Note that there are at least 5 separate png() devices, so Linux was not
using the (default) device used on Windows.
In general, the device-limits info is not on the help page because we do
not know it. On Windows the default device limits depend on the OS
version, 32/64-bit, RAM and the graphics hardware. This sounds like the
last: you were asking for 49 megapixels which is far larger than the
largest screens. (Or all but the highest-end digital cameras, so one
could well ask what you can usefully do with such an image.)
Normally you will get warning(s) accompanying that Error, but it might
just be
Warning: unable to allocate bitmap
Warning: opening device failed
The first of those is reporting what the GraphApp toolkit said, talking
directly to Windows GDI (and look at the Windows documentation for e.g.
CreateCompatibleBitmap to see that no limits are mentioned).
Even on Windows you have the option of using other png() devices:
png(filename = "Rplot03d.png",
width = 480, height = 480, units = "px", pointsize = 12,
bg = "white", res = NA, family = "", restoreConsole = TRUE,
type = c("windows", "cairo", "cairo-png"), antialias)
Try the other 2 types: the cairo devices do not use your graphics
hardware nor MicroSoft's GDI. (The other 2 devices are Xlib on a
Unix-alike and Quartz on macOS.)
On 10/02/2017 16:54, Martin Maechler wrote:
Dario Strbenac <dstr7...@uni.sydney.edu.au>
on Fri, 10 Feb 2017 02:00:08 +0000 writes:
> Good day,
> Could the documentation of graphics devices give some explanation of how
big the bitmap limits are? For example,
>> png("Figure1A.png", h = 7, w = 7, res = 1000, units = "cm")
> Results in Error: unable to start png() device,
This is amazing to me. I see
------------------------------------------------------------------------------
png("Figure1A.png", h = 7, w = 7, res = 1000, units = "cm")
plot(1)
dev.off()
null device
1
file.info("Figure1A.png")[1:5]
size isdir mode mtime ctime
Figure1A.png 41272 FALSE 644 2017-02-10 17:40:42 2017-02-10 17:40:42
------------------------------------------------------------------------------
in three different versions of R I've tried (all were 64-bit Linux).
Note how *small* the file is.
Now, I've also tried a 32-bit version of Linux (Ubuntu 14.04 LTS) and get
a similar result (not exactly the same number of bytes for the file size).
but the help page of devices doesn't explain that there are any limits or how
they are determined. The wording of the error message could also be improved,
to explain that the resolution is too high or the dimensions are too large.
If one/some of those who can reproduce the problem in their
versions of R provide (concise and not hard to read) patches to
the source of R, we'd probably gratefully accept them..
Martin Maechler
>> sessionInfo()
> R version 3.3.2 Patched (2017-02-07 r72138)
> Platform: i386-w64-mingw32/i386 (32-bit)
> Running under: Windows 7 (build 7601) Service Pack 1
> --------------------------------------
> Dario Strbenac
> University of Sydney
> Camperdown NSW 2050
> Australia
--
Brian D. Ripley, rip...@stats.ox.ac.uk
Emeritus Professor of Applied Statistics, University of Oxford
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