SNP File Format
From Wikipedia, the free encyclopedia
| Snapshot File | |
|---|---|
| File name extension | .snp |
| Developed by | Microsoft |
| Type of format | Access report output, multi-page, precise |
| Container for | EMF (contained pages) |
| Contained by | CAB (compression wrapper) |
The SNP file format is used by Microsoft Access to store Report Snapshots in a single file which can be viewed and printed by the Microsoft Snapshot Viewer, available as a free download from Microsoft (runs on Windows only). This allows report output to be exported and viewed on Windows computers which do not have Microsoft Access installed.
Contents |
[edit] File Format
SNP files are based on the Microsoft Compound File Binary Format (CFBF), which is also the basis for the Advanced Authoring Format (AAF)[1]. CFBF is a reasonably simple container format which can store multiple files, directories and so on. For SNP files, Access uses CFBF to store each page as a separate Enhanced Metafile (EMF) containing all of the graphics commands required to reproduce the page. Since CFBF files are not compressed, Microsoft's CAB format is used to reduce the size of the CFBF, resulting in a compact file format which may be only a few kilobytes in size for each page of text and simple graphics - lines, boxes, etc.
Working with the pages of an SNP file programmatically involves the following steps:
- Extract contents of SNP file using CAB decompression routines (such as the Windows API "SetupDecompressOrCopyFile" from the "SetupAPI" library)
- Open the resulting file "_AccRpt_.snp" as a CFBF file
- Enumerate the files in the CFBF to find the EMF files for each page
- Extract the EMF file(s) from the CFBF for the desired page(s)
The resultant EMF files are suitable for display or import in a number of graphics programs, can be added to Word documents, Powerpoint presentations, etc. This is useful especially because there is limited or no support for SNP files in most places where EMF files can be used.
The above can be implemented in Visual Basic for Applications, which gives Access developers the ability to create custom report interfaces by loading the EMF files into Image objects and so on.
[edit] Disclaimer & License
The investigation of the SNP file format which lead to the above information was conducted with information and tools which are freely available online. The author therefore believes that the above does not represent any breach of copyright or infringement on the intellectual property of any person or organisation. As such the Author explicitly agrees to license this article under the GFDL.
Licensing information for the SNP[2], CAB[3] and AAF[4] are probably available from their respective creators/owners.
[edit] References
The following references relate to the Compound File Binary Format format:
- Microsoft Compound Document File Format (PDF). OpenOffice.org CFBF description. Retrieved on 2006-05-22.
- Advanced Authoring Format Low-Level Container Specification (PDF). Microsoft Structured Storage version 3 specification (PDF). Retrieved on 2006-05-22.
[edit] See also
[edit] External links
- Microsoft Snapshot Viewer
