Text slightly shifted in PPT output & width and height arguments ignored

[tomwenseleers]

I am having trouble with text being slightly shifted vertically in the PPT output compared to what I see onscreen (e.g. the X axis labels touch the X axis tickmarks in the PPT when they don't touch onscreen). Also, the width & height argument appears to be ignored, as my graph is always stretched across the slide, which I don't want here (sorry if that's a silly issue).
Reproducible example:

library(ggplot2)
library(devtools)
devtools::install_github("davidgohel/rvg")
devtools::install_github("davidgohel/officer")
devtools::install_github("davidgohel/gdtools")
library(rvg)
library(gdtools)

plot_data <- data.frame (a = runif (1:20), b = seq (1:20))

x11 (width =  3, height = 3)

z <- ggplot(data = plot_data, mapping = aes (x = a, y = b)) +
  geom_point() +
  labs(x = "my x-label", y = "my y-label") +
  theme(panel.background = element_blank(),
        panel.border = element_rect (fill = NA, size = 0.5),
        axis.ticks = element_line (color = "black", lineend = "round", size=0.5),
        axis.ticks.length = unit (2, "mm"),
        axis.text = element_text (color = "black"),
        plot.margin = unit(rep (0, 4), "cm"),
        text = element_text (size=18,  
                             family="sans", 
                             color = "black")
  )
z

library(officer)
doc <- read_pptx()
doc <- add_slide(doc, "Title and Content", "Office Theme")
doc <- ph_with(doc, dml(ggobj = z, width = 3, height = 3), # I get the same output with extra argument fonts = list(sans = "TT Arial")), 
               location = ph_location_type(type = "body"))
fileout <- "test.pptx"
print(doc, target = fileout)

test.pptx

sessionInfo()
# R version 3.5.3 (2019-03-11)
# Platform: x86_64-w64-mingw32/x64 (64-bit)
# Running under: Windows 10 x64 (build 18362)
# 
# Matrix products: default
# 
# locale:
#   [1] LC_COLLATE=English_United States.1252  LC_CTYPE=English_United States.1252    LC_MONETARY=English_United States.1252
# [4] LC_NUMERIC=C                           LC_TIME=English_United States.1252    
# 
# attached base packages:
#   [1] stats     graphics  grDevices utils     datasets  methods   base     
# 
# other attached packages:
#   [1] officer_0.3.6.015    gdtools_0.2.1        rvg_0.2.2.001        usethis_1.5.1        devtools_2.0.2       ggplot2_3.2.1       
# [7] RevoUtils_11.0.3     RevoUtilsMath_11.0.0
# 
# loaded via a namespace (and not attached):
#   [1] zip_2.0.4         Rcpp_1.0.2        pillar_1.4.2      compiler_3.5.3    base64enc_0.1-3   prettyunits_1.0.2 remotes_2.0.4    
# [8] tools_3.5.3       uuid_0.1-2        testthat_2.2.1    digest_0.6.20     pkgbuild_1.0.5    pkgload_1.0.2     memoise_1.1.0    
# [15] tibble_2.1.3      gtable_0.3.0      pkgconfig_2.0.2   rlang_0.4.0       cli_1.1.0         rstudioapi_0.10   curl_3.3         
# [22] xml2_1.2.2        withr_2.1.2       dplyr_0.8.3       systemfonts_0.1.1 fs_1.3.1          desc_1.2.0        rprojroot_1.3-2  
# [29] grid_3.5.3        tidyselect_0.2.5  glue_1.3.1        R6_2.4.0          processx_3.4.1    sessioninfo_1.1.1 purrr_0.3.2      
# [36] callr_3.3.1       magrittr_1.5      htmltools_0.3.6   scales_1.0.0      backports_1.1.4   ps_1.3.0          assertthat_0.2.1 
# [43] colorspace_1.4-1  labeling_0.3      lazyeval_0.2.2    munsell_0.5.0     crayon_1.3.4