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The following page has been changed by JeremiasMaerki:
http://wiki.apache.org/xmlgraphics-fop/AFPOutput

The comment on the change is:
A note about glyph positioning in AFP

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  One difficulty will be mapping Unicode scalar values to GCGIDs (Graphic 
Character Global Identifier from IBM's CDRA). GCGIDs are character names with a 
length of 4 to 8 characters. A large collection of Unicode characters can be 
mapped to GCGIDs but there's no 1:1 relationship. However, for most use cases, 
using this subset would probably be sufficient. So far, no machine-readable map 
for Unicode to GCGID could be found. A human-readable map can be found here: 
http://www-01.ibm.com/software/globalization/gcgid/gcgid.jsp. If you have an 
AFP fonts with GCUIDs (Graphic Character UCS Identifier) instead of GCGIDs, 
that might also work because GCUIDs just especially prefixed Unicode values 
expressed as 8 byte string. At the moment, the mapping from Unicode to code 
points (8bit inside the codepage) happens through the "encoding" setting on the 
font configuration element. However, that codepage file/object might also be 
generated by FOP.
  
+ == Glyph positioning ==
+ 
+ It is best practice to use PTOCA's SIA (Set Intercharacter Adjustment) and 
SVI (Set Variable Space Character Increment) structures for glyph positioning 
where possible. Only for kerning effects or fixed-width spaces should relative 
cursor movements be used. This is done to keep print file sizes small and 
performance high. However, there's a catch. Experiments have shown that there's 
no consensus about the interpretation of those two features. Currently, FOP 
uses them but the result may not be as expected on every target environment. In 
the new AFPPainter there are now two different implementations, one using above 
structures and one doing glyph positioning exclusively using RMI (Relative Move 
Inline). The latter is currently disabled. If the need should arise, an option 
could be implemented to let the user choose which implementation to use.
+ 
  == Random Notes ==
  
   * We should include resource (especially fonts) at the beginning of the 
print file. That makes sure the resources are available to the viewers and 
reduces the complex setup of fonts. Furthermore, it guarantees that the printer 
always has the most current font files.

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