calculates x-y values for (part of) an ellipse; the ellipse can be rotated

1 2 | ```
getellipse(rx = 1, ry = rx, mid = c(0, 0), dr = 0.01,
angle = 0, from = -pi, to = pi)
``` |

`rx ` |
long radius of ellipse. |

`ry ` |
short radius of ellipse. |

`mid ` |
midpoint of ellipse. |

`dr ` |
size of segments, in radians, to specify ellipse (decrease for smoother). |

`angle ` |
rotation angle, degrees. |

`from ` |
starting angle for ellipse segment, radians. |

`to ` |
final angle for ellipse segment, radians. The segment is generated counterclockwise. The default is draw a full ellipse. |

`rx`

and `ry`

are the horizontal and vertical radiusses of the
ellipses.

points `from`

and `to`

are joined counterclockwise. (this has changed
since version 1.3.4).

a 2-column matrix with x-y values of the ellipse

Karline Soetaert <karline.soetaert@nioz.nl>

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 | ```
plot(getellipse(1, from = 0, to = pi/2), type = "l", col = "red",
lwd = 2, main = "getellipse")
lines(getellipse(0.5, 0.25, mid = c(0.5, 0.5)), type = "l",
col = "blue", lwd = 2)
lines(getellipse(0.5, 0.25, mid = c(0.5, 0.5), angle = 45),
type = "l", col = "green", lwd = 2)
lines(getellipse(0.2, 0.2, mid = c(0.5, 0.5), from = 0, to = pi/2),
type = "l", col = "orange", lwd = 2)
lines(getellipse(0.2, 0.2, mid = c(0.5, 0.5), from = pi/2, to = 0),
type = "l", col = "black", lwd = 2)
lines(getellipse(0.1, 0.1, mid = c(0.75, 0.5), from = -pi/2, to = pi/2),
type = "l", col = "black", lwd = 2)
emptyplot(main = "getellipse")
col <- femmecol(90)
for (i in seq(0, 180, by = 2))
lines(getellipse(0.5, 0.25, mid = c(0.5, 0.5), angle = i),
type = "l", col = col[(i/2)+1], lwd = 2)
``` |

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