Bugzilla #40676: Update site documentation about PNG image loading configuration and support. Submitted by Luis Bernardo.

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@1351540 13f79535-47bb-0310-9956-ffa450edef68

src/documentation/content/xdocs/trunk/configuration.xml

@@ -281,6 +281,24 @@
       treated as zero penalty in most cases. For more details on the image loading framework,
       please consult the documentation there.
     </p>
+    <p>
+      The ImageLoaderPNG and ImageLoaderRawPNG have a hard-coded penalty of 1000 and as such the
+      ImageLoaderImageIO image loader will be selected by default when loading PNGs unless
+      the latter is disabled by awarding a INFINITE penalty to it, or one of the former two is 
+      promoted by awarding a strong negative penalty (say, -10000) to it.
+    </p>
+    <source><![CDATA[<fop version="1.0">
+  [..]
+  <image-loading>
+    <penalty value="-10000"
+      class="org.apache.xmlgraphics.image.loader.impl.ImageLoaderRawPNG"/>
+    <penalty value="INFINITE"
+      class="org.apache.xmlgraphics.image.loader.impl.ImageLoaderPNG"/>
+    <penalty value="INFINITE"
+      class="org.apache.xmlgraphics.image.loader.impl.imageio.ImageLoaderImageIO"/>
+  </image-loading>
+  <renderers....
+</fop>]]></source>
   </section>
   <section id="renderers">
     <title>Renderer configuration</title>

src/documentation/content/xdocs/trunk/graphics.xml

@@ -108,7 +108,7 @@
         <tr>
           <td><a href="#png">PNG</a> (Portable Network Graphic)</td>
           <td>bitmap</td>
-          <td/>
+          <td>(X)</td>
           <td/>
           <td>X</td>
         </tr>
@@ -217,8 +217,8 @@
           </tr>
           <tr>
             <td><a href="#png">PNG</a> (Portable Network Graphic)</td>
-            <td>X</td>
-            <td>X</td>
+            <td>X [2]</td>
+            <td>X [2]</td>
             <td>X</td>
             <td>X</td>
             <td>X</td>
@@ -383,8 +383,11 @@
       <section id="png">
         <title>PNG</title>
         <p>
-          PNG images are supported through an Image&amp;nbsp;I/O codec. Transparency is supported but
-          not guaranteed to work with every output format.
+          FOP native support of PNG only includes the variants with 8 bits per channel and without
+          interlacing. Native support requires using the ImageLoaderRawPNG image loader.
+          Support through a Image I/O codec can use either the internal XGC PNG codec or the JRE PNG
+          codec. The associated image loaders are, respectively, ImageLoaderPNG and ImageLoaderImageIO. 
+          Transparency is supported but not guaranteed to work with every output format.
         </p>
       </section>
       <section id="svg">

status.xml

@@ -63,6 +63,9 @@
       documents. Example: the fix of marks layering will be such a case when it's done.
     -->
     <release version="FOP Trunk" date="TBD">
+      <action context="Images" dev="GA" type="update" fixes-bug="40676" due-to="Luis Bernardo">
+        Update site documentation about PNG image loading configuration and support.
+      </action>
       <action context="Images" dev="GA" type="update" fixes-bug="40676" due-to="Luis Bernardo">
         Fix newly introduced findbugs warnings.
       </action>