.set({ 'file': file });            if (!this.prepared) this.prepareElements();            this.prepareBuffers(file);        },        _displayFile: function() {            this.context.clearRect( 0, 0, this.cwidth, this.cheight );            this.context.drawImage( this.buffer, 0, 0 );                    }    });    return Spritesheet;});