Segment start

GDDM V3R2 Base Application Programming Reference

Segment start

GDDM V3R2 Base Application Programming Reference
SC33-0868-02

This order corresponds to the GSSEG call. In the short form, the order is truncated immediately after the SEGMENT-ID field. In this case, all segment attributes are taken from the current initial segment attributes as set by the Segment Attribute order (see topic 10.7.40), or by the GSSATI call.

Segment attribute information can be extended by using a segment prolog. The presence of a segment prolog is shown by a flag bit in the Segment Start order.


Fld len	Content		Meaning
1	X'70'		Segment Start order code
1	X'0C' or		Length of following data
	X'04'
4	SEGMENT-ID		The identifier to be given to the following segment, or 0 if unnamed. A four-byte (fullword) positive or zero integer (as in GSSEG).
2		Flags (omitted in short form):
		B'`0.......` `........`'		Visible
		B'`1.......` `........`'		Invisible
		B'`.1......` `........`'		Reserved
		B'`..0.....` `........`'		Nondetectable
		B'`..1.....` `........`'		Detectable
		B'`...1....` `........`'		Reserved
		B'`....0...` `........`'		No highlighting
		B'`....1...` `........`'		Highlighting
		B'`.....100` `........`'		Reserved
		B'`........` `0.......`'		Chained
		B'`........` `1.......`'		Nonchained
		B'`........` `.00.....`'		Reserved
		B'`........` `...0....`'		No prolog
		B'`........` `...1....`'		Prolog
		B'`........` `....0...`'		Nontransformable
		B'`........` `....1...`'		Transformable
		B'`........` `.....000`'		Reserved
2	L2		Length of segment (see Note) (omitted in short form)
4	X'00000000'		Reserved (omitted in short form)

Notes:

1. GDDM returns the length of a fixed-point GDF segment in the Segment Start order retrieved using GSGET. The length of segment is ignored on GSPUT; segments must be closed by an explicit Segment End order. When the length of a segment cannot be represented as a 2-byte unsigned number, a length of zero is set.

2. The segment attributes in the Segment Start order override the initial segment attributes that are in effect at the time the segment is created. The segment attributes can be altered by GSSATS in the usual way.

3. Within the prolog of a segment, only the following orders are valid:

A no-operation (X'00')
Comment (X'01')
Process Specific Control (X'02')
Segment Characteristics (X'04')
Pop (X'3F')
Marker Scale (X'41')
The attribute orders shown below:

Arc Parameters

(X'22' or X'62')

Character Angle

(X'34' or X'74')

Character Box

(X'03' or X'33')

Character-Box Spacing

(X'36' or X'76')

Character Direction

(X'3A' or X'7A')

Character Precision

(X'39' or X'79')

Character Set

(X'38' or X'78')

Character Shear

(X'35' or X'75')

Color and Extended Color

(X'0A', X'4A', X'26', or X'66')

Fractional Line Width

(X'11' or X'51')

Line Type

(X'18' or X'58')

Line Width

(X'19' or X'59')

Marker Box

(X'37' or X'77')

Marker Type

(X'29' or X'69')

Foreground Color Mix

(X'0C' or X'4C')

Model Transform

(X'24' or X'64')

Pattern

(X'28' or X'09')

Pick (Tag) Identifier

(X'43' or X'23').

Segment Viewing Window

(X'27')

Text Alignment

(X'10' or X'50').

Primitive attributes in the segment prolog are treated as being ordinary primitive attributes. GDDM does not create any primitive attributes apart from the transform in the segment prolog. For upward compatibility of GDF, it is advisable not to place primitive attribute orders (other than the Model Transform order) within the segment prolog.

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