proc redline :  redbutton_clicked
{
	if(redbutton_clicked == true)
	{
		currentColour = "red";
	}
}

proc greenline :  greenbutton_clicked
{
	if(greenbutton_clicked == true)
	{
		currentColour = "green";
	}    
}

proc blueline :  bluebutton_clicked
{
	if(bluebutton_clicked == true)
	{
		currentColour = "blue";
	}    
}

proc colourMode: currentColour
{
	if(currentColour =="red")
	{
		greenX=greenX;
		greenY=greenY;
		redX is mouseClickX-errorX;
		redY is mouseClickY-errorY;
	}
	else if(currentColour == "green")
	{
		redX=redX;
		redY=redY;
		greenX is mouseClickX-errorX;
	    greenY is mouseClickY-errorY;
	}
	else if(currentColour == "blue")
	{
		redX=redX;
		redY=redY;
		greenX is mouseClickX-errorX;
	    greenY is mouseClickY-errorY;
	}
	else
	{
	}
}