overlay for fixed values aka labels?

[gdevenyi]

I have a set of labels I want to overlay on my anatVol.

I can almost get what I want by overriding the col with a fixed value colourmap, however, it gets smoothed into a continuous map somewhere inside the code:

col = c("#bf823b","#9473c6","#6ca75d","#cc546d"),

[jasonlerch]

We tend to accomplish this by directly defining colours for each label rather than using a look-up table. I.e. the colour_hex_triplet from our mouse anatomy tree. The smoothing you describe happens quite deeply somewhere in the grid library, and also is (if I remember) somewhat dependent on output (i.e. looks different in pdf vs png).