GPHIGS C FUNCTIONS - PICK WITHOUT INTERACTION

PICK WITHOUT INTERACTION

PXPICK

CALL SEQUENCE

void pxpick(

Pint	ws_id,	/* workstation identifier	(input)	*/
Pint	pick_dev_num,	/* pick device number	(input)	*/
Pint	depth,	/* pick path depth	(input)	*/
Ppoint	*point,	/* located point in DC	(input)	*/
Pin_status	*status,	/* return status	(output)	*/
Ppick_path	*pick_path	/* return pick path	(output)	*/

TYPES

typedef struct {
	Pfloat	x,y;	/* coordinates	*/
} Ppoint;

typedef enum {
	PIN_STATUS_NONE,
	PIN_STATUS_OK,
	PIN_STATUS_NO_IN
} Pin_status;

typedef struct {
	Pint	depth;
	Ppick_path_elem	*path_list;
} Ppick_path;

typedef struct {
	Pint	struct_id;
	Pint	pick_id;
	Pint	elem_pos;
} Ppick_path_elem;

PHIGS STATE

(PHOP,WSOP,*,*)

EFFECT

GPHIGS uses this function to simulate a PICK without interaction. A DC point, coming from an input device external to GPHIGS, is given to this function, and this function return the same information as the function SAMPLE PICK.

Use of this function overcomes the differences in concept between an event-driven model ( MOTIF ) and the classic sequential model required for the use of PHIGS input.

NOTES

If the DC point is obtained as the result of an X event, it is necessary, before sending it to the function, to transform from X device coordinates to GPHIGS device coordinates. The origin of an X window is located at upper-left corner while the origin of a GPHIGS workstation is located at the lower-left corner. It is, therefore, necessary to invert the Y values in the following manner :

point.y = window.height - ev.xbutton.y ;

where window.height is the height in pixels of the X window and ev.xbutton.y is the Y position acquired with the event.

ERRORS

3: Ignoring function, function requires state (PHOP, WSOP,*,*)
54: Ignoring function, the specified workstation is not open