Add ggplot2 elements to cheat sheet.

content/cheatsheet.md

@@ -6,12 +6,69 @@ description: >
   and maybe it is helpful for you, too, internet wanderer.
 date: 2024-11-05T08:00:00+0100
 draft: false
+toc: true
 ---
 {{< git-info >}}
 {{< param "description" >}}
 
 ## R
 
+## ggplot2 elements
+
+I can never remember which part of a [ggplot2][] graph/figure is the "plot"
+and which is the "panel", so I made this little figure:
+
+{{< figure src="/img/ggplot2-elements.png" >}}
+
+The figure was generated with this code:
+
+```r
+library(tidyverse)
+tibble(x = 1:3, y = 1:3) |>
+  ggplot(aes(x = x, y = y)) +
+  geom_col(fill = "white") +
+  geom_text(
+    label = "The green area is the PANEL BACKGROUND",
+    x = 0.5,
+    y = 3.5,
+    hjust = 0,
+    color = "dark green",
+    fontface = "bold"
+  ) +
+  geom_text(
+    label = "The blue border at the top and the right is the PLOT BORDER",
+    x = 0.5,
+    y = 3.2,
+    hjust = 0,
+    color = "navy",
+    fontface = "bold"
+  ) +
+  geom_text(
+    label = "The gray area is the PLOT BACKGROUND",
+    x = 0.5,
+    y = -0.5,
+    hjust = 0,
+    color = "black",
+    fontface = "bold"
+  ) +
+  coord_cartesian(clip = "off") +
+  scale_x_continuous(expand = expansion(), limits = c(0, 4)) +
+  scale_y_continuous(expand = expansion(), limits = c(0, 4)) +
+  theme(
+    panel.border = element_rect(fill = "light blue", color = "blue"),
+    panel.background = element_rect(fill = "light green", color = "green"),
+    plot.background = element_rect(fill = "gray", color = "black"),
+    plot.margin = unit(rep(0.1, 4), units = "npc")
+  )
+ggsave(
+  "ggplot2-elements.png",
+  width = 9,
+  height = 6,
+  units = "in",
+  dpi = 96
+)
+```
+
 ### Print R objects so that they can be re-generated from code
 
 ```r
@@ -100,4 +157,6 @@ starwars |>
 
 ### Human interaction with IMAP servers
 
-<https://geekmungus.co.uk/?p=4358>
+<https://geekmungus.co.uk/?p=4358>
+
+[ggplot2]: https://ggplot2.tidyverse.org