In ES2, Livecycle introduced support for arbitrary unicode characters in Zebra Labels. Prior to this only latin-I charset was supported. Though there was support for Asian encoding like GBK(Simplified Chinese), Shift-JIS (Japanese), BIG-5 (Traditional Chinese) and KSC-5601 (Korean) but generic unicode support was missing.
Another pain was LC didn’t allow any font that is not present on the printer, to be specified in the label. This combined with above became a real problem with the middle east customers. The problem with Zebra is one cannot embed fonts inside the document like Postscript as downloading fonts on the printer is awfully slow. So the only option we left with is to rasterize the text and represent it as an image in the generated label. This way, the form author can get what he sees on the screen in pdf or in designer. Even with this approach, we felt that there is considerable file size bloating even after compressing the images of the document. Since XTG was rasterizing all the text present in the font other than the printer, which was not necessary sometime. For example, if the text is specified in english in Arial font, the end user might want to substitute it with the font present on the printer. In fact this is what we used to do before this change.
An option in XDC file is used to map to a font which is to be rasterized. The general font mapping sequence that is allowed in XTG needs both from and to font and along with it one can specify which unicodeRange to target. But here, the form author might not know before hand what data is going to be merged with the form. For example, there can be multiple textfields in the form with different fonts specified. The data to be merged in the form may contain non-english characters for some of the textfield. If the end user wants to map the form font into printer font, she has to specify that many mapping in the config file. So to ease the effort on the end user side, we exposed this option in xdc file where one needs to specify only to font and unicodeRange. This is a shortcut to the existing font mapping sequence.
<xdp>
<xdc>
<deviceInfo>
<option>
...
<!-- ========================================== -->
<!-- Raster Substitution Font -->
<!-- ========================================== -->
<rasterSubstitutionFont typeface="CG Triumvirate_Normal_Normal" unicodeRange="U+20-U+FF"/>
</option>
</deviceInfo>
</xdc>
</xdp>
The above entry is shortcut to the following config option:
<fontInfo> <map from="FONT_TO_BE_RASTERED" to="CG Triumvirate_Normal_Normal" unicodeRange="U+20-U+FF"/> </fontInfo>
Here the printer driver for Zebra printer in XTG determines which font is going to be rasterized and based on that map that font to the specified rasterSubstitutionFont present in the xdc file.
There can be multiple rasterSubstitutionFont in the XDC file for different unicodeRange just like the font substitution entry.