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| <a href="#libvips-header.synopsis" class="shortcut">Top</a> |
| | |
| <a href="#libvips-header.description" class="shortcut">Description</a> |
| </td></tr> |
| </table> |
| <div class="refentry" title="header"> |
| <a name="libvips-header"></a><div class="titlepage"></div> |
| <div class="refnamediv"><table width="100%"><tr> |
| <td valign="top"> |
| <h2><span class="refentrytitle"><a name="libvips-header.top_of_page"></a>header</span></h2> |
| <p>header — get, set and walk image headers</p> |
| </td> |
| <td valign="top" align="right"></td> |
| </tr></table></div> |
| <div class="refsect1" title="Stability Level"> |
| <a name="libvips-header.stability-level"></a><h2>Stability Level</h2> |
| Stable, unless otherwise indicated |
| </div> |
| <div class="refsynopsisdiv" title="Synopsis"> |
| <a name="libvips-header.synopsis"></a><h2>Synopsis</h2> |
| <pre class="synopsis"> |
| #include <vips/vips.h> |
| |
| <span class="returnvalue">int</span> <a class="link" href="libvips-header.html#im-header-int" title="im_header_int ()">im_header_int</a> (<em class="parameter"><code><span class="type">IMAGE</span> *im</code></em>, |
| <em class="parameter"><code>const <span class="type">char</span> *field</code></em>, |
| <em class="parameter"><code><span class="type">int</span> *out</code></em>); |
| <span class="returnvalue">int</span> <a class="link" href="libvips-header.html#im-header-double" title="im_header_double ()">im_header_double</a> (<em class="parameter"><code><span class="type">IMAGE</span> *im</code></em>, |
| <em class="parameter"><code>const <span class="type">char</span> *field</code></em>, |
| <em class="parameter"><code><span class="type">double</span> *out</code></em>); |
| <span class="returnvalue">int</span> <a class="link" href="libvips-header.html#im-header-string" title="im_header_string ()">im_header_string</a> (<em class="parameter"><code><span class="type">IMAGE</span> *im</code></em>, |
| <em class="parameter"><code>const <span class="type">char</span> *field</code></em>, |
| <em class="parameter"><code><span class="type">char</span> **out</code></em>); |
| <span class="returnvalue">int</span> <a class="link" href="libvips-header.html#im-header-as-string" title="im_header_as_string ()">im_header_as_string</a> (<em class="parameter"><code><span class="type">IMAGE</span> *im</code></em>, |
| <em class="parameter"><code>const <span class="type">char</span> *field</code></em>, |
| <em class="parameter"><code><span class="type">char</span> **out</code></em>); |
| <span class="returnvalue">GType</span> <a class="link" href="libvips-header.html#im-header-get-typeof" title="im_header_get_typeof ()">im_header_get_typeof</a> (<em class="parameter"><code><span class="type">IMAGE</span> *im</code></em>, |
| <em class="parameter"><code>const <span class="type">char</span> *field</code></em>); |
| <span class="returnvalue">int</span> <a class="link" href="libvips-header.html#im-header-get" title="im_header_get ()">im_header_get</a> (<em class="parameter"><code><span class="type">IMAGE</span> *im</code></em>, |
| <em class="parameter"><code>const <span class="type">char</span> *field</code></em>, |
| <em class="parameter"><code><span class="type">GValue</span> *value_copy</code></em>); |
| <span class="returnvalue">void</span> * (<a class="link" href="libvips-header.html#im-header-map-fn" title="im_header_map_fn ()">*im_header_map_fn</a>) (<em class="parameter"><code><span class="type">IMAGE</span> *Param1</code></em>, |
| <em class="parameter"><code>const <span class="type">char</span> *Param2</code></em>, |
| <em class="parameter"><code><span class="type">GValue</span> *Param3</code></em>, |
| <em class="parameter"><code><span class="type">void</span> *Param4</code></em>); |
| <span class="returnvalue">void</span> * <a class="link" href="libvips-header.html#im-header-map" title="im_header_map ()">im_header_map</a> (<em class="parameter"><code><span class="type">IMAGE</span> *im</code></em>, |
| <em class="parameter"><code><a class="link" href="libvips-header.html#im-header-map-fn" title="im_header_map_fn ()"><span class="type">im_header_map_fn</span></a> fn</code></em>, |
| <em class="parameter"><code><span class="type">void</span> *a</code></em>); |
| <span class="returnvalue">int</span> <a class="link" href="libvips-header.html#im-histlin" title="im_histlin ()">im_histlin</a> (<em class="parameter"><code><span class="type">IMAGE</span> *image</code></em>, |
| <em class="parameter"><code>const <span class="type">char</span> *fmt</code></em>, |
| <em class="parameter"><code>...</code></em>); |
| <span class="returnvalue">int</span> <a class="link" href="libvips-header.html#im-updatehist" title="im_updatehist ()">im_updatehist</a> (<em class="parameter"><code><span class="type">IMAGE</span> *out</code></em>, |
