[R] jpeg() saving blank files?

Sarah Berke skberke at gmail.com
Wed Mar 31 00:14:32 CEST 2010


Phil and Jim--

Ah, thank you so much!  I had read all the help files on jpeg() and
dev.off(), but I had not caught on to the fact that image.plot() comes
*between* jpeg() and dev.off(), not before them!  (though I guess it's
supposed to be obvious from the example code).

Again, thanks!
--Sarah


On Tue, Mar 30, 2010 at 4:17 PM, Phil Spector <spector at stat.berkeley.edu> wrote:
> Sarah -
>   Those lines alone only open the jpeg device -- they
> don't actually produce any output.  Normally, you'd steps
> like this to save a JPEG file
>
> jpeg(filename='myfile.jpg',height .....
>  --- plotting commands go here ---
> dev.off()
>
> The call to dev.off() is what actually creates the file.
>
> If you've already created the image, and want to transfer
> it to a jpeg file, take a look at ?dev.copy
>
> Hope this helps.
>
>                                        - Phil Spector
>                                         Statistical Computing Facility
>                                         Department of Statistics
>                                         UC Berkeley
>                                         spector at stat.berkeley.edu
>
>
>
>
> On Tue, 30 Mar 2010, Sarah Berke wrote:
>
>> Hi,
>>
>> I am having trouble saving graphics from R.  jpeg() saves a file with
>> the correct name to the correct directory, but it consists of a blank
>> (white) jpeg with the specified dimensions--the image itself is not
>> being saved.
>>
>> My code is
>>
>> jpeg(filename="myfile.jpg",
>>                height = 2.5, width = 8, units = "in", res = 72,
>>                pointsize = 12, quality = 100, bg = "white",
>>                restoreConsole = TRUE)
>>
>> I have tried different heights and widths, thinking that I had a
>> margins problem, but no luck.  I have also verified that ghostscript
>> is installed, and that the environmental variable "R_GSCMD" is set to
>> the correct path to gswin32c.exe.  Oh, and the image device itself
>> displays properly in the R graphics window.  I can just manually save
>> it through the menu, but I want to have more control over the
>> dimensions.
>>
>> I have also tried bitmap() and png() to no avail.
>>
>> Any advice would be much appreciated!
>>
>> Thanks,
>> Sarah
>>
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>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>



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