R: Transition in and out of events

tween_events {tweenr} | R Documentation

## Transition in and out of events

### Description

This tweening function is a more powerful version of `tween_appear()`, with support for newer features such as enter/exits and tween phase identification. The tweener treats each row in the data as unique events in time, and creates frames with the correct events present at any given time.

### Usage

    tween_events(
      .data,
      ease,
      nframes,
      start,
      end = NULL,
      range = NULL,
      enter = NULL,
      exit = NULL,
      enter_length = 0,
      exit_length = 0
    )

### Arguments

`.data` | A data.frame with components at different stages
`ease` | The easing function to use. Either a single string or one for each column in the data set.
`nframes` | The number of frames to calculate for the tween
`start, end` | The start (and potential end) of the event encoded in the row, as unquoted expressions. Will be evaluated in the context of `.data` so can refer to columns in it. If `end = NULL` the event will be without extend and only visible in a single frame, unless `enter` and/or `exit` is given.
`range` | The range of time points to include in the tween. If `NULL` it will use the range of `time`
`enter` | functions that calculate a start state for new observations that appear in `to` or an end state for observations that are not present in `to`. If `NULL` the new/old observations will not be part of the tween. The function gets a data.frame with either the start state of the exiting observations, or the end state of the entering observations and must return a modified version of that data.frame. See the Match, Enter, and Exit section for more information.
`exit` | functions that calculate a start state for new observations that appear in `to` or an end state for observations that are not present in `to`. If `NULL` the new/old observations will not be part of the tween. The function gets a data.frame with either the start state of the exiting observations, or the end state of the entering observations and must return a modified version of that data.frame. See the Match, Enter, and Exit section for more information.
`enter_length` | The lenght of the opening and closing transitions if `enter` and/or `exit` is given. Measured in the same units as `time`
`exit_length` | The lenght of the opening and closing transitions if `enter` and/or `exit` is given. Measured in the same units as `time`

### Value

A data.frame with the same columns as `.data` along with `.id` giving the component id, `.phase` giving the state of each component in each frame, and `.frame` giving the frame membership of each row.

### See Also

Other data.frame tween: `tween_along()`, `tween_appear()`, `tween_components()`, `tween_elements()`, `tween_states()`

### Examples

    d <- data.frame(
      x = runif(20),
      y = runif(20),
      time = runif(20),
      duration = runif(20, max = 0.1)
    )
    from_left <- function(x) {
      x$x <- -0.5
      x
    }
    to_right <- function(x) {
      x$x <- 1.5
      x
    }

    tween_events(d, 'cubic-in-out', 50, start = time, end = time + duration,
                 enter = from_left, exit = to_right, enter_length = 0.1,
                 exit_length = 0.05)

[Package tweenr version 1.0.2 Index]