Unimplemented Features in Xpdf
This list corresponds to Xpdf 4.04.05 and PDF 2.0.
Categories are as follows:
- appearance: features which affect document content appearance
- optional appearance: features which have optional effects on document appearance
- color management: features which affect color management (or other output device effects)
- transparency: transparency-related features
- user interface: features which affect the Xpdf user interface
- text extraction: features which affect text extraction only
- PostScript generation: features which affect PostScript generation only
- error checking: situations where an error (or warning) should be reported
- misc: anything that doesn't fit in any of the other categories
| 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 | 7.6.4.2 |
| public-key security handlers | appearance | 7.6.5 |
| crypt filters (partially implemented) |
appearance | 7.4.10 7.6.6 |
| 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 | 7.7.3.3 |
| 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 | 8.6.6.5 |
| DeviceN color space attributes (partially implemented) |
color management | 8.6.6.5 |
| 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 | 8.9.5.1 8.9.5.3 |
| 'SMaskInData' field for JPX images | transparency | 8.9.5.1 |
| alternate images | optional appearance | 8.9.5.4 |
| reference XObjects | optional appearance | 8.10.4 |
| optional content auto state (usage and usage application dicts) | optional appearance / user interface | 8.11.4.4 |
| Chapter 9: Text | ||
| text knockout | transparency | 9.3.8 |
| FD entry in CIDFont FontDescriptor | misc | 9.8.3.3 |
| Chapter 10: Rendering | ||
| black generation and undercolor removal (when converting DeviceRGB to DeviceCMYK) | color management | 10.4.2.3 |
| 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 11.6.6 |
| 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 11.6.5 11.6.6 11.7.2 |
| shape vs. opacity; the "alpha is shape" (AIS) flag | transparency | 11.6.4 |
| transfer function for soft masks | transparency | 11.6.5.1 |
| 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 |
| structure destinations | user interface | 12.3.2.3 |
| 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 12.3.6 |
| 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 13.3 13.4 13.7 |
| 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 14.8 |
| accessibility support | text extraction / misc | 14.9 |
| Web Capture support | misc | 14.10 (deprecated) |
| prepress support | misc | 14.11 |
| document parts, including GoToDPart action |
user interface / misc | 14.12 12.6.4.5 |
| associated files | user interface / misc | 14.13 |
| Appendix F: Linearized PDF | ||
| linearization hints | misc | F.4 |