hcl_spin.R

library(pitchRx)
library(colorspace)
vals <- rainbow_hcl(361)
data(pitches)
pitches$spin_dir <- with(pitches, factor(round(spin_dir), levels = seq(0, 360)))
p1 <- strikeFX(pitches, color = "spin_dir", point.alpha = 0.3, 
        adjust = TRUE, contour = TRUE) + facet_grid(pitch_type ~ stand) + 
        theme(legend.position = "none") +
        scale_colour_manual(values = vals) + coord_equal()

df <- data.frame(
  variable = factor(vals, levels = unique(vals)),
  value = rep(1, 361)
)
p2 <- ggplot(df, aes(x = "", y = value, fill = variable)) +
        geom_bar(width = 1, stat = "identity") +
        scale_fill_manual(values = vals) +
        coord_polar("y") + theme(legend.position = "none") +
        ylab("Spin direction legend") + xlab("")

library(gridExtra)
grid.arrange(p1, p2, nrow = 1)