old_contents: var SCREEN_WIDTH = 680
    , SCREEN_HEIGHT = 960
    , SCREEN_CENTER_Y = SCREEN_WIDTH / 2
    , SCREEN_CENTER_X = SCREEN_HEIGHT / 2;
  
  tm.main(function() {
    var app = tm.app.CanvasApp("#world");
    app.resize(SCREEN_WIDTH, SCREEN_HEIGHT);
  
    app.fitWindow();
    app.background = "rgba(250, 250, 250, 1.0";
    app.replaceScene( GameScene() );
  });
  
  tm.define("GameScene", {
    superClass: "tm.app.Scene",
  
    init: function() {
      this.superInit();
    }
  });
  
new_contents: var SCREEN_WIDTH = 680
    , SCREEN_HEIGHT = 960
    , SCREEN_CENTER_Y = SCREEN_WIDTH / 2
    , SCREEN_CENTER_X = SCREEN_HEIGHT / 2;
  
  tm.main(function() {
    var app = tm.app.CanvasApp("#world");
    app.resize(SCREEN_WIDTH, SCREEN_HEIGHT);
  
    app.fitWindow();
    app.background = "rgba(250, 250, 250, 1.0)";
    app.replaceScene( GameScene() );
  });
  
  tm.define("GameScene", {
    superClass: "tm.app.Scene",
  
    init: function() {
      this.superInit();
    }
  });
  
subject: Repair background setting.