PRINTING THE SCREEN:

The OutSc option has the advantage that you can capture many screen images rapidly while collecting data on a volatile system, then print them out later. You could accomplish the same thing with Print Screen by saving each data file with OutDt during the active session, and later recalling each with InDat for printing.

To use Print Screen, you must install a printer driver before the Daqarta session. Then, when you have set the desired color palette and have a selected trace on-screen, hit the Print Screen key (PrtSc) and you will be prompted with:

 'Page eject after Print Screen? (Y default/N):'

Daqarta handles the SHIFT-Print Screen key identically to the unshifted key.

A major purpose of the page-eject prompt is to give you a chance to bail out if you realize that you have not loaded the printer driver. If you try to print anyway, you will get "unpredictable" results... probably a hung system or a page full of trash. (Daqarta has no direct way to check for the presence of the driver before accepting the command.)

If there is something wrong with the printer or its connection to the computer, Daqarta will attempt to give diagnostic error messages. These include:

 'Printer not found.'      (Printer cable connected?)
 'Printer off-line.'       (Check button on printer.)
 'Printer out of paper.'
 'Printer error.'          (No printer or unknown error.)

Printing the screen can take a fairly long time, during which the keyboard will not respond. Eventually you will see:

 'Ready for next command:'

If you have numerous screens to print, you will probably want to create a Key Macro which can do this unattended using the Loop command.

INSTALLING THE PRINTER DRIVER:

You may also want to experiment with third-party printer drivers.

NOTE:
The GRAPHICS.COM that came with versions of DOS prior to 4.00 will NOT work with Daqarta... it only supports CGA screen resolutions, not the 640 x 350 resolution used by Daqarta. The DOS 4.xx version supports this resolution, but only works with a limited range of printers. Windows 95 and 98 no longer supply this DOS driver... you can use the OutSc option to save a .BMP file that can later be printed by Windows Paint or other software.

To install GRAPHICS.COM from the command line, you just enter 'GRAPHICS' followed by the printer type. The types are:

 COLOR1            IBM Color Printer, black ribbon
 COLOR4            IBM Color Printer, 4-color RGB
                   (Red, Green, Blue, Black) ribbon
 COLOR8            IBM Color Printer, 4-color CMY
                   (Cyan, Magenta, Yellow, Black) ribbon
 DESKJET           Hewlett-Packard DeskJet
 GRAPHICS          IBM Graphics Printer, Proprinter, or
                   Quietwriter, and most Epson compatibles
 GRAPHICSWIDE      Wide-carriage versions of above
 HPDEFAULT         Any Hewlett-Packard PCL printer
 LASERJET          Hewlett-Packard LaserJet
 LASERJETII        Hewlett-Packard LaserJetII and III
 PAINTJET          Hewlett-Packard PaintJet
 QUIETJET          Hewlett-Packard QuietJet
 QUIETJETPLUS      Hewlett-Packard QuietJet Plus
 RUGGEDWRITER      Hewlett-Packard RuggedWriter
 RUGGEDWRITERWIDE  Wide version of RuggedWriter
 THERMAL           IBM PC Convertible Thermal Printer
 THINKJET          Hewlett-Packard ThinkJet

After the printer type, you may give an optional "switch" command. (See your DOS manual for more details.) For COLOR4 or COLOR8 printers only, /B will print the background in color instead of white.

The /R switch is used to reverse black and white colors. By default, the areas that are brightest on the screen will be printed in black, and vice-versa. However, this default revrsal only applies to the brightest and darkest colors... those in between follow a normal gray-scale. And if the screen background (Panel color) is white, that part won't be reversed to black. Thus, the /R switch restores a normal gray-scale to the entire image.

If you use the /R option, you can use the GrayS Gray-scale command to preview what the printed output will look like on a color monitor. Note, however, that while GrayS gives 16 shades of gray, your printer may not support that many. The typical dot-matrix printer (using the GRAPHICS type from the list above) will only show 8 of these.

While you probably want as many shades of gray as possible for Spectrogram output, you may want more contrast for normal waveform and spectrum traces. A fair amount of experimentation with color palettes may be required to get optimum printed output. Be sure to save the best palettes for each job to your palette files for later use.

The default MAIN.PAL and SGRAM.PAL palette files that come with Daqarta each contain palettes that should give decent printed output to get you started. These palettes assume a VGA system: EGA users will need to experiment.

The 'Print' palette in Spectrogram mode is designed for use without the /R option, and includes a pre-reversed maximum value to print black at maximum fading down to white at minimum and background areas. With the /R option, try 'GreyR' for this same appearance, or 'Grey' for white maximum and black minimum and background.

Enterprising experimenters with a knowledge of printer command sets may want to note that the GRAPHICS.COM program gets all its printer model information from the associated GRAPHICS.PRO file, which is in plain ASCII text. You may be able to adapt this to support different printer types.

For each model, there is a 'PRINTER' line giving the type as it appears on the command line, followed by several lines that control the actual output for different screen display modes.

The 640x350 mode used by Daqarta is specified by a section that begins with 'DISPLAYMODE 15,16' and is followed by a 'SETup' line that gives the proper setup commands for that model and mode, then a 'GRAPHICS' line that gives the actual graphics commands, a 'PRINTBOX' line that tells how may pixels of the printer output correspond to each pixel on the screen (and possibly a 'ROTATE' code to indicate that the output will be rotated 90 degrees on the page). Finally, there may be a 'RESTORE' line giving any special commands needed to exit.

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