pad area coordinates only with needed ggplot_build() data (#467)

Author: simonpcouch

NEWS.md

@@ -2,6 +2,9 @@
 
 To be released as infer v1.0.4.
 
+* Fixed bug in p-value shading where shaded regions no longer correctly overlaid
+  histogram bars.
+
 # infer v1.0.3
 
 * Fix R-devel HTML5 NOTEs.

R/shade_p_value.R

@@ -336,7 +336,8 @@ hist_area <- function(data, obs_stat, direction, yval) {
   # "almost vertical" lines with `geom_area()` usage. If don't do this, then
   # area might be shaded under line segments connecting edges of consequtive
   # histogram bars.
-  x_extra <- sort(c(x, g_data[["xmin"]], g_data[["xmax"]]))
+  x_extra <- switch(direction, left = g_data[["xmax"]], right = g_data[["xmin"]])
+  x_extra <- sort(c(x, x_extra))
   x_grid <- switch(
     # `direction` can be one of "left" or "right" at this point of execution
     direction,