SET CURVE APPROXIMATION CRITERIA

PSCACN

CALL SEQUENCE

CALL PSCACN(ACRI,LDR,DATREC)

INPUT PARAMETERS

INTEGER ACRI

Curve approximation criteria type

INTEGER LDR

Length of data record array

CHARACTER*80DATREC(LDR)

Data record

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:

PWDCA workstation dependent

PCBNCA constant parametric subdivision between knots

PCSWCA chordal size in WC

PCNSCA chordal size in NPC

PCSDCA chordal size in DC

PCDWCA chordal deviation in WC

PCDNCA chordal deviation in NPC

PCDDCA chordal deviation in DC

PRWCA relative in WC

PRNCA relative in NPC

PRDCA relative in DC

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

DATREC parameters to build CURVE APPROXIMATION CRITERIA DATA RECORD

For ACRI = 2(PCBNCA) :

The IA array contains :

- The actual data of count

The other arrays are empty.

IL = 1

IA(1) = count

RL = 0

RA = ()

SL =0

LSTR =()

STR =()

DATREC parameters to build CURVE APPROXIMATION CRITERIA DATA RECORD

For ACRI = 3(PCSWCA) or 4(PCSNCA) or 5(PCSDCA) or 6(PCDWCA) or 7(PCDNCA) or 8(PCDDCA) or 9 (PRWCA) or 10(PRNCA) or 11(PRDCA) :

The RA array contains :

- The actual data of approximation value

The other arrays are empty.

IL = 0

IA = ()

RL = 1

RA(1) = approximation value

SL = 0

LSTR = ()

STR = ()

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