| <em class="parameter"><code>const <span class="type">char</span> *name</code></em>, |
| <em class="parameter"><code><span class="type">int</span> argc</code></em>, |
| <em class="parameter"><code><span class="type">char</span> *argv[]</code></em>); |
| const <span class="returnvalue">char</span> * <a class="link" href="libvips-header.html#im-history-get" title="im_history_get ()">im_history_get</a> (<em class="parameter"><code><span class="type">IMAGE</span> *im</code></em>); |
| </pre> |
| </div> |
| <div class="refsect1" title="Description"> |
| <a name="libvips-header.description"></a><h2>Description</h2> |
| <p> |
| These functions let you get at image header data (including metadata) in a |
| uniform way. They are handy for language bindings but less useful for C |
| users. |
| </p> |
| <p> |
| They first search the |
| VIPS header |
| fields (see <a class="link" href="libvips-image.html" title="image">image</a>), then search for |
| a metadata field of that name (see |
| <a class="link" href="libvips-meta.html" title="meta">meta</a>). |
| Use <a class="link" href="libvips-header.html#im-header-get-typeof" title="im_header_get_typeof ()"><code class="function">im_header_get_typeof()</code></a> to test for the |
| existance and <span class="type">GType</span> |
| of a header field. |
| </p> |
| <p> |
| See <a class="link" href="libvips-meta.html" title="meta">meta</a> |
| for a set of functions for adding new metadata to an image. |
| </p> |
| </div> |
| <div class="refsect1" title="Details"> |
| <a name="libvips-header.details"></a><h2>Details</h2> |
| <div class="refsect2" title="im_header_int ()"> |
| <a name="im-header-int"></a><h3>im_header_int ()</h3> |
| <pre class="programlisting"><span class="returnvalue">int</span> im_header_int (<em class="parameter"><code><span class="type">IMAGE</span> *im</code></em>, |
| <em class="parameter"><code>const <span class="type">char</span> *field</code></em>, |
| <em class="parameter"><code><span class="type">int</span> *out</code></em>);</pre> |
| <p> |
| Gets <em class="parameter"><code>out</code></em> from <em class="parameter"><code>im</code></em> under the name <em class="parameter"><code>field</code></em>. This function searches for |
| int-valued fields. |
| </p> |
| <p> |
| See also: <a class="link" href="libvips-header.html#im-header-get" title="im_header_get ()"><code class="function">im_header_get()</code></a>, <a class="link" href="libvips-header.html#im-header-get-typeof" title="im_header_get_typeof ()"><code class="function">im_header_get_typeof()</code></a> |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>im</code></em> :</span></p></td> |
| <td>image to get the header field from |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>field</code></em> :</span></p></td> |
| <td>field name |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>out</code></em> :</span></p></td> |
| <td>return field value |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> |
| <td> 0 on success, -1 otherwise. |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2" title="im_header_double ()"> |
| <a name="im-header-double"></a><h3>im_header_double ()</h3> |
| <pre class="programlisting"><span class="returnvalue">int</span> im_header_double (<em class="parameter"><code><span class="type">IMAGE</span> *im</code></em>, |
| <em class="parameter"><code>const <span class="type">char</span> *field</code></em>, |
| <em class="parameter"><code><span class="type">double</span> *out</code></em>);</pre> |
| <p> |
| Gets <em class="parameter"><code>out</code></em> from <em class="parameter"><code>im</code></em> under the name <em class="parameter"><code>field</code></em>. |
| This function searches for |
| double-valued fields. |
| </p> |
| <p> |
| See also: <a class="link" href="libvips-header.html#im-header-get" title="im_header_get ()"><code class="function">im_header_get()</code></a>, <a class="link" href="libvips-header.html#im-header-get-typeof" title="im_header_get_typeof ()"><code class="function">im_header_get_typeof()</code></a> |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>im</code></em> :</span></p></td> |
| <td>image to get the header field from |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>field</code></em> :</span></p></td> |
| <td>field name |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>out</code></em> :</span></p></td> |
| <td>return field value |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> |
| <td> 0 on success, -1 otherwise. |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2" title="im_header_string ()"> |
| <a name="im-header-string"></a><h3>im_header_string ()</h3> |
