In WilliamTylerBradley/flowfieldfigments: Flow Field Generative Art

knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)

This vignette contains one large script for all the code in this package. This file makes it easy if you want to change, adapt, or tear apart what happens here.

# Libraries
library(tidyverse)
library(tidyr)
library(purrr)
library(ambient)
library(mvtnorm)
library(gifski)
library(stringr)

# Base colors
get_color <- function(angle, percentage) {
  vectors <- data.frame(
    v1 = c(
      0.99258009214842,
      0,
      -0.121592601216663
    ),
    v2 = c(
      0.0172593263893888,
      0.989874705747223,
      0.14089067596698
    ),
    p = c(
      0,
      0,
      74.8443331534229
    )
  )

  v <- vectors[["p"]] +
    (percentage / 100 * 63) * cos(angle * pi / 180) * vectors[["v1"]] +
    (percentage / 100 * 63) * sin(angle * pi / 180) * vectors[["v2"]]

  hue <- (atan2(v[2], v[1]) * 180 / pi) %% 360
  chroma <- sqrt(v[1]^2 + v[2]^2)
  luminance <- v[3]

  hcl(hue, chroma, luminance, fixup = FALSE)
}

# Subset colors
get_color_subset <- function(center, width, angle, percentage) {
  get_color(width * sin(angle * pi / 180) + center, percentage)
}

# Directional vectors
get_vectors <- function(points, seeds) {
  vectors <- points %>%
    mutate(
      x_direction = gen_simplex(x,
        y,
        frequency = .01,
        seed = seeds[1]
      ),
      y_direction = gen_simplex(x,
        y,
        frequency = .01,
        seed = seeds[2]
      )
    ) %>%
    mutate(vector_length = sqrt(x_direction^2 +
      y_direction^2)) %>%
    mutate(
      x_direction = x_direction / vector_length,
      y_direction = y_direction / vector_length
    ) %>%
    select(-vector_length)
}

# Move points
move_points <- function(points, seeds) {
  points <- points %>%
    get_vectors(seeds) %>%
    mutate(
      x = x + x_direction * .5,
      y = y + y_direction * .5,
      time = time + 1
    )
  return(points)
}

# Set up anchor points
get_anchor_points <- function(seeds, size, anchor_layout,
                              hue_turn, color_scheme,
                              color_subset_center, color_subset_width) {
  if (anchor_layout == "random") {
    # random layout
    points <- as.data.frame(rmvnorm(
      n = size,
      sigma = diag(size * 4 / (floor(log10(size)) + 1),
        nrow = 2
      )
    )) %>% # sd is number 4/digits
      rename(
        x = V1,
        y = V2
      ) %>%
      mutate(id = row_number())
  } else if (anchor_layout == "spiral") {
    # spiral layout
    golden <- ((sqrt(5) + 1) / 2) * (2 * pi)

    points <- data.frame(
      x = sqrt(seq(1, size)) * cos(golden * seq(1, size)) * 2.5,
      y = sqrt(seq(1, size)) * sin(golden * seq(1, size)) * 2.5
    ) %>%
      mutate(id = row_number())
  } else {
    # diamond grid
    grid_width <- ifelse(size <= 1500 / 2, ceiling(sqrt(size)), floor(sqrt(size)))

    points <- expand_grid(
      x_start = seq(1, grid_width) - (grid_width / 2) - .5,
      y_start = seq(1, grid_width) - (grid_width / 2) - .5
    ) %>%
      mutate(
        x = (x_start * cos(45 * pi / 180) -
          y_start * sin(45 * pi / 180)) * 5,
        y = (x_start * sin(45 * pi / 180) +
          y_start * cos(45 * pi / 180)) * 5,
        id = row_number()
      ) %>%
      select(-x_start, -y_start)
  }

  if (color_scheme == "subset") {
    points <- get_vectors(points, seeds) %>%
      mutate(distance = gen_simplex(x,
        y,
        frequency = .01,
        seed = seeds[3]
      )) %>%
      mutate(
        angle =
          (atan2(y_direction, x_direction) * 180 / pi) %%
            360 + hue_turn,
        percentage = pnorm(distance,
          mean = 0,
          sd(distance)
        ) * 100
      ) %>%
      rowwise() %>%
      mutate(
        hex_color = get_color_subset(
          color_subset_center,
          color_subset_width,
          angle,
          percentage
        ),
        time = 0
      ) %>%
      ungroup() %>%
      select(
        id, x, y,
        hex_color, percentage, time
      )
  } else {
    points <- get_vectors(points, seeds) %>%
      mutate(distance = gen_simplex(x,
        y,
        frequency = .01,
        seed = seeds[3]
      )) %>%
      mutate(
        angle =
          (atan2(y_direction, x_direction) * 180 / pi) %%
            360 + hue_turn,
        percentage = pnorm(distance,
          mean = 0,
          sd(distance)
        ) * 100
      ) %>%
      rowwise() %>%
      mutate(
        hex_color = get_color(angle, percentage),
        time = 0
      ) %>%
      ungroup() %>%
      select(
        id, x, y,
        hex_color, percentage, time
      )
  }

