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Graphics Hints

When using PicSure's "LINE STYLE" command or GRAFMAKER's "JXLINE" subroutine to plot a dashed line through your data points you may notice that some portions of the line may not be dashed and in some cases the entire line will appear solid. This happens when you use an end-adjusted line style, usually line styles 1 thru 128, to plot data points which are close together. The end-adjust line styles cause a dash to be started at each data point and if the points are close together then one dash may not end before the next data point is reached and a new dash is started, causing a solid line to be formed.

The solution to this problem is to use line styles from the range 129-255 remembering that line styles which are a multiple of 4 will be solid lines. These line styles are what are called in-phase dashed lines which means the spacing of dashes and gaps is preserved no matter how close together the points making up the line may be. One word of caution, since line styles are device dependent this may not look exactly the same on every graphics device.

Sending ``qplot'' Output to a Specific Plotter:

Sometimes it is desirable to send ``qplot'' output to a plotter other than the one to which it normally goes. This can be accomplished by using the ``op='' qplot argument to specify the machine and the device name of the plotter you want your plot drawn on. For example, the command:

	   $ qplot x=xfile,a y=yfile,a -h op="-meg /dev/plt0"

would cause the plot to be drawn on the "/dev/plt0" plotter connected to the "eg" machine. Remember, qplot only plots on Hewlett-Packard 7221 plotters, so using this technique will not work with other models of plotters.

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