OPEN FONT FORMAT
TrueType format is an outline font standard originally developed by Apple Computer in the late 1980s which was later licensed to Microsoft. OpenType was built on TrueType, retaining TrueType's basic structure and adding many intricate data structures for prescribing typographic behavior.
OpenType is a registered trademark of Microsoft Corporation. Open Font format is extension of Open Type format. International Organization for Standardization (ISO) had adopted OpenType 1.4 for adoption of the new standard called Open Font Format (OFF). The second edition of the Open Font Format was published in 2009 (ISO/IEC 14496-22:2009) and it is declared as "technically equivalent" to the "OpenType font format specification". It is a free, publicly available standard. OFF fonts may have extensions .OTF, .TTF or .TTC depending on the type of outlines in the font. The OpenType format is a superset of the existing TrueType font formats. It provides improved cross-platform document portability, rich linguistic support, powerful typographic capabilities, and simplified font management requirements.
OpenType support consists of three types: basic OpenType support (the fonts work like any other fonts); Unicode support (access to extended language character sets); and OpenType layout support (support for advanced typographic features). Some operating systems (or operating system extensions) can provide support for one or more of these, but support for Unicode and layout features requires that an application be programmed to provide this functionality.
OTF and OFF are technically synonymous. OTF/OFF based fonts developed by C-DAC have been made available in the language CDs and also downloadable from http://www.ildc.in which work on both windows and Linux. Sakal Bharati is OTF which supports all 22 Indian Languages maintaining same height and width across languages. Sakal Bharati font can be downloaded from TDIL-DC Portal.