Parameters for gescape

The hpcgm driver recognizes a number of gescape functions. Following are the supported functions and definition of when they may be invoked.

After gopen, but before any other graphical activity:

CGMESC_ENCODING — Selects CGM encoding.
CGMESC_MET_NAME — Defines metafile name.
CGMESC_TOP_MODE — Selects TOP mode for metafile generation.
CGMESC_VDC_PREC — Selects VDC integer precision.

Anytime after gopen:

CGMESC_APPL_DATA — Generates CGM application data element.
CGMESC_ESCAPE_ELT — Generates CGM escape element.
CGMESC_FONT_IX — Allows application to select fonts.
CGMESC_MESSAGE — Generates CGM message element.
CGMESC_PIC_NAME — Defines picture name.

For information on CGM elements, read the section “CGM Elements Produced by the HP CGM Driver ” in Appendix A of this manual.

The gescape function allows the application program to input or output to a device in a device dependent manner. The syntax for the gescape function is:

/* gescape_arg is typedef defined in starbase.c.h */
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gescape_arg arg1, arg2;
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gescape (fildes, ESCAPE_OP_CODE, &arg1, &arg2);

A fildes is the file descriptor of the device to be accessed (returned by the Starbase call gopen).

The 〈op〉 is the opcode that specifies the action to be performed.

The arg1 and arg2 parameters provide information needed by a gescape.

A detailed discussion on each of the gescape functions can be found in Appendix A of this manual.

Parameters for gescape

Technical documentation

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