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tk_getfontfromobj(3tk) [opensolaris man page]

Tk_AllocFontFromObj(3TK)				       Tk Library Procedures					  Tk_AllocFontFromObj(3TK)

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NAME
Tk_AllocFontFromObj, Tk_GetFont, Tk_GetFontFromObj, Tk_NameOfFont, Tk_FreeFontFromObj, Tk_FreeFont - maintain database of fonts SYNOPSIS
#include <tk.h> Tk_Font | Tk_AllocFontFromObj(interp, tkwin, objPtr) | Tk_Font | Tk_GetFont(interp, tkwin, string) | Tk_Font | Tk_GetFontFromObj(tkwin, objPtr) | CONST char * Tk_NameOfFont(tkfont) Tk_Font | Tk_FreeFontFromObj(tkwin, objPtr) | void Tk_FreeFont(tkfont) ARGUMENTS
Tcl_Interp *interp (in) Interpreter to use for error reporting. If NULL, then no error messages are left after errors. Tk_Window tkwin (in) Token for window in which font will be used. Tcl_Obj *objPtr (in/out) | Gives name or description of font. See documentation for the font command for details on acceptable for- | mats. Internal rep will be modified to cache corresponding Tk_Font. | const char *string (in) | Same as objPtr except description of font is passed as a string and resulting Tk_Font isn't cached. Tk_Font tkfont (in) Opaque font token. _________________________________________________________________ DESCRIPTION
Tk_AllocFontFromObj finds the font indicated by objPtr and returns a token that represents the font. The return value can be used in sub- | sequent calls to procedures such as Tk_GetFontMetrics, Tk_MeasureChars, and Tk_FreeFont. The Tk_Font token will remain valid until | Tk_FreeFontFromObj or Tk_FreeFont is called to release it. ObjPtr can contain either a symbolic name or a font description; see the docu- | mentation for the font command for a description of the valid formats. If Tk_AllocFontFromObj is unsuccessful (because, for example, | objPtr did not contain a valid font specification) then it returns NULL and leaves an error message in interp's result if interp isn't | NULL. Tk_AllocFontFromObj caches information about the return value in objPtr, which speeds up future calls to procedures such as | Tk_AllocFontFromObj and Tk_GetFontFromObj. | Tk_GetFont is identical to Tk_AllocFontFromObj except that the description of the font is specified with a string instead of an object. | This prevents Tk_GetFont from caching the matching Tk_Font, so Tk_GetFont is less efficient than Tk_AllocFontFromObj. | Tk_GetFontFromObj returns the token for an existing font, given the window and description used to create the font. Tk_GetFontFromObj | doesn't actually create the font; the font must already have been created with a previous call to Tk_AllocFontFromObj or Tk_GetFont. The | return value is cached in objPtr, which speeds up future calls to Tk_GetFontFromObj with the same objPtr and tkwin. Tk_AllocFontFromObj and Tk_GetFont maintain a database of all fonts they have allocated. If the same font is requested multiple times (e.g. by different windows or for different purposes), then a single Tk_Font will be shared for all uses. The underlying resources will be freed automatically when no-one is using the font anymore. The procedure Tk_NameOfFont is roughly the inverse of Tk_GetFont. Given a tkfont that was created by Tk_GetFont (or Tk_AllocFontFromObj), the return value is the string argument that was passed to Tk_GetFont to create the font. The string returned by Tk_NameOfFont is only guaranteed to persist until the tkfont is deleted. The caller must not modify this string. When a font is no longer needed, Tk_FreeFontFromObj or Tk_FreeFont should be called to release it. For Tk_FreeFontFromObj the font to | release is specified with the same information used to create it; for Tk_FreeFont the font to release is specified with its Tk_Font token. | There should be exactly one call to Tk_FreeFontFromObj or Tk_FreeFont for each call to Tk_AllocFontFromObj or Tk_GetFont. SEE ALSO
Tk_FontId(3TK) KEYWORDS
font ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +--------------------+-----------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +--------------------+-----------------+ |Availability | SUNWTk | +--------------------+-----------------+ |Interface Stability | Uncommitted | +--------------------+-----------------+ NOTES
Source for Tk is available on http://opensolaris.org. Tk 8.1 Tk_AllocFontFromObj(3TK)
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