 routine. This routine sets up a second thread that handles the plotting window's message queue. This is an important point because OS/2 programs are supposed to process their system messages promptly (within 1/10 of a second). By having the queue processing done on a separate thread, lengthy calculations won't cause annoying slowdowns. The bgnplt() routine also creates a basic user interface that allows the user to zoom and pan, export the plot to one of several graphics formats, and copy the plot to the clipboard. All of these features are provided without your having to make a single Presentation Manager API call. If you want to dig deeper, however, GraphiC allows you to do that. Routines are available for text input and output, as well as memory allocation/deallocation. All of these routines are available on the various platforms, so that the same source code can be compiled for any of them.
<P>The graphics output capabilities of GraphiC are very powerful. Graphs are stored in a high resolution vector format and can be quickly redisplayed using an included executable play.exe. The available output formats are PIC, GEM, HPGL/HPGL-2, Postscript (levels 1 and 2), CGM, SCODL, TIFF, and formats specific to the OS, such as the OS/2 bitmap format. It is obvious that the GraphiC programmers spent a great deal of effort designing and implementing the graphics output routines. Color plots look nice on the screen, but most publications still want black and white, and GraphiC does a very good job converting color plots for output to a black and white printer. However, at the time of submitting this article I was having problems with some of the conversion routines. The HPGL converter would cause SYS3175 error (protection fault) when I tried to run it. In some situations the Postscript converter would lock the system input queue on my machine, and Ctrl-Esc would not rescue it, necessitating a reboot. However, the technical support at Scientific Endeavors is very responsive and I have no doubt that these problems will be resolved in short order. Technical support can be contacted by phone, FAX, e-mail or on CompuServe (GO SCIEND), and they are in the process of setting up a WWW homepage.
<H3>The Price Tag</H3>
The GraphiC license allows you to use the library for personal applications. If you wish to distribute an application developed with the library, you must negotiate an additional license. The terms of additional licenses seem very reasonable, though. For programs to be sold to others, a royalty of around 5% is usually charged, but Scientific Endeavors will negotiate a license that is mutually beneficial. Two examples of commercial plotting packages that use the GraphiC library are Axum and Gauss.
<P>In short, if you are proficient in C and are looking for maximum control over the appearance of your plots or need a multiplatform solution, GraphiC may be ideal for you. However, since many scientists, including myself, are more comfortable working in Fortran, Scientific Endeavors is working on a package which will simplify using the library from Fortran. Of course, you can use the library as it is from Fortran, but if you do not have any experience doing mixed-language programming, plan to spend some time coming up to speed on the issues that must be addressed such as subroutine calls and variable addressing. I am very impressed by the depth of features in this library which has a list price of US$495 but can be found at mail order companies for about $395.
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| GraphiC | - by Dr. Dirk Terrell |
GraphiC is a very powerful multi-platform scientific and technical graphics library by Scientific Endeavors Corporation. Unlike scientific graphics programs such as SigmaPlot and Xact, GraphiC is a library of routines written in C that can be customized to fit your needs because the source code is included. This flexibility comes at the expense of having to write C/C++ code to produce plots, but the included sample files make it very easy to pick up on the library's functions even if you have only modest experience with these languages. If you want total control over the way your data are presented, GraphiC is a tool you should consider. The multi-platform nature of GraphiC may also appeal to some users. Versions of the library also exist for DOS, Windows 3.1, and Windows NT.
The installation program is well-done, enabling the user to specify the locations of all files as well as the C compiler to be used. I tested GraphiC with the IBM VisualAge C++ compiler, but the Borland and Watcom compilers are also supported, as is the older IBM CSet++. The on-line help for the installation program explains all of the options clearly. Once the installation is completed, you can choose to have the installation program compile the library or you can do it manually, but makefiles are supplied, making this a relatively effortless task. The library can be compiled into a DLL or the routines can be statically linked to an executable.
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