[R] different hights & centering in one device region

[Felix Wave]

Hello,
I have a question. I creat a PDF file with four rows and
two cols. 
Is it possible to:
-create a plot regions with different hights (example: rows 1 & 2-4)
-ro center an image in the whole width (example: rows 4)

Thank's a lot.

Felix




example:
--------
	      Title
--------------------------------
|Text		|Text		|
|Text		|Text		|
---------------------------------
|		|		|
|		|		|
|    image	|     image	|
|		|		|
|		|		|
---------------------------------
|		|		|
|		|		|
|    image	|     image	|
|		|		|
|		|		|
---------------------------------
|	|		|	|
|	|		|	|
|	|    image	|	|
|	|		|	|
|	|		|	|
---------------------------------



R-Code:
-------

pdf(pPDF, height=13.7, paper="special")
par(oma=c(0,0,1,0), mfrow=c(4,2) )

#Text field
plot.new()
text(0, 0.6, pos=4, cex=1.2, paste("Text") ) 
text(0, 0.4, pos=4, cex=1.2, paste("Text") )

plot.new()
text(0, 0.6, pos=4, cex=1.2, paste("Text") )  
text(0, 0.4, pos=4, cex=1.2, paste("Text") )

image(zMEDIAN_1)              
image(zMEDIAN_2)              
image(zSD_1) 
 
#Title
par(mfrow=c(1,1), oma=c(0,0,1,0))
mtext("Darstellung der Differenz zweier Exportfiles V0.03", 3, outer = TRUE, cex = par("cex.main"))

dev.off()