/*
    * Copyright 2002 - 2008 JEuclid, http://jeuclid.sf.net
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *      http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  /* $Id: PreloaderMathML.java,v 32023847f457 2009/03/20 14:20:15 maxberger $ */
  
  package net.sourceforge.jeuclid.xmlgraphics;
  
  import java.awt.Graphics2D;
  import java.awt.Image;
  import java.awt.image.BufferedImage;
  import java.io.IOException;
  import java.io.InputStream;
  
  import javax.xml.transform.Source;
  import javax.xml.transform.dom.DOMSource;
  import javax.xml.transform.stream.StreamSource;
  
  import net.sourceforge.jeuclid.Constants;
  import net.sourceforge.jeuclid.context.LayoutContextImpl;
  import net.sourceforge.jeuclid.elements.AbstractJEuclidElement;
  import net.sourceforge.jeuclid.elements.generic.MathImpl;
  import net.sourceforge.jeuclid.layout.JEuclidView;
  import net.sourceforge.jeuclid.parser.Parser;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.fop.util.UnclosableInputStream;
  import org.apache.xmlgraphics.image.loader.ImageContext;
  import org.apache.xmlgraphics.image.loader.ImageException;
  import org.apache.xmlgraphics.image.loader.ImageInfo;
  import org.apache.xmlgraphics.image.loader.ImageSize;
  import org.apache.xmlgraphics.image.loader.impl.AbstractImagePreloader;
  import org.apache.xmlgraphics.image.loader.impl.ImageXMLDOM;
  import org.apache.xmlgraphics.image.loader.util.ImageUtil;
  import org.w3c.dom.Document;
  import org.w3c.dom.Element;
  import org.xml.sax.SAXException;
  
  /**
   * @version $Revision: 32023847f457 $
   */
  public class PreloaderMathML extends AbstractImagePreloader {
      /**
       * Convert from point to millipoint.
       */
      public static final float MPT_FACTOR = 1000.0f;
  
      /**
       * Logger for this class
       */
      private static final Log LOGGER = LogFactory
              .getLog(PreloaderMathML.class);
  
      /**
       * Default Constructor.
       */
      public PreloaderMathML() {
          // Empty on purpose
      }
  
      /** {@inheritDoc} */
      public ImageInfo preloadImage(final String uri, final Source src,
              final ImageContext context) throws ImageException, IOException {
          final Document n = this.parseSource(src);
          if (n != null) {
              return this.createImageInfo(uri, context, n);
          }
  
          return null;
      }
  
      @SuppressWarnings("unchecked")
      private ImageInfo createImageInfo(final String uri,
              final ImageContext context, final Document n) {
          final ImageInfo info = new ImageInfo(uri, Constants.MATHML_MIMETYPE);
          final ImageSize size = new ImageSize();
          final Image tempimage = new BufferedImage(1, 1,
                  BufferedImage.TYPE_INT_ARGB);
          final Graphics2D tempg = (Graphics2D) tempimage.getGraphics();
          final JEuclidView view = new JEuclidView(n, LayoutContextImpl
                  .getDefaultLayoutContext(), tempg);
          final int descentMpt = (int) (view.getDescentHeight() * PreloaderMathML.MPT_FACTOR);
          final int ascentMpt = (int) (view.getAscentHeight() * PreloaderMathML.MPT_FACTOR);
  
          size.setSizeInMillipoints(
                  (int) (view.getWidth() * PreloaderMathML.MPT_FACTOR),
                 ascentMpt + descentMpt);
         size.setBaselinePositionFromBottom(descentMpt);
         // Set the resolution to that of the FOUserAgent
         size.setResolution(context.getSourceResolution());
         size.calcPixelsFromSize();
         info.setSize(size);
 
         // The whole image had to be loaded for this, so keep it
         final ImageXMLDOM xmlImage = new ImageXMLDOM(info, n,
                 AbstractJEuclidElement.URI);
         info.getCustomObjects().put(ImageInfo.ORIGINAL_IMAGE, xmlImage);
         return info;
     }
 
     private Document parseSource(final Source src) {
         Document n = null;
         InputStream in = null;
         try {
             if (src instanceof DOMSource) {
                 final DOMSource domSrc = (DOMSource) src;
                 n = (Document) domSrc.getNode();
             } else {
                 in = new UnclosableInputStream(ImageUtil.needInputStream(src));
                 final int length = in.available();
                 in.mark(length + 1);
                 n = Parser.getInstance().parseStreamSource(
                         new StreamSource(in));
             }
             final Element rootNode = n.getDocumentElement();
             if (!(AbstractJEuclidElement.URI.equals(rootNode
                     .getNamespaceURI()) || MathImpl.ELEMENT.equals(rootNode
                     .getNodeName()))) {
                 n = null;
             }
         } catch (final IOException e) {
             n = null;
         } catch (final SAXException e) {
             n = null;
         } catch (final IllegalArgumentException e) {
             n = null;
         } catch (final NullPointerException e) {
             // Due to a bug in xmlgraphics-commons 1.3.1 which sometimes
             // creates wrapper around null streams if files do not exist.
             n = null;
         }
         try {
             if (in != null) {
                 in.reset();
             }
         } catch (final IOException ioe) {
             PreloaderMathML.LOGGER.warn("Should never happen: "
                     + ioe.getMessage());
         } catch (final NullPointerException e) {
             // Due to a bug in xmlgraphics-commons 1.3.1 which sometimes
             // creates wrapper around null streams if files do not exist.
             n = null;
         }
         return n;
     }
 }