gdk-fonts.html

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<td>The body size of the font in 10ths of a point.
(A <em class="firstterm">point</em> is 1/72.27 inch) </td>
</tr>
<tr>
<td>Resolution X</td>
<td>The horizontal resolution that the font was designed for.</td>
</tr>
<tr>
<td>Resolution Y</td>
<td>The vertical resolution that the font was designed for .</td>
</tr>
<tr>
<td>Spacing</td>
<td>The type of spacing for the font - can be 'p' for proportional,
'm' for monospaced or 'c' for charcell.</td>
</tr>
<tr>
<td>Average Width</td>
<td>The average width of a glyph in the font. For monospaced
and charcell fonts, all glyphs in the font have this width</td>
</tr>
<tr>
<td>Charset Registry</td>
<td>The registration authority that owns the encoding for
the font. Together with the Charset Encoding field, this
defines the character set for the font.</td>
</tr>
<tr>
<td>Charset Encoding</td>
<td>An identifier for the particular character set encoding.</td>
</tr>
</tbody>
</table></div>
<p>
</p>
<p>
When specifying a font via a X logical Font Description,
'*' can be used as a wildcard to match any portion of
the XLFD. For instance, the above example could
also be specified as
</p>
<div class="informalexample"><pre class="programlisting">
"-*-helvetica-bold-r-normal--*-120-*-*-*-*-iso8859-1"
</pre></div>
<p>

It is generally a good idea to use wildcards for any
portion of the XLFD that your program does not care
about specifically, since that will improve the
chances of finding a matching font.
</p>
<p>
A <em class="firstterm">fontset</em> is a list of fonts
that is used for drawing international text that may
contain characters from a number of different character
sets. It is represented by a list of XLFD's. 
</p>
<p>
The font for a given character set is determined by going
through the list of XLFD's in order. For each one, if
the registry and and encoding fields match the desired
character set, then that font is used, otherwise if
the XLFD contains wild-cards for the registry and encoding
fields, the registry and encoding for the desired character
set are substituted in and a lookup is done. If a match is found
that font is used. Otherwise, processing continues
on to the next font in the list.
</p>
<p>
The functions for determining the metrics of a string
come in several varieties that can take a number
of forms of string input:

</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term">8-bit string</span></p></td>
<td><p>
    When using functions like <a class="link" href="gdk-Fonts.html#gdk-string-width"><code class="function">gdk_string_width()</code></a> that
    take a <span class="type">gchar *</span>, if the font is of type
    <a class="link" href="gdk-Fonts.html#GDK-FONT-FONT:CAPS"><code class="literal">GDK_FONT_FONT</code></a> and is an 8-bit font, then each
    <span class="type">gchar</span> indexes the glyphs in the font directly.
    </p></td>
</tr>
<tr>
<td><p><span class="term">16-bit string</span></p></td>
<td><p>
    For functions taking a <span class="type">gchar *</span>, if the
    font is of type <a class="link" href="gdk-Fonts.html#GDK-FONT-FONT:CAPS"><code class="literal">GDK_FONT_FONT</code></a>, and is a 16-bit
    font, then the <span class="type">gchar *</span> argument is
    interpreted as a <span class="type">guint16 *</span> cast to
    a <span class="type">gchar *</span> and each <span class="type">guint16</span>
    indexes the glyphs in the font directly.
    </p></td>
</tr>
<tr>
<td><p><span class="term">Multibyte string</span></p></td>
<td><p>
    For functions taking a <span class="type">gchar *</span>, if the
    font is of type <a class="link" href="gdk-Fonts.html#GDK-FONT-FONTSET:CAPS"><code class="literal">GDK_FONT_FONTSET</code></a>, then the input
    string is interpreted as a <em class="firstterm">multibyte</em>
    encoded according to the current locale. (A multibyte
    string is one in which each character may consist
    of one or more bytes, with different lengths for different
    characters in the string). They can be converted to and
    from wide character strings (see below) using
    <a class="link" href="gdk-Fonts.html#gdk-wcstombs"><code class="function">gdk_wcstombs()</code></a> and <a class="link" href="gdk-Fonts.html#gdk-mbstowcs"><code class="function">gdk_mbstowcs()</code></a>.) The string will
    be rendered using one or more different fonts from
    the fontset.
    </p></td>
</tr>
<tr>
<td><p><span class="term">Wide character string</span></p></td>
<td><p>
    For a number of the text-measuring functions, GDK
    provides a variant (such as <a class="link" href="gdk-Fonts.html#gdk-text-width-wc"><code class="function">gdk_text_width_wc()</code></a>) which
    takes a <span class="type">GdkWChar *</span> instead of a 
    <span class="type">gchar *</span>. The input is then taken to
    be a wide character string in the encoding of the
    current locale. (A wide character string is a string
    in which each character consists of several bytes,
    and the width of each character in the string is 
    constant.)
    </p></td>
</tr>
</tbody>
</table></div>
<p>
</p>
<p>
GDK provides functions to determine a number of different
measurements (metrics) for a given string. (Need diagram
here).

