Page:Calligraphy for computers (Hershey, 1967) (IA DTIC AD0662398).djvu/28

 when the conversion factor is assumed to be 0.011. This is compatible with the standard size of Roman alphabet.

The digitalizations in the present investigation are limited to characters with a nominal height of 21 raster units. With some omission of detail in tight spaces and some overflow in complicated cases this size is believed to be adequate for all characters in Nelson's dictionary except No. 5444. Inasmuch as this character represents dragons in motion, it is of doubtful utility. The remaining characters either have been simplified or can be digitalized without too much distortion provided the minimum spacing between lines can be as small as two raster units. Even character No. 5444 can be digitalized when the nominal height of character is 42 raster units.

DOT DATA

Smooth straight lines can be generated with a dot plotter only in limited directions where the discrete increments $$\Delta X, \Delta Y$$ from one dot to the next have simple integral values. Primary directions are generated when the lines are defined by the increments

$$ \begin{align} (\Delta X, \Delta Y) = & (2, 0) \\ (\Delta X, \Delta Y) = & (2, 1) \\ (\Delta X, \Delta Y) = & (1, 1) \end{align} $$

or by any permutation of magnitude or reversal of sign among these increments. Secondary directions are generated when the lines are defined by alternation between the following pairs of increments 22