CGM and CGI

We have written this book principally for users and practitioners of computer graphics. In particular, system designers, independent software vendors, graphics system implementers, and application program developers need to understand the basic standards being put in place at the so-called Virtual Device Interface and how they relate to other industry standards, both formal and de facto. Secondarily, the book has been targetted at technical managers and advanced students who need some understanding of the graphics standards and how they fit together, along with a good overview of the Computer Graphics Interface (CGI) proposal and Computer Graphics Metafile (CGM) standard in particular. Part I, Chapters 1,2, and 3; Part II, Chapters 10 and 11; Part III, Chapters 15, 16, and 17; and some of the Appendices will be of special interest. Finally, these same sections will interest users in government and industry who are responsible for selecting, buying and installing commercial implementations of the standards. The CGM is already a US Federal Information Processing Standard (FIPS 126), and we expect the same status for the CGI when its development is completed and it receives formal approval by the standards-making bodies.

I: The Computer Graphics Interface.- 1: Introduction to Computer Graphics Standards.- 1.1 Overview of Various Graphics Standards.- 1.1.1 A Reference Model.- 1.1.2 The Application Programmer Interface.- 1.1.3 The Virtual Device Interface.- 1.1.4 Developments in the Reference Architecture.- 1.2 Organization of the Book.- 2: The Computer Graphics Interface.- 2.1 What is the CGI?.- 2.2 Purpose.- 2.3 Uses and Benefits.- 2.4 Design Requirements.- 2.5 Design Criteria.- 2.6 Relationship with Other Standards.- 2.6.1 CGI Data Encodings Standard.- 2.6.2 CGI Language Binding Standards.- 2.6.3 Relationship of CGI Data Encoding and Language Binding Standards.- 2.6.4 Relationship with GKS.- 2.6.5 Relationship with GKS-3D and PHIGS.- 2.6.6 Relationship with the CGM.- 2.6.7 Relationship with Window Managers.- 2.6.8 Relationship with PostScript.- 2.6.9 Relationship with ISO Register of Graphical Items.- 2.7 Main Concepts.- 2.7.1 The CGI Pipeline.- 2.7.2 The CGI State Model.- 2.7.3 Interrogation and Inquiry.- 2.7.4 CGI Error Philosophy.- 3: Elementary CGI Output and Attribute Functions.- 3.1 Introduction.- 3.2 Line Class Graphic Objects.- 3.2.1 Line Class Primitives.- 3.2.2 Attributes of Line Class Primitives.- 3.3 Polymarker Primitive and Attributes.- 3.4 Text.- 3.4.1 Introduction to Text Primitives and Attributes.- 3.4.2 Font Description Coordinate System.- 3.4.3 Character Expansion Factor and Character Spacing.- 3.4.4 Character Orientation.- 3.4.5 Text Path.- 3.4.6 Text Alignment.- 3.4.7 Text Precision.- 3.5 Filled Area Primitives.- 4: Control and Error Handling.- 4.1 Virtual Device Management.- 4.1.1 Managing a Dialogue Session.- 4.1.2 Managing the Display Surface.- 4.1.3 Controlling Deferral Modes and Regeneration.- 4.1.4 Classes of CGI Devices.- 4.2 Characteristics of Output Devices.- 4.3 Coordinate Space Control.- 4.4 Clipping Control.- 4.5 Error Model.- 4.5.1 Error Classification Scheme.- 4.5.2 Mechanism for Error Reporting.- 4.6 Interrogation and Inquiry.- 4.7 Interrogation and Negotiation.- 4.8 Miscellaneous Control.- 5: The Raster Functions in the CGI.- 5.1 Introduction.- 5.2 Representation and Storage of Bitmaps.- 5.3 Bitmap Data Structure.- 5.4 Control of Bitmap Manipulations.- 5.5 Pixel Array.- 5.6 BITMAP Interior Style.- 5.7 Displayable Bitmaps.- 6: Synchronous Input.- 6.1 Introduction.- 6.2 Logical Input Devices and Their Measures.- 6.3 Coordinate Systems for Stroke and Locator.- 6.4 CGI Input Model.- 6.5 Triggers.- 6.6 Request Input.- 6.7 Echoing, Prompting, and Acknowledgement.- 6.8 Setting Initial Conditions for Devices.- II: Advanced Features of the CGI.- 7: Segmentation in the CGI.- 7.1 Introduction.- 7.2 Segments in the CGI.- 7.3 Creation of Segments.- 7.4 Segment Attributes.- 7.5 Segment Display.- 7.6 Segment Manipulations.- 7.7 Pick Input and Segmentation.- 7.8 Segment Interrogations and Inquiries.- 7.9 Segment Storage Overflow Handling.- 8: Further CGI Output and Attribute Functions.- 8.1 Introduction.- 8.2 Additional Line Class Primitives.- 8.2.1 Disjoint Polyline.- 8.2.2 Circular ARC Centre Backwards.- 8.2.3 Elliptical ARC.- 8.3 Further Text Primitives.- 8.3.1 Append Text.- 8.3.2 The Restricted Text Primitive.- 8.4 Additional Filled Area Primitives.- 8.5 Closed Figures.- 8.6 Controlling Edge Visibility.- 8.7 Cell Array Primitive.