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.