ft2-cache_subsystem.html

Free type 2.1.0 Documents

<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>note</b></em></td></tr><tr><td>
<p>This function doesn't return <a href="ft2-cache_subsystem.html#FTC_Node">FTC_Node</a> handles, since there is no real use for them with typical uses of charmaps.</p>
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<table align=center width="75%"><tr><td>
<h4><a name="FTC_ImageCache">FTC_ImageCache</a></h4>
<table align=center width="87%"><tr bgcolor="#D6E8FF"><td><pre>

  <span class="keyword">typedef</span> <span class="keyword">struct</span> FTC_ImageCacheRec_*  <b>FTC_ImageCache</b>;

</pre></table><br>
<table align=center width="87%"><tr><td>
<p>A handle to an glyph image cache object. They are designed to hold many distinct glyph images while not exceeding a certain memory threshold.</p>
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</td></tr></table><hr width="75%">
<table align=center width="75%"><tr><td>
<h4><a name="FTC_ImageCache_New">FTC_ImageCache_New</a></h4>
<table align=center width="87%"><tr bgcolor="#D6E8FF"><td><pre>

  FT_EXPORT( <a href="ft2-basic_types.html#FT_Error">FT_Error</a> )
  <b>FTC_ImageCache_New</b>( <a href="ft2-cache_subsystem.html#FTC_Manager">FTC_Manager</a>      manager,
                      <a href="ft2-cache_subsystem.html#FTC_ImageCache">FTC_ImageCache</a>  *acache );

</pre></table><br>
<table align=center width="87%"><tr><td>
<p>Creates a new glyph image cache.</p>
</td></tr></table><br>
<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>input</b></em></td></tr><tr><td>
<table cellpadding=3>
<tr valign=top><td><b>manager</b></td><td>
<p>The parent manager for the image cache.</p>
</td></tr>
</table>
</td></tr></table>
<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>output</b></em></td></tr><tr><td>
<table cellpadding=3>
<tr valign=top><td><b>acache</b></td><td>
<p>A handle to the new glyph image cache object.</p>
</td></tr>
</table>
</td></tr></table>
<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>return</b></em></td></tr><tr><td>
<p>FreeType error code. 0 means success.</p>
</td></tr></table>
</td></tr></table><hr width="75%">
<table align=center width="75%"><tr><td>
<h4><a name="FTC_ImageCache_Lookup">FTC_ImageCache_Lookup</a></h4>
<table align=center width="87%"><tr bgcolor="#D6E8FF"><td><pre>

  FT_EXPORT( <a href="ft2-basic_types.html#FT_Error">FT_Error</a> )
  <b>FTC_ImageCache_Lookup</b>( <a href="ft2-cache_subsystem.html#FTC_ImageCache">FTC_ImageCache</a>  cache,
                         FTC_ImageType   type,
                         <a href="ft2-basic_types.html#FT_UInt">FT_UInt</a>         gindex,
                         <a href="ft2-glyph_management.html#FT_Glyph">FT_Glyph</a>       *aglyph,
                         <a href="ft2-cache_subsystem.html#FTC_Node">FTC_Node</a>       *anode );

</pre></table><br>
<table align=center width="87%"><tr><td>
<p>Retrieves a given glyph image from a glyph image cache.</p>
</td></tr></table><br>
<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>input</b></em></td></tr><tr><td>
<table cellpadding=3>
<tr valign=top><td><b>cache</b></td><td>
<p>A handle to the source glyph image cache.</p>
</td></tr>
<tr valign=top><td><b>type</b></td><td>
<p>A pointer to a glyph image type descriptor.</p>
</td></tr>
<tr valign=top><td><b>gindex</b></td><td>
<p>The glyph index to retrieve.</p>
</td></tr>
</table>
</td></tr></table>
<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>output</b></em></td></tr><tr><td>
<table cellpadding=3>
<tr valign=top><td><b>aglyph</b></td><td>
<p>The corresponding <a href="ft2-glyph_management.html#FT_Glyph">FT_Glyph</a> object. 0 in case of failure.</p>
</td></tr>
<tr valign=top><td><b>anode</b></td><td>
<p>Used to return the address of of the corresponding cache node after incrementing its reference count (see note below).</p>
</td></tr>
</table>
</td></tr></table>
<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>return</b></em></td></tr><tr><td>
<p>FreeType error code. 0 means success.</p>
</td></tr></table>
<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>note</b></em></td></tr><tr><td>
<p>The returned glyph is owned and managed by the glyph image cache. Never try to transform or discard it manually! You can however create a copy with <a href="ft2-glyph_management.html#FT_Glyph_Copy">FT_Glyph_Copy</a> and modify the new one.</p>
<p>If `anode' is <i>not</i> NULL, it receives the address of the cache node containing the glyph image, after increasing its reference count. This ensures that the node (as well as the FT_Glyph) will always be kept in the cache until you call <a href="ft2-cache_subsystem.html#FTC_Node_Unref">FTC_Node_Unref</a> to `release' it.</p>
<p>If `anode' is NULL, the cache node is left unchanged, which means that the FT_Glyph could be flushed out of the cache on the next call to one of the caching sub-system APIs. Don't assume that it is persistent!</p>
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</td></tr></table><hr width="75%">
<table align=center width="75%"><tr><td>
<h4><a name="FTC_SBit">FTC_SBit</a></h4>
<table align=center width="87%"><tr bgcolor="#D6E8FF"><td><pre>

