Scripted PDF

The point of this exercise is to demonstrate flexible rendering of subscripts and superscripts. We want to write expressions for column labels and units that are fairly readable as they are, and yet can be easily rendered with equivalent results in plotmath, html, or pdf.

First we load some packages.

library(magrittr)
library(ggplot2)
library(tablet)
library(yamlet)
library(dplyr)
library(kableExtra)

We create some example data.

x <- data.frame(
  time = 1:10, 
  work = (1:10)^1.5, 
  group = 1:2, 
  set = c(rep('delta',5), rep('gamma', 5))
)
x %<>% decorate('
 time: [ Time_cum.^alpha, h ]
 work: [ Work_total_obs\\n, kg*m^2/s^2 ]
 group: [ Group, [ Second\\nGroup^\\*: 2, First\\nGroup^#: 1 ]]
 set: [ Set, [ gamma, delta ]]
')
x %>% decorations

## - time
##  - label: Time_cum.^alpha
##  - guide: h
## - work
##  - label: Work_total_obs\n
##  - guide: kg*m^2/s^2
## - group
##  - label: Group
##  - guide
##   - Second\nGroup^\*: 2
##   - First\nGroup^#: 1
## - set
##  - label: Set
##  - guide: gamma, delta

The label for column work has nested subscripts suggesting $\sf{Work_{total_{obs}}}$. The label for column time suggests $\sf{Time_{cum}{}^{\alpha}}$. The dot closes the subscript to distinguish this from $\sf{Time_{cum^{\alpha}}}$. Backslash-n requests a line break.

How does this look when we plot it?

x %>% 
  resolve %>% 
  ggplot(aes(time, work, color = group, shape = set)) + 
  geom_point()

By default, we get verbatim labels and units as substitutes for column names.

Next, we use enscript() instead of resolve() to indicate that the labels should be understood as potentially having subscripts and superscripts. For this to work well, units should be constructed using *, /, and ^ (even though the “units” package supports other encodings).

x %>% 
  enscript %>% 
  ggplot(aes(time, work, color = group, shape = set)) + 
  facet_grid(~ group) +
  geom_point()

In the background, enscript() is writing expression and plotmath attributes (consumed by ggplot() ) and title attributes (consumed by tablet() ). We illustrate the latter.

x %>% 
  enscript %>% 
  group_by(group, set) %>%
  tablet %>%
  as_kable

In summary, we have decorated our data with labels and units containing markup for subscripts and superscripts. If everything goes well, these render similarly in figures and tables. They also render similarly in html and pdf. Please see the html version of this document.