Graphics

Since there are 24 pins in each column, you must make a calculation for each of the three sections in each column. As you can see, this method of planning and printing dot graphics requires considerable calculation. Because triple-density uses 180 columns per inch, printing a single line of triple-density graphics only one inch long requires 540 numbers. Fortunately, commercial software can do the calculations for you.

Before you can put these numbers in a graphics program, however, you need to know the format of the graphics command.

The graphics command

The graphics mode command is quite different from the other

commands used by the LQ. For most of the other LQ modes, such as emphasized and double-wide, 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. After the LQ receives this code, it interprets the next numbers as pin patterns and prints them on the paper.

The LQ has one command that allows you to use any of the 11 graphics options. The format of the command is:

ESC * m nl n2 data

In this command, m selects the graphics option and nl and n2 specify the number of columns to reserve for graphics. The available graphics options are listed on the next page.

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