SET CURVE APPROXIMATION CRITERIA

PSET_CURVE_APPROX_CRIT

CALL SEQUENCE

void pset_curve_approx_crit (

Pcurve_approx_crit	*data	/* curve approximation criteria data record	*/

)

TYPES

typedef struct {
	Pint	type;		/* curve approximation criteria type	*/
	union Pcurve_approx_crit_data {
		struct Pcurve_approx_const_param_subd {
			Pint	count;	/* value	*/
		} const_param_subd;
		struct Pcurve_approx_chordal_size_wc {
			Pfloat	approx;
		} chordal_size_wc;
		struct Pcurve_approx_chordal_size_npc {
			Pfloat	approx;
		} chordal_size_npc;
		struct Pcurve_approx_chordal_size_dc {
			Pfloat	approx;
		} chordal_size_dc;
		struct Pcurve_approx_chordal_dev_wc {
			Pfloat	approx;
		} chordal_dev_wc;
		struct Pcurve_approx_chordal_dev_npc {
			Pfloat	approx;
		} chordal_dev_npc;
		struct Pcurve_approx_chordal_dev_dc {
			Pfloat	approx;
		} chordal_dev_dc;
		struct Pcurve_approx_rel_wc {
			Pfloat	approx;
		} rel_wc;
		struct Pcurve_approx_rel_npc {
			Pfloat	approx;
		} rel_npc;
		struct Pcurve_approx_rel_dc {
			Pfloat	approx;
		} rel_dc;
	} data;
} Pcurve_approx_crit;

PHIGS STATE

EFFECT

A SET CURVE APPROXIMATION CRITERIA element is inserted in the open structure after element pointer or replaces the element indicated by element pointer, depending on the edit mode value. Element pointer is updated and points to the SET CURVE APPROXIMATION CRITERIA structure element. The values specified in the function are associated with the element.

When an element of this type is interpreted, the current curve approximation criteria entry in the traversal state list is set to the values associated with the element. These values are used when displaying subsequent output primitives when the current curve approximation criteria ASF in the traversal state list is INDIVIDUAL.

Curve approximation criteria TYPES are as follows:

PCURVE_APPROX_WS_DEP workstation dependent

PCURVE_APPROX_CONST_PARAM_SUBD constant parametric subdivision between knots

PCURVE_APPROX_CHORDAL_SIZE_WC chordal size in WC

PCURVE_APPROX_CHORDAL_SIZE_NPC chordal size in NPC

PCURVE_APPROX_CHORDAL_SIZE_DC chordal size in DC

PCURVE_APPROX_CHORDAL_DEV_WC chordal deviation in WC

PCURVE_APPROX_CHORDAL_DEV_NPC chordal deviation in NPC

PCURVE_APPROX_CHORDAL_DEV_DC chordal deviation in DC

PCURVE_APPROX_REL_WC relative in WC

PCURVE_APPROX_REL_NPC relative in NPC

PCURVE_APPROX_REL_DC relative in DC

When an element of this type is interpreted, if the specified approximation type is not available on a workstation, type PCURVE_APPROX_WS_DEP is used.

EXTENSION TO THE PHIGS STANDARD

If GPHIGS is in NRS mode, the effect of this function is different from the effect described in the standard.

In NRS mode, (see OPEN PIPE), the element is not stored in a structure. It is sent to the workstation on which the pipe is opened.

ERRORS

5

Ignoring function, function requires state (PHOP,*, STOP,*)

138

Ignoring function, one or more of the fields in the specified data record is inconsistent with the specified type

SEE ALSO

non-uniform b-spline curve 3, non-uniform b-spline curve 3 with colour, open structure, open pipe (ext), inquire current element content, inquire current element type and size