Newbie mistakes saving images to files

On Thu, Jan 14, 2010 at 2:15 PM, Rex C. Eastbourne <rex.eastbourne at gmail.com

wrote:

I am encountering problems using the png() function to save around 20
charts to separate files.

My script is conceptually structured as follows:

### <script>
png("Image %03d.png")

# the following are calls to user-defined functions I wrote that call plot,
barchart, etc. with special arguments.
?myPlot("a")
myPlot("b")
myPlot("c")

myBarchart("a")
myBarchart("b")
myBarchart("c")

?myBarchart2("a")
myBarchart2("b")
myBarchart2("c")

dev.off()
### </script>

When I run the code a few lines at a time it generates the images
correctly. However, when I execute all lines of the script at once (Ctrl+A,
Ctrl+R in the Rgui editor), the output doesn't get generated right. Most
notably:

- Only one plot created by myBarchart (or myBarchart2) gets saved, instead
of all 3
- Some images are blank

I'm having trouble isolating the problem to one line of code.

I suspect there is some fundamental paradigm I'm not aware of about how R
devices and images work, perhaps relating to the importance of the order in
which the calls to png, dev.off(), etc. are executed, the required state of
my workspace before I run the code (e.g. whether the previous plot window
should be open or closed), or maybe even time dependency (do I need to
insert timed pauses so that my diagram has time to render before saving to a
file?).

Does this ring a bell to anyone? I read the R documentation on devices and
png(), and searched the mailing list archives and the web, but haven't
figured out how to get this working. Any help would be appreciated.

Thanks,

Rex

I'm on Windows 7 and R 2.9.2, BTW.

? ? ? ?[[alternative HTML version deleted]]