Name

DELPA − Specifies the 2D, shorthand form of the elliptical arc primitive. 

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

Syntax

DELPA (PX, PY, MAJORX, MAJORY, MINORX, MINORY, SANGLE, EANGLE)

Argument     Data Type     Access    Description
---------------------------------------------------------------------------
PX, PY       Real          Read      Center point of the elliptical arc,
                                     in modeling coordinates
MAJORX,      Real          Read      Vector that defines the x-axis
MAJORY
MINORX,      Real          Read      Vector that defines the y-axis
MINORY
SANGLE       Real          Read      Starting angle for drawing the arc,
                                     in radians
EANGLE       Real          Read      Ending angle for drawing the arc,
                                     in radians
---------------------------------------------------------------------------

Description

DELPA specifies the two-dimensional (x and y), shorthand form of the elliptical arc primitive.  The elliptical arc local coordinate system is the xy-plane as defined in the modeling coordinate system.  Digital PHIGS assumes the z-coordinate is 0. 

Depending on the edit mode, this function either inserts the new structure element directly after the element indicated by the pointer or replaces the element indicated by the pointer. The pointer then points to the new elliptical arc element. 

During structure traversal, Digital PHIGS generates an elliptical arc from the start angle to the end angle, in a counterclockwise direction.  Digital PHIGS binds the current values of the polyline primitive, as defined in the PHIGS traversal state list, to the primitive, and renders it according to the current curve approximation criteria. 

If the magnitudes of both axes are less than or equal to 0, Digital PHIGS displays a dot.  If one of the axes is less than or equal to 0, Digital PHIGS displays a line of the correct magnitude.  If the axes do not define the system (the vectors are parallel and nonzero), Digital PHIGS uses (1,0,0) for the major axis and (0,1,0) for the minor axis. 

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

See Also

PADS
PQPLF
PRES
PSDCI
PSHRID
PSIASF
PSLN
PSLWSC
PSPKID
PSPLC
PSPLCI
PSPLI
PSPLSM
PSVWI