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Freetype
From The Linux Foundation
Contents |
libFreeType2
Description
From http://freetype.sourceforge.net/freetype2/index.html
FreeType 2 is a software font engine that is designed to be small, efficient, highly customizable and portable while capable of producing high-quality output (glyph images). It can be used in graphics libraries, display servers, font conversion tools, text image generation tools, and many other products as well.
Note that FreeType 2 is a font service and doesn't provide APIs to perform higher-level features, like text layout or graphics processing (e.g. colored text rendering, "hollowing", etc.) However, it greatly simplifies these tasks by providing a simple, easy to use and uniform interface to access the content of font files.
Features
The following is a non-exhaustive list of features provided by FreeType 2:
- FreeType 2 provides a simple and easy-to-use API to access font content in a uniform way, independently of the file format. Additionally, some format-specific APIs can be used to access special data in the font file.
- FreeType 2 supports scalable font formats like TrueType or Type 1 natively and can return the outline data (and control instructions/hints) to client applications.
- By default, FreeType 2 supports the following font formats:
- TrueType fonts (and collections)
- Type 1 fonts
- CID-keyed Type 1 fonts
- CFF fonts
- OpenType fonts (both TrueType and CFF variants)
- SFNT-based bitmap fonts
- X11 PCF fonts
- Windows FNT fonts
- BDF fonts (including anti-aliased ones)
- PFR fonts
- Type42 fonts (limited support)
- From a given glyph outline, FreeType 2 is capable of producing a high-quality monochrome bitmap, or anti-aliased pixmap, using 256 levels of "gray". This is much better than the 5 levels used by Windows 9x/98/NT/2000 or FreeType 1.
- FreeType 2 supports all the character mappings defined by the TrueType and OpenType specification. It is also capable of automatically synthesizing a Unicode charmap from Type 1 fonts, which puts an end to the painful "encoding translation" headache common with this format (of course, original encodings are also available in the case where you need them..).
- The FreeType 2 core API provides simple functions to access advanced information like glyph names or kerning data.
- FreeType2 includes a full-featured and efficient TrueType bytecode interpreter that can produce excellent output at small point sizes.
- For those who don't need or want to use the bytecode interpreter for TrueType fonts, FreeType has developed an automatic hinter module. It is also used by other scalable formats.
- FreeType 2 provides information that is often not available from other similar font engines, like kerning distances, glyph names, vertical metrics, etc.
Requirements
FreeType 2 is written in industry-standard ANSI C and should compile easily with any compliant C compiler with no warnings.
Apart from a standard ANSI C library, FreeType 2 doesn't have any external dependencies and can be compiled and installed on its own on any kind of system.
Patents issues
Some parts of the TrueType specification are covered by patents owned by Apple Computer. A default build of the FreeType 2 sources will not use any of the patented techniques to render TrueType glyphs.
For more information, see: http://freetype.sourceforge.net/patents.html
Future Tracker
This library is tracked on futures here - http://www.linuxbase.org/futures/candidates/freetype/index.html
List of apps and libraries using this library
According to Keith Packard,
- Essentially every current X application uses FreeType; it is the
- standard font access mechanism for Gtk+, Qt, Mozilla and OpenOffice
- based applications.
- It is also used by the X server to rasterize outline fonts, and will
- (someday) be used as the exclusive font access mechanism within the X
- server as PCF and BDF format fonts are retired in favor of the more
- efficient SFNT format.
- It's hard to find a more central library within the system than FreeType
- for desktop computing.
API documentation
There is a collection of papers documenting FreeType 2 at http://freetype.sourceforge.net/freetype2/documentation.html
API documentation can be found at http://freetype.sourceforge.net/freetype2/docs/reference/ft2-toc.html
Related test suites
There are no known test cases.
Library analysis data
Raw data included here: FreeTypeData.txt
Most commonly used interfaces
Any test suite should include all of the stable interfaces in the specification.
Validation and caching code should be excluded: According to an email from David Turner (freetype developer) the code for otvalid and gxvalid is experimental and the cache subsystem is considered to be "in beta."
Interfaces chosen for LSB
According to http://freetype.sourceforge.net/freetype2/docs/design/design-2.html applications primarily use the base layer API. This is the library that should be added to the specification first. Research also shows the Glyph library is popular and should be considered in the future.
According to an email from David Turner (freetype developer) the API has been stable since v 2.1.5 which was released 9/2/2003. (Note that the API for the beta caching subsystem is not stable.)
| Base Layer | ||||
| FT_Set_Char_Size | 8 | FT_Set_Pixel_Sizes | 8 | |
| FT_Load_Glyph | 16 | FT_Load_Char | 0 | |
| FT_STYLE_FLAG_XXX | 0 | FT_LOAD_XXX | 0 | |
| FT_Set_Transform | 8 | FT_Render_Mode | 0 | |
| ft_render_mode_xxx | 0 | FT_Render_Glyph | 11 | |
| FT_Kerning_Mode | 0 | ft_kerning_default | 0 | |
| FT_Init_FreeType | 16 | ft_kerning_unfitted | 0 | |
| FT_Library_Version | 0 | ft_kerning_unscaled | 0 | |
| FT_Done_FreeType | 11 | FT_Get_Kerning | 1 | |
| FT_OPEN_XXX | 0 | FT_Get_Glyph_Name | 0 | |
| FT_Parameter | 0 | FT_Get_Postscript_Name | 5 | |
| FT_Open_Args | 0 | FT_Select_Charmap | 6 | |
| FT_New_Face | 17 | FT_Set_Charmap | 7 | |
| FT_New_Memory_Face | 0 | FT_Get_Charmap_Index | 1 | |
| FT_Open_Face | 2 | FT_Get_Char_Index | 9 | |
| FT_Attach_File | 0 | FT_Get_First_Char | 0 | |
| FT_Attach_Stream | 0 | FT_Get_Next_Char | 0 | |
| FT_Done_Face | 17 | FT_Get_Name_Index | 8 |
| Non Base Layer | |||
| FT_Activate_Size | 4 | ||
| FT_Add_Default_Modules | 1 | ||
| FT_Done_Glyph | 6 | ||
| FT_Done_Library | 1 | ||
| FT_Done_Size | 4 | ||
| FT_Get_BDF_Charset_ID | 4 | ||
| FT_Get_BDF_Property | 1 | ||
| FT_Get_Glyph | 8 | ||
| FT_Get_MM_Var | 1 | ||
| FT_Get_PS_Font_Info | 6 | ||
| FT_Get_Sfnt_Name | 8 | ||
| FT_Get_Sfnt_Name_Count | 7 | ||
| FT_Get_Sfnt_Table | 6 | ||
| FT_Get_X11_Font_Format | 4 | ||
| FT_Glyph_Copy | 1 | ||
| FT_Glyph_Get_CBox | 1 | ||
| FT_Glyph_Stroke | 1 | ||
| FT_Glyph_To_Bitmap | 3 | ||
| FT_Has_PS_Glyph_Names | 5 | ||
| FT_MulDiv | 1 | ||
| FT_MulFix | 4 | ||
| FT_New_Library | 1 | ||
| FT_New_Size | 6 | ||
| FT_Outline_Decompose | 5 | ||
| FT_Outline_Get_BBox | 4 | ||
| FT_Set_Var_Design_Coordin | 1 | ||
| FT_Stream_Pos | 4 | ||
| FT_Stream_Seek | 4 | ||
| FT_Stroker_Done | 1 | ||
| FT_Stroker_New | 1 | ||
| FT_Stroker_Set | 1 | ||
| FT_Vector_Transform | 7 |
Other information
Uncategorized information goes here