Tk_GetFont(3)
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NAME
Tk_GetFont, Tk_NameOfFont, Tk_FreeFont - maintain database
of fonts
SYNOPSIS
#include <<tk.h>>
Tk_Font
Tk_GetFont(interp, tkwin, string)
char *
Tk_NameOfFont(tkfont)
void
Tk_FreeFont(tkfont)
ARGUMENTS
Tcl_Interp *interp (in) Interpreter to use for
error reporting.
Tk_Window tkwin (in) Token for window on the
display in which font
will be used.
const char *string (in) Name or description of
desired font. See docu-
mentation for the font
command for details on
acceptable formats.
Tk_Font tkfont (in) Opaque font token.
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DESCRIPTION
Tk_GetFont finds the font indicated by string and returns
a token that represents the font. The return value can be
used in subsequent calls to procedures such as Tk_FontMet-
rics, Tk_MeasureChars, and Tk_FreeFont. The token
returned by Tk_GetFont will remain valid until Tk_FreeFont
is called to release it. String can be either a symbolic
name or a font description; see the documentation for the
font command for a description of the valid formats. If
Tk_GetFont is unsuccessful (because, for example, string
was not a valid font specification) then it returns NULL
and stores an error message in interp->result.
Tk_GetFont maintains a database of all fonts it has allo-
cated. If the same string is requested multiple times
(e.g. by different windows or for different purposes),
then additional calls for the same string will be handled
without involving the platform-specific graphics server.
The procedure Tk_NameOfFont is roughly the inverse of
Tk_GetFont. Given a tkfont that was created by Tk_Get-
Font, 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 returned by Tk_GetFont is no longer needed,
Tk_FreeFont should be called to release it. There should
be exactly one call to Tk_FreeFont for each call to
Tk_GetFont. When a font is no longer in use anywhere
(i.e. it has been freed as many times as it has been got-
ten) Tk_FreeFont will release any platform-specific stor-
age and delete it from the database.
KEYWORDS
font