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Why my code for using png logos in axis labels in ggtext is not working

I am trying to learn 'Improving Visualisations in R' presently following this fabulous post.

For the first part it seems working greatly. But the part where axis text is replaced by logos is not working. The error displayed is -

Error in png::readPNG(get_file(path), native = TRUE) : 
  file is not in PNG format
In addition: Warning message:
Removed 18 rows containing missing values (geom_point).

For this blog post it is again throwing same error (i.e. file is not in PNG format)

Full reprex is as below (upto the part where it stops working)

library(tidyverse)
library(ggtext)
library(tools)


streaming <- tibble::tribble(
  ~service, ~`2020`, ~`2021`,
  "netflix",    29, 20,
  "prime",      21, 16,
  "hulu",       16, 13,
  "disney",     12, 11,
  "apple",       4,  5,
  "peacock",     0,  5,
  "hbo",         3, 12,
  "paramount",   2,  3,
  "other",      13, 15,
)

## pivot to long format with the 
## year and share as their own columns
streaming_long <- tidyr::pivot_longer(streaming, 
                                      cols = -service, 
                                      names_to = "year", 
                                      values_to = "share")

## plot the years side-by-side in the original order
p <- ggplot(streaming_long) + 
  geom_col(aes(factor(service, levels = streaming$service), 
               share, fill = year), position = position_dodge(width = 0.9)) + 
  ## add a hidden set of points to make the legend circles easily
  geom_point(aes(x = service, y = -10, color = year, fill = year), size = 4) + 
  ## add the percentages just above each bar
  geom_text(aes(service, share + 1, label = paste0(share, "%"), group = year),
            position = position_dodge(width = 0.9), size = 3) +
  ## use similar colours to the original
  scale_fill_manual(values = c(`2020` = "red3", `2021` = "black")) +
  scale_color_manual(values = c(`2020` = "red3", `2021` = "black")) + 
  ## hide the fill legend and make the color legend horizontal
  guides(fill = "none", color = guide_legend(direction = "horizontal")) +
  scale_y_continuous(labels = scales::percent_format(scale = 1), 
                     limits = c(0, 35)) +
  labs(title = "US Streaming Market Share", 
       subtitle = "2020 vs 2021", 
       caption = "Source: Ampere Analytics via The Wrap
       
       Other Streatming Services include ESPN+, Showtime,
       Sling TV, Youtube TV, and Starz",
       x = "", y = "") +
  theme_minimal() + 
  theme(axis.text = element_text(size = 10),
        plot.title = element_text(size = 28, hjust= 0.5), 
        plot.subtitle = element_text(size = 28, hjust = 0.5),
        plot.caption = element_text(size = 7, color = "grey60"),
        plot.background = element_rect(fill = "#f4f7fc", size = 0),
        legend.title = element_blank(),
        legend.text= element_text(size = 12),
        panel.grid = element_blank(),
        ## move the color legend to an inset 
        legend.position = c(0.85, 0.8)) 
p
#> Warning: Removed 18 rows containing missing values (geom_point).

Create a folder images in working directory



wiki <- "https://upload.wikimedia.org/wikipedia/commons/thumb/"
logos <- tibble::tribble(
  ~service, ~logo,
  "netflix", paste0(wiki, "0/08/Netflix_2015_logo.svg/340px-Netflix_2015_logo.svg.png"),
  "prime", paste0(wiki, "1/11/Amazon_Prime_Video_logo.svg/450px-Amazon_Prime_Video_logo.svg.png"),
  "hulu", paste0(wiki, "e/e4/Hulu_Logo.svg/440px-Hulu_Logo.svg.png"),
  "disney", paste0(wiki, "3/3e/Disney%2B_logo.svg/320px-Disney%2B_logo.svg.png"),
  "apple",  paste0(wiki, "2/28/Apple_TV_Plus_Logo.svg/500px-Apple_TV_Plus_Logo.svg.png"),
  "peacock", paste0(wiki, "d/d3/NBCUniversal_Peacock_Logo.svg/440px-NBCUniversal_Peacock_Logo.svg.png"),
  "hbo", paste0(wiki, "d/de/HBO_logo.svg/440px-HBO_logo.svg.png"),
  "paramount", paste0(wiki, "a/a5/Paramount_Plus.svg/440px-Paramount_Plus.svg.png"),
  "other", "other.png"
) %>% 
  mutate(path = file.path("images", paste(service, tools::file_ext(logo), sep = ".")))
labels <- setNames(paste0("<img src='", logos$path, "' width='35' />"), logos$service)
labels[["other"]] <- "other<br />streaming<br />services"

for (r in 1:8) {
  download.file(logos$logo[r], logos$path[r])
}
#> Error in download.file(logos$logo[r], logos$path[r]): cannot open destfile 'images/netflix.png', reason 'No such file or directory'



p <- p + 
  scale_x_discrete(labels = labels) + 
  theme(axis.text.x = ggtext::element_markdown())
p
#> Warning: Removed 18 rows containing missing values (geom_point).
#> Error in png::readPNG(get_file(path), native = TRUE): unable to open images/netflix.png

Created on 2021-08-27 by the reprex package (v2.0.1)

