How to change font family globally in ComplexHeatmap

In grid, every viewport is associated with its own graphics parameters and it by default inherits graphics parameters from its parent viewport. So, to globally change the font family in a ComplexHeatmap plot, we can simply put the heatmap into a “global viewport” where we can set a specific font family (also other graphics parameters) there:

library(ComplexHeatmap)
m = matrix(rnorm(100), 10)

pushViewport(viewport(gp = gpar(fontfamily = "HersheyScript")))
ht = Heatmap(m, top_annotation = HeatmapAnnotation(foo = 1:10),
    right_annotation = rowAnnotation(bar = anno_text(month.name[1:10])),
    column_title = "A small matrix")
draw(ht, newpage = FALSE)
popViewport()

Note in draw(), setting newpage = FALSE is important.