Tk_FontId (3)

SYNOPSIS

#include <tk.h>
Font
Tk_FontId(tkfont)
void
Tk_GetFontMetrics(tkfont, fmPtr)
int
Tk_PostscriptFontName(tkfont, dsPtr)

ARGUMENTS

Tk_FontMetrics *dsPtr Tk_Font tkfont in Opaque font token being queried. Must have been returned by a previous call to Tk_GetFont. Tk_FontMetrics *fmPtr out Pointer to structure in which the font metrics for tkfont will be stored. Tcl_DString *dsPtr out Pointer to an initialized Tcl_DString to which the name of the Postscript font that corresponds to tkfont will be appended.

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 multiple 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 Postcript 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, Helvetica, Monaco, New Century Schoolbook, New York, Palatino, Symbol, 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. 8.0 br

DATA STRUCTURES

The Tk_FontMetrics data structure is used by Tk_GetFontMetrics to return information about a font and is defined as follows: typedef struct Tk_FontMetrics { int ascent; int descent; int linespace; } Tk_FontMetrics; The linespace 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 below 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.

KEYWORDS

font '\" '\" Copyright (c) 1995-1996 Sun Microsystems, Inc. '\" '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" '\" RCS: @(#) $Id: QWinEvent.3,v 1.2 1998/09/14 18:22:53 stanton Exp $ '\" '\" The definitions below are for supplemental macros used in Tcl/Tk '\" manual entries. '\" '\" .AP type name in/out ?indent? '\" Start paragraph describing an argument to a library procedure. '\" type is type of argument (int, etc.), in/out is either "in", "out", '\" or "in/out" to describe whether procedure reads or modifies arg, '\" and indent is equivalent to second arg of .IP (shouldn't ever be '\" needed; use .AS below instead) '\" '\" .AS ?type? ?name? '\" Give maximum sizes of arguments for setting tab stops. Type and '\" name are examples of largest possible arguments that will be passed '\" to .AP later. If args are omitted, default tab stops are used. '\" '\" .BS '\" Start box enclosure. From here until next .BE, everything will be '\" enclosed in one large box. '\" '\" .BE '\" End of box enclosure. '\" '\" .CS '\" Begin code excerpt. '\" '\" .CE '\" End code excerpt. '\" '\" .VS ?version? ?br? '\" Begin vertical sidebar, for use in marking newly-changed parts '\" of man pages. The first argument is ignored and used for recording '\" the version when the .VS was added, so that the sidebars can be '\" found and removed when they reach a certain age. If another argument '\" is present, then a line break is forced before starting the sidebar. '\" '\" .VE '\" End of vertical sidebar. '\" '\" .DS '\" Begin an indented unfilled display. '\" '\" .DE '\" End of indented unfilled display. '\" '\" .SO '\" Start of list of standard options for a Tk widget. The '\" options follow on successive lines, in four columns separated '\" by tabs. '\" '\" .SE '\" End of list of standard options for a Tk widget. '\" '\" .OP cmdName dbName dbClass '\" Start of description of a specific option. cmdName gives the '\" option's name as specified in the class command, dbName gives '\" the option's name in the option database, and dbClass gives '\" the option's class in the option database. '\" '\" .UL arg1 arg2 '\" Print arg1 underlined, then print arg2 normally. '\" '\" RCS: @(#) $Id: man.macros,v 1.2 1998/09/14 18:39:54 stanton Exp $ '\" '\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages. t .wh -1.3i ^B ^l \n(.l b '\" # Start an argument description AP !"\\$4"" .TP \\$4 \{\ !"\\$2"" .TP \\n()Cu .TP 15