R: Create closed b-spline shapes

geom_bspline_closed {ggforce} | R Documentation

## Create closed b-spline shapes

### Description

This geom creates closed b-spline curves and draws them as shapes. The closed b-spline is achieved by wrapping the control points rather than the knots. The *0 version uses the `grid::xsplineGrob()` function with `open = FALSE` and can thus not be manipulated as a shape geom in the same way as the base version (expand, contract, etc).

### Usage

    stat_bspline_closed(
      mapping = NULL,
      data = NULL,
      geom = "shape",
      position = "identity",
      na.rm = FALSE,
      n = 100,
      show.legend = NA,
      inherit.aes = TRUE,
      ...
    )

    geom_bspline_closed(
      mapping = NULL,
      data = NULL,
      stat = "bspline",
      position = "identity",
      n = 100,
      na.rm = FALSE,
      show.legend = NA,
      inherit.aes = TRUE,
      ...
    )

    geom_bspline_closed0(
      mapping = NULL,
      data = NULL,
      stat = "identity",
      position = "identity",
      na.rm = FALSE,
      show.legend = NA,
      inherit.aes = TRUE,
      ...
    )

### Arguments

`mapping` | Set of aesthetic mappings created by `aes()` or `aes_()`. If specified and `inherit.aes = TRUE` (the default), it is combined with the default mapping at the top level of the plot. You must supply `mapping` if there is no plot mapping.
`data` | The data to be displayed in this layer. There are three options: If `NULL`, the default, the data is inherited from the plot data as specified in the call to `ggplot()`. A `data.frame`, or other object, will override the plot data. All objects will be fortified to produce a data frame. See `fortify()` for which variables will be created. A `function` will be called with a single argument, the plot data. The return value must be a `data.frame`, and will be used as the layer data. A `function` can be created from a `formula` (e.g. `~ head(.x, 10)`).
`geom` | The geometric object to use display the data
`position` | Position adjustment, either as a string, or the result of a call to a position adjustment function.
`na.rm` | If `FALSE`, the default, missing values are removed with a warning. If `TRUE`, missing values are silently removed.
`n` | The number of points generated for each spline
`show.legend` | logical. Should this layer be included in the legends? `NA`, the default, includes if any aesthetics are mapped. `FALSE` never includes, and `TRUE` always includes. It can also be a named logical vector to finely select the aesthetics to display.
`inherit.aes` | If `FALSE`, overrides the default aesthetics, rather than combining with them. This is most useful for helper functions that define both data and aesthetics and shouldn't inherit behaviour from the default plot specification, e.g. `borders()`.
`...` | Other arguments passed on to `layer()`. These are often aesthetics, used to set an aesthetic to a fixed value, like `colour = "red"` or `size = 3`. They may also be parameters to the paired geom/stat.
`stat` | The statistical transformation to use on the data for this layer, as a string.

### Aesthetics

geom_bspline_closed understand the following aesthetics (required aesthetics are in bold):

- x

- y

- color

- fill

- size

- linetype

- alpha

### Computed variables

x, y

  The coordinates for the path describing the spline

index

  The progression along the interpolation mapped between 0 and 1

### Author(s)

Thomas Lin Pedersen. The C++ code for De Boor's algorithm has been adapted from Jason Yu-Tseh Chi implementation

### Examples

    # Create 6 random control points
    controls <- data.frame(
      x = runif(6),
      y = runif(6)
    )

    ggplot(controls, aes(x, y)) +
      geom_polygon(fill = NA, colour = 'grey') +
      geom_point(colour = 'red') +
      geom_bspline_closed(alpha = 0.5)

    # The 0 version approximates the correct shape
    ggplot(controls, aes(x, y)) +
      geom_polygon(fill = NA, colour = 'grey') +
      geom_point(colour = 'red') +
      geom_bspline_closed0(alpha = 0.5)

    # But only the standard version supports geom_shape operations
    # Be aware of self-intersections though
    ggplot(controls, aes(x, y)) +
      geom_polygon(fill = NA, colour = 'grey') +
      geom_point(colour = 'red') +
      geom_bspline_closed(alpha = 0.5, expand = unit(2, 'cm'))

[Package ggforce version 0.3.3 Index]