  <span class="keyword">typedef</span> <span class="keyword">struct</span> FTC_SBitRec_*  <b>FTC_SBit</b>;

</pre></table><br>
<table align=center width="87%"><tr><td>
<p>A handle to a small bitmap descriptor. See the <a href="ft2-cache_subsystem.html#FTC_SBitRec">FTC_SBitRec</a> structure for details.</p>
</td></tr></table><br>
</td></tr></table><hr width="75%">
<table align=center width="75%"><tr><td>
<h4><a name="FTC_SBitRec">FTC_SBitRec</a></h4>
<table align=center width="87%"><tr bgcolor="#D6E8FF"><td><pre>

  <span class="keyword">typedef</span> <span class="keyword">struct</span>  FTC_SBitRec_
  {
    <a href="ft2-basic_types.html#FT_Byte">FT_Byte</a>   width;
    <a href="ft2-basic_types.html#FT_Byte">FT_Byte</a>   height;
    <a href="ft2-basic_types.html#FT_Char">FT_Char</a>   left;
    <a href="ft2-basic_types.html#FT_Char">FT_Char</a>   top;

    <a href="ft2-basic_types.html#FT_Byte">FT_Byte</a>   format;
    <a href="ft2-basic_types.html#FT_Byte">FT_Byte</a>   max_grays;
    <a href="ft2-basic_types.html#FT_Short">FT_Short</a>  pitch;
    <a href="ft2-basic_types.html#FT_Char">FT_Char</a>   xadvance;
    <a href="ft2-basic_types.html#FT_Char">FT_Char</a>   yadvance;

    <a href="ft2-basic_types.html#FT_Byte">FT_Byte</a>*  buffer;

  } <b>FTC_SBitRec</b>;

</pre></table><br>
<table align=center width="87%"><tr><td>
<p>A very compact structure used to describe a small glyph bitmap.</p>
</td></tr></table><br>
<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>fields</b></em></td></tr><tr><td>
<table cellpadding=3>
<tr valign=top><td><b>width</b></td><td>
<p>The bitmap width in pixels.</p>
</td></tr>
<tr valign=top><td><b>height</b></td><td>
<p>The bitmap height in pixels.</p>
</td></tr>
<tr valign=top><td><b>left</b></td><td>
<p>The horizontal distance from the pen position to the left bitmap border (a.k.a. `left side bearing', or `lsb').</p>
</td></tr>
<tr valign=top><td><b>top</b></td><td>
<p>The vertical distance from the pen position (on the baseline) to the upper bitmap border (a.k.a. `top side bearing'). The distance is positive for upwards Y coordinates.</p>
</td></tr>
<tr valign=top><td><b>format</b></td><td>
<p>The format of the glyph bitmap (monochrome or gray).</p>
</td></tr>
<tr valign=top><td><b>max_grays</b></td><td>
<p>Maximum gray level value (in the range 1 to 255).</p>
</td></tr>
<tr valign=top><td><b>pitch</b></td><td>
<p>The number of bytes per bitmap line. May be positive or negative.</p>
</td></tr>
<tr valign=top><td><b>xadvance</b></td><td>
<p>The horizontal advance width in pixels.</p>
</td></tr>
<tr valign=top><td><b>yadvance</b></td><td>
<p>The vertical advance height in pixels.</p>
</td></tr>
<tr valign=top><td><b>buffer</b></td><td>
<p>A pointer to the bitmap pixels.</p>
</td></tr>
</table>
</td></tr></table>
</td></tr></table><hr width="75%">
<table align=center width="75%"><tr><td>
<h4><a name="FTC_SBitCache">FTC_SBitCache</a></h4>
<table align=center width="87%"><tr bgcolor="#D6E8FF"><td><pre>

