trace_position tidy evaluation

[sheridar]

Currently an expression passed to trace_position is captured with substitute() and evaluated strictly within the context of the data. This means the user cannot use environment variables with trace_position. Ideally the user would be able to include both environment and data variables such as in the example below, which does not work with ggtrace v0.2.0.

To accomplish this, need to include a data mask (with rlang::eval_tidy()) when evaluating trace_position

create_trace_plot <- function(data, traceVar = "xVar", traceThreshold = -1) {

  pl <- ggplot(data = data, aes(xVar, yVar, fill = fill_var), color = "#000000") +
    geom_point_trace(
      trace_position = !!sym(traceVar) < traceThreshold,

      fill = "#FFFFFF",
      background_params = list(color = "#000000", fill = "#CC0000")
    ) +
    ggtitle(str_c("Threshold: ", traceThreshold))

  pl
}

[sheridar]

Closed with #59