- 8.8 Generalized Drawing Primitive.- 8.9 Output and Attribute Control Functions.- 8.9.1 Specification Modes and Colour Definition.- 8.9.2 Transparency.- 8.9.3 Setting Bundle Table Contents.- 8.10 Save and Restore Primitive Attributes Settings.- 8: (Cont).- 8.11 Inquiry and Interrogation.- 8.12 New CGI Pipeline Model.- 8.13 Fonts and Character Sets.- 9: Asynchronous Input.- 9.1 Introduction.- 9.2 Event Input.- 9.3 Event Queue Management.- 9.4 Echo Request Input Mode.- 10: CGI Conformance and Constituency Profiles.- 10.1 Purpose.- 10.2 Conformance and Constituency Profiles.- 11: Implementations of the CGI.- 11.1 Overview.- 11.2 Traditional Output Primitives and Attributes.- 11.3 Raster Graphics Capabilities.- 11.4 Control.- 11.5 Segmentation.- 11.6 Input.- 11.7 Hardware Manifestations of the CGI.- III: The Computer Graphics Metafile.- 12: CGM Concepts and Purposes.- 12.1 Metafiles.- 12.1.1 GKS Metafiles.- 12.1.2 The Computer Graphics Metafile.- 12.2 A Reference Model for Data Interchange.- 12.3 Purposes of Metafiles.- 12.3.1 Picture File Transfer and Storage.- 12.3.2 Product Definition Data Base Transfer and Storage.- 12.3.3 Transaction Recording.- 12.3.4 Symbol Libraries.- 13: CGM Elements.- 13.1 Delimiter Elements.- 13.2 Metafile Descriptor Elements.- 13.3 Picture Descriptor Elements.- 13.4 Control Elements.- 13.5 CGM Tailoring.- 13.6 Graphical Primitive Elements.- 13.7 Attribute Elements.- 13.8 Escape and External Elements.- 13.9 Metafile Defaults.- 14: CGM Encodings.- 14.1 Binary Encoding.- 14.1.1 Overview.- 14.1.2 List of Binary Encoding Metafile Element Codes.- 14.1.3 Binary Encoding Defaults.- 14.2 Clear Text Encoding.- 14.2.1 Overview.- 14.2.2 List of Clear Text Encoding Derived Element Names.- 14.2.3 Clear Text Encoding Defaults.- 14.3 Character Encoding.- 14.3.1 Overview.- 14.3.2 List of Character Encoding Metafile Element Codes.- 14.3.3 Character Encoding Defaults.- 14.4 Private Encodings.- 15: Relationship of the CGM to Other Standards.- 15.1 CGI.- 15.2 GKS.- 15.3 Registration of Graphical Items.- 15.4 Office Document Architecture.- 15.5 Standard Generalized Markup Language.- 16: Implementations of the CGM.- 16.1 CGM Exporters.- 16.1.1 On Mainframes, Minicomputers, and Workstations.- 16.1.2 On Personal Computers and in Hardware.- 16.2 CGM Importers.- 16.2.1 On Mainframes, Minicomputers, and Workstations.- 16.2.2 On Personal Computers and in Hardware.- 16.3 CGM Editors.- 16.4 NCGAGraphNet’88.- 16.5 Practical Considerations.- 16: (Cont).- 16.5.1 Barriers to Interchange.- 16.5.2 Using Outside CGMs.- 16.5.3 Issues for the Application Developer.- 17: Future Extensions to the CGM.- 17.1 The CGM as a GKS Metafile.- 17.2 Global Segments.- 17.3 New Elements from the CGI.- 17.4 3D Elements.- 17.5 Other Requirements.- 17.5.1 Purpose.- 17.5.2 Scope.- 17.5.3 Suggested New Elements.- IV: The Appendices.- Appendix A: Glossary.- Appendix B: Bibliography.- B.1 Standards Documents.- B.2 Books.- B.3 Journal Articles.- Appendix C: The Standards-Making System.- C.1 Standards Bodies.- C.2 The ANSI Process.- C.3 The ISO Process.- C.4 Standards Status.- Appendix D: CGI Description Tables and State Lists.- D.1 Device Description Table.- D.2 Output Description Table.- D.3 Attributes Description Table.- D.4 Raster Description Table.- D.5 Segmentation Description Table.- D.6 Input Description Table.- D.7 Echo Output Description Table.- D.8 Output State List.- Appendix D (Cont).- D.9 Control State List.- D. 10 Raster State List.- D. 11 Segmentation State List.- D. 12 Logical Input Device State List.- D. 13 Event Queue State List.- D. 14 Echo Entity State List.- Appendix E: CGI Functions and Parameterization.- E.1 Introduction and Conventions.- E.2 Part 2 Functions.- E.2.1 Virtual Device Management.- E.2.2 Coordinate Space Control.- E.2.3 Error Handling.- E.2.4 Miscellaneous Control.- E.3 Part 3 Functions.- E.3.1 Graphical Primitives.- E.3.2 Attribute Functions.- E.3.3 Output and Attribute Control Functions.- E.4 Part 4 Functions.- E.4.1 Segment Manipulation.- E.4.2 Segment Attributes.- E.4.3 Segment Interrogations.- E.5 Part 5 Functions.- E.5.1 Logical Input Device Functions.- E.5.2 Echo Output Functions.- E.6 Part 6 Functions.- E.6.1 Output and Attributes.- E.6.2 Raster Control Functions.- E.6.3 Raster Inquiry Functions.- Appendix F: TOP CGM Application Profile.- F.1 What is an Application Profile?.- F.2 The Technical Office Protocols Organization.- F.3 TOP Version 3.0.- F.4 Constraints on the Metafile Contents.- F.5 Constraints on Generators and Interpreters.