fix bad default for legend spacing variables. closes #2943. (#3276)

Author: clauswilke

NEWS.md

@@ -112,6 +112,9 @@ core developer team.
 * `geom_violin()` no longer throws an error when quantile lines fall outside 
   the violin polygon (@thomasp85, #3254).
 
+* `guide_legend()` and `guide_colorbar()` now use appropriate spacing between legend
+  key glyphs and legend text even if the legend title is missing (@clauswilke, #2943).
+
 * Default labels are now generated more consistently; e.g., symbols no longer
   get backticks, and long expressions are abbreviated with `...`
   (@yutannihilation, #2981).

R/guide-colorbar.r

@@ -342,7 +342,8 @@ guide_gengrob.colorbar <- function(guide, theme) {
 
   title_width <- width_cm(grob.title)
   title_height <- height_cm(grob.title)
-  title_fontsize <- title.theme$size %||% calc_element("legend.title", theme)$size %||% 0
+  title_fontsize <- title.theme$size %||% calc_element("legend.title", theme)$size %||%
+    calc_element("text", theme)$size %||% 11
 
   # gap between keys etc
   # the default horizontal and vertical gap need to be the same to avoid strange

R/guide-legend.r

@@ -327,7 +327,8 @@ guide_gengrob.legend <- function(guide, theme) {
 
   title_width <- width_cm(grob.title)
   title_height <- height_cm(grob.title)
-  title_fontsize <- title.theme$size %||% calc_element("legend.title", theme)$size %||% 0
+  title_fontsize <- title.theme$size %||% calc_element("legend.title", theme)$size %||%
+    calc_element("text", theme)$size %||% 11
 
   # gap between keys etc
   # the default horizontal and vertical gap need to be the same to avoid strange