pset_curve_approx_crit(3g) — Subroutines

Name

pset_curve_approx_crit − Indicates the minimum quality desired for the approximation of the curve’s geometry.

Operating States: PHOP, ∗, STOP, ∗
PHIGS PLUS function
Creates a structure element

Syntax

void pset_curve_approx_crit (
const Pcurve_approx_crit ∗data /∗ (I) Curve approximation criteria
data record ∗/
)

Data Structures

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

Constants

Data Structure Constants Constant                   Description
---------------------------------------------------------------------------
Curve approximation       PCURVE_APPROX_WS_DEP       Workstation-dependent
types                                                method
                          PCURVE_APPROX_CONST_       Constant parametric
                          PARAM_SUBD                 subdivision between
                                                     knots
                          PCURVE_APPROX_CHORDAL_     Chordal size, in world
                          SIZE_WC                    coordinate units
                          PCURVE_APPROX_CHORDAL_     Chordal size, in
                          SIZE_NPC                   normalized projection
                                                     units
                          PCURVE_APPROX_CHORDAL_     Chordal size, in
                                                     device coordinate
                                                     units
                          PCURVE_APPROX_CHORDAL_     Chordal deviation,
                          DEV_WC                     in world coordinates
                          PCURVE_APPROX_CHORDAL_     Chordal deviation, in
                          DEV_NPC                    normalized projection
                                                     coordinates
                          PCURVE_APPROX_CHORDAL_     Chordal deviation, in
                          DEV_DC                     device coordinates
                          PCURVE_APPROX_REL_WC       Relative, in world
                                                     coordinate units
                          PCURVE_APPROX_REL_NPC      Relative, in
                                                     normalized projection
                                                     coordinates
                          PCURVE_APPROX_REL_DC       Relative, in device
                                                     coordinate units
---------------------------------------------------------------------------

Description

pset_curve_approx_crit indicates the minimum quality desired for the approximation of the curve’s geometry. Depending on the edit mode, this function either inserts the new structure element directly after the pointer or replaces the element indicated by the pointer. The pointer then points to the new set curve approximation criteria element.

During structure traversal, if the specified approximation type is undefined, Digital PHIGS uses type 1.

If Digital PHIGS is in immediate mode, it performs this function immediately, but the function does not create a structure element.