bgnline(3G)

NAME
     bgnline, endline - delimit the vertices of a line

C SPECIFICATION
     void bgnline()

     void endline()

PARAMETERS
     none

DESCRIPTION
     Vertices specified after bgnline and before endline are interpreted as
     endpoints of a series of line segments. Use the v routine to specify a
     vertex. The first vertex connects to the second; the second connects to
     the third; and so on until the next-to-last vertex connects to the last
     one.  The last vertex does not connect to the first vertex.  Use
     bgnclosedline to connect the first and last points. All segments use the
     current linestyle, which is reset prior to the first segment and
     continues through subsequent segments.

     Between bgnline and endline, you can issue only the following Graphics
     Library routines:  c, color, cpack, lmbind, lmcolor, lmdef, n, RGBcolor,
     t, and v.  lmdef and lmbind can be used to respecify only materials and
     their properties. If the color changes between a pair of vertices, the
     color of the line segment will be constant if the current shading model
     is FLAT and interpolated if the current shading model is GOURAUD.  In
     color map mode, the colors vary through the color map; to get reasonable
     results, the color map should contain a ramp.

     There is no limit to the number of vertices that can be specified between
     bgnline and endline.  After endline, the current graphics position is
     undefined.

     By default, line vertices are forced to the nearest pixel center prior to
     scan conversion.  Line accuracy is improved when this coercion is
     defeated with the subpixel command.  Subpixel vertex positioning is
     especially important when lines are scan-converted with antialiasing
     enabled (see linesmooth).

SEE ALSO
     bgnclosedline, c, linesmooth, linewidth, lsrepeat, scrsubdivide,
     setlinestyle, shademodel, subpixel, v

BUGS
     On the IRIS-4D B and G models, and on the Personal Iris without Turbo
     Graphics, if the color changes between a pair of vertices, the color of
     the line segment will be constant regardless of the current shading
     model.
     On the IRIS-4D GT and GTX models, if the color changes between a pair of
     vertices, the color of the line segment will be interpolated regardless
     of the current shading model.

     On the IRIS-4D B and G models, the linestyle is reset at the start of
     each segment, rather than only at the start of the first segment.