Improving legend style

[dominicroye]

I would like to propose a change in the style of the legend by changing to open axes with arrows. The following are changes I made on the basis of a biscale's older version.

leg <- tidyr::separate(x, bi_class, into = c("x", "y"), 
                        sep = "-")
 leg <- dplyr::mutate(leg, x = as.integer(x), y = as.integer(y))
 legend <- ggplot2::ggplot() + ggplot2::geom_tile(data = leg, 
                                                  mapping = ggplot2::aes(x = x, y = y, fill = bi_fill), 
                                                  lwd = pad_width, col = pad_color) + ggplot2::scale_fill_identity() + 
   ggplot2::labs(x = xQN, y = yQN) + bi_theme() + 
   ggplot2::theme_light() +
   ggplot2::theme(panel.border=element_blank(), 
                  axis.title.x = element_text(vjust = -.7, hjust = .2, size = size),
                  axis.title.y = element_text(vjust = .7, hjust = .2, size = size),
                  axis.line = element_line( size = .5, arrow = arrow(type = "closed", length = unit(.07, "in"))), 
                  axis.ticks = element_blank(),
                  axis.text = element_blank(),
                  panel.grid = element_blank(),
                  panel.background = element_blank(),
                  plot.background = element_blank()) + 
   lemon::coord_capped_cart(bottom="both", left = "both") 

Example: