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Database Graphics Toolkit - Blackhawk Data Corporation by Mark Hirst

The toolkit is a collection of standalone programs designed to be run from various database applications such as dBase, Clarion and Revelation. It allows text based applications to display graphics and integrate them in display windows.

The Software

No special installation procedure is required. The contents of the diskette are simply XCOPYed to a directory and if necessary, the DOS path is changed to include the toolkit programs. In this review, a subdirectory was created below the main AREV directory.

The diskette contains three display programs, a laser printing utility, a variety of video utilities and a library of video images from the public domain. The PHOTO and VCR display programs are designed to place a graphic on the screen over any existing screen contents. This means that an entry window displaying personnel information can have an accompanying picture of the person concerned. This is done by taking a 'photograph' of the text screen, switching the screen to graphics mode, putting it back, and overlaying part of it with the graphic. A variety of options can be passed to the program to control the size, position and appearance of the graphic. Display algorithms are used to shrink the pictures to fit the view area with remarkable clarity. The screen colours are redefined by the program to make the images as realistic as possible with interesting side- effects. Since the original Revelation screen was displayed using the standard screen colours, it reappears with the picture for example, having blue redefined as dark red. This effect can be prevented but colour images are somewhat inferior as a result. The PHOTO program uses 16 colours to display pictures, while the similar VCR utility uses 256 colours with larger dots. Black and white images are specially processed when shrunk, into 16 levels of gray producing excellent photograph-like images.

The EXHIBIT utility is virtually identical to PHOTO and VCR but uses the entire screen to display the image. It has an additional feature of being able to view parts of large graphics and then pan the view. The panning feature is fast.

All programs can use a time delay feature or user key press to return to Revelation and multiple images such as a face and a signature can be placed. They also feature a prominent copyright message which documentation suggests can be suppressed, though not in the demo version. The software is totally self-configuring to the video hardware.

The LASRTAX printing utility is a TSR occupying about 24K which can send the contents of the screen to a Laserjet compatible printer in three sizes. Users of this feature should ensure that the printer has plenty of RAM; in tests on a standard Laserjet II, only the smallest size could be printed satisfactorily. Clarity however was quite good and took about one minute to emerge from the printer.

An input/output routine to allow databases to accept input from a user whilst displaying graphics does not apparently work with Revelation because Revelation cannot link to it. Miscellaneous utilities to capture and modify images complete the toolkit.


Graphics terminology is used throughout the manuals, though this should present no real obstacle to a developer. However knowledge of adapters and image scanning would probably be advantageous. All programs and their options are defined conventionally with a short section on how to call the utilities from Revelation using symbolics or R/BASIC code.

The remainder of the manual briefly discusses how images can be created using scanners, camera and conversion software. The very relevant issue of storage is also discussed. The twenty tow images supplied with the toolkit occupy 800K of space. Optical storage is mentioned as a 'cheaper per unit cost' solution.


The product provides a simple and effective method of displaying images alongside your data. It is not a total solution product, the issue of collecting and storing images is a separate area entirely and the toolkit would form part of a collection of software and hardware required to provide image support in your application. Some users may find the omission on direct TIFF file compatibility and PostScript support inconvenient. As a general purpose tool, the toolkit is a neat and attractive way of bolting graphics onto Revelation.


PC compatible running MSDOS 2.11+, EGA, VGA or Paradise SuperVGA adapter. LASRTRAX requires Laserjet compatible printer. Supports PCS, GIF, SCX and print ready PGL images.

(Volume 2, Issue 7, Page 5)
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