About Text Filter
The SPLOT program is able to process a multilingual text in your HP-GL (or DXY-GL) files. As known, plotters receive only the ASCII characters in the range of 0 to 127. Therefore, if the instruction for the output of the text (LB at HP-GL and P at DXY-GL resp.) contains the ASCII characters with the value higher than 127, the plotter will not draw them or will ignore the highest bit of characters and will draw the corresponding characters from the lower half of the ASCII table. For example, if you use the following statement in GW-BASIC (handle #1 represents the plotter),
PRINT #1, "LBGröße";CHR$(3)
the plotter will draw only the text
Gre or Grae respectively.
If you want to draw the text correctly, you have to use the following statements, e.g.:
PRINT #1, "CS0;CA33;SS;LBGr";CHR$(3)
PRINT #1, "SA;LB|~";CHR$(3)
PRINT #1, "SS;LBe;CHR$(3)
However, e.g., if you own the HP ColorPro 7440A plotter without an additional HP 17440A graphics cartridge, it will not help you either.
The above mentioned example concerns the use of a German text, but similar problems occur also in other languages which use the ASCII characters from the upper half of the table.
Therefore, the SPLOT program offers the Text Filter function. You switch on this function by checking the Text Filter item in the Plotter section of the Preferences dialog. Then all the ASCII characters from the value of 128 to 175 and ß character will be plotted according to the selected Code Page. And it does not matter what character set of the plotter is just set. This will enable to write multilingual texts in your HP-GL (DXY-GL) files directly without complicated switching of character sets. The HP-GL (DXY-GL) file created in this way must be exported to a new HP-GL (DXY-GL) form through the HP-GL (DXY-GL) export with the Text Filter switched on, and only such a newly originated file can be drawn on the plotter. Or you can print the image directly to the plotter if you have an appropriate Windows plotter driver installed. (For details about exporting and printing see the Exporting and Printing topics or the Export and Print dialogs).
To demonstrate using this method of writing multilingual texts we recommend you to study over the enclosed demonstration file ASCII.PLT and display it at first with the Text Filter being switched off and then on.