[BioC] heatmap smoother representation

[Auer Michael]

Is there a possibility to adjust the coloring of the heatmap according to
the range of the values.
Eg.
matr<-cbind("X1"=c(11,12,14,8,7,9,10,11),"X2"=c(1,3,2,5,7,6,3,2))
heatmap(matr, col = rev(dChip.colors(50)), hclustfun = hclust)

The heatmap shows uniformly the colors red for X2 and blue for X1. But is
there not a possibility to adjust the range for the colors. To make a long
story short, I want a smoother representation. Can anybody help me with
this?

Thanks