function Brush () {
  Module.call(this, 'brush')

  this.speed = 0
  this.swatch = new Swatch()

  this.pointers = [
    new Pointer({ offset: { x: 0, y: 0 } })
  ]

  this.methods.add = new Method('add', 'x,y&mirror_x,mirror_y', 'Add a new pointer to the brush', function (q) {
    var offset = q.length ? q[0] : q
    var mirror = q.length ? q[1] : null
    ronin.brush.pointers.push(new Pointer({ offset: offset, mirror: mirror }))
  })

  this.methods.remove = new Method('remove', '', 'Remove last pointer', function (q) {
    ronin.brush.pointers.pop()
  })

  this.methods.pick = new Method('pick', 'x,y', "Set brush color to a position's pixel.", function (q) {
    var pixel = (ronin.commander.input_el.value == '~' ? ronin.guide : ronin.cursor.target).context().getImageData(q.x * 2, q.y * 2, 1, 1).data
    var c = new Color().rgb_to_hex(pixel)
    var color = new Color(c)
    ronin.cursor.color = color.hex
  })

  this.methods.set_color = new Method('set_color', '#ff0033', 'Set color', function (q) {
    ronin.cursor.color = q
  })

  this.absolute_thickness = 0

  this.thickness = function (line) {
    var ratio = clamp(1 - (ronin.brush.speed / 20), 0, 1)
    var t = ronin.cursor.size * ratio
    this.absolute_thickness = t > this.absolute_thickness ? this.absolute_thickness + 0.25 : this.absolute_thickness - 0.25
    return this.absolute_thickness
  }

  this.stroke = function (line) {
    this.speed = distance_between(line.from, line.to)

    for (pointer_id in this.pointers) {
      this.pointers[pointer_id].stroke(line)
    }
  }

  this.erase = function (line) {
    this.speed = distance_between(line.from, line.to)

    for (pointer_id in this.pointers) {
      this.pointers[pointer_id].stroke(line, true)
    }
  }

  this.pick = function (line) {
    if (!line.to) {
      line.to = line.from
    }

    var pixel = ronin.cursor.target.context().getImageData(line.to.x * 2, line.to.y * 2, 1, 1).data
  }

  this.mod_size = function (mod) {
    ronin.cursor.size = clamp(parseInt(ronin.cursor.size) + mod, 1, 100)
  }

  function clamp (v, min, max) {
    return v < min ? min : v > max ? max : v
  }

  function distance_between (a, b) {
    return a && b ? Math.sqrt((a.x - b.x) * (a.x - b.x) + (a.y - b.y) * (a.y - b.y)) : 0
  }
}

function Pointer (options) {
  this.options = options

  this.stroke = function (line, erase = false) {
    var ctx = ronin.cursor.target.context()

    if (this.options.mirror) {
      line.from.x = (this.options.mirror.x * 2) - line.from.x
      line.to.x = (this.options.mirror.x * 2) - line.to.x
    }

    if (!line.to) {
      line.to = line.from
    }

    ctx.beginPath()
    ctx.globalCompositeOperation = erase ? 'destination-out' : 'source-over'
    ctx.moveTo((line.from.x * 2) + this.options.offset.x, (line.from.y * 2) + this.options.offset.y)
    ctx.lineTo((line.to.x * 2) + this.options.offset.x, (line.to.y * 2) + this.options.offset.y)
    ctx.lineCap = 'round'
    ctx.lineWidth = ronin.brush.thickness(line)
    ctx.strokeStyle = ronin.brush.swatch.color()
    ctx.stroke()
    ctx.closePath()
  }

  function clamp (v, min, max) {
    return v < min ? min : v > max ? max : v
  }
}