[R] Problems with Heatmap

[michael watson (IAH-C)]

Hi

I am having some problems getting my heatmap to be the right size!  Let
me explain.  I am experienced at getting an hclust or a dendrogram
object to be the right size.  

For example, I have a dataset which has 4000 rows, which I clustered
using hclust and I wanted to plot it as a horizontal dendrogram.  So I
used jpeg(), set the image height to be 4000 and plotted the dendrogram
and got the result I expected - ie the dendrogram filled up the whole
image and I had roughly one pixel per row of data.  However, if I run
heatmap() instead of hclust(), the resulting image DOES NOT fill up the
whole jpeg() - instead, it sits right in the middle of it, the same size
as it would be if I had ran heatmap() normally into an x11() window.

I've figured out how to use the margins= argument of heatmap() to set
the margins, but how do I make my heatmap fill up all of the available
space in a jpeg()?

Mick