Unimplemented Features in Xpdf

This list corresponds to Xpdf 3.04.31 and PDF 2.0 (2017-01-09 draft).

Categories are as follows:

feature category PDF Ref (2.0)
Chapter 7: Syntax
F/FFilter/FDecodeParms keys (external file) in stream dictionaries appearance 7.3.8
encryption version 3
(note: undocumented and deprecated)
appearance 7.6.2
revision 3 security bits misc
public-key security handlers appearance 7.6.5
crypt filters
(partially implemented)
appearance 7.4.10
PDF version as Version key in Catalog dictionary misc 7.7.2
PageLayout and PageMode keys in Catalog dictionary user interface 7.7.2
OpenAction key in Catalog dictionary user interface 7.7.2
user space units - UserUnit key in Page dictionary
(partially implemented)
optional appearance
Order key in sampled function dictionaries optional appearance 7.10.2
embedded file streams misc 7.11.4
URLs as file specifications misc 7.11.5
Chapter 8: Graphics
use of BlackPoint in CalGray, CalRGB, and Lab color spaces color management 8.6.5
NChannel-subtype DeviceN color spaces optional appearance
DeviceN color space attributes
(partially implemented)
color management
color operators not allowed in Type 3 glyphs and uncolored tiling patterns error checking 8.6.8
'Interpolate' flag in image dictionaries
(partially implemented)
optional appearance
'SMaskInData' field for JPX images transparency
alternate images optional appearance
reference XObjects optional appearance 8.10.4
optional content auto state (usage and usage application dicts) optional appearance / user interface
Chapter 9: Text
text knockout transparency 9.3.8
Chapter 10: Rendering
black generation and undercolor removal (when converting DeviceRGB to DeviceCMYK) color management
halftones color management 10.6
smoothness tolerance optional appearance 10.7.3
Chapter 11: Transparency
page groups (transparency group in page object) transparency 11.4.7
blending color space (for transparency groups and page groups); blending in CalRGB, CalGray, ICCBased color spaces
(currently handled for soft masks, but not for transparency groups)
transparency 11.6.3
shape vs. opacity; the "alpha is shape" (AIS) flag transparency 11.6.4
transfer function for soft masks transparency
transparency in patterns transparency 11.6.7
rendering parameters and transparency transparency 11.7.5
Chapter 12: Interactive Features
viewer preferences user interface 12.2
zoom factor in destinations user interface 12.3.2
color and style flags for outline entries user interface 12.3.3
thumbnail images user interface 12.3.4
collections and navigators user interface 12.3.5
page labels user interface 12.4.2
article threads user interface 12.4.3
presentation features user interface 12.4.4
annotation types other than links, widgets, and stamps
(partially implemented)
user interface / appearance 12.5.6
trigger events / additional-actions dictionaries (in annotations, fields, pages, and catalog) user interface 12.6.3
action types other than GoTo, GoToR, Launch, URI, Named; this includes JavaScript actions user interface 12.6.4
interactive forms (AcroForms), FDF files
(partially implemented)
user interface / appearance 12.7
XFA forms
(partially implemented)
user interface / appearance (deprecated)
digital signatures misc 12.8
measurement properties user interface 12.9
geospatial features user interface 12.10
document requirements user interface 12.11
Chapter 13: Multimedia Features
multimedia features appearance 13.2
3D artwork appearance 13.6
Chapter 14: Document Interchange
XML metadata streams misc 14.3.2
logical structure and tagged PDF,
including SD entry in GoTo/GoToR actions
text extraction / misc 14.7
accessibility support text extraction / misc 14.9
Web Capture support misc 14.10
prepress support misc 14.11
document parts,
including GoToDPart action
user interface / misc 14.12
associated files user interface / misc 14.13
Appendix F: Linearized PDF
linearization hints misc F.4