1PLGRADIENT(3plplot)               PLplot API               PLGRADIENT(3plplot)
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NAME

6       plgradient - Draw linear gradient inside polygon
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SYNOPSIS

9       plgradient(n, x, y, angle)
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DESCRIPTION

12       Draw  a linear gradient using cmap1 inside the polygon defined by the n
13       points (x[i], y[i]).  Interpretation of the polygon is the same as  for
14       plfill(3plplot).   The  polygon  coordinates and the gradient angle are
15       all expressed in world coordinates.  The angle from the x axis for both
16       the  rotated  coordinate system and the gradient vector is specified by
17       angle.  The magnitude of the gradient vector is the difference  between
18       the maximum and minimum values of x for the vertices in the rotated co‐
19       ordinate system.  The origin of the gradient vector can be  interpreted
20       as  being anywhere on the line corresponding to the minimum x value for
21       the vertices in the rotated coordinate system.  The distance along  the
22       gradient  vector is linearly transformed to the independent variable of
23       color map 1 which ranges from 0. at the tail of the gradient vector  to
24       1. at the head of the gradient vector.  What is drawn is the RGBA color
25       corresponding to the independent variable of cmap1.  For more  informa‐
26       tion about cmap1 (see the PLplot documentation).
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28       Redacted form: plgradient(x,y,angle)
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30       This function is used in examples 25 and 30.
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ARGUMENTS

33       n (PLINT(3plplot), input)
34              Number of vertices in polygon.
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36       x (PLFLT_VECTOR(3plplot), input)
37              A vector containing the x coordinates of vertices.
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39       y (PLFLT_VECTOR(3plplot), input)
40              A vector containing the y coordinates of vertices.
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42       angle (PLFLT(3plplot), input)
43              Angle (degrees) of gradient vector from x axis.
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AUTHORS

47       Many  developers  (who  are  credited at http://plplot.org/credits.php)
48       have contributed to PLplot over its long history.
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SEE ALSO

51       PLplot documentation at http://plplot.org/documentation.php.
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55                                February, 2022             PLGRADIENT(3plplot)
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