| <pre class="programlisting"><span class="returnvalue">int</span> im_header_string (<em class="parameter"><code><span class="type">IMAGE</span> *im</code></em>, |
| <em class="parameter"><code>const <span class="type">char</span> *field</code></em>, |
| <em class="parameter"><code><span class="type">char</span> **out</code></em>);</pre> |
| <p> |
| Gets <em class="parameter"><code>out</code></em> from <em class="parameter"><code>im</code></em> under the name <em class="parameter"><code>field</code></em>. |
| This function searches for |
| string-valued fields. |
| </p> |
| <p> |
| See also: <a class="link" href="libvips-header.html#im-header-get" title="im_header_get ()"><code class="function">im_header_get()</code></a>, <a class="link" href="libvips-header.html#im-header-get-typeof" title="im_header_get_typeof ()"><code class="function">im_header_get_typeof()</code></a> |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>im</code></em> :</span></p></td> |
| <td>image to get the header field from |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>field</code></em> :</span></p></td> |
| <td>field name |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>out</code></em> :</span></p></td> |
| <td>return field value |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> |
| <td> 0 on success, -1 otherwise. |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2" title="im_header_as_string ()"> |
| <a name="im-header-as-string"></a><h3>im_header_as_string ()</h3> |
| <pre class="programlisting"><span class="returnvalue">int</span> im_header_as_string (<em class="parameter"><code><span class="type">IMAGE</span> *im</code></em>, |
| <em class="parameter"><code>const <span class="type">char</span> *field</code></em>, |
| <em class="parameter"><code><span class="type">char</span> **out</code></em>);</pre> |
| <p> |
| Gets <em class="parameter"><code>out</code></em> from <em class="parameter"><code>im</code></em> under the name <em class="parameter"><code>field</code></em>. |
| This function will read any field, returning it as a printable string. |
| You need to free the string with <code class="function">g_free()</code> when you are done with it. |
| </p> |
| <p> |
| See also: <a class="link" href="libvips-header.html#im-header-get" title="im_header_get ()"><code class="function">im_header_get()</code></a>, <a class="link" href="libvips-header.html#im-header-get-typeof" title="im_header_get_typeof ()"><code class="function">im_header_get_typeof()</code></a>. |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>im</code></em> :</span></p></td> |
| <td>image to get the header field from |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>field</code></em> :</span></p></td> |
| <td>field name |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>out</code></em> :</span></p></td> |
| <td>return field value as string |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> |
| <td> 0 on success, -1 otherwise. |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2" title="im_header_get_typeof ()"> |
| <a name="im-header-get-typeof"></a><h3>im_header_get_typeof ()</h3> |
| <pre class="programlisting"><span class="returnvalue">GType</span> im_header_get_typeof (<em class="parameter"><code><span class="type">IMAGE</span> *im</code></em>, |
| <em class="parameter"><code>const <span class="type">char</span> *field</code></em>);</pre> |
| <p> |
| Read the GType for a header field. Returns zero if there is no |
| field of that name. |
| </p> |
| <p> |
| See also: <a class="link" href="libvips-header.html#im-header-get" title="im_header_get ()"><code class="function">im_header_get()</code></a>. |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>im</code></em> :</span></p></td> |
| <td>image to test |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>field</code></em> :</span></p></td> |
| <td>the name to search for |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> |
| <td> the GType of the field, or zero if there is no |
| field of that name. |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2" title="im_header_get ()"> |
| <a name="im-header-get"></a><h3>im_header_get ()</h3> |
| <pre class="programlisting"><span class="returnvalue">int</span> im_header_get (<em class="parameter"><code><span class="type">IMAGE</span> *im</code></em>, |
| <em class="parameter"><code>const <span class="type">char</span> *field</code></em>, |
| <em class="parameter"><code><span class="type">GValue</span> *value_copy</code></em>);</pre> |
| <p> |
| Fill <em class="parameter"><code>value_copy</code></em> with a copy of the header field. <em class="parameter"><code>value_copy</code></em> must be zeroed |
| but uninitialised. |
| </p> |
| <p> |