</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term">ascent</span></p></td>
<td><p>
    The vertical distance from the origin of the drawing
    opereration to the top of the drawn character.
    </p></td>
</tr>
<tr>
<td><p><span class="term">descent</span></p></td>
<td><p>
    The vertical distance from the origin of the drawing
    opereration to the bottom of the drawn character.
    </p></td>
</tr>
<tr>
<td><p><span class="term">left bearing</span></p></td>
<td><p>
    The horizontal distance from the origin of the drawing
    operation to the left-most part of the drawn character.
    </p></td>
</tr>
<tr>
<td><p><span class="term">right bearing</span></p></td>
<td><p>
    The horizontal distance from the origin of the drawing
    operation to the right-most part of the drawn character.
    </p></td>
</tr>
<tr>
<td><p><span class="term">width bearing</span></p></td>
<td><p>
    The horizontal distance from the origin of the drawing
    operation to the correct origin for drawing another
    string to follow the current one. Depending on the
    font, this could be greater than or less than the 
    right bearing.
    </p></td>
</tr>
</tbody>
</table></div>
<p>
</p>
</div>
<div class="refsect1" lang="en">
<a name="id3160754"></a><h2>Details</h2>
<div class="refsect2" lang="en">
<a name="id3160764"></a><h3>
<a name="GdkFont"></a>GdkFont</h3>
<a class="indexterm" name="id3160779"></a><pre class="programlisting">typedef struct {
  GdkFontType type;
  gint ascent;
  gint descent;
} GdkFont;
</pre>
<div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
<h3 class="title">Warning</h3>
<p><code class="literal">GdkFont</code> is deprecated and should not be used in newly-written code.</p>
</div>
<p>
The <span class="structname">GdkFont</span> structure represents a font or fontset. It
contains the following public fields. A new <span class="structname">GdkFont</span>
structure is returned by <a class="link" href="gdk-Fonts.html#gdk-font-load"><code class="function">gdk_font_load()</code></a> or <a class="link" href="gdk-Fonts.html#gdk-fontset-load"><code class="function">gdk_fontset_load()</code></a>,
and is reference counted with <a class="link" href="gdk-Fonts.html#gdk-font-ref"><code class="function">gdk_font_ref()</code></a> and <a class="link" href="gdk-Fonts.html#gdk-font-unref"><code class="function">gdk_font_unref()</code></a>
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><a class="link" href="gdk-Fonts.html#GdkFontType">GdkFontType</a>&#160;<em class="structfield"><code>type</code></em>;</span></p></td>
<td>a value of type <a class="link" href="gdk-Fonts.html#GdkFontType"><span class="type">GdkFontType</span></a> which indicates
  whether this font is a single font or a fontset.
</td>
</tr>
<tr>
<td><p><span class="term"><a
href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gint"
>gint</a>&#160;<em class="structfield"><code>ascent</code></em>;</span></p></td>
<td>the maximum distance that the font, when drawn,
  ascends above the baseline.
</td>
</tr>
<tr>
<td><p><span class="term"><a
href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gint"
>gint</a>&#160;<em class="structfield"><code>descent</code></em>;</span></p></td>
<td>the maximum distance that the font, when drawn,
descends below the baseline.

</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2" lang="en">
<a name="id3160936"></a><h3>
<a name="GdkFontType"></a>enum GdkFontType</h3>
<a class="indexterm" name="id3160951"></a><pre class="programlisting">typedef enum
{
  GDK_FONT_FONT,
  GDK_FONT_FONTSET
} GdkFontType;
</pre>
<div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
<h3 class="title">Warning</h3>
<p><code class="literal">GdkFontType</code> is deprecated and should not be used in newly-written code.</p>
</div>
<p>
Indicates the type of a font. The possible values
are currently:
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><a name="GDK-FONT-FONT:CAPS"></a><code class="literal">GDK_FONT_FONT</code></span></p></td>
<td>the font is a single font.
</td>
</tr>
<tr>
<td><p><span class="term"><a name="GDK-FONT-FONTSET:CAPS"></a><code class="literal">GDK_FONT_FONTSET</code></span></p></td>
<td>the font is a fontset.

</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2" lang="en">
<a name="id3161029"></a><h3>
<a name="gdk-font-load"></a>gdk_font_load ()</h3>
<a class="indexterm" name="id3161044"></a><pre class="programlisting"><a class="link" href="gdk-Fonts.html#GdkFont">GdkFont</a>*            gdk_font_load                       (const <a
href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gchar"
>gchar</a> *font_name);</pre>
<div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
<h3 class="title">Warning</h3>
<p><code class="literal">gdk_font_load</code> is deprecated and should not be used in newly-written code.</p>
</div>
<p>
Loads a font.
</p>
<p>
The font may be newly loaded or looked up the font in a cache. 
You should make no assumptions about the initial reference count.</p>
<p>
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>font_name</code></em>&#160;:</span></p></td>
<td> a XLFD describing the font to load.
</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span>&#160;:</span></p></td>
<td> a <a class="link" href="gdk-Fonts.html#GdkFont"><span class="type">GdkFont</span></a>, or <a
href="/usr/share/gtk-doc/html/liboil/liboil-liboiljunk.html#NULL:CAPS"
><code class="literal">NULL</code></a> if the font could not be loaded.
</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2" lang="en">
<a name="id3161141"></a><h3>
<a name="gdk-font-load-for-display"></a>gdk_font_load_for_display ()</h3>