Plot/image size in exams2nops and in exams2pdf without modifying the template

Question

I have an R/exams exercise like scatterplot.Rmd and tried to include different chunk options into the exams2pdf/exams2nops command, but nothing changed the size of the included image for me:

• height = 50, width = 50
• height = 5, width = 5
• height = 0.5, width = 0.5
• fig.height = 0.5, fig.width = 0.5
• out.width = 0.5

Am I doing something wrong?

I saw that I can adapt the LaTeX template but if possible I would avoid it. Is there another way?

Answer 1

Main answer: The advice from the other answer you linked applies: How to reduce plot (image) size for `exams2pdf` output?

Short recap:

• With the chunk options fig.height and fig.width you only control the size of the graphics file which has an influence on the relative size of the annotation etc.
• The scaling of this graphics file in the PDF document (e.g., 50% or 80% of the text width etc.) may differ from the size of the graphics file, e.g., set via the LaTeX Gin keys.
• In the default plain.tex template used in exams2pdf() graphics are included with 80% of the text width because the template sets \setkeys{Gin}{width=0.8\textwidth}. You can copy and modify the template if you want to use other options.
• In exams2nops() no Gin is set so that graphics files are included "as is" (and thus fig.height and fig.width have a direct effect on the relative size as well).

Additional answer: If you want to set a different Gin for the entire document (e.g., 50% of the text width), you can do this in both exams2nops() and exams2pdf() via some LaTeX code passed to the header argument.

exams2pdf("scatterplot.Rmd", header = list(`setkeys{Gin}` = "width=0.5\\textwidth"))
exams2nops("scatterplot.Rmd", header = "\\setkeys{Gin}{width=0.5\\textwidth}")

Note: The list() specification would also work in exams2nops(). The simpler vector specification should also be supported in exams2pdf() in future versions of the package.