view_zoom: Pan and zoom smoothly between different states

In thomasp85/gganimate: A Grammar of Animated Graphics

Pan and zoom smoothly between different states

Description

This view is in many ways equivalent to view_step() and view_step_manual() but instead of simply tweening the bounding box of each view it implement the smooth zoom and pan technique developed by Reach & North (2018). It gradually zooms out and then in during the pan to allow a smooth transition of the view. As with view_step() the standard version will look at the data present in the calculated frames and set the ranges based on that, while the ⁠_manual⁠ version will allow you to define your own ranges to zoom between.

Usage

view_zoom(
  pause_length = 1,
  step_length = 1,
  nsteps = NULL,
  look_ahead = 0,
  delay = 0,
  include = FALSE,
  pan_zoom = 0,
  ease = "sine-in-out",
  wrap = TRUE,
  pause_first = TRUE,
  fixed_x = FALSE,
  fixed_y = FALSE,
  exclude_layer = NULL,
  aspect_ratio = 1
)

view_zoom_manual(
  pause_length = 1,
  step_length = 1,
  xmin,
  xmax,
  ymin,
  ymax,
  delay = 0,
  pan_zoom = 0,
  ease = "sine-in-out",
  wrap = TRUE,
  pause_first = TRUE,
  fixed_x = FALSE,
  fixed_y = FALSE,
  exclude_layer = NULL,
  aspect_ratio = 1
)

Arguments

pause_length	The relative length the view will be kept static. Will be recycled to match the number of steps
step_length	The relative length the view will use to transition to the new position. Will be recycled to match the number of steps
nsteps	The number of steps. If NULL it will be set to the max length of pause_length or step_length
look_ahead	A relative length to look ahead in the animation to get the new zoom area. Allow the view to zoom to where the data will be
delay	A relative length to switch the view back and forth relative to the actual frames. E.g. if delay is calculated to 5 frames, frame 6 will get the view intended for frame 1.
include	Should the steps include both the start and end frame range
pan_zoom	The tradeoff between pan- and zoom-induced movement. Negative values will value zoom over pan and positive values will value pan over zoom
ease	The easing function used for the step
wrap	As in transition_states(). Should the view wrap around and zoom back to the first state.
pause_first	Should the view start with a pause. The default is to start with a step so that it is aligned to the static period in transition_states()
fixed_x, fixed_y	Either a logical indicating if the dimension should not be modified by the view, or a numeric vector giving the lower and upper bounds of the dimension. For the latter, an NA value will be substituted for whatever is calculated by the view (e.g. fixed_x = c(0, NA)) will fix the minimum x value to 0 and let the view calculate the upper bound.
exclude_layer	Integer vector of layer indices that should be ignored when calculating the view
aspect_ratio	If the coord is fixed, ensure that the view matches the given aspect ratio. Will override anything given in fixed_x/fixed_y
xmin, xmax, ymin, ymax	Vectors of even length defining the boundaries of the different views to go through

References

Reach, A., North, C. (2018) Smooth, Efficient, and Interruptible Zooming and Panning. IEEE Transactions on Visualization and Computer Graphics DOI:10.1109/TVCG.2018.2800013

See Also

Other views: view_follow(), view_static(), view_step()

Examples

anim <- ggplot(iris, aes(Petal.Length, Petal.Width, colour = Species)) +
  geom_point() +
  transition_states(Species, transition_length = 2, state_length = 1) +
  shadow_mark(past = TRUE, future = TRUE, colour = 'grey') +
  view_zoom(pause_length = 1, step_length = 2, nsteps = 3)

# Use pan_zoom to change the relationship between pan- and zoom movement
# Mainly zooming
anim1 <- ggplot(iris, aes(Petal.Length, Petal.Width, colour = Species)) +
  geom_point() +
  transition_states(Species, transition_length = 2, state_length = 1) +
  shadow_mark(past = TRUE, future = TRUE, colour = 'grey') +
  view_zoom(pause_length = 1, step_length = 2, nsteps = 3, pan_zoom = -3)

# Mainly panning
anim2 <- ggplot(iris, aes(Petal.Length, Petal.Width, colour = Species)) +
  geom_point() +
  transition_states(Species, transition_length = 2, state_length = 1) +
  shadow_mark(past = TRUE, future = TRUE, colour = 'grey') +
  view_zoom(pause_length = 1, step_length = 2, nsteps = 3, pan_zoom = -3)

thomasp85/gganimate documentation built on Feb. 29, 2024, 11:16 p.m.