public FieldView(Element elem) 
{
        super(elem);
}

Constructs a new FieldView wrapped on an element.

Parameters:

elem - the element

 protected Shape adjustAllocation(Shape a) 
{
        if (a != null) {
            Rectangle bounds = a.getBounds();
            int vspan = (int) getPreferredSpan(Y_AXIS);
            int hspan = (int) getPreferredSpan(X_AXIS);
            if (bounds.height != vspan) {
                int slop = bounds.height - vspan;
                bounds.y += slop / 2;
                bounds.height -= slop;
            }
            // horizontal adjustments
            Component c = getContainer();
            if (c instanceof JTextField) {
                JTextField field = (JTextField) c;
                BoundedRangeModel vis = field.getHorizontalVisibility();
                int max = Math.max(hspan, bounds.width);
                int value = vis.getValue();
                int extent = Math.min(max, bounds.width - 1);
                if ((value + extent)  > max) {
                    value = max - extent;
                }
                vis.setRangeProperties(value, extent, vis.getMinimum(),
                                       max, false);
                if (hspan <  bounds.width) {
                    // horizontally align the interior
                    int slop = bounds.width - 1 - hspan;
                    int align = ((JTextField)c).getHorizontalAlignment();
                    if(Utilities.isLeftToRight(c)) {
                        if(align==LEADING) {
                            align = LEFT;
                        }
                        else if(align==TRAILING) {
                            align = RIGHT;
                        }
                    }
                    else {
                        if(align==LEADING) {
                            align = RIGHT;
                        }
                        else if(align==TRAILING) {
                            align = LEFT;
                        }
                    }
                    switch (align) {
                    case SwingConstants.CENTER:
                        bounds.x += slop / 2;
                        bounds.width -= slop;
                        break;
                    case SwingConstants.RIGHT:
                        bounds.x += slop;
                        bounds.width -= slop;
                        break;
                    }
                } else {
                    // adjust the allocation to match the bounded range.
                    bounds.width = hspan;
                    bounds.x -= vis.getValue();
                }
            }
            return bounds;
        }
        return null;
}

Adjusts the allocation given to the view to be a suitable allocation for a text field. If the view has been allocated more than the preferred span vertically, the allocation is changed to be centered vertically. Horizontally the view is adjusted according to the horizontal alignment property set on the associated JTextField (if that is the type of the hosting component).

 Shape adjustPaintRegion(Shape a) 
{
        return adjustAllocation(a);
}

Adjusts a based on the visible region and returns it.

 protected FontMetrics getFontMetrics() 
{
        Component c = getContainer();
        return c.getFontMetrics(c.getFont());
}

Fetches the font metrics associated with the component hosting this view.

 public float getPreferredSpan(int axis) 
{
        switch (axis) {
        case View.X_AXIS:
            Segment buff = SegmentCache.getSharedSegment();
            Document doc = getDocument();
            int width;
            try {
                FontMetrics fm = getFontMetrics();
                doc.getText(0, doc.getLength(), buff);
                width = Utilities.getTabbedTextWidth(buff, fm, 0, this, 0);
                if (buff.count  > 0) {
                    Component c = getContainer();
                    firstLineOffset = sun.swing.SwingUtilities2.
                        getLeftSideBearing((c instanceof JComponent) ?
                                           (JComponent)c : null, fm,
                                           buff.array[buff.offset]);
                    firstLineOffset = Math.max(0, -firstLineOffset);
                }
                else {
                    firstLineOffset = 0;
                }
            } catch (BadLocationException bl) {
                width = 0;
            }
            SegmentCache.releaseSharedSegment(buff);
            return width + firstLineOffset;
        default:
            return super.getPreferredSpan(axis);
        }
}

Determines the preferred span for this view along an axis.

 public int getResizeWeight(int axis) 
{
        if (axis == View.X_AXIS) {
            return 1;
        }
        return 0;
}

Determines the resizability of the view along the given axis. A value of 0 or less is not resizable.

 public  void insertUpdate(DocumentEvent changes,
    Shape a,
    ViewFactory f) 
{
        super.insertUpdate(changes, adjustAllocation(a), f);
        updateVisibilityModel();
}

Gives notification that something was inserted into the document in a location that this view is responsible for.

 public Shape modelToView(int pos,
    Shape a,
    Bias b) throws BadLocationException 
{
        return super.modelToView(pos, adjustAllocation(a), b);
}

Provides a mapping from the document model coordinate space to the coordinate space of the view mapped to it.

 public  void paint(Graphics g,
    Shape a) 
{
        Rectangle r = (Rectangle) a;
        g.clipRect(r.x, r.y, r.width, r.height);
        super.paint(g, a);
}

Renders using the given rendering surface and area on that surface. The view may need to do layout and create child views to enable itself to render into the given allocation.

 public  void removeUpdate(DocumentEvent changes,
    Shape a,
    ViewFactory f) 
{
        super.removeUpdate(changes, adjustAllocation(a), f);
        updateVisibilityModel();
}

Gives notification that something was removed from the document in a location that this view is responsible for.

  void updateVisibilityModel() 
{
        Component c = getContainer();
        if (c instanceof JTextField) {
            JTextField field = (JTextField) c;
            BoundedRangeModel vis = field.getHorizontalVisibility();
            int hspan = (int) getPreferredSpan(X_AXIS);
            int extent = vis.getExtent();
            int maximum = Math.max(hspan, extent);
            extent = (extent == 0) ? maximum : extent;
            int value = maximum - extent;
            int oldValue = vis.getValue();
            if ((oldValue + extent)  > maximum) {
                oldValue = maximum - extent;
            }
            value = Math.max(0, Math.min(value, oldValue));
            vis.setRangeProperties(value, extent, 0, maximum, false);
        }
}

Update the visibility model with the associated JTextField (if there is one) to reflect the current visibility as a result of changes to the document model. The bounded range properties are updated. If the view hasn't yet been shown the extent will be zero and we just set it to be full until determined otherwise.

 public int viewToModel(float fx,
    float fy,
    Shape a,
    Bias[] bias) 
{
        return super.viewToModel(fx, fy, adjustAllocation(a), bias);
}

Provides a mapping from the view coordinate space to the logical coordinate space of the model.