generativeart

Create Generative Art with R.

Description

One overly simple but useful definition is that generative art is art programmed using a computer that intentionally introduces randomness as part of its creation process. -- Why Love Generative Art? - Artnome

The R package generativeart let's you create images based on many thousand points. The position of every single point is calculated by a formula, which has random parameters. Because of the random numbers, every image looks different.

In order to make an image reproducible, generative art implements a log file that saves the file_name, the seed and the formula.

Install

You can install the package with the devtools package directly from Github:

devtools::install_github("cutterkom/generativeart")

generativeart uses the packages ggplot2, magrittr, purrr and dplyr.

Usage

The package works with a specific directory structure that fits my needs best. The first step is to create it with setup_directories(). All images are saved by default in img/everything/. I use img/handpicked/ to choose the best ones. In logfile/ you will find a csv file that saves the file_name, the seed and the used formula.

library(generativeart)

# set the paths
IMG_DIR <- "img/"
IMG_SUBDIR <- "everything/"
IMG_SUBDIR2 <- "handpicked/"
IMG_PATH <- paste0(IMG_DIR, IMG_SUBDIR)

LOGFILE_DIR <- "logfile/"
LOGFILE <- "logfile.csv"
LOGFILE_PATH <- paste0(LOGFILE_DIR, LOGFILE)

# create the directory structure
generativeart::setup_directories(IMG_DIR, IMG_SUBDIR, IMG_SUBDIR2, LOGFILE_DIR)

# include a specific formula, for example:
my_formula <- list(
  x = quote(runif(1, -1, 1) * x_i^2 - sin(y_i^2)),
  y = quote(runif(1, -1, 1) * y_i^3 - cos(x_i^2))
)

# call the main function to create five images with a polar coordinate system
generativeart::generate_img(formula = my_formula, nr_of_img = 5, polar = TRUE, filetype = "png", color = "black", background_color = "white")

You can create as many images as you want by setting nr_of_img.
For every image a seed is drawn from a number between 1 and 10000.
This seed determines the random numbers in the formula.
You can choose between cartesian and polar coordinate systems by setting polar = TRUE or polar = FALSE
You can choose the colors with color = 'black' and background_color = 'hotpink'
You can save the output image in various formats. Default is png, the alternatives are defined by the device options of ggplot::ggsave().
the formula is a list()

Examples

It is a good idea to use the sine and cosine in the formula, since it guarantees nice shapes, especially when combined with a polar coordinate system. One simple example:

my_formula <- list(
  x = quote(runif(1, -1, 1) * x_i^2 - sin(y_i^2)),
  y = quote(runif(1, -1, 1) * y_i^3 - cos(x_i^2))
)

generativeart::generate_img(formula = my_formula, nr_of_img = 5, polar = TRUE, color = "black", background_color = "white")

Two possible images:

seed = 1821, polar = TRUE:

seed = 5451, polar = FALSE:

The corresponding log file looks like that:

file_name	seed	formula_x	formula_y
2018-11-16-17-13_seed_1821.png	1821	runif(1, -1, 1) * x_i^2 - sin(y_i^2)	runif(1, -1, 1) * y_i^3 - cos(x_i^2)
2018-11-16-17-12_seed_5451.png	5451	runif(1, -1, 1) * x_i^2 - sin(y_i^2)	runif(1, -1, 1) * y_i^3 - cos(x_i^2)

Inspiration

The basic concept is heavily inspired by Fronkonstin's great blog.

My note

Main function: generative_img.R

The main job of generative_img

Call generate_data(formula) and get a returned dataframe storing x-y-points-pairs evaluated in terms of the formula
Call geneate_plot (to create plot with ggplot2) with the dataframe obtained from step 1 passed as argument

Data generation: generate_data.R

Prerequsites:

%>% is called the forward pipe operator
- The LHS of %>% will be put into the first argument of the RHS function
length(seq(from = -pi, to = pi, by = 0.01)) is a vector of length 629

Code:

seq(from = -pi, to = pi, by = 0.01) %>% expand.grid(x_i = ., y_i = .)

expand.grid will return a (629^2 by 2) dataframe consists of rows in the form (x_i, y_i). i.e. all possible combinations of elements of the vectors passed in
- See usage of expand.grid

seq(from = -pi, to = pi, by = 0.01) %>%
    expand.grid(x_i = ., y_i = .) %>%
    dplyr::mutate(!!!formula)

Triple exclamation marks on R
The mutate function in dplyr packages will create variables and column bind the new variable into the dataframe passed in.
So after the line of code executed, the dataframe becomes dimension of (629^2 by 4)
The (x, y) pair is added in col3 and col4 respectively, with their value evaluated by the formula provided by the user

Plotting: generate_plot.R

Learn ggplot2 with R-for-data-science

Learn ggplot2 with this comprehensive guide

We only plot the last two columns of the dataframe returned by generate_data.R, which is (x, y).
Note that by default the angle is mapped to the x variable, but you can set theta = "y" to map the angle to the y variable.

loijilai/generativeart