Tk_GetFontStruct(3) Tk Library Procedures Tk_GetFontStruct(3)_________________________________________________________________NAME
Tk_GetFontStruct, Tk_NameOfFontStruct, Tk_FreeFontStruct -
maintain database of fonts
SYNOPSIS
#include <tk.h>
XFontStruct *
Tk_GetFontStruct(interp, tkwin, nameId)
char *
Tk_NameOfFontStruct(fontStructPtr)Tk_FreeFontStruct(fontStructPtr)ARGUMENTS
Tcl_Interp *interp (in) Interpreter to
use for error
reporting.
Tk_Window tkwin (in) Token for window
in which font
will be used.
Tk_Uid nameId (in) Name of desired
font.
XFontStruct *fontStructPtr (in) Font structure to
return name for
or delete.
_________________________________________________________________DESCRIPTION
Tk_GetFont loads the font indicated by nameId and returns
a pointer to information about the font. The pointer
returned by Tk_GetFont will remain valid until Tk_FreeFont
is called to release it. NameId can be either a font name
or pattern; any value that could be passed to XLoadQuery-
Font may be passed to Tk_GetFont. If Tk_GetFont is unsuc-
cessful (because, for example, there is no font corre-
sponding to nameId) 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 nameId is requested multiple times
(e.g. by different windows or for different purposes),
then additional calls for the same nameId will be handled
very quickly, without involving the X server. For this
reason, it is generally better to use Tk_GetFont in place
of X library procedures like XLoadQueryFont.
Tk 1
Tk_GetFontStruct(3) Tk Library Procedures Tk_GetFontStruct(3)
The procedure Tk_NameOfFontStruct is roughly the inverse
of Tk_GetFontStruct. If its fontStructPtr argument was
created by Tk_GetFontStruct, then the return value is the
nameId argument that was passed to Tk_GetFontStruct to
create the font. If fontStructPtr was not created by a
call to Tk_GetFontStruct, then the return value is a hex-
adecimal string giving the X identifier for the associated
font. Note: the string returned by Tk_NameOfFontStruct
is only guaranteed to persist until the next call to
Tk_NameOfFontStruct.
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 it to the X server and
delete it from the database.
KEYWORDS
font
Tk 2
