ISO/IEC 7942-1:1994

INTERNATIONAL
ISO/IEC
STANDARD
7942-1
Second edition
1994-11-01
Information technology - Computer
graphics and image processing -
Graphical Kerne1 System (GKS) -
Part 1:
Functional description
Technologies de I ’information - Infographie et traitement d ’image -
Systeme graphique GKS -
Partie 1: Descrip tion fonctionnelle
Reference nurnber
lSO/IEC 7942-1 :1994(E)

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ISO/IEC 7942-1: 1994(E)
Contents
...
Vlll
Foreword .
ix
Introduction .
1
.................................................................................................................
1 Scope
2
2 Normative references .
3
3 Definitions .
9
.....................................................................................................
4 Conformance
9
Specification .
4.1
9
Registration .
4.2
10
........................................................................................................
5 Concepts.
10
Bietures .
5s
10
Output primitive classes and attributes .
5.2
10
Werkstations .
5.3
14
Coordinate Systems and transformations .
5.4
14
Logical Input devices .
5.5
14
Picture part store .
56
14
State lists .
5:7
14
Description tables .
5.8
14
Metafiles and archives .
5.
15
Routing to the backdrop .
5.
15
5.11 Audi% trail .
15
512 Segments .
..................................................... 15
5,13 Compatibility with ISO 7942: 1985
95
51 SUl?lIlXil-y .
17
.........................................................................
The Graphical Kerne1 System
17
Initialization .
6.1
17
..................................................................................
6.2 Graphical output
17
Output primitive classes .
62.1
17
Output primitive attributes .
6.2.2
19
............................................................
6.3 Normalkation transformations
20
..................................................................................
6.4 Bicture part store
20
Bicture gart creation .
6AJ
20
Picture part functions .
20
Adding picture parts .
20
Pic ture part archiving .
6.4*4
20
.................................................................................
65 The NDC gicture
20
Introduction .
6.5.1
21
NIX picture operations .
63.2
21
NDC metafiles .
653
21
................................................................................
6.6 Sektion criterion
22
....................................................................................
6,7 Graphical input
22
...........................
6.7s Introduction to logical input devices
23
.........................................
6.7.2 Logical input device model
................. ..2 4
6.7.3 Operating modes of logical input devices
........................... 25
6.7.4 Input queue and current event report
0 ISO/IEC 1994
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Printed in Switzerland
ii

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ISO/IEC 7942=1:1994(E)
OISO/IEC
26
..................................................................................
68 . Inquiry functions
26
.....................................................................................
69 Error handling
..2 6
.........
6110 Special interfaces between GKS and the application prograrn
26
.............................................................................................
6.11 Backdrap
27
..............................................................................
6.12 Audit and playback
28
........................................................................
7 Workstation dependent control
28
.........................................................................................
7.1 Introduction
28
.................................................................
Workstation characteristics
7.2
29
........................................................................
7.3 Selecting a workstation
29
7.4 Selec tion criteria .
30
Viewing .
75 .
30
...............................................................
76 Workstation transformations
31
.................................................................................
7:7 Output primitives
32
7.8 Colour .
33
.........................................................................
79 Setting representations
34
..........................................................................
7110 Removing a backdrop
34
................................................................................
7.11 Visual effect state
34
.................................................................................
7.12 Realized metafile
34
...........................................................................
7.13 Logical input devices
34
Introduction .
7.13.1
.......................... 35
Initialization of logical input devices
7.13.2
..3 5
....
Definition of logical and composite input devices
7.13.3
35
.....................................................
7.14 Sending messages to a workstation
36
.............................................................................................
8 Output primitives
36
Introduc tion .
8.1
36
.......................................................................
Curve output primitives
82 .
36
..........................................................
8.2.1 Curve primitives
37
............................................................
Curve attributes
8.2.2
37
.....................................................................
Marker output primitives
8.3
38
.........................................................................
Area output primitives
8.4
38
............................................................
Area primitives
8.4.1
38
....................................................
Definition of interior
8.4.2
38
..............................................................
Area attributes
8.4.3
40
.................................................................
Character output primitives
8.5
40
.................................................................
8.5.1 Introduction
41
......................................................
8.5.2 Glyph specification
42
....................................................................
8.5.3 Glyph size
42
...................................................................
8.5.4 Text extent
43
................................................................
8.5.5 Text skewing
44
.............................................................
8.5.6 Text alignment
46
............................................................
8.5.7 Text orientation
47
..........................................................
8.5.8 Transformed text
47
8.5.9 Precision .
48
.................................................
8.5.10 Estimate of text extent
48
.......................................................................
8.6 Image output primitives
49
......................................................................
8.7 Design output primitives
49
.................................................................
8.7.1 Introduction
50
8.7.2 S tencils .
52
..........................................................
8.7.3 S tencil attributes
53
.....................................................
8.7.4 S tencil composi tion
57
...................................................................
8.7.5 Tiling store
59
..........................................
8.7.6 Stencil and tiling functions
. . .
111

