/**
  * Provides a mapping from the document model coordinate space to the coordinate space of the view
  * mapped to it.
  *
  * @param pos the position to convert >= 0
  * @param a the allocated region to render into
  * @param b a bias value of either <code>Position.Bias.Forward</code> or <code>
  *     Position.Bias.Backward</code>
  * @return the bounding box of the given position
  * @exception BadLocationException if the given position does not represent a valid location in
  *     the associated document
  * @see View#modelToView
  */
 public Shape modelToView(int pos, Shape a, Position.Bias b) throws BadLocationException {
   boolean isBackward = (b == Position.Bias.Backward);
   int testPos = (isBackward) ? Math.max(0, pos - 1) : pos;
   if (isBackward && testPos < getStartOffset()) {
     return null;
   }
   int vIndex = getViewIndexAtPosition(testPos);
   if ((vIndex != -1) && (vIndex < getViewCount())) {
     View v = getView(vIndex);
     if (v != null && testPos >= v.getStartOffset() && testPos < v.getEndOffset()) {
       Shape childShape = getChildAllocation(vIndex, a);
       if (childShape == null) {
         // We are likely invalid, fail.
         return null;
       }
       Shape retShape = v.modelToView(pos, childShape, b);
       if (retShape == null && v.getEndOffset() == pos) {
         if (++vIndex < getViewCount()) {
           v = getView(vIndex);
           retShape = v.modelToView(pos, getChildAllocation(vIndex, a), b);
         }
       }
       return retShape;
     }
   }
   throw new BadLocationException("Position not represented by view", pos);
 }
  /**
   * Provides a mapping from the document model coordinate space to the coordinate space of the view
   * mapped to it.
   *
   * @param p0 the position to convert &gt;= 0
   * @param b0 the bias toward the previous character or the next character represented by p0, in
   *     case the position is a boundary of two views; either <code>Position.Bias.Forward</code> or
   *     <code>Position.Bias.Backward</code>
   * @param p1 the position to convert &gt;= 0
   * @param b1 the bias toward the previous character or the next character represented by p1, in
   *     case the position is a boundary of two views
   * @param a the allocated region to render into
   * @return the bounding box of the given position is returned
   * @exception BadLocationException if the given position does not represent a valid location in
   *     the associated document
   * @exception IllegalArgumentException for an invalid bias argument
   * @see View#viewToModel
   */
  public Shape modelToView(int p0, Position.Bias b0, int p1, Position.Bias b1, Shape a)
      throws BadLocationException {
    if (p0 == getStartOffset() && p1 == getEndOffset()) {
      return a;
    }
    Rectangle alloc = getInsideAllocation(a);
    Rectangle r0 = new Rectangle(alloc);
    View v0 = getViewAtPosition((b0 == Position.Bias.Backward) ? Math.max(0, p0 - 1) : p0, r0);
    Rectangle r1 = new Rectangle(alloc);
    View v1 = getViewAtPosition((b1 == Position.Bias.Backward) ? Math.max(0, p1 - 1) : p1, r1);
    if (v0 == v1) {
      if (v0 == null) {
        return a;
      }
      // Range contained in one view
      return v0.modelToView(p0, b0, p1, b1, r0);
    }
    // Straddles some views.
    int viewCount = getViewCount();
    int counter = 0;
    while (counter < viewCount) {
      View v;
      // Views may not be in same order as model.
      // v0 or v1 may be null if there is a gap in the range this
      // view contains.
      if ((v = getView(counter)) == v0 || v == v1) {
        View endView;
        Rectangle retRect;
        Rectangle tempRect = new Rectangle();
        if (v == v0) {
          retRect =
              v0.modelToView(p0, b0, v0.getEndOffset(), Position.Bias.Backward, r0).getBounds();
          endView = v1;
        } else {
          retRect =
              v1.modelToView(v1.getStartOffset(), Position.Bias.Forward, p1, b1, r1).getBounds();
          endView = v0;
        }

        // Views entirely covered by range.
        while (++counter < viewCount && (v = getView(counter)) != endView) {
          tempRect.setBounds(alloc);
          childAllocation(counter, tempRect);
          retRect.add(tempRect);
        }

        // End view.
        if (endView != null) {
          Shape endShape;
          if (endView == v1) {
            endShape = v1.modelToView(v1.getStartOffset(), Position.Bias.Forward, p1, b1, r1);
          } else {
            endShape = v0.modelToView(p0, b0, v0.getEndOffset(), Position.Bias.Backward, r0);
          }
          if (endShape instanceof Rectangle) {
            retRect.add((Rectangle) endShape);
          } else {
            retRect.add(endShape.getBounds());
          }
        }
        return retRect;
      }
      counter++;
    }
    throw new BadLocationException("Position not represented by view", p0);
  }