扩展RColorBrewer以支持更多颜色？

RColorBrewer允许您获得少量视觉上令人愉悦的颜色,如下所示:

> library(RColorBrewer)
> brewer.pal(11, "Spectral")
 [1] "#9E0142" "#D53E4F" "#F46D43" "#FDAE61" "#FEE08B" "#FFFFBF" "#E6F598"
 [8] "#ABDDA4" "#66C2A5" "#3288BD" "#5E4FA2"

但是如果你要求超过这个金额,他们只会给你相同的最大金额:

> brewer.pal(12, "Spectral")
 [1] "#9E0142" "#D53E4F" "#F46D43" "#FDAE61" "#FEE08B" "#FFFFBF" "#E6F598"
 [8] "#ABDDA4" "#66C2A5" "#3288BD" "#5E4FA2"
Warning message:
In brewer.pal(12, "Spectral") :
  n too large, allowed maximum for palette Spectral is 11
Returning the palette you asked for with that many colors

如果提供更大的数字,是否可以获得更多的颜色(可能通过在最远的颜色之间插值)？