Need to move shiny app additional x scale code into ssdtools ssd_plot function

[sebdalgarno]

3 key additions required for ssd_plot prediction plot

• ability to adjust x-axis limits
• vertical offset of concentration estimate value
• bold face of concentration estimate value

since new scale_x_continuous is required in app it overrides the scale created in ssd_plot

not tested well and buggy so better for functionality to live in ssdtools

[sebdalgarno]

 gp <- ssdtools::ssd_plot(x, pred,
    left = conc, label = label, xbreaks = xbreaks, size = label_size,
    color = colour, shape = shape, hc = proportion, ci = FALSE,
    shift_x = label_adjust %>% as.numeric(),
    xlab = xaxis, ylab = yaxis, trans = trans
  ) +
    ggplot2::scale_x_continuous(
      name = xaxis, breaks = xbreaks,
      limits = c(xmin, xmax),
      labels = function(lab) {
        do.call(
          expression,
          lapply(lab, function(x) {
            mark <- label_comma(x, big.mark = big.mark)
            if (!is.na(x) & x == conc_value) {
              y <- paste0("\n", mark)
            } else {
              y <- mark
            }
            y
          })
        )
      }
    ) +
    ggplot2::scale_color_brewer(palette = palette, name = legend_colour) +
    ggplot2::scale_shape(name = legend_shape)
  
  # get breaks again for bold face as limits convert some to NA 
  actual_breaks <- gp_xbreaks(gp)
  
  gp <- 
    gp +
    ggplot2::ggtitle(title) +
    ggplot2::theme_classic() +
    ggplot2::theme(
      axis.text = ggplot2::element_text(color = "black", size = text_size),
      axis.text.x = ggplot2::element_text(face =  bold_conc(conc_value, actual_breaks)),
      axis.title = ggplot2::element_text(size = text_size),
      legend.text = ggplot2::element_text(size = text_size),
      legend.title = ggplot2::element_text(size = text_size),
    )