| This will return -1 and add a message to the error buffer if the field |
| does not exist. Use <a class="link" href="libvips-header.html#im-header-get-typeof" title="im_header_get_typeof ()"><code class="function">im_header_get_typeof()</code></a> to test for the |
| existence |
| of a field first if you are not certain it will be there. |
| </p> |
| <p> |
| For example, to read a double from an image (though of course you would use |
| <a class="link" href="libvips-header.html#im-header-double" title="im_header_double ()"><code class="function">im_header_double()</code></a> in practice): |
| </p> |
| <p> |
| </p> |
| <div class="informalexample"><pre class="programlisting"> |
| GValue value = { 0 }; |
| double d; |
| |
| if( im_header_get( im, field, &value ) ) |
| return( -1 ); |
| |
| if( G_VALUE_TYPE( &value ) != G_TYPE_DOUBLE ) { |
| im_error( "mydomain", _( "field \"%s\" is of type %s, not double" ), |
| field, g_type_name( G_VALUE_TYPE( &value ) ) ); |
| g_value_unset( &value ); |
| return( -1 ); |
| } |
| |
| d = g_value_get_double( &value ); |
| g_value_unset( &value ); |
| |
| return( 0 ); |
| </pre></div> |
| <p> |
| </p> |
| <p> |
| See also: <a class="link" href="libvips-header.html#im-header-get-typeof" title="im_header_get_typeof ()"><code class="function">im_header_get_typeof()</code></a>, <a class="link" href="libvips-header.html#im-header-double" title="im_header_double ()"><code class="function">im_header_double()</code></a>. |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>im</code></em> :</span></p></td> |
| <td>image to get the field from from |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>field</code></em> :</span></p></td> |
| <td>the name to give the metadata |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>value_copy</code></em> :</span></p></td> |
| <td>the GValue is copied into this |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> |
| <td> 0 on success, -1 otherwise. |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2" title="im_header_map_fn ()"> |
| <a name="im-header-map-fn"></a><h3>im_header_map_fn ()</h3> |
| <pre class="programlisting"><span class="returnvalue">void</span> * (*im_header_map_fn) (<em class="parameter"><code><span class="type">IMAGE</span> *Param1</code></em>, |
| <em class="parameter"><code>const <span class="type">char</span> *Param2</code></em>, |
| <em class="parameter"><code><span class="type">GValue</span> *Param3</code></em>, |
| <em class="parameter"><code><span class="type">void</span> *Param4</code></em>);</pre> |
| </div> |
| <hr> |
| <div class="refsect2" title="im_header_map ()"> |
| <a name="im-header-map"></a><h3>im_header_map ()</h3> |
| <pre class="programlisting"><span class="returnvalue">void</span> * im_header_map (<em class="parameter"><code><span class="type">IMAGE</span> *im</code></em>, |
| <em class="parameter"><code><a class="link" href="libvips-header.html#im-header-map-fn" title="im_header_map_fn ()"><span class="type">im_header_map_fn</span></a> fn</code></em>, |
| <em class="parameter"><code><span class="type">void</span> *a</code></em>);</pre> |
| <p> |
| This function calls <em class="parameter"><code>fn</code></em> for every header field, including every item of |
| metadata. |
| </p> |
| <p> |
| Like all _map functions, the user function should return <code class="literal">NULL</code> to continue |
| iteration, or a non-<code class="literal">NULL</code> pointer to indicate early termination. |
| </p> |
| <p> |
| See also: <a class="link" href="libvips-header.html#im-header-get-typeof" title="im_header_get_typeof ()"><code class="function">im_header_get_typeof()</code></a>, <a class="link" href="libvips-header.html#im-header-get" title="im_header_get ()"><code class="function">im_header_get()</code></a>. |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>im</code></em> :</span></p></td> |
| <td>image to map over |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>fn</code></em> :</span></p></td> |
| <td>function to call for each header field |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>a</code></em> :</span></p></td> |
| <td>user data for function |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> |
| <td> <code class="literal">NULL</code> on success, the failing pointer otherwise. |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2" title="im_histlin ()"> |
| <a name="im-histlin"></a><h3>im_histlin ()</h3> |
| <pre class="programlisting"><span class="returnvalue">int</span> im_histlin (<em class="parameter"><code><span class="type">IMAGE</span> *image</code></em>, |
| <em class="parameter"><code>const <span class="type">char</span> *fmt</code></em>, |
| <em class="parameter"><code>...</code></em>);</pre> |
| <p> |
