R: Draw horizontal diagonals

geom_diagonal {ggforce} | R Documentation

## Draw horizontal diagonals

### Description

A diagonal is a bezier curve where the control points are moved perpendicularly towards the center in either the x or y direction a fixed amount. The versions provided here calculates horizontal diagonals meaning that the x coordinate is moved to achieve the control point. The `geom_diagonal()` and `stat_diagonal()` functions are simply helpers that takes care of calculating the position of the control points and then forwards the actual bezier calculations to `geom_bezier()`.

### Usage

    stat_diagonal(
      mapping = NULL,
      data = NULL,
      geom = "path",
      position = "identity",
      n = 100,
      strength = 0.5,
      na.rm = FALSE,
      show.legend = NA,
      inherit.aes = TRUE,
      ...
    )

    geom_diagonal(
      mapping = NULL,
      data = NULL,
      stat = "diagonal",
      position = "identity",
      n = 100,
      na.rm = FALSE,
      strength = 0.5,
      show.legend = NA,
      inherit.aes = TRUE,
      ...
    )

    stat_diagonal2(
      mapping = NULL,
      data = NULL,
      geom = "path_interpolate",
      position = "identity",
      na.rm = FALSE,
      show.legend = NA,
      n = 100,
      strength = 0.5,
      inherit.aes = TRUE,
      ...
    )

    geom_diagonal2(
      mapping = NULL,
      data = NULL,
      stat = "diagonal2",
      position = "identity",
      arrow = NULL,
      lineend = "butt",
      na.rm = FALSE,
      show.legend = NA,
      inherit.aes = TRUE,
      n = 100,
      strength = 0.5,
      ...
    )

    stat_diagonal0(
      mapping = NULL,
      data = NULL,
      geom = "bezier0",
      position = "identity",
      na.rm = FALSE,
      show.legend = NA,
      inherit.aes = TRUE,
      strength = 0.5,
      ...
    )

    geom_diagonal0(
      mapping = NULL,
      data = NULL,
      stat = "diagonal0",
      position = "identity",
      arrow = NULL,
      lineend = "butt",
      na.rm = FALSE,
      show.legend = NA,
      inherit.aes = TRUE,
      strength = 0.5,
      ...
    )

### 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.
`n` | The number of points to create for each segment
`strength` | The proportion to move the control point along the x-axis towards the other end of the bezier curve
`na.rm` | If `FALSE`, the default, missing values are removed with a warning. If `TRUE`, missing values are silently removed.
`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.
`arrow` | Arrow specification, as created by `grid::arrow()`.
`lineend` | Line end style (round, butt, square).

### Aesthetics

geom_diagonal and geom_diagonal0 understand the following aesthetics (required aesthetics are in bold):

- x

- y

- xend

- yend

- color

- size

- linetype

- alpha

- lineend

geom_diagonal2 understand the following aesthetics (required aesthetics are in bold):

- x

- y

- group

- color

- size

- linetype

- alpha

- lineend

### Computed variables

x, y

  The interpolated point coordinates

index

  The progression along the interpolation mapped between 0 and 1

### Examples

    data <- data.frame(
      x = rep(0, 10),
      y = 1:10,
      xend = 1:10,
      yend = 2:11
    )

    ggplot(data) +
      geom_diagonal(aes(x, y, xend = xend, yend = yend))

    # The standard version provides an index to create gradients
    ggplot(data) +
      geom_diagonal(aes(x, y, xend = xend, yend = yend, alpha = stat(index)))

    # The 0 version uses bezierGrob under the hood for an approximation
    ggplot(data) +
      geom_diagonal0(aes(x, y, xend = xend, yend = yend))

    # The 2 version allows you to interpolate between endpoint aesthetics
    data2 <- data.frame(
      x = c(data$x, data$xend),
      y = c(data$y, data$yend),
      group = rep(1:10, 2),
      colour = sample(letters[1:5], 20, TRUE)
    )
    ggplot(data2) +
      geom_diagonal2(aes(x, y, group = group, colour = colour))

    # Use strength to control the steepness of the central region
    ggplot(data, aes(x, y, xend = xend, yend = yend)) +
      geom_diagonal(strength = 0.75, colour = 'red') +
      geom_diagonal(strength = 0.25, colour = 'blue')

[Package ggforce version 0.3.3 Index]