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Tk_FontId(3)		     Tk	Library	Procedures		  Tk_FontId(3)

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NAME
       Tk_FontId,  Tk_GetFontMetrics,  Tk_PostscriptFontName  -	accessor func-
       tions for fonts

SYNOPSIS
       #include	<tk.h>

       Font
       Tk_FontId(tkfont)

       Tk_GetFontMetrics(tkfont, fmPtr)

       int
       Tk_PostscriptFontName(tkfont, dsPtr)

ARGUMENTS
       Tk_Font tkfont (in)		   Opaque font	token  being  queried.
					   Must	have been returned by a	previ-
					   ous call to Tk_GetFont.

       Tk_FontMetrics *fmPtr (out)	   Pointer to structure	in  which  the
					   font	 metrics  for  tkfont  will be
					   stored. See DATA  STRUCTURES	 below
					   for details.

       Tcl_DString *dsPtr (out)		   Pointer     to    an	   initialized
					   Tcl_DString to which	 the  name  of
					   the	Postscript  font  that	corre-
					   sponds to tkfont will be appended.
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DESCRIPTION
       Given a tkfont, Tk_FontId returns the token  that  should  be  selected
       into  an	 XGCValues  structure in order to construct a graphics context
       that can	be used	to draw	text in	the specified font.

       Tk_GetFontMetrics computes the ascent, descent, and  linespace  of  the
       tkfont in pixels	and stores those values	in the structure pointer to by
       fmPtr.  These values can	be used	in computations	such as	to space  mul-
       tiple lines of text, to align the baselines of text in different	fonts,
       and to vertically align text in a given region.	See the	 documentation
       for  the	font command for definitions of	the terms ascent, descent, and
       linespace, used in font metrics.

       Tk_PostscriptFontName maps a tkfont  to	the  corresponding  Postscript
       font  name  that	should be used when printing.  The return value	is the
       size in points of the tkfont and	the Postscript font name  is  appended
       to  dsPtr.   DsPtr  must	 refer to an initialized Tcl_DString.  Given a
       "reasonable" Postscript printer,	the  following	screen	font  families
       should print correctly:

	      Avant  Garde, Arial, Bookman, Courier, Courier New, Geneva, Hel-
	      vetica, Monaco, New Century Schoolbook, New York,	Palatino, Sym-
	      bol, Times, Times	New Roman, Zapf	Chancery, and Zapf Dingbats.

       Any  other  font	 families may not print	correctly because the computed
       Postscript font name may	be incorrect or	not exist on the printer.

DATA STRUCTURES
       The Tk_FontMetrics data structure is used by Tk_GetFontMetrics  to  re-
       turn information	about a	font and is defined as follows:
	      typedef struct Tk_FontMetrics {
		  int ascent;
		  int descent;
		  int linespace;
	      }	Tk_FontMetrics;

       The ascent field	is the amount in pixels	that the tallest letter	sticks
       up above	the baseline, plus any extra blank space added by the designer
       of the font.

       The  descent is the largest amount in pixels that any letter sticks be-
       low the baseline, plus any extra	blank space added by the  designer  of
       the font.

       The  linespace is the sum of the	ascent and descent.  How far apart two
       lines of	text in	the same font should be	placed so  that	 none  of  the
       characters in one line overlap any of the characters in the other line.

SEE ALSO
       font(n),	MeasureChar(3)

KEYWORDS
       font, measurement, Postscript

Tk				      8.0			  Tk_FontId(3)

NAME | SYNOPSIS | ARGUMENTS | DESCRIPTION | DATA STRUCTURES | SEE ALSO | KEYWORDS

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