196 lines
7.3 KiB
Groff
196 lines
7.3 KiB
Groff
.\" Copyright \(co 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1994, 1996 X Consortium
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.\"
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.\" Permission is hereby granted, free of charge, to any person obtaining
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.\" a copy of this software and associated documentation files (the
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.\" "Software"), to deal in the Software without restriction, including
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.\" without limitation the rights to use, copy, modify, merge, publish,
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.\" distribute, sublicense, and/or sell copies of the Software, and to
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.\" permit persons to whom the Software is furnished to do so, subject to
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.\" the following conditions:
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.\"
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.\" The above copyright notice and this permission notice shall be included
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.\" in all copies or substantial portions of the Software.
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.\"
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.\" THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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.\" OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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.\" MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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.\" IN NO EVENT SHALL THE X CONSORTIUM BE LIABLE FOR ANY CLAIM, DAMAGES OR
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.\" OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
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.\" ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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.\" OTHER DEALINGS IN THE SOFTWARE.
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.\"
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.\" Except as contained in this notice, the name of the X Consortium shall
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.\" not be used in advertising or otherwise to promote the sale, use or
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.\" other dealings in this Software without prior written authorization
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.\" from the X Consortium.
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.\"
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.\" Copyright \(co 1985, 1986, 1987, 1988, 1989, 1990, 1991 by
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.\" Digital Equipment Corporation
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.\"
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.\" Portions Copyright \(co 1990, 1991 by
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.\" Tektronix, Inc.
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.\"
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.\" Permission to use, copy, modify and distribute this documentation for
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.\" any purpose and without fee is hereby granted, provided that the above
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.\" copyright notice appears in all copies and that both that copyright notice
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.\" and this permission notice appear in all copies, and that the names of
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.\" Digital and Tektronix not be used in in advertising or publicity pertaining
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.\" to this documentation without specific, written prior permission.
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.\" Digital and Tektronix makes no representations about the suitability
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.\" of this documentation for any purpose.
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.\" It is provided "as is" without express or implied warranty.
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.\"
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.\"
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.ds xT X Toolkit Intrinsics \- C Language Interface
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.ds xW Athena X Widgets \- C Language X Toolkit Interface
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.ds xL Xlib \- C Language X Interface
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.ds xC Inter-Client Communication Conventions Manual
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.TH XTextExtents __libmansuffix__ __xorgversion__ "XLIB FUNCTIONS"
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.SH NAME
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XTextExtents, XTextExtents16, XQueryTextExtents, XQueryTextExtents16 \- compute or query text extents
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.SH SYNTAX
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.HP
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int XTextExtents\^(\^XFontStruct *\fIfont_struct\fP\^, _Xconst char *\fIstring\fP\^,
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int \fInchars\fP\^, int *\fIdirection_return\fP\^, int
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*\fIfont_ascent_return\fP, int *\fIfont_descent_return\fP\^, XCharStruct
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*\fIoverall_return\fP\^);
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.HP
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int XTextExtents16\^(\^XFontStruct *\fIfont_struct\fP\^, _Xconst XChar2b
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*\fIstring\fP\^, int \fInchars\fP\^, int *\fIdirection_return\fP\^, int
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*\fIfont_ascent_return\fP, int *\fIfont_descent_return\fP\^, XCharStruct
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*\fIoverall_return\fP\^);
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.HP
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int XQueryTextExtents\^(\^Display *\fIdisplay\fP\^, XID \fIfont_ID\fP\^, _Xconst char
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*\fIstring\fP\^, int \fInchars\fP\^, int *\fIdirection_return\fP\^, int
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*\fIfont_ascent_return\fP, int *\fIfont_descent_return\fP\^, XCharStruct
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*\fIoverall_return\fP\^);
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.HP
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int XQueryTextExtents16\^(\^Display *\fIdisplay\fP\^, XID \fIfont_ID\fP\^,
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_Xconst XChar2b *\fIstring\fP\^, int \fInchars\fP\^, int *\fIdirection_return\fP\^,
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int *\fIfont_ascent_return\fP, int *\fIfont_descent_return\fP\^, XCharStruct
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*\fIoverall_return\fP\^);
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.SH ARGUMENTS
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.IP \fIdirection_return\fP 1i
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Returns the value of the direction hint
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.RB ( FontLeftToRight
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or
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.BR FontRightToLeft ).
