TGnlData
#include <PrintTraps.h>
typedef struct TGnlData { Size Offset Description short iOpCode; 2 0 One of 5 possible subsidiary data
blocks
short iError; 2 2 0=noErr; 1=noSuchRsl;
2=opNotImpl
long lReserved; 4 4 (not used )
variable length data depending on routine selected by opcode specified in the first
field
structure are set according to the type of printer being used and the style
and resolution of the output.
The first field specifies an opcode that serves as a routine selector for
subsidiary data blocks and can be:
When either opcode 4 or opcode 5 occupies the first field of the TGnlData record you are letting the application know what resolutions the printer
supports -- and then specifying the desired resolution. Opcodes 6 and 7
tell you whether or not you can print bitmaps in draft mode on the
ImageWriter. Opcode 8 informs the application that the page has been
rotated to print sideways.
The iError field only returns the result produced by the print code and
only reflects conditions that occur during a PrGeneral call. It will be one of:
noErr (0) No error
noSuchRsl (1) Specified resolution not available
opNotImpl (2) Printer driver doesn't support this opcode
After the four-byte reserved field, the rest of the data block will be filled
in with one or another of the subsidiary data blocks specified by the opcode
listed in the first field (iOpCode).