animatrixr

animatrixr is a toy package that allows you to pipe together animations of matrix transformations. For example:

(rotate) %>% (sheer) %>% (reflect) %>% ANIMATE

library(dplyr)
library(animatrixr)

rotate_90 <- animatrixr::rotation_matrix(pi/2)

sheer_vertical <- tribble( ~ x, ~ y,
                           1, 0,
                           0.5, 1) %>%
  as.matrix()

reflect_x <- tribble( ~ x, ~ y,
                      1, 0,
                      0,-1) %>%
  as.matrix() 

example_transformations <-
  add_transformation(m = rotate_90, seq_fun = animatrixr::seq_matrix_lp) %>%
  add_transformation(m = sheer_vertical) %>%
  add_transformation(m = reflect_x)

animate_matrix(example_transformations)

You can use seq_fun argument to specify the function used to explicitly define the frames in-between the start and end of an animation of a matrix transformation.

Adding coordinates

You can use the points_start argument to graph coordinates on the animation.

animate_matrix(example_transformations,
               points_start = animatrixr::morpheus)
#> x, y coordinates of `points_start` scaled so that maximum magnitude is 5.

Setting datasaurus = TRUE is a way to add the datasarus to the animation and is equivalent to setting points_start = filter(datasauRus::datasaurus_dozen, dataset == "dino").

Use at your own risk + limitations

animatrixr is a toy package I wrote (hastily) to support a blog post on exploring animating matrix transformations using gganimate. The blog post doubles as providing documentation on how animatrixr is set-up and some of its limitations. I had also written an initial blog post the week prior on animating matrix transformations that contains further documentation on some of the functions that ultimately wound-up in animatrixr.

The matrix multiplications create tiny rounding errors that make reading the matrices when printing more difficult. To clean these up you can simply round the values , e.g. by doing purrr::modify(example_transformations, round, 10).

Almost no work has gone into setting-up tests, catching errors, considering potential users, etc. Also, many visualizations you might try to make may look unintuitive (or simply come-out incorrect) – especially involving rotations when starting outside of unit vectors.

Installation

If you still want to check-it out, you can install it from my github page:

devtools::install_github("brshallo/animatrixr")