R How to build angled column headings above columns in heatmap.2: pass (text) plot to the layout?

Question

I am very close to the heatmap I want, but I have been struggling for several days to figure out the headings problem. I want angled headings (such as 45 or 50 degrees) at

Answer 1

Here's a hack that doesn't involve pulling apart the convoluted code of heatmap.2:

  pos2 <- locator() #will return plotting coordinates after doing this:
  # Shift focus to the graphics window by clicking on an edge 
  # Left-Click once where you want the first label to be centered
  # Left-click again on the point where you want the last label centered
  # Right-Click, then return focus to the console session window

 pos2 <- structure(list(x = c(0.27149971320082, 0.858971646016485), 
                        y = c(0.861365598392473, 0.857450478257082)),
                       .Names = c("x", "y"))

  text(x=seq(pos2$x[1], pos2$x[2], len=5), y=rep(pos2$y[1],5)  ,
       srt=50, xpd=TRUE, adj = 0,
       labels=c("Sept 2008","March 2010","Sept 2010",
                "March 2011","Sept 2011") )

I don't know if you actually need the xpd in there, since it appears that after heatmap.2 is finished it returns the window to its native coordinates: [0,1]x[0,1]