mat = matrix(rnorm(100), 10)
colnames(mat) = letters[1:10]
rownames(mat) = LETTERS[1:10]
long_cn = do.call("paste0", rep(list(colnames(mat)), 4)) # just to construct long text
ha_rot_cn = HeatmapAnnotation(text = anno_text(long_cn, rot = 45, offset = unit(5, "mm")))
Heatmap(mat, name = "foo", top_annotation = ha_rot_cn, top_annotation_height = unit(1.2, "cm"))
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