From: John Matthews <jvm@li...> - 2004-07-01 04:52:39
1) PBM driver renders crosshatch pattern in contour plot where PNG
driver renders patches of color. How to make PBM give the same image as
2) Does anyone have a listing of files and clear instructions to get
libpng, zlib, and gd all installed and working with plplot on Windows
2000 using MinGW/MSYS?
I apologize in advance if I've missed this in the documentation
somewhere (and in the source, where I poked around for a bit).
I've currently got this very hacky plplot code that renders some data as
a contour plot to an image file which is then read in from the
filesystem by another part of the program for rendering on the screen.
Ugly, yes. But it works.
On Linux, I use PNG to accomplish this, and it works.
I need the same application to work in Windows, but I can't seem to get
libpng, zlib, and gd to play ball. (I finally got it down to the point
where configure said that my gd DLL didn't support PNG or JPG, which the
site that provided the binary DLL claims it does, and I gave up.)
So I figured since PBM appears supported, why not use that instead?
The problem is that I get a crosshatch pattern instead of solid color
patches for my contour plot, which makes it nigh useless, since the
"weave" of the crosshatching is so wide.
Nothing else changed in *my* code except to change the driver from PNG
to PBM (two lines, one to set the driver and one to set the filename),
so there must be something I need to know about the PBM driver to make
it perform as the PNG one does.
Having taken the code back from Windows to Linux, I see it behaves
precisely the same way, so it isn't some freaking Windows-specific
Many thanks in advance for any help you've got. :^)
From: Alan W. Irwin <irwin@be...> - 2004-07-01 15:29:35
On 2004-07-01 00:52-0400 John Matthews wrote:
> Quick version:
> 1) PBM driver renders crosshatch pattern in contour plot where PNG
> driver renders patches of color. How to make PBM give the same image as
That's the result of our software fill routine which is pretty lame but
better than nothing. The software fill kicks in if the device doesn't have
the fill capability at all. Perhaps more work (or higher resolution) for
the software fill routine would make your results look substantially better,
but other aspects of the PBM results look poor to me as well (again, it may
just be the default resolution) so that whole area of our code probably
needs some maintenance. If you don't want to do that yourself, then
probably it is best to avoid the PBM device for now.
> 2) Does anyone have a listing of files and clear instructions to get
> libpng, zlib, and gd all installed and working with plplot on Windows
> 2000 using MinGW/MSYS?
I don't have windows or mingw experience, but others on this list do so I
hope they are able to provide you with some help with libgd on windows.
Alan W. Irwin
Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).
Programming affiliations with the PLplot scientific plotting software
package (plplot.org), the Yorick front-end to PLplot (yplot.sf.net), the
Loads of Linux Links project (loll.sf.net), and the Linux Brochure Project