selection_box.coffee

class @Rectangle
  constructor: (@left, @top, @width, @height) ->

  expand: (amount) ->
    yamount = amount / @width * @height

    new Rectangle(
      @left - amount
      @top - yamount
      @width + amount * 2
      @height + yamount * 2
    )

  fitIn: (rectangle) ->
    newRectangle = new Rectangle(@left, @top, @width, @height)

    factor = rectangle.width / rectangle.height
    boundsFactor = @width / @height

    if factor > boundsFactor
      newWidth = @height * factor
      newRectangle.left -= (newWidth - @width) / 2
      newRectangle.width = newWidth
    else
      factor = rectangle.height / rectangle.width
      newHeight = @width * factor
      newRectangle.top -= (newHeight - @height) / 2
      newRectangle.height = @width * factor

    newRectangle