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ISO/IEC 7942-1: 1994(E) OISO/IEC
8.8 Generalized drawing primitive . 59
9 Logical input device classes . 60
9.1 Introduction . . 60
Measures of each logical input device class . 60
92
9:3 Transformation of LOCATOR and STROKE input . . 61
9.3.1 Transformation of LOCATOR input . 61
.............................. 63
9.3.2 Transformation of STROKE input
63
9.4 Prompt and echo types .
LOCATOR prompt and echo types . 63
9.4.1
9.4.2 STROKE prompt and echo types . 64
9.4.3 VALUATOR prompt and echo types . 64
9.4.4 CHOICE prompt and echo types . 65
9.4.5 PICK prompt and echo types . 65
9.4.6 STRING prompt and echo types . 66
10 Segments and workstation activation . 67
10.1 Introduction . . 67
10.2 Selection criteria . 67
Segment state list . 68
10.3
10.4 Workstation activation . 68
10.5 Segment creation . 68
10.6 Segment manipulation . 68
69
10.7 Segment attributes .
69
10.8 Segment storage .
69
10.9 Clear workstation .
70
11 Data types . .
70
11.1 Data type definitions .
70
11.1.1 Notational conventions .
72
11.1.2 Basic types .
73
11.1.3 Data types for GKS control .
.................................. 73
11.1.4 Data types for output primitives
................................... 75
11.1.5 Data types for output attributes
Data types for transformations . 78
11.1.6
11.1.7 Data types for NDC picture . 79
11.1.8 Data types for metafiles . 79
Data types for picture parts and archives . .7 9
11.1.9
Data types for Utility functions . 80
11.1.10
............................................... 80
11.1.11 Data types for Segments
..................................................... 81
11.1.12 Data types for input
.............................. 82
11.1.13 Data types for workstation control
83
11.1.14 Data types for inquiry functions .
83
11.1.15 Data types for operating state .
.84
11.1.16 Data types for font and glyph functions .
84
11.1.17 Data types for audit trails .
84
11.1.18 Data types for selection criteria .
11.1.19 Data types for paths, tilings and stencils . .85
11.2 Data type definitions for state lists and description tables. . .87
11.2.1 Introduction . 87
87
11.2.2 Operating state list (OSL) .
11.2.3 GKS description table (GDT) . 87
11.2.4 GKS state list (GSL) . 87
11.2.5 Workstation state list (WSL) . 88
11.2.6 Workstation description table (WDT) . .88
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OISO/IEC ISOIIEC 7942=1:1994(E)
11.2.7 Error state list (ESL) . 90
11.2.8 Segment state list (SSL) . 90
11.2.9 Stencil state list (STSL) . 90
11.3 Initial values of state lists and description tables . 90
11.3.1 Operating state list . 90
11.3.2 GKS description table . 90
11.3.3 GKS state list . 90
11.3.4 Workstation state list . 92
........................ .92
11.3.5 Generic workstation description table
Error state list . 92
11.3.6
11.3.7 92
Segment state list .
92
11.3.8 Stencil state list .
93
12 Workstation independent functions .
12.1 Conti-01 functions . 93
12.2 Output functions . 94
12.3 Design output functions . 95
12.4 Output attributes . 97
12.5 Normalization transformation functions . 98
12.6 NDC picture functions . 99
100
12.7 Metafile functions .
100
12.8 Picture part store functions .
103
12.9 Input functions .
................................................................... 104
12.10 Font and glyph functions
............................................................ 104
12.11 Audit and playback functions
12.12 Inquiry functions . 105
................................................................................. 107
12.13 Utility functions
Utility functions for output primitives . 107
12.14
................................................................................... 109
13 Workstation functions
............................................................................... 109
13.1 Conti-01 functions
13.2 Inquiry functions . 112
............................................................................. 114
13.3 Retrieval functions
13.4 Viewing utility functions . 115
13.5 Colour Utility functions . 115
14 Segment and workstation activation functions . 116
116
14.1 Segment functions .
118
14.2 Workstation activation functions .
14.3 Utility func tions . 119
Annexes
............................................................................. 120
A Function and data type list
Functions alphabetic . 120
A.1
A.2 Functions Order of appearance . 122
......................................................................... 126
A.3 Data types alphabetic
........................................................................................................ 128
B Error list
.............................................................................. 128
B.1 Function error list
Error list ordered by error number . 138
B.2
Language binding considerations . 140
C
................................................................................... 146
D Allowable differentes
General . . 146
D.1
............................................................................. 146
D.2 Global differentes
................................................... 146
D.3 Workstation dependent differentes
............ ................................................................................... 149
E Colour models
................................................................................................. 150
F Bibliography
V

