density argument when reading pdf not respected

Seems like reading a pdf into magick through pdftools always comes in as 72 dpi

npqleg = 'npq_legend.pdf'

> image_read_pdf(npqleg,density=288)
# A tibble: 1 x 7
  format width height colorspace matte filesize density
  <chr>  <int>  <int> <chr>      <lgl>    <int> <chr>  
1 PNG     1259   1402 sRGB       TRUE         0 +72x+72
> pdftools::pdf_render_page(npqleg, dpi=288, antialias=T) %>% image_read(density="288")
# A tibble: 1 x 7
  format width height colorspace matte filesize density
  <chr>  <int>  <int> <chr>      <lgl>    <int> <chr>  
1 PNG     1259   1402 sRGB       TRUE         0 +72x+72

Just pdf_render_page seems to work without errors:

> pdftools::pdf_render_page(npqleg, dpi=288, antialias=T)
4 channel 1259x1402 bitmap array: 'bitmap' raw [1:4, 1:1259, 1:1402] ff ff ff ff ...

image_read works ok though

> image_read(npqleg,density=288)
# A tibble: 1 x 7
  format width height colorspace matte filesize density  
  <chr>  <int>  <int> <chr>      <lgl>    <int> <chr>    
1 PDF     1259   1402 sRGB       TRUE     19261 +288x+288

in the case of pdftools::pdf_render_page(npqleg, dpi=288, antialias=T) %>% png::writePNG('test2.png', dpi=288) why does image_read('test2.png') return an image with density 113? I expected ether 288 or 72. If i open test2.png in an image viewer it recognizes it to have dpi=288.

npq_legend.pdf

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I'm trying to put together several plots from matplotlib that are formatted like npq_legend above. I have the figures saved as rasters at 100 dpi, but i'm trying to get a better legend so I saved a single copy as a pdf. i'm trying to follow this advice of supersampling to get decent text. http://www.imagemagick.org/discourse-server/viewtopic.php?p=54853&sid=1525b3ad11155f1b4ff1ad4d0a76ca5e#p54853

this is what i'm trying to crop:

image_read(npqleg, density=288) %>% image_draw()
rect(1075, 1175, 1250, 200, border='red')

> sessionInfo()
R version 3.6.0 (2019-04-26)
Platform: x86_64-redhat-linux-gnu (64-bit)
Running under: CentOS Linux 7 (Core)

Matrix products: default
BLAS/LAPACK: /usr/lib64/R/lib/libRblas.so

locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C               LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8     LC_MONETARY=en_US.UTF-8   
 [6] LC_MESSAGES=en_US.UTF-8    LC_PAPER=en_US.UTF-8       LC_NAME=C                  LC_ADDRESS=C               LC_TELEPHONE=C            
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C       

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
 [1] glue_1.4.0      magick_2.3      fs_1.4.1.9000   here_0.1        forcats_0.5.0   stringr_1.4.0   dplyr_0.8.5     purrr_0.3.3     readr_1.3.1    
[10] tidyr_1.0.2     tibble_3.0.0    ggplot2_3.3.0   tidyverse_1.3.0

loaded via a namespace (and not attached):
 [1] qpdf_1.1         tidyselect_1.0.0 haven_2.2.0      lattice_0.20-38  colorspace_1.4-1 vctrs_0.2.4      generics_0.0.2   utf8_1.1.4       rlang_0.4.5     
[10] pillar_1.4.3     withr_2.1.2      DBI_1.1.0        dbplyr_1.4.2     modelr_0.1.6     readxl_1.3.1     lifecycle_0.2.0  munsell_0.5.0    gtable_0.3.0    
[19] cellranger_1.1.0 rvest_0.3.5      fansi_0.4.1      broom_0.5.5      pdftools_2.3     Rcpp_1.0.4       scales_1.1.0     backports_1.1.6  jsonlite_1.6.1  
[28] hms_0.5.3        askpass_1.1      png_0.1-7        stringi_1.4.6    grid_3.6.0       rprojroot_1.3-2  cli_2.0.2        tools_3.6.0      magrittr_1.5    
[37] crayon_1.3.4     pkgconfig_2.0.3  ellipsis_0.3.0   xml2_1.3.0       reprex_0.3.0     lubridate_1.7.8  assertthat_0.2.1 httr_1.4.1       rstudioapi_0.11 
[46] R6_2.4.1         nlme_3.1-139     compiler_3.6.0

ropensci / magick

density argument when reading pdf not respected #243

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