hline chips away part of vertical lines within table

[ltcamara]

The following RMarkdown example reproduces the problem that I have. It can directly be used and encircles the problem I am facing in my current use case.

---
title: "Display issues with hline translation to LaTex"
header-includes:
  \usepackage{picture}
output:
  pdf_document:
    latex_engine: xelatex
---
\begin{picture}(0, 0)(0, 0)
  \put(125, -159){\circle{10cm}}
  \put(180, -159){\circle{10cm}}
  \put(290, -159){\circle{10cm}}
  \put(345, -159){\circle{10cm}}
\end{picture}

```{r setup, include=FALSE}
library(flextable)
library(dplyr)
# Please set your directory here
setwd("SET_YOUR_DIRECTORY_HERE")

data_test <- flextable(mtcars[1:20, 1:6])

data_test <- data_test %>%
  fontsize(size = 9, part = "all") %>%
  hline_bottom(part = "header") %>% # add the header bottom line
  border_inner_v(part = "all") # add vertical lines

data_test <- data_test %>%
  hline(i = 7, j = 4, part = "body",
        border = officer::fp_border("red"))
\``` <----- eliminate escape to run

```{r, ft.align = "center", message=FALSE, echo=FALSE}
data_test
\``` <----- eliminate escape to run

Description of the problem Since flextable translates hline into the "\hhline" command of LaTex, it does it by making use of the tilde "~" for cells without a line and for the cell with a line it assigns the corresponding element. In my case, this translates to the following, in LaTex: \hhline{~~~>{\arrayrulecolor[HTML]{FF0000}\global\arrayrulewidth=1pt}-~~} The issue: It chips away vertical lines from the other columns as the circles in the executed markdown illustrate.

Potential solution If the lines are converted to \hhline{~|~|~>{\arrayrulecolor[HTML]{FF0000}\global\arrayrulewidth=1pt}-|~|~} the problem will go away. Issue here: it needs to be known where the "|" must be set.

**Session info**
> sessionInfo()
R version 4.2.2 Patched (2022-11-10 r83330)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Ubuntu 20.04.5 LTS

Matrix products: default
BLAS:   /usr/lib/x86_64-linux-gnu/blas/libblas.so.3.9.0
LAPACK: /usr/lib/x86_64-linux-gnu/lapack/liblapack.so.3.9.0

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

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

other attached packages:
[1] rmarkdown_2.14

loaded via a namespace (and not attached):
 [1] rstudioapi_0.13  xml2_1.3.3       knitr_1.39       magrittr_2.0.3   uuid_1.1-0       tidyselect_1.1.2
 [7] munsell_0.5.0    colorspace_2.0-3 R6_2.5.1         rlang_1.0.6      fastmap_1.1.0    fansi_1.0.3     
[13] dplyr_1.0.9      tools_4.2.2      grid_4.2.2       gtable_0.3.0     xfun_0.31        utf8_1.2.2      
[19] cli_3.4.1        htmltools_0.5.2  ellipsis_0.3.2   yaml_2.3.5       digest_0.6.29    tibble_3.1.7    
[25] lifecycle_1.0.1  crayon_1.5.1     zip_2.2.0        officer_0.4.4    purrr_0.3.4      ggplot2_3.3.6   
[31] vctrs_0.4.1      glue_1.6.2       evaluate_0.15    compiler_4.2.2   pillar_1.7.0     generics_0.1.2  
[37] scales_1.2.0     pkgconfig_2.0.3 

[davidgohel]

Thanks a lot, that is very useful - I will try to fix soon.

[ltcamara]

I just had another idea, that may be helpful. Maybe \cline is easier to adapt than \hhline for this? Just an idea.

[ltcamara]

Exchanging the relevant line in the generated .tex code:

leads to the desired result:

[davidgohel]

It should be fixed now. It was hard. Thanks for the clues you gave, it was very helpful.

• cline can not be used when there is a background color; in that case, hhline is used. Now both can be used by flextable.
• hhline and | are difficult to manage when cells are vertically merged.

However, now many display issues related to 'flextable' and latex borders are fixed (and it feels good).

One issue remains with your test case when the table has a background color. I hope to fix it later, not sure if I can.

[ltcamara]

Thanks a lot, David.

[github-actions[bot]]

This old thread has been automatically locked. If you think you have found something related to this, please open a new issue and link to this old issue if necessary.