| Add a line to the image history. The <em class="parameter"><code>fmt</code></em> and arguments are expanded, the |
| date and time is appended prefixed with a hash character, and the whole |
| string is appended to the image history and terminated with a newline. |
| </p> |
| <p> |
| For example: |
| </p> |
| <p> |
| </p> |
| <div class="informalexample"><pre class="programlisting"> |
| im_histlin( im, "vips im_invert %s %s", in->filename, out->filename ); |
| </pre></div> |
| <p> |
| </p> |
| <p> |
| Might add the string |
| </p> |
| <p> |
| </p> |
| <div class="informalexample"><pre class="programlisting"> |
| "vips im_invert /home/john/fred.v /home/john/jim.v # Fri Apr 3 23:30:35 |
| 2009\n" |
| </pre></div> |
| <p> |
| </p> |
| <p> |
| VIPS operations don't add history lines for you because a single action at |
| the application level might involve many VIPS operations. History must be |
| recorded by the application. |
| </p> |
| <p> |
| See also: <a class="link" href="libvips-header.html#im-updatehist" title="im_updatehist ()"><code class="function">im_updatehist()</code></a>. |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>im</code></em> :</span></p></td> |
| <td>add history liine to this image |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>fmt</code></em> :</span></p></td> |
| <td>printf() format string |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>...</code></em> :</span></p></td> |
| <td>arguments to format string |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> |
| <td> 0 on success, -1 on error. |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2" title="im_updatehist ()"> |
| <a name="im-updatehist"></a><h3>im_updatehist ()</h3> |
| <pre class="programlisting"><span class="returnvalue">int</span> im_updatehist (<em class="parameter"><code><span class="type">IMAGE</span> *out</code></em>, |
| <em class="parameter"><code>const <span class="type">char</span> *name</code></em>, |
| <em class="parameter"><code><span class="type">int</span> argc</code></em>, |
| <em class="parameter"><code><span class="type">char</span> *argv[]</code></em>);</pre> |
| <p> |
| Formats the name/argv as a single string and calls <a class="link" href="libvips-header.html#im-histlin" title="im_histlin ()"><code class="function">im_histlin()</code></a>. A |
| convenience function for command-line prorams. |
| </p> |
| <p> |
| See also: <a class="link" href="libvips-header.html#im-history-get" title="im_history_get ()"><code class="function">im_history_get()</code></a>. |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>out</code></em> :</span></p></td> |
| <td>image to attach history line to |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>name</code></em> :</span></p></td> |
| <td>program name |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>argc</code></em> :</span></p></td> |
| <td>number of program arguments |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>argv</code></em> :</span></p></td> |
| <td>program arguments |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> |
| <td> 0 on success, -1 on error. |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2" title="im_history_get ()"> |
| <a name="im-history-get"></a><h3>im_history_get ()</h3> |
| <pre class="programlisting">const <span class="returnvalue">char</span> * im_history_get (<em class="parameter"><code><span class="type">IMAGE</span> *im</code></em>);</pre> |
| <p> |
| This function reads the image history as a C string. The string is owned |
| by VIPS and must not be freed. |
| </p> |
| <p> |
| VIPS tracks the history of each image, that is, the sequence of operations |
| that generated that image. Applications built on VIPS need to call |
| <a class="link" href="libvips-header.html#im-histlin" title="im_histlin ()"><code class="function">im_histlin()</code></a> for each action they perform setting the command-line |
| equivalent for the action. |
| </p> |
| <p> |
| See also: <a class="link" href="libvips-header.html#im-histlin" title="im_histlin ()"><code class="function">im_histlin()</code></a>. |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>im</code></em> :</span></p></td> |
| <td>get history from here |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> |
| <td> The history of <em class="parameter"><code>im</code></em> as a C string. Do not free! |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| </div> |
| <div class="refsect1" title="See Also"> |
| <a name="libvips-header.see-also"></a><h2>See Also</h2> |
| <a class="link" href="libvips-meta.html" title="meta">meta</a>, |
| <a class="link" href="libvips-check.html" title="check">check</a> |
| </div> |
| </div> |
| <div class="footer"> |
| <hr> |
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