NAME

       plgradient - Draw linear gradient inside polygon

SYNOPSIS

       plgradient(n, x, y, angle)

DESCRIPTION

       Draw  a  linear  gradient  using  colour  map 1 inside the polygon defined by the n points
       (x[i], y[i]).  Interpretation of the polygon is the  same  as  for  plfill(3plplot).   The
       polygon  coordinates  and  the gradient angle are all expressed in world coordinates.  The
       angle from the x axis for both the rotated coordinate system and the  gradient  vector  is
       specified  by  angle.   The magnitude of the gradient vector is the difference between the
       maximum and minimum values of x for the vertices in the rotated  coordinate  system.   The
       origin  of  the  gradient  vector  can  be  interpreted  as  being  anywhere  on  the line
       corresponding to the minimum x value for the vertices in the  rotated  coordinate  system.
       The distance along the gradient vector is linearly transformed to the independent variable
       of colour map 1 which ranges from 0. at the tail of the gradient vector to 1. at the  head
       of the gradient vector.  What is drawn is the RGBA colour corresponding to the independent
       variable of colour map 1.  For more  information  about  colour  map  1  (see  the  PLplot
       documentation).

       Redacted form: plgradient(x,y,angle)

       This function is used in examples 25,30.

ARGUMENTS

       n (PLINT, input)
              Number of vertices in polygon.

       x (const PLFLT *, input)
              Pointer to array with x coordinates of vertices.

       y (const PLFLT *, input)
              Pointer to array with y coordinates of vertices.

       angle (PLFLT, input)
              Angle (degrees) of gradient vector from x axis.

AUTHORS

       Many  developers  (who  are  credited  at  http://plplot.sourceforge.net/credits.php) have
       contributed to PLplot over its long history.

SEE ALSO

       PLplot documentation at http://plplot.sourceforge.net/documentation.php.

                                          February, 2016                      PLGRADIENT(3plplot)