  return(points)
}

# Create the paths
get_paths <- function(points, seeds) {
  paths <- accumulate(
    .x = rep(list(seeds), 100),
    .f = move_points,
    .init = points
  )
  paths <- bind_rows(paths)
  paths <- paths %>%
    group_by(id) %>%
    mutate(
      xend = lead(x),
      yend = lead(y)
    ) %>%
    filter(!is.na(xend)) %>%
    filter(time <= percentage)
}

get_point_paths <- function(points, paths) {
  # Handle paths that were dropped because they didn't go anywhere
  point_paths <- points %>%
    anti_join(paths, by = "id") %>%
    mutate(
      hex_color = get_color(0, 0),
      alpha_value = 1
    )
}

# Create a png file
create_png <- function(seeds, size, anchor_layout, hue_turn, color_scheme,
                       color_subset_center, color_subset_width,
                       alpha_taper, output_file) {
  points <- get_anchor_points(
    seeds, size, anchor_layout,
    hue_turn, color_scheme,
    color_subset_center, color_subset_width
  )
  paths <- get_paths(points, seeds)
  point_paths <- get_point_paths(points, paths)

  if (alpha_taper == "start") {
    paths <- paths %>%
      group_by(id) %>%
      mutate(alpha_value = 1 - (max(time) - time) /
        (max(time) + 1)) %>%
      ungroup()
  } else if (alpha_taper == "end") {
    paths <- paths %>%
      group_by(id) %>%
      mutate(alpha_value = 1 - (time / (max(time) + 1))) %>%
      ungroup()
  } else {
    paths <- paths %>%
      group_by(id) %>%
      mutate(alpha_value = 1 - (abs(time - median(time)) /
        (median(time) + 1))) %>%
      ungroup()
  }

  axes_limits <- max(c(abs(c(
    paths$x,
    paths$y,
    paths$xend,
    paths$yend
  ))))

  ggplot() +
    geom_point(
      data = point_paths,
      aes(
        x = x, y = y,
        color = hex_color,
        alpha = alpha_value
      ),
      size = .25,
      stroke = 0, shape = 16
    ) +
    geom_segment(
      data = paths,
      aes(
        x = x, y = y,
        xend = xend, yend = yend,
        color = hex_color,
        alpha = alpha_value
      ),
      lineend = "round",
      linejoin = "round",
      size = .15
    ) +
    scale_color_identity() +
    scale_alpha_identity() +
    scale_x_continuous(limits = c(-axes_limits, axes_limits)) +
    scale_y_continuous(limits = c(-axes_limits, axes_limits)) +
    coord_equal() +
    theme_void() +
    theme(plot.background = element_rect(
      color = "white",
      fill = "white"
    ))

  ggsave(
    filename = output_file,
    device = "png",
    widt = 2.5,
    height = 2.5
  )
}

# Create a gif file
create_gif <- function(seeds, size, anchor_layout, hue_turn, color_scheme,
                       color_subset_center, color_subset_width,
                       movement, output_file) {
  points <- get_anchor_points(
    seeds, size, anchor_layout,
    hue_turn, color_scheme,
    color_subset_center, color_subset_width
  )
  paths <- get_paths(points, seeds)
  point_paths <- get_point_paths(points, paths)

  axes_limits <- max(c(abs(c(
    paths$x,
    paths$y,
    paths$xend,
    paths$yend
  ))))

  tp_dr <- tempdir()

  if (movement == "march") {
    max_frame <- max(paths$time) + 9
    for (frame in 0:max_frame) {
      sub_paths <- paths %>%
        ungroup() %>%
        filter(time > frame - 10 & time <= frame) %>%
        mutate(alpha_value = 1 - (max(time) - time) / 10)

      if (frame <= 10) {
        point_paths <- point_paths %>%
          mutate(alpha_value = (10 - frame) / 10)
      } else {
        point_paths <- point_paths[0, ]
      }

