/*
    * Copyright 2007 - 2007 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: AbstractRoot.java,v bc1d5fde7b73 2009/06/01 14:40:54 maxberger $ */
  
  package net.sourceforge.jeuclid.elements.presentation.general;
  
  import java.awt.Color;
  import java.awt.FontMetrics;
  import java.awt.Graphics2D;
  import java.util.List;
  
  import net.sourceforge.jeuclid.LayoutContext;
  import net.sourceforge.jeuclid.context.Parameter;
  import net.sourceforge.jeuclid.elements.AbstractJEuclidElement;
  import net.sourceforge.jeuclid.elements.support.GraphicsSupport;
  import net.sourceforge.jeuclid.elements.support.attributes.AttributesHelper;
  import net.sourceforge.jeuclid.layout.GraphicsObject;
  import net.sourceforge.jeuclid.layout.LayoutInfo;
  import net.sourceforge.jeuclid.layout.LayoutStage;
  import net.sourceforge.jeuclid.layout.LayoutView;
  import net.sourceforge.jeuclid.layout.LayoutableNode;
  import net.sourceforge.jeuclid.layout.LineObject;
  
  import org.apache.batik.dom.AbstractDocument;
  import org.w3c.dom.mathml.MathMLRadicalElement;
  
  /**
   * common superclass for root like elements (root, sqrt).
   * 
   * @version $Revision: bc1d5fde7b73 $
   */
  public abstract class AbstractRoot extends AbstractJEuclidElement implements
          MathMLRadicalElement {
  
      private static final String EXTRA_SPACE = "0.1ex";
  
      private static final String ROOT_WIDTH = "0.5em";
  
      /**
       * Default constructor. Sets MathML Namespace.
       * 
       * @param qname
       *            Qualified name.
       * @param odoc
       *            Owner Document.
       */
      public AbstractRoot(final String qname, final AbstractDocument odoc) {
          super(qname, odoc);
      }
  
      /**
       * retrieve the content of this radical element.
       * 
       * @return A List<MathElement> with the contents for this element.
       */
      protected abstract List<LayoutableNode> getContent();
  
      /** {@inheritDoc} */
      // CHECKSTYLE:OFF
      // This function is too long, but it depends on too many parameters.
      @Override
      protected void layoutStageInvariant(final LayoutView view,
              final LayoutInfo info, final LayoutStage stage,
              final LayoutContext context) {
          // CHECKSTYLE:ON
  
          // Basic Calculations
          final Graphics2D g = view.getGraphics();
          final LayoutContext now = this.applyLocalAttributesToContext(context);
          final float middleShift = this.getMiddleShift(g, context);
          final float linethickness = GraphicsSupport.lineWidth(now);
          final float extraSpace = AttributesHelper.convertSizeToPt(
                  AbstractRoot.EXTRA_SPACE, now, "");
          final float rootwidth = AttributesHelper.convertSizeToPt(
                  AbstractRoot.ROOT_WIDTH, context, "");
          final Color color = (Color) now.getParameter(Parameter.MATHCOLOR);
          float xPos = linethickness;
          final LayoutableNode index = (LayoutableNode) this.getIndex();
          final List<GraphicsObject> graphicObjects = info.getGraphicObjects();
          graphicObjects.clear();
  
          // Draw Index
          float indexAscent;
          if (index == null) {
              indexAscent = 0.0f;
         } else {
             final LayoutInfo indexInfo = view.getInfo(index);
             final float indexPos = middleShift + linethickness / 2.0f
                     + extraSpace + indexInfo.getDescentHeight(stage);
             indexInfo.moveTo(xPos, -indexPos, stage);
             xPos += indexInfo.getWidth(stage);
             graphicObjects.add(new LineObject(linethickness, -middleShift,
                     xPos, -middleShift, linethickness, color));
             indexAscent = indexPos + indexInfo.getAscentHeight(stage);
         }
 
         // Skip Root Space
         xPos += rootwidth;
 
         // Draw Content below Root
         final float contentStartX = xPos;
         final FontMetrics metrics = this
                 .getFontMetrics(view.getGraphics(), now);
         float maxAscent = metrics.getAscent();
         float maxDescent = metrics.getDescent();
         for (final LayoutableNode child : this.getContent()) {
             final LayoutInfo childInfo = view.getInfo(child);
             childInfo.moveTo(xPos, 0, stage);
             maxAscent = Math.max(maxAscent, childInfo.getAscentHeight(stage));
             maxDescent = Math
                     .max(maxDescent, childInfo.getDescentHeight(stage));
             xPos += childInfo.getWidth(stage);
         }
         xPos += 2 * extraSpace;
         final float topLinePos = maxAscent + 2 * extraSpace + linethickness
                 / 2.0f;
 
         // Fill in Info
         info.setAscentHeight(Math.max(topLinePos + linethickness / 2.0f,
                 indexAscent), stage);
         info.setDescentHeight(maxDescent + linethickness / 2.0f, stage);
         info.setHorizontalCenterOffset(xPos / 2.0f, stage);
         info.setWidth(xPos + linethickness, stage);
         info.setStretchAscent(maxAscent);
         info.setStretchDescent(maxDescent);
 
         // Add Root Glyph
         graphicObjects.add(new LineObject(contentStartX - rootwidth,
                 -middleShift, contentStartX - rootwidth / 2.0f, maxDescent,
                 linethickness, color));
         graphicObjects.add(new LineObject(contentStartX - rootwidth / 2.0f,
                 maxDescent, contentStartX, -topLinePos, linethickness, color));
         graphicObjects.add(new LineObject(contentStartX, -topLinePos, xPos,
                 -topLinePos, linethickness, color));
     }
 }