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.

Texte du rabat

This book describes two ISO standardization projects - the Computer Graphics Interface (CGI) and the Computer Graphics Metafile (CGM). It has been written principally for users and practitioners of computer graphics. In particular, system designers, independent software vendors, graphics system implementors, and application program developers need to understand the basic standards being put into place at the so-called Virtual Device Interface. Technical managers, graduate students in computer science specializing in graphics, and buyers in government and industry will also find this book valuable. The CGI project is standardizing a functional and syntactic specification for the exchange of device-independent data and associated control information between systems with graphical capabilities. The CGI defines idealized abstract classes of graphical devices capable of accepting input and generating, storing and manipulating pictures. The CGM provides a file format suitable for the storage and retrieval of device-independent picture descriptions. Pictures described by a sequence of CGI function invocations can be written to disk and stored compactly as CGMs, and CGMs can be interpreted and displayed efficiently using a CGI implementation. Formal standards documents are difficult to read. They are dry, complex and lack tutorial material. This book is intended to supplement the standards documents themselves. Organized into four parts comprising seventeen chapters, it includes many illustrations and examples not found in the standards. The book also explains the relationship of the CGI and CGM to other standards, both formal and de facto, describes some early commercial implementations of the standards, and gives the reader insight into the future evolution of these standards.

Contenu
I: The Computer Graphics Interface.- 1: Introduction to Computer Graphics Standards.- 2: The Computer Graphics Interface.- 3: Elementary CGI Output and Attribute Functions.- 4: Control and Error Handling.- 5: The Raster Functions in the CGI.- 6: Synchronous Input.- II: Advanced Features of the CGI.- 7: Segmentation in the CGI.- 8: Further CGI Output and Attribute Functions.- 9: Asynchronous Input.- 10: CGI Conformance and Constituency Profiles.- 11: Implementations of the CGI.- III: The Computer Graphics Metafile.- 12: CGM Concepts and Purposes.- 13: CGM Elements.- 14: CGM Encodings.- 15: Relationship of the CGM to Other Standards.- 16: Implementations of the CGM.- 17: Future Extensions to the CGM.- 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.3.3Output 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.