      ggplot() +
        geom_point(
          data = point_paths,
          aes(
            x = x, y = y,
            color = hex_color,
            alpha = alpha_value
          ),
          size = .25,
          stroke = 0, shape = 16
        ) +
        geom_segment(
          data = sub_paths,
          aes(
            x = x, y = y,
            xend = xend, yend = yend,
            color = hex_color,
            alpha = alpha_value
          ),
          lineend = "round",
          linejoin = "round",
          size = .15
        ) +
        scale_color_identity() +
        scale_alpha_identity() +
        scale_x_continuous(limits = c(-axes_limits, axes_limits)) +
        scale_y_continuous(limits = c(-axes_limits, axes_limits)) +
        coord_equal() +
        theme_void() +
        theme(plot.background = element_rect(
          color = "white",
          fill = "white"
        ))

      ggsave(
        filename = file.path(
          tp_dr,
          paste0("image_", str_pad(frame, 3, pad = "0"), ".png")
        ),
        widt = 2.5,
        height = 2.5
      )
    }
  } else {
    max_frame <- max(paths$time) * 2
    for (frame in 0:max_frame) {
      if (frame <= max_frame / 2) {
        sub_paths <- paths %>%
          filter(time <= frame)
      } else {
        sub_paths <- paths %>%
          filter(time >= frame - max_frame / 2)

        point_paths <- point_paths[0, ]
      }

      ggplot() +
        geom_point(
          data = point_paths,
          aes(
            x = x, y = y,
            color = hex_color
          ),
          size = .25,
          stroke = 0, shape = 16
        ) +
        geom_segment(
          data = sub_paths,
          aes(
            x = x, y = y,
            xend = xend, yend = yend,
            color = hex_color
          ),
          lineend = "round",
          linejoin = "round",
          size = .15
        ) +
        scale_color_identity() +
        scale_alpha_identity() +
        scale_x_continuous(limits = c(-axes_limits, axes_limits)) +
        scale_y_continuous(limits = c(-axes_limits, axes_limits)) +
        coord_equal() +
        theme_void() +
        theme(plot.background = element_rect(
          color = "white",
          fill = "white"
        ))

      ggsave(
        filename = file.path(
          tp_dr,
          paste0("image_", str_pad(frame, 3, pad = "0"), ".png")
        ),
        widt = 2.5,
        height = 2.5
      )
    }
  }

  ggplot() +
    scale_color_identity() +
    scale_alpha_identity() +
    scale_x_continuous(limits = c(-axes_limits, axes_limits)) +
    scale_y_continuous(limits = c(-axes_limits, axes_limits)) +
    coord_equal() +
    theme_void() +
    theme(plot.background = element_rect(
      color = "white",
      fill = "white"
    ))

  ggsave(
    filename = file.path(
      tp_dr,
      paste0("image_", str_pad(frame + 1, 3, pad = "0"), ".png")
    ),
    widt = 2.5,
    height = 2.5
  )

  imgs <- file.path(tp_dr, list.files(tp_dr, pattern = "^image_...\\.png$"))
  gifski(imgs,
    delay = 1 / 15,
    gif_file = output_file,
    width = 750,
    height = 750,
    progress = FALSE
  )

  # Clean up
  unlink(imgs)
}

# Create a mp4 file
create_mp4 <- function(seeds, size, anchor_layout, hue_turn, color_scheme,
                       color_subset_center, color_subset_width,
                       movement, output_file) {
  points <- get_anchor_points(
    seeds, size, anchor_layout,
    hue_turn, color_scheme,
    color_subset_center, color_subset_width
  )
  paths <- get_paths(points, seeds)
  point_paths <- get_point_paths(points, paths)

  axes_limits <- max(c(abs(c(
    paths$x,
    paths$y,
    paths$xend,
    paths$yend
  ))))

  tp_dr <- tempdir()

  if (movement == "march") {
    max_frame <- max(paths$time) + 9
    for (frame in 0:max_frame) {
      sub_paths <- paths %>%
        ungroup() %>%
        filter(time > frame - 10 & time <= frame) %>%
        mutate(alpha_value = 1 - (max(time) - time) / 10)

      if (frame <= 10) {
        point_paths <- point_paths %>%
          mutate(alpha_value = (10 - frame) / 10)
      } else {
        point_paths <- point_paths[0, ]
      }

