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Diffstat (limited to 'tk8.6/doc/FontId.3')
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diff --git a/tk8.6/doc/FontId.3 b/tk8.6/doc/FontId.3 new file mode 100644 index 0000000..9d35ae6 --- /dev/null +++ b/tk8.6/doc/FontId.3 @@ -0,0 +1,94 @@ +'\" +'\" Copyright (c) 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. +'\" +.TH Tk_FontId 3 8.0 Tk "Tk Library Procedures" +.so man.macros +.BS +.SH NAME +Tk_FontId, Tk_GetFontMetrics, Tk_PostscriptFontName \- accessor functions for +fonts +.SH SYNOPSIS +.nf +\fB#include <tk.h>\fR +.sp +Font +\fBTk_FontId(\fItkfont\fB)\fR +.sp +\fBTk_GetFontMetrics(\fItkfont, fmPtr\fB)\fR +.sp +int +\fBTk_PostscriptFontName(\fItkfont, dsPtr\fB)\fR +.SH ARGUMENTS +.AS Tk_FontMetrics *dsPtr +.AP Tk_Font tkfont in +Opaque font token being queried. Must have been returned by a previous +call to \fBTk_GetFont\fR. +.AP Tk_FontMetrics *fmPtr out +Pointer to structure in which the font metrics for \fItkfont\fR will +be stored. See \fBDATA STRUCTURES\fR below for details. +.AP Tcl_DString *dsPtr out +Pointer to an initialized \fBTcl_DString\fR to which the name of the +Postscript font that corresponds to \fItkfont\fR will be appended. +.BE +.SH DESCRIPTION +.PP +Given a \fItkfont\fR, \fBTk_FontId\fR 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. +.PP +\fBTk_GetFontMetrics\fR computes the ascent, descent, and linespace of the +\fItkfont\fR in pixels and stores those values in the structure pointer to by +\fIfmPtr\fR. 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 \fBfont\fR command for definitions of the terms +ascent, descent, and linespace, used in font metrics. +.PP +\fBTk_PostscriptFontName\fR maps a \fItkfont\fR to the corresponding +Postscript font name that should be used when printing. The return value +is the size in points of the \fItkfont\fR and the Postscript font name is +appended to \fIdsPtr\fR. \fIDsPtr\fR must refer to an initialized +\fBTcl_DString\fR. Given a +.QW reasonable +Postscript printer, the +following screen font families should print correctly: +.IP +\fBAvant Garde\fR, \fBArial\fR, \fBBookman\fR, \fBCourier\fR, +\fBCourier New\fR, \fBGeneva\fR, \fBHelvetica\fR, \fBMonaco\fR, +\fBNew Century Schoolbook\fR, \fBNew York\fR, \fBPalatino\fR, \fBSymbol\fR, +\fBTimes\fR, \fBTimes New Roman\fR, \fBZapf Chancery\fR, and +\fBZapf Dingbats\fR. +.PP +Any other font families may not print correctly because the computed +Postscript font name may be incorrect or not exist on the printer. +.SH "DATA STRUCTURES" +.PP +The \fBTk_FontMetrics\fR data structure is used by \fBTk_GetFontMetrics\fR to +return information about a font and is defined as follows: +.CS +typedef struct Tk_FontMetrics { + int \fIascent\fR; + int \fIdescent\fR; + int \fIlinespace\fR; +} \fBTk_FontMetrics\fR; +.CE +.PP +The \fIascent\fR 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. +.PP +The \fIdescent\fR 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. +.PP +The \fIlinespace\fR 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. +.SH "SEE ALSO" +font(n), MeasureChar(3) +.SH KEYWORDS +font, measurement, Postscript |