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<refmeta>
<refentrytitle>XTextExtents</refentrytitle>
<manvolnum>3X11</manvolnum>
<refmiscinfo class='date'>__xorgversion__</refmiscinfo>
<refmiscinfo class='source'>XLIB FUNCTIONS</refmiscinfo>
</refmeta>
<refnamediv id='name'>
<refname>XTextExtents</refname>
<refname>XTextExtents16</refname>
<refname>XQueryTextExtents</refname>
<refname>XQueryTextExtents16</refname>
<refpurpose>compute or query text extents</refpurpose>
</refnamediv>
<!-- body begins here -->

<refsect1 id='syntax'><title>SYNTAX</title>

<para>int XTextExtents&hairsp;(&hairsp;XFontStruct *<emphasis remap='I'>font_struct</emphasis>&hairsp;, char *<emphasis remap='I'>string</emphasis>&hairsp;,
int <emphasis remap='I'>nchars</emphasis>&hairsp;, int *<emphasis remap='I'>direction_return</emphasis>&hairsp;, int
*<emphasis remap='I'>font_ascent_return</emphasis>, int *<emphasis remap='I'>font_descent_return</emphasis>&hairsp;, XCharStruct
*<emphasis remap='I'>overall_return</emphasis>&hairsp;);</para> 

<para>int XTextExtents16&hairsp;(&hairsp;XFontStruct *<emphasis remap='I'>font_struct</emphasis>&hairsp;, XChar2b
*<emphasis remap='I'>string</emphasis>&hairsp;, int <emphasis remap='I'>nchars</emphasis>&hairsp;, int *<emphasis remap='I'>direction_return</emphasis>&hairsp;, int
*<emphasis remap='I'>font_ascent_return</emphasis>, int *<emphasis remap='I'>font_descent_return</emphasis>&hairsp;, XCharStruct
*<emphasis remap='I'>overall_return</emphasis>&hairsp;);</para> 

<para>int XQueryTextExtents&hairsp;(&hairsp;Display *<emphasis remap='I'>display</emphasis>&hairsp;, XID <emphasis remap='I'>font_ID</emphasis>&hairsp;, char
*<emphasis remap='I'>string</emphasis>&hairsp;, int <emphasis remap='I'>nchars</emphasis>&hairsp;, int *<emphasis remap='I'>direction_return</emphasis>&hairsp;, int
*<emphasis remap='I'>font_ascent_return</emphasis>, int *<emphasis remap='I'>font_descent_return</emphasis>&hairsp;, XCharStruct
*<emphasis remap='I'>overall_return</emphasis>&hairsp;);</para>

<para>int XQueryTextExtents16&hairsp;(&hairsp;Display *<emphasis remap='I'>display</emphasis>&hairsp;, XID <emphasis remap='I'>font_ID</emphasis>&hairsp;,
XChar2b *<emphasis remap='I'>string</emphasis>&hairsp;, int <emphasis remap='I'>nchars</emphasis>&hairsp;, int *<emphasis remap='I'>direction_return</emphasis>&hairsp;,
int *<emphasis remap='I'>font_ascent_return</emphasis>, int *<emphasis remap='I'>font_descent_return</emphasis>&hairsp;, XCharStruct
*<emphasis remap='I'>overall_return</emphasis>&hairsp;);</para> 
</refsect1>

<refsect1 id='arguments'><title>ARGUMENTS</title>
<variablelist remap='IP'>
  <varlistentry>
  <term><emphasis remap='I'>direction_return</emphasis></term>
  <listitem>
<para>Returns the value of the direction hint
(<emphasis remap='I'>&hairsp;FontLeftToRight&hairsp;</emphasis>
or
<emphasis remap='I'>&hairsp;FontRightToLeft&hairsp;</emphasis>).</para>
  </listitem>
  </varlistentry>
  <varlistentry>
  <term><emphasis remap='I'>display</emphasis></term>
  <listitem>
<para>Specifies the connection to the X server.</para>
  </listitem>
  </varlistentry>
  <varlistentry>
  <term><emphasis remap='I'>font_ID</emphasis></term>
  <listitem>
<para>Specifies either the font ID or the 
<emphasis remap='I'>&hairsp;GContext&hairsp;</emphasis>
ID that contains the font.</para>
  </listitem>
  </varlistentry>
  <varlistentry>
  <term><emphasis remap='I'>font_ascent_return</emphasis></term>
  <listitem>
<para>Returns the font ascent.</para>
  </listitem>
  </varlistentry>
  <varlistentry>
  <term><emphasis remap='I'>font_descent_return</emphasis></term>
  <listitem>
<para>Returns the font descent.</para>
  </listitem>
  </varlistentry>
  <varlistentry>
  <term><emphasis remap='I'>font_struct</emphasis></term>
  <listitem>
<para>Specifies the 
<emphasis remap='I'>&hairsp;XFontStruct&hairsp;</emphasis>
structure.</para>
  </listitem>
  </varlistentry>
  <varlistentry>
  <term><emphasis remap='I'>nchars</emphasis></term>
  <listitem>
<para>Specifies the number of characters in the character string.</para>
  </listitem>
  </varlistentry>
  <varlistentry>
  <term><emphasis remap='I'>string</emphasis></term>
  <listitem>
<para>Specifies the character string.</para>
  </listitem>
  </varlistentry>
  <varlistentry>
  <term><emphasis remap='I'>overall_return</emphasis></term>
  <listitem>
<para>Returns the overall size in the specified
<emphasis remap='I'>&hairsp;XCharStruct&hairsp;</emphasis>
structure.</para>
  </listitem>
  </varlistentry>
</variablelist>
</refsect1>