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OISO/IEC
ISO/IEC 7942-1: 1994(E)
....................................... 151
G An approach to compatibility with ISO 7942: 1985
151
G.1 Introduction .
151
G.2 Format .
151
G.2.1 Compatibility aspects .
151
G.2.2 Language binding .
....................................... 151
G.2.3 Notation used in this annex
................................................................................... 151
G.3 Data structures
151
Introduction .
G.3.1
............................................ 152
G.3.2 Compatibility data types
G.3.3 Compatibility operating state list (COSL) .152
................
list (CGSL) .152
G.3.4 Compatibility GKS state .
.152
G.3.5 Compatibility workstation state list (CWSL) .
.153
G.3.6 Compatibility Segment state list (CSSL) .
............................................................................... 153
G.4 Control functions
OPEN GKS . 153
G.4.1
153
G.4.2 OPEN WORKSTATION .
154
G.4.3 CLOSE WORKSTATION .
ACTIVATE WORKSTATION . 154
G.4.4
DEACTIVATE WORKSTATION . 155
G.4.5
155
G.4.6 CLEAR WORKSTATION .
G.4.7 Deferral states . 155
156
G.5 Output and attribute functions .
G.6 Transformation functions . 156
G.6.1 SET VIEWPORT . 156
157
G.6.2 SET WINDOW .
G.6.3 SELECT NORMALIZATION
157
TRANSFORMATION .
............................................... 157
G.7 Workstation transformation functions
157
G.8 Segment functions .
............................................................... 157
G.8.1 Introduction
CREATE SEGMENT . 157
G.8.2
DELETE SEGMENT FROM WORKSTATION.15 7
G.8.3
ASSOCIATE SEGMENT WITH WORKSTATION158
G.8.4
SEGMENT TO WORKSTATION .158
G.8.5 COPY .
158
G.8.6 INSERT SEGMENT .
158
G.8.7 Segment attributes .
158
G.9 Input functions .
158
G.9.1 Introduction .
159
G.9.2 Simultaneous events .
Pick input 160
G.9.3 .
............................................................................................... 160
G.10 GKSM
G.lO.1 READ ITEM FROM GKSM . 160
G.lO.2 GET ITEM FROM GKSM . 160
INTERPRET ITEM 160
G.lO.3 .
WRITE ITFM TO GKSM . 161
G.lO.4
G.11 Inquiry functions . 161
G.ll.1 functions for operating state value .16 1
Inquiry .
.161
G.ll.2 Inquiry functions for GKS description table .
........................... 161
G.ll.3 Inquiry functions for GKS state list
.161
G.ll.4 Inquiry functions for workstation state list .
G.ll.5 Inquiry functions for workstation
161
description table .
vi

