cairo-scaled-font.xml

按照官方的说法：Cairo is a vector graphics library with cross-device output support. 翻译过来

          font designer's intent as to how the the font should
          align with elements below it.
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><link linkend="double">double</link>&nbsp;<structfield>height</structfield>;</term>
<listitem><simpara> the recommended vertical distance between baselines when
         setting consecutive lines of text with the font. This
         is greater than <parameter>ascent</parameter>+<parameter>descent</parameter> by a
         quantity known as the <firstterm>line spacing</firstterm>
         or <firstterm>external leading</firstterm>. When space
         is at a premium, most fonts can be set with only
         a distance of <parameter>ascent</parameter>+<parameter>descent</parameter> between lines.
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><link linkend="double">double</link>&nbsp;<structfield>max_x_advance</structfield>;</term>
<listitem><simpara> the maximum distance in the X direction that
        the the origin is advanced for any glyph in the font.
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><link linkend="double">double</link>&nbsp;<structfield>max_y_advance</structfield>;</term>
<listitem><simpara> the maximum distance in the Y direction that
        the the origin is advanced for any glyph in the font.
        this will be zero for normal fonts used for horizontal
        writing. (The scripts of East Asia are sometimes written
        vertically.)
</simpara></listitem>
</varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-scaled-font-extents" role="function"/>cairo_scaled_font_extents ()</title>
<indexterm><primary>cairo_scaled_font_extents</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_scaled_font_extents       (<link linkend="cairo-scaled-font-t">cairo_scaled_font_t</link> *scaled_font,
                                             <link linkend="cairo-font-extents-t">cairo_font_extents_t</link> *extents);</programlisting>
</refsect2>
<refsect2>
<title><anchor id="cairo-text-extents-t" role="struct"/>cairo_text_extents_t</title>
<indexterm><primary>cairo_text_extents_t</primary></indexterm><programlisting>typedef struct {
    double x_bearing;
    double y_bearing;
    double width;
    double height;
    double x_advance;
    double y_advance;
} cairo_text_extents_t;
</programlisting>
<para>
The <link linkend="cairo-text-extents-t"><type>cairo_text_extents_t</type></link> structure stores the extents of a single
glyph or a string of glyphs in user-space coordinates. Because text
extents are in user-space coordinates, they are mostly, but not
entirely, independent of the current transformation matrix. If you call
<literal>cairo_scale(cr, 2.0, 2.0)</literal>, text will
be drawn twice as big, but the reported text extents will not be
doubled. They will change slightly due to hinting (so you can't
assume that metrics are independent of the transformation matrix),
but otherwise will remain unchanged.</para>
<para>

