如何使用PhysicsJS向画布添加文本

Question

I'm doing a simple project with Physics.JS and I want to be able to add text to a PhysicsJS World. I looked in the documentation but I couldn't find something that can allow me to do such thing. Is there a way to add text and to also be able to manipulate parts of it, like increasing velocity, restitution and other things from the engine?

Answer 1

Just extend a rectangle body, and change its view to a canvas with text on it:

 Physics.body('text', 'rectangle', function (parent) {
      var canv = document.createElement('canvas');
      canv.width = 310;
      canv.height = 60;
      var ctx  = canv.getContext("2d");
      ctx.fillStyle = "#ffffff";
      ctx.textAlign = "left"
      ctx.textBaseline = "top";
      ctx.font = "80px sans-serif";

      return {
           // Called when the body is initialized
           init: function(options) {
               parent.init.call(this, options);
               ctx.fillText(options.text,0,0);
            },
            // Called when the body is added to a world
            connect: function() {
                this.view = canv;
            }
      }
  });

Then, to instantiate it:

 Physics.body('text', {
     x: 400,
     y: 570,
     width: 310,
     height: 60,
     text: "Some text here",
 })

You specify the string of text via options.text .
Of-course, one would make it more dynamic, by allowing to specify the font parameters in the options, then auto-calculate the dimension on init, and so on...