PDFNet comes with base 14 fonts (i.e. standard PDF fonts), however these do not include full Unicode set (which could be prohibitive in terms of the file size etc).
If your device or application includes extra fonts you can let PDFNet know using PDFNet.AddFontSubst(...) method.
PDFNet.addFontSubst("StoneSans-Semibold", " /Fonts/comic.ttf");
PDFNet.addFontSubst(PDFNet.e_Identity, "arialuni.ttf");
PDFNet.addFontSubst(PDFNet.e_Japan1, " Acrobat/Resource/CIDFont/KozMinProVI-Regular.otf");
PDFNet.addFontSubst(PDFNet.e_Japan2, "myfonts/KozMinProVI-Regular.otf");
PDFNet.addFontSubst(PDFNet.e_Korea1, "AdobeMyungjoStd-Medium.otf");
PDFNet.addFontSubst(PDFNet.e_CNS1, "AdobeSongStd-Light.otf");
PDFNet.addFontSubst(PDFNet.e_GB1, "AdobeMingStd-Light.otf");
For example, see comments in PDFDraw sample:
http://www.pdftron.com/pdfnet/samplecode.html#PDFDraw
The following font mapping (using standard Windows fonts) works well on many Japanese documents:
<subst name="HGGothicE" file="Fonts\HGRGE.TTC"/>
<subst name="HGPGothicE" file="Fonts\HGRGE.TTC"/>
<subst name="HGSGothicE" file="Fonts\HGRGE.TTC"/>
<subst name="HGGothicM" file="Fonts\HGRGM.TTC"/>
<subst name="HGPGothicM" file="Fonts\HGRGM.TTC"/>
<subst name="HGSGothicM" file="Fonts\HGRGM.TTC"/>
<subst name="HGMaruGothicMPRO" file="Fonts\HGRSMP.TTF"/>
<subst name="HGKyokashotai" file="Fonts\HGRKK.TTC"/>
<subst name="HGPKyokashotai" file="Fonts\HGRKK.TTC"/>
<subst name="HGSKyokashotai" file="Fonts\HGRKK.TTC"/>
<subst name="HGGyoshotai" file="Fonts\HGRGY.TTC"/>
<subst name="HGPGyoshotai" file="Fonts\HGRGY.TTC"/>
<subst name="HGSGyoshotai" file="Fonts\HGRGY.TTC"/>
<subst name="HGSeikaishotaiPRO" file="Fonts\HGRSKP.TTF"/>
<subst name="HGSoeiPresenceEB" file="Fonts\HGRPRE.TTC"/>
<subst name="HGPSoeiPresenceEB" file="Fonts\HGRPRE.TTC"/>
<subst name="HGSSoeiPresenceEB" file="Fonts\HGRPRE.TTC"/>
<subst name="HGSoeiKakugothicUB" file="Fonts\HGRSGU.TTC"/>
<subst name="HGPSoeiKakugothicUB" file="Fonts\HGRSGU.TTC"/>
<subst name="HGSSoeiKakugothicUB" file="Fonts\HGRSGU.TTC"/>
<subst name="HGSoeiKakupoptai" file="Fonts\HGRPP1.TTC"/>
<subst name="HGPSoeiKakupoptai" file="Fonts\HGRPP1.TTC"/>
<subst name="HGSSoeiKakupoptai" file="Fonts\HGRPP1.TTC"/>
<subst name="HGMinchoB" file="Fonts\HGRMB.TTC"/>
<subst name="HGPMinchoB" file="Fonts\HGRMB.TTC"/>
<subst name="HGSMinchoB" file="Fonts\HGRMB.TTC"/>
<subst name="HGMinchoE" file="Fonts\HGRME.TTC"/>
<subst name="HGPMinchoE" file="Fonts\HGRME.TTC"/>
<subst name="HGSMinchoE" file="Fonts\HGRME.TTC"/>
<subst name="MSGothic" file="Fonts\msgothic.ttc"/>
<subst name="MSPGothic" file="Fonts\msgothic.ttc"/>
<subst name="MSUIGothic" file="Fonts\msgothic.ttc"/>
<subst name="MSMincho" file="Fonts\msmincho.ttc"/>
<subst name="MSPMincho" file="Fonts\msmincho.ttc"/>
<subst name="Meiryo" file="Fonts\meiryo.ttc"/>
<subst name="MeiryoItalic" file="Fonts\meiryo.ttc"/>
<subst name="MeiryoBold" file="Fonts\meiryob.ttc"/>
<subst name="MeiryoBoldItalic" file="Fonts\meiryob.ttc"/>