Figure 6-8 shows the design modified to take advantage of the higher resolution of 24-dot graphics. Notice that the curves are smoother and the edges are less ragged. This illustrates the major advantage of 24-dot graphics. The vertical resolution is approximately three times that of B-dot graphics which means you can produce better-looking graphics.

Figure 6-8. Eight-dot (top) and 24-dot (bottom) versions of the density

Using the SQ-2000 as a Plotter

One of the best applications of the SQ-2000 graphics capabilities is to print graphics images. Graphics images can range from business bar charts to computer-created art.

Since the SQ-2000 can’t move the paper in both directions, it can’t plot a curve continuously like a pen plotter does. To print a complete graphics image on the SQ-2000 the entire image must be assembled in the computer’s memory and, when complete, sent to the printer one line at a time. (Of course, if the image can be created from the top down, it can be printed as it is created.)

In many cases, the part of the computer’s memory that stores the image while it is being assembled is the same part of the computer’s memory that produces the display on the screen. In other words, the image is created on the screen of the computer and then a screen dump is done to print the screen image on the printer. This method is typical of many business graphics program.

However, the SQ-2000 can print graphics with much higher resolution than that of a computer screen. This means that using the screen to create an image and then using the screen dump to print it out actually limits the quality of your graphics.

Here is a short BASIC program that sets up a buffer in the computer’s memory, creates a simple graphic image, and then prints it on the SQ-2000 (see Figure 6-9).

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