Revert "remove logo"

This reverts commit 35559a2.

logo/BGGplotU.R

@@ -0,0 +1,59 @@
+library(ggraph)
+library(tidygraph)
+library(hexSticker)
+
+dat <-
+  tibble::tribble(
+  ~from, ~to,
+  "SEM", "BGU",
+  "SEM", "S1",
+  "SEM", "S2",
+  "SEM", "...",
+  "SEM", "S40",
+  "Psych", "SEM",
+  "Psych", "BGU"
+) %>% 
+  as_tbl_graph() %E>%
+    mutate(dir = c("<", "<", "<", "<", "<", "<", "<>")) %N>% 
+  arrange(name) %>% 
+  mutate(type = c(rep("Obs",6), "Lat"))
+
+dat %>% 
+  as.data.frame()
+
+arrow_cap     <- circle(4, 'mm')
+label.padding <- unit(0.3,"lines")
+
+sem_p <- ggraph(dat, layout = "manual",
+                x = c(1, 2.5, 2.5, 1, 1, 1, 2)/40,
+                y = -c(2.75, 3.5, 1.5, 1.75, 2.25, 3.25, 2.5)/80) +
+  # edges
+  geom_node_label(aes(filter = type=="Obs",
+                      label  = name),
+                  label.r       = unit(0, "lines"),
+                  label.padding = label.padding) +
+  geom_node_label(aes(filter = type!="Obs",
+                      label  = name),
+                  label.r       = unit(0.4, "lines"),
+                  label.padding = label.padding) +
+  # edges
+  geom_edge_link(aes(filter = dir == "<"),
+                 arrow     = arrow(20, unit(.1, "cm"), type = "closed"),
+                 start_cap = arrow_cap,
+                 end_cap   = arrow_cap) +
+  geom_edge_arc(aes(filter = dir == "<>"),
+                arrow     = arrow(20, unit(.1, "cm"), type = "closed", ends = "both"),
+                start_cap = arrow_cap,
+                end_cap   = arrow_cap) +
+  # theme_bw() +
+  theme_transparent() +
+  coord_cartesian(xlim = c(0.02, 0.07),
+                  ylim = -c(0.015, 0.047))
+
+
+sticker(sem_p, package="SEM - Practical Applications in R",
+        filename = "BGUHex.png",
+        s_x = 0.9, s_y = 0.8, s_width = 1.6, s_height = 1.2,
+        p_color = "white", p_size = 8,
+        h_color = "grey", h_fill = "orange",
+        spotlight = TRUE, l_y = 1.2)