Tk_GetFont(3) Tk Library Procedures Tk_GetFont(3)______________________________________________________________________________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 report‐
ing.
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.
_________________________________________________________________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 descrip‐
tion 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 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 got‐
ten) Tk_FreeFont will release any platform-specific storage and delete
it from the database.
KEYWORDS
font
TkTk_GetFont(3)