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.IP \fIdisplay\fP 1i
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Specifies the connection to the X server.
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.IP \fIfont_ID\fP 1i
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Specifies either the font ID or the
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.B GContext
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ID that contains the font.
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.IP \fIfont_ascent_return\fP 1i
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Returns the font ascent.
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.IP \fIfont_descent_return\fP 1i
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Returns the font descent.
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.IP \fIfont_struct\fP 1i
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Specifies the
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.B XFontStruct
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structure.
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.IP \fInchars\fP 1i
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Specifies the number of characters in the character string.
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.IP \fIstring\fP 1i
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Specifies the character string.
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.IP \fIoverall_return\fP 1i
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Returns the overall size in the specified
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.B XCharStruct
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structure.
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.SH DESCRIPTION
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The
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.B XTextExtents
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and
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.B XTextExtents16
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functions
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perform the size computation locally and, thereby,
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avoid the round-trip overhead of
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.B XQueryTextExtents
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and
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.BR XQueryTextExtents16 .
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Both functions return an
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.B XCharStruct
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structure, whose members are set to the values as follows.
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.LP
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The ascent member is set to the maximum of the ascent metrics of all
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characters in the string.
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The descent member is set to the maximum of the descent metrics.
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The width member is set to the sum of the character-width metrics of all
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characters in the string.
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For each character in the string,
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let W be the sum of the character-width metrics of all characters preceding
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it in the string.
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Let L be the left-side-bearing metric of the character plus W.
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Let R be the right-side-bearing metric of the character plus W.
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The lbearing member is set to the minimum L of all characters in the string.
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The rbearing member is set to the maximum R.
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.LP
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For fonts defined with linear indexing rather than 2-byte matrix indexing,
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each
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.B XChar2b
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structure is interpreted as a 16-bit number with byte1 as the
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most significant byte.
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If the font has no defined default character,
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undefined characters in the string are taken to have all zero metrics.
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.LP
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The
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.B XQueryTextExtents
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and
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.B XQueryTextExtents16
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functions return the bounding box of the specified 8-bit and 16-bit
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character string in the specified font or the font contained in the
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specified GC.
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These functions query the X server and, therefore, suffer the round-trip
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overhead that is avoided by
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.B XTextExtents
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and
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.BR XTextExtents16 .
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Both functions return a
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.B XCharStruct
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structure, whose members are set to the values as follows.
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.LP
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The ascent member is set to the maximum of the ascent metrics
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of all characters in the string.
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The descent member is set to the maximum of the descent metrics.
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The width member is set to the sum of the character-width metrics
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of all characters in the string.
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For each character in the string,
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let W be the sum of the character-width metrics of all characters preceding
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it in the string.
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Let L be the left-side-bearing metric of the character plus W.
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Let R be the right-side-bearing metric of the character plus W.
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The lbearing member is set to the minimum L of all characters in the string.
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The rbearing member is set to the maximum R.
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.LP
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For fonts defined with linear indexing rather than 2-byte matrix indexing,
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each
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.B XChar2b
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structure is interpreted as a 16-bit number with byte1 as the
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most significant byte.
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If the font has no defined default character,
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undefined characters in the string are taken to have all zero metrics.
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.LP
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Characters with all zero metrics are ignored.
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If the font has no defined default_char,
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the undefined characters in the string are also ignored.
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.LP
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.B XQueryTextExtents
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and
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.B XQueryTextExtents16
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can generate
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.B BadFont
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and
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.B BadGC
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errors.
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.SH DIAGNOSTICS
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.TP 1i
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.B BadFont
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A value for a Font or GContext argument does not name a defined Font.
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.TP 1i
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.B BadGC
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A value for a GContext argument does not name a defined GContext.
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.SH "SEE ALSO"
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XLoadFont(__libmansuffix__),
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XTextWidth(__libmansuffix__)
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.br
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\fI\*(xL\fP
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