Tk_GetFont(3) Tk 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
documentation 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_FontMetrics, 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
allocated. If the same string is requested multiple times
(e.g. by different windows or for different purposes), then
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Tk_GetFont(3) Tk Tk_GetFont(3)
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_GetFont,
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 gotten) Tk_FreeFont will
release any platform-specific storage and delete it from the
database.
KEYWORDS
font
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