docs/reference/figures/plot_greta_legend.R

In greta-dev/greta: Simple and Scalable Statistical Modelling in R

# plot legend
library(DiagrammeR)
library(raster)

ns <- 0.3
# bespoke set of nodes for legend
# pad operation with some invisible nodes to get in the right position
nodes1 <- create_node_df(
  n = 6,
  label = c("data", "variable", "distribution", "", "operation", ""),
  type = "lower",
  style = "filled",
  fontcolor = greta_col('dark'),
  fontname = 'Helvetica',
  fontsize = 12,
  fillcolor = c(
    'white',
    greta_col('super_light'),
    greta_col('lighter'),
    'white',
    'lightgray',
    'white'
  ),
  color = c(
    greta_col('lighter'),
    greta_col('lighter'),
    greta_col('light'),
    'white',
    'lightgray',
    'white'
  ),
  penwidth = 2,
  shape = c("square", "circle", "diamond", "circle", "circle", "circle"),
  width = c(0.5, 0.6, 1, 0.01, 0.2, 0.01),
  height = c(0.5, 0.6, 0.8, 0.01, 0.2, 0.01)
)

gr1 <- create_graph(nodes1)
gr1$global_attrs[1, 'value'] <- 'dot'
f_nodes <- tempfile(fileext = '.png')
export_graph(gr1, file_name = f_nodes, width = 1005, height = 249)

ns <- 0.01
nodes2 <- create_node_df(
  n = 4,
  label = '',
  type = "lower",
  alpha = 0,
  style = "filled",
  fillcolor = rep('#ffffff00', 4),
  color = rep('#ffffff00', 4),
  shape = rep("circle", 4),
  width = rep(ns, 4)
)

edges2 <- create_edge_df(
  from = c(1, 3),
  to = c(2, 4),
  label = c('deterministic', 'stochastic'),
  color = rep('Gainsboro', 2),
  fontname = 'Helvetica',
  fontcolor = greta_col('dark'),
  fontsize = 12,
  penwidth = 3,
  style = c('solid', 'dashed')
)

gr2 <- create_graph(nodes2, edges2)
gr2$global_attrs[1, 'value'] <- 'dot'
f_edges <- tempfile(fileext = '.png')

export_graph(gr2, file_name = f_edges, width = 631, height = 249)

# combine the two panels into one

# load images
nodes <- brick(f_nodes)
edges <- brick(f_edges)

# drop 2 pixels on each side to deal with crappy rendering of graphs
nodes <- crop(nodes, extent(nodes) - 4)
edges <- crop(edges, extent(edges) - 4)

dim_pixels <- c(width = round(1005 + 631 + 1005 / 16), height = 249)

dim_inches <- dim_pixels / 10

# layout with a gap inbetween
mat <- matrix(rep(c(1, 2, 3), c(16, 1, 10)), nrow = 1)

png(
  'plotlegend.png',
  width = dim_pixels['width'] * 2,
  height = dim_pixels['height'] * 2
)

layout(mat)
raster::plotRGB(nodes, maxpixels = Inf)
plot.new()
raster::plotRGB(edges, maxpixels = Inf)

dev.off()


pdf(
  'plotlegend.pdf',
  width = dim_inches['width'],
  height = dim_inches['height']
)

layout(mat)
raster::plotRGB(nodes, maxpixels = Inf)
plot.new()
raster::plotRGB(edges, maxpixels = Inf)

dev.off()