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
19       coordinate system.  The origin of the gradient  vector  can  be  inter‐
20       preted  as  being  anywhere  on the line corresponding to the minimum x
21       value for the vertices in the rotated coordinate system.  The  distance
22       along  the  gradient  vector is linearly transformed to the independent
23       variable of color map 1 which ranges from 0. at the tail of the  gradi‐
24       ent  vector to 1. at the head of the gradient vector.  What is drawn is
25       the RGBA color corresponding to the independent variable of cmap1.  For
26       more information 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.source‐
48       forge.net/credits.php) have contributed to PLplot over  its  long  his‐
49       tory.
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SEE ALSO

52       PLplot    documentation   at   http://plplot.sourceforge.net/documenta‐
53       tion.php.
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57                                 August, 2017              PLGRADIENT(3plplot)
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