Add "thirdcircle" option to allow narrowed hemicycles

DESCRIPTION

@@ -25,7 +25,7 @@ Suggests:
     scales,
     markdown
 VignetteBuilder: knitr
-RoxygenNote: 6.1.1
+RoxygenNote: 7.3.2
 Encoding: UTF-8
 Collate:
     'ggparliament_package.R'

R/ggparliament_package.R

@@ -1,7 +1,6 @@
 #' ggparliament
 #' @name ggparliament-package
-#' @docType package
-#' @keywords package
+#' @keywords "_PACKAGE"
 #'
 #' @import ggplot2
 #'

R/helper_funcs.R

@@ -19,9 +19,16 @@ calc_coordinates <- function(N, M, limits, segment = 0.5) {
     lapply(1:M, function(i) {
       # find how many seats for this parl_row
       counts[i] <<- round(N * radii[i] / sum(radii[i:M]))
-      # seq from 0-180degress for the row for the cartesian position
-      ### ROB- Need to symmetry-ise this for non 0.5/1 values of segment ###
-      theta <- seq(0, segment * 2 * pi, len = counts[i])
+      # For a hemicycle, seq from 0-180degrees for the row for the cartesian position
+      # For a narrower cycle (where segment < 0.5), calculate the offset (theta_narrow)
+      # in radians from each side
+      theta_narrow <- (0.5 - segment) * pi
+      # theta_left is the left-hand start of the arc
+      theta_left <- theta_narrow
+      # theta_right is the right-hand end of the arc
+      theta_right <- pi - theta_narrow
+      theta <- seq( theta_left, theta_right,
+                   len = counts[i])
       # subtract the seats already plotted from N
       # N becomes 'seats left to calculate'
       N <<- N - counts[i]

R/parliament_data.R

@@ -29,6 +29,8 @@ parliament_data <- function(election_data = NULL,
                             type = c(
                               "horseshoe",
                               "semicircle",
+                              "thirdcircle",
+                              "third_circle",
                               "circle",
                               "classroom",
                               "opposing_benches"
@@ -44,13 +46,17 @@ parliament_data <- function(election_data = NULL,
   else if (type == "semicircle") {
     parl_layout <- calc_coordinates(sum(party_seats), parl_rows, c(1, 2))
   }
+
+  else if (type == "thirdcircle" | type == "third_circle") {
+    parl_layout <- calc_coordinates(sum(party_seats), parl_rows, c(1, 2), segment = 1/3)
+  }
 
   else if (type == "circle") {
     parl_layout <- calc_coordinates(sum(party_seats), parl_rows, c(1, 2), segment = 1)
   }
 
   else if (type == "classroom") {
-    # calculate parl_layour by expanding a grid of rows vs the length each row needs to be
+    # calculate parl_layout by expanding a grid of rows vs the length each row needs to be
     parl_layout <- expand.grid(
       y = 1:parl_rows,
       x = seq_len(ceiling(sum(party_seats) / parl_rows))
@@ -120,8 +126,14 @@ parliament_data <- function(election_data = NULL,
     election_data <- election_data[order(-group, -party_seats), ]
   }
 
-  else if (is.null(type) | !type %in% c("horseshoe", "semicircle", "circle", "classroom", "opposing_benches")) {
-    warning("Warning: parliament layout 'type' not supported.")
+  else if (is.null(type) | !type %in% c("horseshoe", "thirdcircle",
+                                        "third_circle", "semicircle", "circle", "classroom", "opposing_benches")) {
+    if (is.null(type)) {
+      type_name <- "<null>"
+    } else {
+      type_name <- type
+    }
+    warning("Warning: parliament layout \"", type_name, "\" not supported.")
   }
 
   # if election data is not null, bind layout to original data

vignettes/a_basic-parliament-plots_1.Rmd

@@ -127,6 +127,37 @@ au <- ggplot(australia_horseshoe, aes(x = x,
 au
 ```
 
+
+
+### Narrower "hemicycle" Parliament
+
+```{r}
+australia_sen <- election_data %>%
+    filter(country == "Australia" &
+               house == "Senate" &
+               year == 2016) 
+
+australia_senate <- parliament_data(election_data = australia_sen,
+                                       party_seats = australia_sen$seats,
+                                       parl_rows = 5,
+                                       type = "thirdcircle")
+```
+
+```{r,fig.width=4, fig.height=4}
+au_senate <- ggplot(australia_senate, aes(x = x, 
+                                   y = y, 
+                                   colour = party_short)) +
+    geom_parliament_seats() + 
+    theme_ggparliament() +
+    labs(colour = NULL, 
+         title = "Australian Senate") +
+    scale_colour_manual(values = australia_sen$colour, 
+                        limits = australia_sen$party_short) + 
+    theme(legend.position = 'bottom')
+
+au_senate
+```
+
 ### Opposing Benches Parliament
 
 The opposing bench style of parliament calls for a variable to split the left and right bench. Using the ggparliament election data, we split on the government column which is a binary variable.