IBM 4400 manual Graphics, Double Density Double Speed

Graphics, Double Density Double Speed

Graphics, Double Density Double Speed

ASCII Code ESC Y n1 n2

Hex Code	1B 59 n1 n2
Dec Code	27 89 n1 n2
Purpose	Selects double density, double speed bit-image graphics of 120
	dpi horizontally and 72 dpi vertically.
where:	(n1 + 256n2) defines the number of data bytes to follow.
	DATA = ASCII characters for the dot pattern bytes.

NOTE: The DATA can be expressed in a format with the appropriate decimal values of the ASCII characters supplied, especially in cases where the dot patterns of nonprintable characters are required.

“DATA” consist of 8-bit dot columns, with the MSB at the top, and “1” bits producing dots. For more information, refer to Chapter 8, “Graphics.”

Comment This mode prints double density with no adjacent dots. It is similar to ESC L, except that if the graphics data contain horizontally adjacent dots, the data may print incorrectly. This feature is widely used to move the print head precisely, by printing blank dot columns.

Example The following example produces a double density, double speed graphic image of the pattern used in the standard density example. The amount of data must be doubled for double density (the data are used 54 times rather than 27).

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