Multiply colourbar linewidth parameters with *.pt (#4314)

NEWS.md

@@ -228,6 +228,11 @@ small selection of feature refinements.
 
 * ggplot2 now requires R >= 3.3 (#4247).
 
+* The `ticks.linewidth` and `frame.linewidth` parameters of `guide_colourbar()`
+  are now multiplied with `.pt` like elsewhere in ggplot2. It can cause visual
+  changes when these arguments are not the defaults and these changes can be 
+  restored to their previous behaviour by adding `/ .pt` (@teunbrand #4314).
+
 * ggplot2 now uses `rlang::check_installed()` to check if a suggested package is
   installed, which will offer to install the package before continuing (#4375, 
   @malcolmbarrett)

R/guide-colorbar.r

@@ -125,13 +125,13 @@ guide_colourbar <- function(
 
   # frame
   frame.colour = NULL,
-  frame.linewidth = 0.5,
+  frame.linewidth = 0.5 / .pt,
   frame.linetype = 1,
 
   # ticks
   ticks = TRUE,
   ticks.colour = "white",
-  ticks.linewidth = 0.5,
+  ticks.linewidth = 0.5 / .pt,
   draw.ulim= TRUE,
   draw.llim = TRUE,
 
@@ -322,7 +322,7 @@ guide_gengrob.colorbar <- function(guide, theme) {
                     default.units = "cm",
                     gp = gpar(
                       col = guide$frame.colour,
-                      lwd = guide$frame.linewidth,
+                      lwd = guide$frame.linewidth * .pt,
                       lty = guide$frame.linetype,
                       fill = NA)
                     )
@@ -451,7 +451,7 @@ guide_gengrob.colorbar <- function(guide, theme) {
       default.units = "cm",
       gp = gpar(
         col = guide$ticks.colour,
-        lwd = guide$ticks.linewidth,
+        lwd = guide$ticks.linewidth * .pt,
         lineend = "butt"
       )
     )

tests/testthat/test-guides.R

@@ -482,9 +482,9 @@ test_that("colorbar can be styled", {
           low = 'white', high = 'red',
           guide = guide_colorbar(
             frame.colour = "green",
-            frame.linewidth = 1.5,
+            frame.linewidth = 1.5 / .pt,
             ticks.colour = "black",
-            ticks.linewidth = 2.5
+            ticks.linewidth = 2.5 / .pt
             )
         )
     )