Print Head

The graphics mode on the LX-80 is quite different from the text modes, Instead of sending codes for letters and printing functions, you send codes for dot patterns, one number for each column in a line. Since none of the predefined characters or symbols in the prin- ter’s memory is used, your program controls where each dot is printed.

For each column on a print line, the print head prints the pattern of dots you have specified. In the standard graphics mode it uses only the top eight pins on the print head because the computer uses eight data lines to communicate with the printer. Therefore, each of the top eight pins of the print head corresponds to one of the data lines.

To print figures taller than eight dots, the print head makes more than one pass. It prints one line, then advances the paper and prints another, just as it does with text. To keep the print head from leaving gaps between the graphics lines as it does between the text lines, the line spacing must be adjusted to eliminate the space between lines. When the line spacing is properly adjusted, the LX-80 prints finely detailed graphics images that give no indication that they are made up of separate lines, each no more than 1/8 of an inch wide.

To insure the proper alignment of dots in figures that use more than one pass of the print head, the LX-80 abandons the bidirectional printing it uses for draft text. Instead it prints graphics from left to right only.

Each pass of the print head contains one piece of the total pattern, which can be as tall or short and as wide or narrow as you desire. You don’t have to fill the whole page or even an entire line with your graphics figures. In fact, you can use as little or as much space as you like for a figure and put it anywhere on the page.

Graphics Mode

The graphics mode command is quite different from the other commands covered so far in this manual. For most of the other LX-80 modes, such as italic and emphasized, one ESCape code turns the mode on and another turns it off. For graphics, the command is more complicated because the code that turns on a graphics mode also specifies how many columns it will use.

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