ComplexHeatmap, cannot create horizontal legend - r

Question

Hi I'm using the ComplexHeatmap package and followed their vignette however for some reason I cannot seem to force the legend to become horizontal. So for example here is an example,
set.seed(123)
library(ComplexHeatmap)
mat = matrix(rnorm(80, 2), 8, 10)
mat = rbind(mat, matrix(rnorm(40, -2), 4, 10))
rownames(mat) = paste0("R", 1:12)
colnames(mat) = paste0("C", 1:10)
ha_column = HeatmapAnnotation(df = data.frame(type1 = c(rep("a", 5), rep("b", 5))),
col = list(type1 = c("a" = "red", "b" = "blue")),
annotation_legend_param = list(type1 = list(
title_gp = gpar(fontsize = 16),
legend_direction = "horizontal", labels_gp = gpar(fontsize = 8)))
)
ht1 = Heatmap(mat, name = "ht1", column_title = "Heatmap 1", top_annotation = ha_column)
draw(ht1, heatmap_legend_side = "right")
so despite add in legend_direction = "horizontal" I still keep getting this here,

Answer 1

If you need to plot the heatmap legend horizontally and at the bottom of the heatmap, you can use this solution:
ht1 = Heatmap(mat, name = "ht1", column_title = "Heatmap 1", top_annotation = ha_column,
heatmap_legend_param = list(
legend_direction = "horizontal",
legend_width = unit(5, "cm")
)
)
draw(ht1, heatmap_legend_side = "bottom")
Otherwise, if you need to draw your (discrete) annotation legend horizontally and at the top of the heatmap, you can use nrow=1 in annotation_legend_param:
ha_column = HeatmapAnnotation(df = data.frame(type1 = c(rep("a", 5), rep("b", 5))),
col = list(type1 = c("a" = "red", "b" = "blue")),
annotation_legend_param = list(
type1 = list(
title_gp = gpar(fontsize = 16),
labels_gp = gpar(fontsize = 8),
nrow=1)))
ht1 = Heatmap(mat, name = "ht1", column_title = "Heatmap 1", top_annotation = ha_column)
draw(ht1, annotation_legend_side = "top")