Pan and zoom smoothly between different states

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.

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)