<refsect1 id='description'><title>DESCRIPTION</title>
<para>The
<emphasis remap='I'>&hairsp;XTextExtents&hairsp;</emphasis>
and
<emphasis remap='I'>&hairsp;XTextExtents16&hairsp;</emphasis>
functions 
perform the size computation locally and, thereby,
avoid the round-trip overhead of
<emphasis remap='I'>&hairsp;XQueryTextExtents&hairsp;</emphasis>
and
<emphasis remap='I'>&hairsp;XQueryTextExtents16&hairsp;</emphasis>.
Both functions return an
<emphasis remap='I'>&hairsp;XCharStruct&hairsp;</emphasis>
structure, whose members are set to the values as follows.</para>

<para>The ascent member is set to the maximum of the ascent metrics of all
characters in the string.
The descent member is set to the maximum of the descent metrics.
The width member is set to the sum of the character-width metrics of all
characters in the string.
For each character in the string,
let W be the sum of the character-width metrics of all characters preceding 
it in the string.
Let L be the left-side-bearing metric of the character plus W.
Let R be the right-side-bearing metric of the character plus W.
The lbearing member is set to the minimum L of all characters in the string.
The rbearing member is set to the maximum R.</para>

<para>For fonts defined with linear indexing rather than 2-byte matrix indexing,
each 
<emphasis remap='I'>&hairsp;XChar2b&hairsp;</emphasis>
structure is interpreted as a 16-bit number with byte1 as the 
most significant byte.
If the font has no defined default character,
undefined characters in the string are taken to have all zero metrics.</para>

<para>The
<emphasis remap='I'>&hairsp;XQueryTextExtents&hairsp;</emphasis>
and
<emphasis remap='I'>&hairsp;XQueryTextExtents16&hairsp;</emphasis>
functions return the bounding box of the specified 8-bit and 16-bit
character string in the specified font or the font contained in the
specified GC.
These functions query the X server and, therefore, suffer the round-trip
overhead that is avoided by
<emphasis remap='I'>&hairsp;XTextExtents&hairsp;</emphasis>
and 
<emphasis remap='I'>&hairsp;XTextExtents16&hairsp;</emphasis>.
Both functions return a
<emphasis remap='I'>&hairsp;XCharStruct&hairsp;</emphasis>
structure, whose members are set to the values as follows.</para>

<para>The ascent member is set to the maximum of the ascent metrics 
of all characters in the string.
The descent member is set to the maximum of the descent metrics.
The width member is set to the sum of the character-width metrics 
of all characters in the string.
For each character in the string,
let W be the sum of the character-width metrics of all characters preceding
it in the string.
Let L be the left-side-bearing metric of the character plus W.
Let R be the right-side-bearing metric of the character plus W.
The lbearing member is set to the minimum L of all characters in the string.
The rbearing member is set to the maximum R.</para>

<para>For fonts defined with linear indexing rather than 2-byte matrix indexing,
each 
<emphasis remap='I'>&hairsp;XChar2b&hairsp;</emphasis>
structure is interpreted as a 16-bit number with byte1 as the 
most significant byte.
If the font has no defined default character,
undefined characters in the string are taken to have all zero metrics.</para>

<para>Characters with all zero metrics are ignored.
If the font has no defined default_char,
the undefined characters in the string are also ignored.</para>

<para><emphasis remap='I'>&hairsp;XQueryTextExtents&hairsp;</emphasis>
and
<emphasis remap='I'>&hairsp;XQueryTextExtents16&hairsp;</emphasis>
can generate
<emphasis remap='I'>&hairsp;BadFont&hairsp;</emphasis>
and
<emphasis remap='I'>&hairsp;BadGC&hairsp;</emphasis>
errors.</para>
</refsect1>

<refsect1 id='diagnostics'><title>DIAGNOSTICS</title>
<variablelist remap='TP'>
  <varlistentry>
  <term><emphasis remap='I'>&hairsp;BadFont&hairsp;</emphasis></term>
  <listitem>
<para>A value for a Font or GContext argument does not name a defined Font.</para>
  </listitem>
  </varlistentry>
  <varlistentry>
  <term><emphasis remap='I'>&hairsp;BadGC&hairsp;</emphasis></term>
  <listitem>
<para>A value for a GContext argument does not name a defined GContext.</para>
  </listitem>
  </varlistentry>
</variablelist>
</refsect1>

<refsect1 id='see_also'><title>SEE ALSO</title>
<para>XLoadFont(3X11),
XTextWidth(3X11)
<!-- .br -->
<userinput>Xlib - C Language X Interface</userinput></para>
</refsect1>
</refentry>

