class CannonField < Qt::Widget
  signals 'angleChanged(int)', 'forceChanged(int)'
  slots 'setAngle(int)', 'setForce(int)'
  
  def initialize(parent = nil)
    super()

    @currentAngle = 45
    @currentForce = 0

    setPalette(Qt::Palette.new(Qt::Color.new(250, 250, 200)))
    setAutoFillBackground(true)
  end

  def setAngle(angle)
    if angle < 5
      angle = 5
    elsif angle > 70
      angle = 70
    end

    if @currentAngle == angle
      return
    end

    @currentAngle = angle
    update(cannonRect())
    emit angleChanged(@currentAngle)
  end
  
  def setForce(force)
    if force < 0
      force = 0
    end
    if @currentForce == force
      return
    end

    @currentForce = force
    emit forceChanged(@currentForce)
  end

  def paintEvent(event)
    painter = Qt::Painter.new(self)

    painter.setPen(Qt::NoPen)
    painter.setBrush(Qt::Brush.new(Qt::blue))

    painter.translate(0, height())
    painter.drawPie(Qt::Rect.new(-35, -35, 70, 70), 0, 90 * 16)
    painter.rotate(-@currentAngle)
    painter.drawRect(Qt::Rect.new(30, -5, 20, 10))
    painter.end()
  end

  def cannonRect()
    result = Qt::Rect.new(0, 0, 50, 50)
    result.moveBottomLeft(rect().bottomLeft())
    return result
  end
end