On the code suggested by Teunbrand, the following error is returned

> for (r in 1:8) {
+   download.file(logos$logo[r], logos$path[r], method = "curl")
+ }
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
curl: (35) schannel: next InitializeSecurityContext failed: Unknown error (0x80092012) - The revocation function was unable to check revocation for the certificate.
Error in download.file(logos$logo[r], logos$path[r], method = "curl") : 
  'curl' call had nonzero exit status
Solution

  • The following works for me. To highlight a few changes:

    • I changed the path for the downloads destination to tempdir() instead.
    • I changed this line: labels[["other"]] <- "other<br>streaming<br>services"
    • I added the method = "curl" in the download.file() function.
    library(tidyverse)
library(ggtext)
library(tools)


streaming <- tibble::tribble(
  ~service, ~`2020`, ~`2021`,
  "netflix",    29, 20,
  "prime",      21, 16,
  "hulu",       16, 13,
  "disney",     12, 11,
  "apple",       4,  5,
  "peacock",     0,  5,
  "hbo",         3, 12,
  "paramount",   2,  3,
  "other",      13, 15,
)

## pivot to long format with the 
## year and share as their own columns
streaming_long <- tidyr::pivot_longer(streaming, 
                                      cols = -service, 
                                      names_to = "year", 
                                      values_to = "share")

## plot the years side-by-side in the original order
p <- ggplot(streaming_long) + 
  geom_col(aes(factor(service, levels = streaming$service), 
               share, fill = year), position = position_dodge(width = 0.9)) + 
  ## add a hidden set of points to make the legend circles easily
  geom_point(aes(x = service, y = -10, color = year, fill = year), size = 4) + 
  ## add the percentages just above each bar
  geom_text(aes(service, share + 1, label = paste0(share, "%"), group = year),
            position = position_dodge(width = 0.9), size = 3) +
  ## use similar colours to the original
  scale_fill_manual(values = c(`2020` = "red3", `2021` = "black")) +
  scale_color_manual(values = c(`2020` = "red3", `2021` = "black")) + 
  ## hide the fill legend and make the color legend horizontal
  guides(fill = "none", color = guide_legend(direction = "horizontal")) +
  scale_y_continuous(labels = scales::percent_format(scale = 1), 
                     limits = c(0, 35)) +
  labs(title = "US Streaming Market Share", 
       subtitle = "2020 vs 2021", 
       caption = "Source: Ampere Analytics via The Wrap
       
       Other Streatming Services include ESPN+, Showtime,
       Sling TV, Youtube TV, and Starz",
       x = "", y = "") +
  theme_minimal() + 
  theme(axis.text = element_text(size = 10),
        plot.title = element_text(size = 28, hjust= 0.5), 
        plot.subtitle = element_text(size = 28, hjust = 0.5),
        plot.caption = element_text(size = 7, color = "grey60"),
        plot.background = element_rect(fill = "#f4f7fc", size = 0),
        legend.title = element_blank(),
        legend.text= element_text(size = 12),
        panel.grid = element_blank(),
        ## move the color legend to an inset 
        legend.position = c(0.85, 0.8)) 

tmpdir <- tempdir()
wiki <- "https://upload.wikimedia.org/wikipedia/commons/thumb/"
logos <- tibble::tribble(
  ~service, ~logo,
  "netflix", paste0(wiki, "0/08/Netflix_2015_logo.svg/340px-Netflix_2015_logo.svg.png"),
  "prime", paste0(wiki, "1/11/Amazon_Prime_Video_logo.svg/450px-Amazon_Prime_Video_logo.svg.png"),
  "hulu", paste0(wiki, "e/e4/Hulu_Logo.svg/440px-Hulu_Logo.svg.png"),
  "disney", paste0(wiki, "3/3e/Disney%2B_logo.svg/320px-Disney%2B_logo.svg.png"),
  "apple",  paste0(wiki, "2/28/Apple_TV_Plus_Logo.svg/500px-Apple_TV_Plus_Logo.svg.png"),
  "peacock", paste0(wiki, "d/d3/NBCUniversal_Peacock_Logo.svg/440px-NBCUniversal_Peacock_Logo.svg.png"),
  "hbo", paste0(wiki, "d/de/HBO_logo.svg/440px-HBO_logo.svg.png"),
  "paramount", paste0(wiki, "a/a5/Paramount_Plus.svg/440px-Paramount_Plus.svg.png"),
  "other", "other.png"
) %>% 
  mutate(path = file.path(tmpdir, paste(service, tools::file_ext(logo), sep = ".")))
labels <- setNames(paste0("<img src='", logos$path, "' width='35' />"), logos$service)
labels[["other"]] <- "other<br>streaming<br>services"

for (r in 1:8) {
  download.file(logos$logo[r], logos$path[r], method = "curl")
}

p + 
  scale_x_discrete(labels = labels) + 
  theme(axis.text.x = ggtext::element_markdown())
#> Warning: Removed 18 rows containing missing values (geom_point).

    Created on 2021-08-27 by the reprex package (v1.0.0)

    This was done with R 4.0.5 on Windows 10 with ggplot2 v3.3.5 and ggtext v0.1.1.