1PLGRADIENT(3plplot) PLplot API PLGRADIENT(3plplot)
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6 plgradient - Draw linear gradient inside polygon
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9 plgradient(n, x, y, angle)
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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).
27 Redacted form: plgradient(x,y,angle)
29 This function is used in examples 25 and 30.
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33 n (PLINT(3plplot), input)
34 Number of vertices in polygon.
35 x (PLFLT_VECTOR(3plplot), input)
37 A vector containing the x coordinates of vertices.
38 y (PLFLT_VECTOR(3plplot), input)
40 A vector containing the y coordinates of vertices.
41 angle (PLFLT(3plplot), input)
43 Angle (degrees) of gradient vector from x axis.
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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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51 PLplot documentation at http://plplot.org/documentation.php.
52 January, 2021 PLGRADIENT(3plplot)