</para><variablelist role="struct">
<varlistentry>
<term><link linkend="double">double</link>&nbsp;<structfield>x_bearing</structfield>;</term>
<listitem><simpara> the horizontal distance from the origin to the
  leftmost part of the glyphs as drawn. Positive if the
  glyphs lie entirely to the right of the origin.
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><link linkend="double">double</link>&nbsp;<structfield>y_bearing</structfield>;</term>
<listitem><simpara> the vertical distance from the origin to the
  topmost part of the glyphs as drawn. Positive only if the
  glyphs lie completely below the origin; will usually be
  negative.
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><link linkend="double">double</link>&nbsp;<structfield>width</structfield>;</term>
<listitem><simpara> width of the glyphs as drawn
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><link linkend="double">double</link>&nbsp;<structfield>height</structfield>;</term>
<listitem><simpara> height of the glyphs as drawn
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><link linkend="double">double</link>&nbsp;<structfield>x_advance</structfield>;</term>
<listitem><simpara>distance to advance in the X direction
   after drawing these glyphs
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><link linkend="double">double</link>&nbsp;<structfield>y_advance</structfield>;</term>
<listitem><simpara> distance to advance in the Y direction
  after drawing these glyphs. Will typically be zero except
  for vertical text layout as found in East-Asian languages.
</simpara></listitem>
</varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-scaled-font-text-extents" role="function" condition="since:1.2"/>cairo_scaled_font_text_extents ()</title>
<indexterm role="1.2"><primary>cairo_scaled_font_text_extents</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_scaled_font_text_extents  (<link linkend="cairo-scaled-font-t">cairo_scaled_font_t</link> *scaled_font,
                                             const <link linkend="char">char</link> *utf8,
                                             <link linkend="cairo-text-extents-t">cairo_text_extents_t</link> *extents);</programlisting>
<para>Since  1.2
</para></refsect2>
<refsect2>
<title><anchor id="cairo-scaled-font-glyph-extents" role="function"/>cairo_scaled_font_glyph_extents ()</title>
<indexterm><primary>cairo_scaled_font_glyph_extents</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_scaled_font_glyph_extents (<link linkend="cairo-scaled-font-t">cairo_scaled_font_t</link> *scaled_font,
                                             <link linkend="cairo-glyph-t">cairo_glyph_t</link> *glyphs,
                                             <link linkend="int">int</link> num_glyphs,
                                             <link linkend="cairo-text-extents-t">cairo_text_extents_t</link> *extents);</programlisting>
</refsect2>
<refsect2>
<title><anchor id="cairo-scaled-font-get-font-face" role="function" condition="since:1.2"/>cairo_scaled_font_get_font_face ()</title>
<indexterm role="1.2"><primary>cairo_scaled_font_get_font_face</primary></indexterm><programlisting><link linkend="cairo-font-face-t">cairo_font_face_t</link>* cairo_scaled_font_get_font_face
                                            (<link linkend="cairo-scaled-font-t">cairo_scaled_font_t</link> *scaled_font);</programlisting>
<para>Since  1.2
</para></refsect2>
<refsect2>
<title><anchor id="cairo-scaled-font-get-font-options" role="function" condition="since:1.2"/>cairo_scaled_font_get_font_options ()</title>
<indexterm role="1.2"><primary>cairo_scaled_font_get_font_options</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_scaled_font_get_font_options
                                            (<link linkend="cairo-scaled-font-t">cairo_scaled_font_t</link> *scaled_font,
                                             <link linkend="cairo-font-options-t">cairo_font_options_t</link> *options);</programlisting>
<para>Since  1.2
</para></refsect2>
<refsect2>
<title><anchor id="cairo-scaled-font-get-font-matrix" role="function" condition="since:1.2"/>cairo_scaled_font_get_font_matrix ()</title>
<indexterm role="1.2"><primary>cairo_scaled_font_get_font_matrix</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_scaled_font_get_font_matrix
                                            (<link linkend="cairo-scaled-font-t">cairo_scaled_font_t</link> *scaled_font,
                                             <link linkend="cairo-matrix-t">cairo_matrix_t</link> *font_matrix);</programlisting>
<para>Since  1.2
</para></refsect2>
<refsect2>
<title><anchor id="cairo-scaled-font-get-ctm" role="function" condition="since:1.2"/>cairo_scaled_font_get_ctm ()</title>
<indexterm role="1.2"><primary>cairo_scaled_font_get_ctm</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_scaled_font_get_ctm       (<link linkend="cairo-scaled-font-t">cairo_scaled_font_t</link> *scaled_font,
                                             <link linkend="cairo-matrix-t">cairo_matrix_t</link> *ctm);</programlisting>
<para>Since  1.2
</para></refsect2>
<refsect2>
<title><anchor id="cairo-scaled-font-get-type" role="function" condition="since:1.2"/>cairo_scaled_font_get_type ()</title>
<indexterm role="1.2"><primary>cairo_scaled_font_get_type</primary></indexterm><programlisting><link linkend="cairo-font-type-t">cairo_font_type_t</link> cairo_scaled_font_get_type
                                            (<link linkend="cairo-scaled-font-t">cairo_scaled_font_t</link> *scaled_font);</programlisting>
<para>Since  1.2
</para></refsect2>

</refsect1>




</refentry>