a simple 3D heatmap

heatmap_3d.R

rect3D = function(x, y, w, h, l, theta = 60, default.units = "npc", fill = "white", col = "black") {

	if(!is.unit(x)) x = unit(x, default.units)
	if(!is.unit(y)) y = unit(y, default.units)
	if(!is.unit(w)) w = unit(w, default.units)
	if(!is.unit(h)) h = unit(h, default.units)
	if(!is.unit(l)) l = unit(l, default.units)

	x1 = x - w*0.5
	x2 = x + w*0.5
	y1 = y - h*0.5
	y2 = y + h*0.5

	xu = x + l * cos(theta/180*pi)
	yu = y + l * sin(theta/180*pi)

	a1 = xu - w*0.5
	a2 = xu + w*0.5
	b1 = yu - h*0.5
	b2 = yu + h*0.5

	fill = add_luminance(fill)
	# front
	grid.polygon(unit.c(x1, a1, a2, x2), unit.c(y1, b1, b1, y1), gp = gpar(fill = fill[2], col = col))
	# left
	grid.polygon(unit.c(x1, x1, a1, a1), unit.c(y1, y2, b2, b1), gp = gpar(fill = fill[1], col = col))
	# top
	grid.polygon(unit.c(a1, a1, a2, a2), unit.c(b1, b2, b2, b1), gp = gpar(fill = fill[3], col = col))

}

add_luminance = function(col) {
	rgb = col2rgb(col)
	r = rgb[1, ]/255
	g = rgb[2, ]/255
	b = rgb[3, ]/255
	col = as(RGB(r, g, b), "polarLUV")
	value = coords(col)

	sequential_hcl(
	  n = 9,
	  h = value[, "H"],
	  c = value[, "C"],
	  l = c(30, 90)
	 )
}

# grid.newpage()
# rect3D(0.5, 0.5, 0.3, 0.3, 0.2, fill = "red")


m = matrix(sample(100, 36), 6)
ht = Heatmap(m, rect_gp = gpar(type = "none"),
	layer_fun = function(j, i, x, y, w, h, f) {
		v = pindex(m, i, j)
		od = rank(order(-as.numeric(y), -as.numeric(x)))
		for(k in od) {
			grid.rect(x[k], y[k], w[k], h[k], gp = gpar(col = "white", fill = "#EEEEEE"))
		}
		for(k in od) {
			rect3D(x[k], y[k], w[k]*0.6, h[k]*0.6, unit(v[k]/100, "cm"), fill = f[k])
		}
	},
	cluster_rows = FALSE,
	cluster_columns = FALSE,
	show_heatmap_legend = FALSE
)

draw(ht, padding = unit(rep(10, 4), "mm"))