tikz

问题 I have the following code in an rmd file which leverages tikz for diagrams: --- title: "TestNonTufteLua" author: "Me" output: pdf_document : latex_engine: lualatex --- Prove tikz works: ```{r tikTest1, engine = "tikz"} \usetikzlibrary{shapes} \begin{tikzpicture} \node[ellipse, draw=black, align = center] (Data) {Data $y_{n}$}; \end{tikzpicture} ``` Then, when you set `eval = TRUE` in the below code, it will not work. ```{r tikTest2, eval = FALSE, engine = "tikz"} \usetikzlibrary{graphs,

问题 Hi I really have googled this a lot without any joy. Would be happy to get a reference to a website if it exists. I'm struggling to understand the Hadley documentation on polar coordinates and I know that pie/donut charts are considered inherently evil. That said, what I'm trying to do is Create a donut/ring chart (so a pie with an empty middle) like the tikz ring chart shown here Add a second layer circle on top (with alpha=0.5 or so) that shows a second (comparable) variable. Why? I'm