The CGM Standard, as defined by the International standard ISO/IEC 8632:1999, allows for controlled extension of the CGM standard by the process of "registration". Registration applies to such items as linetypes, compression types, etc. After a CGM registration proposal is submitted to ISO, it is reviewed according to a prescribed process, and upon approval is entered into the ISO Registry of Graphical Items (which is available at http://isotc.iso.org/livelink/livelink/fetch/-8916524/8916549/8916590/6208440/iso_items_register.html?nodeid=7395736&vernum=-2).
Not all of the classes of graphical items in the registry are pertinent to CGM, and not all CGM related items are of equal interest in the newer and most widely used profiles. For convenience, in the following summary table we indicate the availability of the registered extension in the WebCGM 1.0 (Second Release) profile.
ITEM/CLASS |
DESCRIPTION
|
WebCGM
|
Linetype
|
These include both the implicitly defined CGM line types 1-5, from the CGM:1999 standard, and a handful of types (6-14) which have been registered for technical illustration usage
|
1-5 and 6-14
|
Markertype
|
These include both the implicitly defined CGM marker types 1-5, from the CGM:1999 standard, and lots of types (6-26) which have been registered for metereological usage
|
1-5.
|
Hatchtype
|
These include both the implicitly defined CGM hatch types 1-6, from the CGM:1999 standard, and lots of types (7-19) which have been registered for architectural/engineering usage.
|
1-6.
|
GDPs
|
These were registered prior to the completion of equivalent standard functionality in CGM Version 3 (1992), and are considered obsolete.
|
None. |
Escape
|
Many of these are not CGM related, and most of the rest were registered prior to the completion of equivalent standard functionality in CGM Version 3 (1992), and are considered obsolete.
|
45, 46*, 47*, 48*
* Removed from WebCGM 2.0
|
Compression types
|
These include those compression types from the CGM:1999 standard, and new ones 7-9 that have been registered for profile usage. Note that the registry has an error:
|
BITONAL TILE: 0*,1*,2,5,6
TILE: 0*,1*,2*,5,6,7,9
*Deprecated in WebCGM 2.0.
|
Colour Models
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These include the colour models from the CGM:1999 standard (1-5), and new ones 6-8 that have been registered for profile usage.
|
1, 6, 7, 8
|
|