Open RPMSG File

RTF File

RPMSG file format can contain actual e-mail content in several different formats including text, HTML and RTF. RTF is short for Rich Text Format and is a format which was introduced by Microsoft to store documents produced by Microsoft Word. Even though this format is rather old it is still very popular because it supports multiple rich formatting features and is supported by various text editors on different platforms.

Rich Text Format is stored in files with RTF file extension. Each RTF file starts with a “{\rtf1” symbol sequence and ends with “}”. Curly braces are used throughout the RTF file to denote group of similarly formatted text. RTF file includes one or multiple formatting instructions each starting with “\” symbol. Instructions located within curly braces only have power within them.

Text in RTF file could only be stored by 7-bit symbols only. Having 7-bit characters only simplifies transfer of RTF files between different platforms but adds complexities with encoding texts in languages other than English. Symbols outside of 7-bit range could be encoded using escape sequences. For example, Unicode symbols will be encoded using \u escape sequence.

RTF files supports embedding of fonts inside the file but more frequently font table coding is used which allows to reference certain number of supported fonts by their names.

RTF file format supports compression using special algorithm designed by Microsoft to compress RTF control words into a dictionary. This algorithm is described in [MS-OXRTFCP]: Rich Text Format (RTF) Compression Algorithm.

Images in various formats could be embedded into RTF file. Supported format include:

• JPEG
• Portable Network Graphics (PNG)
• Enhanced Metafile (EMF)
• Windows Metafile (WMF)
• Apple PICT
• Windows Device Independent Bitmap (DIB)
• OS/2 Metafile

Specific image format support is dependent on RTF reading and writing software. For greater portability PNG or JPEG formats are mostly used but Microsoft Word may still include original WMF or EMF files in RTF documents.

You can download RTF specification documents from Microsoft via following search query on Microsoft.com website. Full RTF specification is available at http://www.biblioscape.com/rtf15_spec.htm.