highlight_rows_and columns.R

m = matrix(rnorm(100), 10)
rownames(m) = paste0("row", 1:10)
colnames(m) = paste0("column", 1:10)
ht = draw(Heatmap(m, name = "mat"))

highlight_row = function(which, padding = unit(1, "mm"), gp = gpar()) {
	row_order = row_order(ht)
	i = which(row_order == which)
	nr = length(row_order)
	decorate_heatmap_body("mat", {
		grid.rect(x = 0.5, y = unit((nr-i+0.5)/nr, "npc"), 
			width = unit(1, "npc") + padding*2,
			height = unit(1/nr, "npc") + padding*2, 
			default.units = "npc",
			gp = gp)
	})
}

highlight_row(3, gp = gpar(fill = "#00FF0040", col = "black", lty = 2))

highlight_column = function(which, padding = unit(1, "mm"), gp = gpar()) {
	column_order = column_order(ht)
	i = which(column_order == which)
	nc = length(column_order)
	decorate_heatmap_body("mat", {
		grid.rect(x = unit((i-0.5)/nc, "npc"), y = 0.5,
			width = unit(1/nc, "npc") + padding*2,
			height = unit(1, "npc") + padding*2, 
			default.units = "npc",
			gp = gp)
	})
}
highlight_column(5, padding = unit(3, "mm"), gp = gpar(fill = "#00FFFF40", col = "orange", lwd = 2))