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OISO/IEC ISO/IEC 794201:1994(E)
G.11.6 Inquiry functions for Segment state list . 162
G.11.7 Pixel inquiries . 162
G.11.8 Inquiry functions for GKS error state list . .162
G.12 Utility functions . 162
G.13 Error handling . 162
G.13.1 Matthing error numbers . 162
162
G.13.2 Using the Utility function .
G.14 Conclusions . 163
H Compatibility with the Computer Graphits Reference Model
164
ISO/IEC 11072: 1992 (informative) .
164
H.l Introduction .
H.2 Environments . 164
H.3 Fan-out and fan-in . 164
H.4 Extemal interfaces . 164
164
HS Processing elements .
164
H.6 Compositions . .
164
H.7 Collec tions .
164
H.8 Clipping .
vii

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ISOAEC 7942-1: 1994(E) OISO/IEC
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commis-
sion) form the specialized System for worldwide standardization. National bodies that are members of ISO or
IEC participate in the development of International Standards through technical committees established by the
respective organization to deal with particular fields of technical activity. ISO and IEC technical committees
Other international organizations, govemmental and non-
collaborate in fields of mutual interest.
govemmental, in liaison with ISO and IEC, also take part in the work.
In the field of information technology, ISO and IEC have established a joint technical committee, ISO/IEC
JTCl. Draft International Standards adopted by the joint technical committee are circulated to national bodies
for voting. Publication as International Standard requires approval by at least 75% of the national bodies cast-
ing a vote.
International Standard ISO/IEC 7942-1 was prepared by Joint Technical Committee ISO/IEC JTCl, Informa-
tion technology, Sub-Committee 24, Computer graphics and image processing.
This second edition cancels and replaces the first edition (ISO 7942: 1985), which has been technically revised.
ISO/IEC 7942 consists of the following Parts, under the general title Information technology - Computer
graphics and image processing - Graphical Kerne1 System (GKS):
Part 1: Functional description
Part 2: NDC metajle
Part 3: Audit trail
Part 4: Picture part archive
Annexes A and B form an integral part of this part of ISO/lEC 7942. Annexes C, D, E, F, G, and H are for
information only.
. . .
Vlll

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OISO/IEC ISO/IEC 794201:1994(E)
Introduction
The Graphical Kerne1 System (GKS) provides a set of functions for Computer graphics programming that tan
be used by a range of applications. The main motivations for standardization are to improve portability of pro-
grams and to define a basic methodology. Portability is achieved by providing all the capabilities necessary in
a device independent way. The following principles are used in specifying GKS:
a) Design: the three goals are consistency of approach, compatibility with related Standards and orthogonal
functionality where possible.
b) Functionality: the goals are completeness with the minimal set of functions. Organization of functions
should be such as to achieve compact programs. Richness should be provided by Utilities and toolkits on
top of GKS rather than non-Standard extensions to GKS.
c) Clarity: the underlying concepts should be easily understood, especially by the application programmer.
To achieve this, GKS is defined using a small set of functions with precise specification of the data struc-
tures that define the state of GKS and the effect that functions have on this state.
d) Error handling: all errors caused by inc
...