private void ellipseTool_Click(object sender, EventArgs e)
 {
     currentTool = tools[2];
 }
 private void cursorTool_Click(object sender, EventArgs e)
 {
     currentTool = tools[0];
 }
 private void rectangleTool_Click(object sender, EventArgs e)
 {
     currentTool = tools[1];
 }
 private void toolStripButton2_Click(object sender, EventArgs e)
 {
     currentTool = tools[3];
 }