/* 22.11.16 22:55  N. Vischer

Opens selected object, adds a constriction line of zero length at the 
middle of the "Dia" line, closes object and re-selects it.
If "Constr" already exists, an error message appears.
Can be used in combination with "Navigate" macros.

Note: Installing macro before the ObjectJ menu
was visible causes an "Unidentified Identifier" error.
In this case, bring macro window to front and choose
"Macros>Install Macros" again.

*/

macro "Add Zero Length Constriction [9]"{
	obj = ojSelectedObject();
	if(obj == 0) exit ("No object is selected");
	if(ojNItems("Constr") > 0) exit ("Constriction already exists");
	ojSelectItem("Dia", 1);
	x = (ojXPos(1) +ojXPos(2))/2;
	y = (ojYPos(1) +ojYPos(2))/2;
	ojOpenObject(obj);

	ojSwitchToItem("Constr");
	ojSetMarker(x, y);
	ojSetMarker(x, y);
	ojCloseObject();
	ojSelectObject(obj);
}