      ggplot() +
        geom_point(
          data = point_paths,
          aes(
            x = x, y = y,
            color = hex_color,
            alpha = alpha_value
          ),
          size = .25,
          stroke = 0, shape = 16
        ) +
        geom_segment(
          data = sub_paths,
          aes(
            x = x, y = y,
            xend = xend, yend = yend,
            color = hex_color,
            alpha = alpha_value
          ),
          lineend = "round",
          linejoin = "round",
          size = .15
        ) +
        scale_color_identity() +
        scale_alpha_identity() +
        scale_x_continuous(limits = c(-axes_limits, axes_limits)) +
        scale_y_continuous(limits = c(-axes_limits, axes_limits)) +
        coord_equal() +
        theme_void() +
        theme(plot.background = element_rect(
          color = "white",
          fill = "white"
        ))

      ggsave(
        filename = file.path(
          tp_dr,
          paste0("image_", str_pad(frame, 3, pad = "0"), ".png")
        ),
        widt = 2.5,
        height = 2.5
      )
    }
  } else {
    max_frame <- max(paths$time) * 2
    for (frame in 0:max_frame) {
      if (frame <= max_frame / 2) {
        sub_paths <- paths %>%
          filter(time <= frame)
      } else {
        sub_paths <- paths %>%
          filter(time >= frame - max_frame / 2)

        point_paths <- point_paths[0, ]
      }

      ggplot() +
        geom_point(
          data = point_paths,
          aes(
            x = x, y = y,
            color = hex_color
          ),
          size = .25,
          stroke = 0, shape = 16
        ) +
        geom_segment(
          data = sub_paths,
          aes(
            x = x, y = y,
            xend = xend, yend = yend,
            color = hex_color
          ),
          lineend = "round",
          linejoin = "round",
          size = .15
        ) +
        scale_color_identity() +
        scale_alpha_identity() +
        scale_x_continuous(limits = c(-axes_limits, axes_limits)) +
        scale_y_continuous(limits = c(-axes_limits, axes_limits)) +
        coord_equal() +
        theme_void() +
        theme(plot.background = element_rect(
          color = "white",
          fill = "white"
        ))

      ggsave(
        filename = file.path(
          tp_dr,
          paste0("image_", str_pad(frame, 3, pad = "0"), ".png")
        ),
        widt = 2.5,
        height = 2.5
      )
    }
  }

  ggplot() +
    scale_color_identity() +
    scale_alpha_identity() +
    scale_x_continuous(limits = c(-axes_limits, axes_limits)) +
    scale_y_continuous(limits = c(-axes_limits, axes_limits)) +
    coord_equal() +
    theme_void() +
    theme(plot.background = element_rect(
      color = "white",
      fill = "white"
    ))

  ggsave(
    filename = file.path(
      tp_dr,
      paste0("image_", str_pad(frame + 1, 3, pad = "0"), ".png")
    ),
    widt = 2.5,
    height = 2.5
  )

  imgs <- file.path(tp_dr, list.files(tp_dr, pattern = "^image_...\\.png$"))
  av_encode_video(imgs,
                      output = output_file,
                      framerate = 15,
                      verbose = FALSE)

  # Clean up
  unlink(imgs)
}

The following snippet uses code from the prior section. This lists out a file for each of the different options for png and mp4.

## Test script
set.seed(1)
# 2 options for full or subset color scheme
# 3 options for anchor layout
# 5 options for (3) png alpha taper + (2) gif movement
for (i in seq(1, 2 * 3 * 5)) {
  seeds <- sample(1:10000, 3)
  size <- sample(seq(50, 1500), 1, replace = TRUE)
  anchor_layout <- c("random", "spiral", "grid")[i %% 3 + 1]
  hue_turn <- runif(1, 0, 360)
  color_scheme <- c("full", "subset")[i %% 2 + 1]
  color_subset_center <- runif(1, 0, 360)
  color_subset_width <- runif(1, 30, 90)
  movement <- c("", "march", "", "glide", "")[i %% 5 + 1]
  alpha_taper <- c("start", "", "end", "", "both")[i %% 5 + 1]

  if ((i %% 5 + 1) %in% c(1, 3, 5)) {
    save_name <- paste0(
      color_scheme, "_",
      anchor_layout, "_",
      alpha_taper, "_",
      i, ".png"
    )
    create_png(
      seeds, size, anchor_layout, hue_turn,
      color_scheme, color_subset_center,
      color_subset_width, alpha_taper,
      save_name
    )
  } else {
    save_name <- paste0(
      color_scheme, "_",
      anchor_layout, "_",
      movement, "_",
      i, ".mp4"
    )
    create_gif(
      seeds, size, anchor_layout, hue_turn,
      color_scheme, color_subset_center,
      color_subset_width, movement,
      save_name
    )
  }
}