NAME

SET POLYLINE SHADING METHOD −  create a structure element that sets the current polyline shading method

SYNOPSIS

C Syntax

void
pset_line_shad_meth ( method )
Pintmethod;shading method

Required PHIGS Operating States

(PHOP, ∗, STOP, ∗)

DESCRIPTION

Purpose

SET POLYLINE SHADING METHOD places a polyline structure element with the value polyline shading method into the open structure. When the current polyline shading method Aspect Source Flag (ASF) is set to INDIVIDUAL, the current value of this attribute applies to the following output primitives:

• POLYLINE

• POLYLINE 3

• POLYLINE SET 3 WITH DATA

• GENERALIZED DRAWING PRIMITIVE (Polyline Primitives)

• GENERALIZED DRAWING PRIMITIVE 3 (Polyline Primitives)

• NON-UNIFORM B-SPLINE CURVE

C Input Parameters

method
The shading method.  The predefined values are:

1PSD_NONENo Shading
2PSD_COLOURColour Interpolation Shading

Execution

Depending on the edit mode, a SET POLYLINE SHADING METHOD element is inserted into the open structure after the element pointer, or replaces the element pointed to by the element pointer.  In either case, the element pointer is updated to point to the newly created SET POLYLINE SHADING METHOD element. 

When the structure is traversed, the current polyline shading method entry in the traversal state list is set to the specified value.  This value is used with subsequent line output primitives when the current polyline shading method ASF entry in the traversal state list is INDIVIDUAL.  During traversal, if the specified shading method is not available on a workstation, method 1 will be used on that workstation. 

When the current polyline shading method ASF is set to BUNDLED, the polyline shading method is taken from the workstation extended representation indicated by the current polyline index.  In this case, the polyline shading method set with SET POLYLINE SHADING METHOD has no effect. 

When the shading method is NONE, each segment of the polyline or curve is drawn in a single colour.  If the primitive specifies per-vertex colour, each segment is drawn using the colour associated with the first vertex of the segment. 

ERRORS

005Ignoring function, function requires state (PHOP,∗,STOP,∗)

SEE ALSO

POLYLINE SET 3 WITH DATA (3P+)
PHIGS WORKSTATION DESCRIPTION TABLE (7P)
NON-UNIFORM B-SPLINE CURVE (3P+)

September 02, 1992