12.3 Mapear colores

Para mapear colores (cmap) basta con hacer una relación entre la gama de \(256^3 = 16,777,216\) de colores a sólo \(256\).

Por ejemplo de diversas intensidades a una escala de verdes:

par(mfrow = c(2, 1), 
    mar=c(0.5, 0.2, 0.5, 0.2), 
    oma = c(4, 4, 0.2, 0.2))
values <- rep(1, 60)
gray_palette <- generate_palette("gray", 
            modification = "go_both_ways", 
            n_colours = length(values), view_palette = FALSE,
            view_labels = FALSE)
barplot(values, col = gray_palette, space = 0.2, 
        ylim = c(0, max(values) * 1.1), yaxt='n', xaxt='n', ann=FALSE)
green_palette <- generate_palette("green", 
            modification = "go_both_ways", 
            n_colours = length(values), view_palette = FALSE,
            view_labels = FALSE)
barplot(values, col = green_palette, space = 0.2, 
        ylim = c(0, max(values) * 1.1), yaxt='n', xaxt='n', ann=FALSE)

cmap “Green”

par(mfrow = c(2, 1), 
    mar=c(0.5, 0.2, 0.5, 0.2), 
    oma = c(4, 4, 0.2, 0.2))
values <- rep(1, 60)
rainbow_palette <- rainbow(length(values), start = 0, end = 5/6)
barplot(values, col = rainbow_palette, space = 0.2, 
        ylim = c(0, max(values) * 1.1), yaxt='n', xaxt='n', ann=FALSE)
title(main = "Mapeando valores originales en un cmap = 'Green'", cex.main = 0.7)
green_palette <- generate_palette("green", 
            modification = "go_both_ways", 
            n_colours = length(values), view_palette = FALSE,
            view_labels = FALSE)
barplot(values, col = green_palette, space = 0.2, 
        ylim = c(0, max(values) * 1.1), yaxt='n', xaxt='n', ann=FALSE)