/// <summary>
/// sets drawingtool to the Linetool
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnLine_CheckedChanged(object sender, EventArgs e)
{
drawingTool = new LineTool(pictureBox1);
showColors();
}
/// <summary>
/// sets drawingtool to the Polygontool
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void Fill_CheckedChanged(object sender, EventArgs e)
{
drawingTool = new DrawPolygon(pictureBox1);
showColors();
}