table-testing.qmd

---
title: Table testing
format: 
  html: default
  pdf: default
---

```{r, warning=FALSE, message=FALSE}
library(tidyverse)
library(gt)

example_table <- tibble::tribble(
  ~thing1, ~thing2, ~thing3,
  1, 2, "3",
  4, 5, "6",
  7, 8, "Really long text goes here blah blah blah it just keeps going forever, maybe even off the side of the page? Can we get it to trail off? Maybe?!"
)
```


This works fine in HTML but breaks in PDF:

```{r eval=TRUE}
example_table %>% 
  gt() %>% 
  cols_label(
    thing1 = "Thing", thing2 = "Other thing", thing3 = "One more longer thing"
  ) %>% 
  cols_width(
    thing1 ~ pct(10),
    thing2 ~ pct(15),
    thing3 ~ pct(75)
  )
```


It breaks in PDF because `gt()` emits things like `10%`, which isn't valid LaTeX:

```tex
\begin{longtable*}{>{\raggedleft\arraybackslash}p{10%}>{\raggedleft
\arraybackslash}p{15%}>{\raggedright\arraybackslash}p{75%}}
```

We can feed widths like `3in` or `6cm` though:

```{r}
example_table %>% 
  gt() %>% 
  cols_label(
    thing1 = "Thing", thing2 = "Other thing", thing3 = "One more longer thing"
  ) %>% 
  cols_width(
    thing1 ~ "1in",
    thing2 ~ "1.25in",
    thing3 ~ "3.5in"
  )
```

And it works for HTML too, but then you have to think about inches in HTML, and that's weird. Percents are better there. Also, here I arbitrarily chose 1, 1.25, and 3 inches, but those aren't the original 10%, 15%, 75% proportions that I used at the beginning. If I have 6 inches of page width to work with, I'd need 75% of that for the 75% column, or 6 × 0.75 = 4.5 inches.

Doing that math is tedious though. And using inches in HTML is annoying.

So we can make a little wrapper function that uses percents when rendering to HTML and that converts percents to inches when rendering to PDF:

```{r}
my_pct <- function(x, page_width = 6) {
  if (knitr::pandoc_to("latex")) {
    paste0(page_width * (x / 100), "in")
  } else {
    gt::pct(x)
  }
}

example_table %>% 
  gt() %>% 
  cols_label(
    thing1 = "Thing", thing2 = "Other thing", thing3 = "One more longer thing"
  ) %>% 
  cols_width(
    thing1 ~ my_pct(10),
    thing2 ~ my_pct(15),
    thing3 ~ my_pct(75)
  )
```

(It's a little wider than the text block width, but I think that's because of internal cell padding)