Size of text/label keys (#5562)

* improve text label

* improve label labels

* add news bullet

Author: teunbrand

NEWS.md

@@ -1,5 +1,7 @@
 # ggplot2 (development version)
 
+* `draw_key_label()` now better reflects the appearance of labels.
+
 * The `minor_breaks` function argument in scales can now take a function with
   two arguments: the scale's limits and the scale's major breaks (#3583).
 

R/legend-draw.R

@@ -236,26 +236,68 @@ draw_key_smooth <- function(data, params, size) {
 #' @export
 #' @rdname draw_key
 draw_key_text <- function(data, params, size) {
-  if(is.null(data$label)) data$label <- "a"
-
-  textGrob(data$label, 0.5, 0.5,
-    rot = data$angle %||% 0,
+  data$label <- data$label %||% "a"
+  just <- rotate_just(data$angle, data$hjust, data$vjust)
+  grob <- titleGrob(
+    data$label,
+    x = unit(just$hjust, "npc"), y = unit(just$vjust, "npc"),
+    angle = data$angle,
+    hjust = data$hjust,
+    vjust = data$vjust,
     gp = gpar(
       col = alpha(data$colour %||% data$fill %||% "black", data$alpha),
-      fontfamily = data$family %||% "",
-      fontface = data$fontface %||% 1,
-      fontsize = (data$size %||% 3.88) * .pt
-    )
+      fontfamily = data$family   %||% "",
+      fontface   = data$fontface %||% 1,
+      fontsize   = (data$size %||% 3.88) * .pt
+    ),
+    margin = margin(0.1, 0.1, 0.1, 0.1, unit = "lines"),
+    margin_x = TRUE, margin_y = TRUE
   )
+  attr(grob, "width")  <- convertWidth(grobWidth(grob),   "cm", valueOnly = TRUE)
+  attr(grob, "height") <- convertHeight(grobHeight(grob), "cm", valueOnly = TRUE)
+  grob
 }
 
 #' @export
 #' @rdname draw_key
 draw_key_label <- function(data, params, size) {
-  grobTree(
-    draw_key_rect(data, list()),
-    draw_key_text(data, list())
+  data$label <- data$label %||% "a"
+  just <- rotate_just(data$angle, data$hjust, data$vjust)
+  padding <- rep(params$label.padding, length.out = 4)
+  descent <- font_descent(
+    family = data$family %||% "",
+    face = data$fontface %||% 1,
+    size = data$size %||% 3.88
+  )
+  grob <- labelGrob(
+    data$label,
+    x = unit(just$hjust, "npc"),
+    y = unit(just$vjust, "npc") + descent,
+    angle = data$angle,
+    just = c(data$hjust, data$vjust),
+    padding = padding,
+    r = params$label.r,
+    text.gp = gpar(
+      col = data$colour %||% "black",
+      fontfamily = data$family   %||% "",
+      fontface   = data$fontface %||% 1,
+      fontsize   = (data$size %||% 3.88) * .pt
+    ),
+    rect.gp = gpar(
+      col = if (isTRUE(all.equal(params$label.size, 0))) NA else data$colour,
+      fill = alpha(data$fill %||% "white", data$alpha),
+      lwd = params$label.size * .pt
+    )
   )
+  angle  <- deg2rad(data$angle %||% 0)
+  text   <- grob$children[[2]]
+  width  <- convertWidth(grobWidth(text),   "cm", valueOnly = TRUE)
+  height <- convertHeight(grobHeight(text), "cm", valueOnly = TRUE)
+  x <- c(0, 0, width, width)
+  y <- c(0, height, height, 0)
+  attr(grob, "width")  <- diff(range(x * cos(angle) - y * sin(angle)))
+  attr(grob, "height") <- diff(range(x * sin(angle) + y * cos(angle)))
+  grob
 }
 
 #' @export