# getellipse: x-y coordinates of ellipse In shape: Functions for Plotting Graphical Shapes, Colors

## Description

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

## Usage

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

## Arguments

 `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.

## Details

`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).

## Value

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

## Author(s)

Karline Soetaert <karline.soetaert@nioz.nl>

`plotellipse`, `filledellipse`

## Examples

 ``` 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) ```

### Example output  ```
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shape documentation built on May 19, 2021, 9:09 a.m.