canvas-loop/index.js

canvas loop/scale utility

var fitter = require('canvas-fit')
var loop = require('raf-loop')

module.exports = function (canvas, opt) {
  if (!canvas) {
    throw new TypeError('must specify a canvas element')
  }
  
  opt = opt || {}
  var fit = fitter(canvas, opt.parent, opt.scale)
  var app = loop()
  var shape = [0, 0]

  resize()

  window.addEventListener('resize', function () {
    resize()
    app.emit('resize')
  }, false)

  Object.defineProperties(app, {
    scale: {
      get: function () {
        return fit.scale
      },
      set: function (s) {
        fit.scale = s
      }
    },
    shape: {
      get: function () {
        return shape
      }
    },
    parent: {
      get: function () {
        return fit.parent
      },
      set: function (p) {
        fit.parent = p
      }
    }
  })

  return app

  function resize () {
    fit()
    var deviceWidth = canvas.width
    var deviceHeight = canvas.height
    shape[0] = deviceWidth / fit.scale
    shape[1] = deviceHeight / fit.scale
  }
}