  <span class="keyword">typedef</span> <span class="keyword">struct</span> FTC_SBitCacheRec_*  <b>FTC_SBitCache</b>;

</pre></table><br>
<table align=center width="87%"><tr><td>
<p>A handle to a small bitmap cache. These are special cache objects used to store small glyph bitmaps (and anti-aliased pixmaps) in a much more efficient way than the traditional glyph image cache implemented by <a href="ft2-cache_subsystem.html#FTC_ImageCache">FTC_ImageCache</a>.</p>
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</td></tr></table><hr width="75%">
<table align=center width="75%"><tr><td>
<h4><a name="FTC_SBitCache_New">FTC_SBitCache_New</a></h4>
<table align=center width="87%"><tr bgcolor="#D6E8FF"><td><pre>

  FT_EXPORT( <a href="ft2-basic_types.html#FT_Error">FT_Error</a> )
  <b>FTC_SBitCache_New</b>( <a href="ft2-cache_subsystem.html#FTC_Manager">FTC_Manager</a>     manager,
                     <a href="ft2-cache_subsystem.html#FTC_SBitCache">FTC_SBitCache</a>  *acache );

</pre></table><br>
<table align=center width="87%"><tr><td>
<p>Creates a new cache to store small glyph bitmaps.</p>
</td></tr></table><br>
<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>input</b></em></td></tr><tr><td>
<table cellpadding=3>
<tr valign=top><td><b>manager</b></td><td>
<p>A handle to the source cache manager.</p>
</td></tr>
</table>
</td></tr></table>
<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>output</b></em></td></tr><tr><td>
<table cellpadding=3>
<tr valign=top><td><b>acache</b></td><td>
<p>A handle to the new sbit cache. NULL in case of error.</p>
</td></tr>
</table>
</td></tr></table>
<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>return</b></em></td></tr><tr><td>
<p>FreeType error code. 0 means success.</p>
</td></tr></table>
</td></tr></table><hr width="75%">
<table align=center width="75%"><tr><td>
<h4><a name="FTC_SBitCache_Lookup">FTC_SBitCache_Lookup</a></h4>
<table align=center width="87%"><tr bgcolor="#D6E8FF"><td><pre>

  FT_EXPORT( <a href="ft2-basic_types.html#FT_Error">FT_Error</a> )
  <b>FTC_SBitCache_Lookup</b>( <a href="ft2-cache_subsystem.html#FTC_SBitCache">FTC_SBitCache</a>    cache,
                        FTC_ImageType    type,
                        <a href="ft2-basic_types.html#FT_UInt">FT_UInt</a>          gindex,
                        <a href="ft2-cache_subsystem.html#FTC_SBit">FTC_SBit</a>        *sbit,
                        <a href="ft2-cache_subsystem.html#FTC_Node">FTC_Node</a>        *anode );

</pre></table><br>
<table align=center width="87%"><tr><td>
<p>Looks up a given small glyph bitmap in a given sbit cache and `lock' it to prevent its flushing from the cache until needed.</p>
</td></tr></table><br>
<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>input</b></em></td></tr><tr><td>
<table cellpadding=3>
<tr valign=top><td><b>cache</b></td><td>
<p>A handle to the source sbit cache.</p>
</td></tr>
<tr valign=top><td><b>type</b></td><td>
<p>A pointer to the glyph image type descriptor.</p>
</td></tr>
<tr valign=top><td><b>gindex</b></td><td>
<p>The glyph index.</p>
</td></tr>
</table>
</td></tr></table>
<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>output</b></em></td></tr><tr><td>
<table cellpadding=3>
<tr valign=top><td><b>sbit</b></td><td>
<p>A handle to a small bitmap descriptor.</p>
</td></tr>
<tr valign=top><td><b>anode</b></td><td>