- 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
- DESCRIPTION
- SEE ALSO
- KEYWORDS
Tk_AllocFontFromObj, Tk_GetFont, Tk_GetFontFromObj, Tk_NameOfFont, Tk_FreeFontFromObj, Tk_FreeFont — maintain database of fonts
#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)
- 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 formats.
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 is not cached.
- Tk_Font tkfont (in)
-
Opaque font token.
Tk_AllocFontFromObj finds the font indicated by objPtr and
returns a token that represents the font. The return value can be used
in subsequent 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 documentation 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 is not 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 does not 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.
Tk_FontId
font
Copyright © 1990-1992 The Regents of the University of California.
Copyright © 1994-1998 Sun Microsystems, Inc.