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package javax.swing.text;

import java.awt.*;
import javax.swing.*;
import javax.swing.event.*;


Extends the multi-line plain text view to be suitable
for a single-line editor view.  If the view is
allocated extra space, the field must adjust for it.
If the hosting component is a JTextField, this view
will manage the ranges of the associated BoundedRangeModel
and will adjust the horizontal allocation to match the
current visibility settings of the JTextField.

Author: Timothy Prinzing
See Also:
/**
 * Extends the multi-line plain text view to be suitable
 * for a single-line editor view.  If the view is
 * allocated extra space, the field must adjust for it.
 * If the hosting component is a JTextField, this view
 * will manage the ranges of the associated BoundedRangeModel
 * and will adjust the horizontal allocation to match the
 * current visibility settings of the JTextField.
 *
 * @author  Timothy Prinzing
 * @see     View
 */
public class FieldView extends PlainView {

    
Constructs a new FieldView wrapped on an element.

Params:
  • elem – the element
/**
     * Constructs a new FieldView wrapped on an element.
     *
     * @param elem the element
     */
    public FieldView(Element elem) {
        super(elem);
    }

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

Returns:the metrics
/**
     * Fetches the font metrics associated with the component hosting
     * this view.
     *
     * @return the metrics
     */
    protected FontMetrics getFontMetrics() {
        Component c = getContainer();
        return c.getFontMetrics(c.getFont());
    }

    
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).

Params:
  • a – the allocation given to the view, which may need
 to be adjusted.
Returns:the allocation that the superclass should use.
/**
     * 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).
     *
     * @param a the allocation given to the view, which may need
     *  to be adjusted.
     * @return the allocation that the superclass should use.
     */
    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;
    }

    
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.

/**
     * 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.
     */
    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);
        }
    }

    // --- View methods -------------------------------------------

    
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.

Params:
  • g – the rendering surface to use
  • a – the allocated region to render into
See Also:
/**
     * 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.
     *
     * @param g the rendering surface to use
     * @param a the allocated region to render into
     *
     * @see View#paint
     */
    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);
    }

    
Adjusts a based on the visible region and returns it.

/**
     * Adjusts <code>a</code> based on the visible region and returns it.
     */
    Shape adjustPaintRegion(Shape a) {
        return adjustAllocation(a);
    }

    
Determines the preferred span for this view along an
axis.

Params:
  • axis – may be either View.X_AXIS or View.Y_AXIS
Returns:  the span the view would like to be rendered into >= 0.
          Typically the view is told to render into the span
          that is returned, although there is no guarantee.
          The parent may choose to resize or break the view.
/**
     * Determines the preferred span for this view along an
     * axis.
     *
     * @param axis may be either View.X_AXIS or View.Y_AXIS
     * @return   the span the view would like to be rendered into &gt;= 0.
     *           Typically the view is told to render into the span
     *           that is returned, although there is no guarantee.
     *           The parent may choose to resize or break the 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 resizability of the view along the
given axis.  A value of 0 or less is not resizable.

Params:
  • axis – View.X_AXIS or View.Y_AXIS
Returns:the weight -> 1 for View.X_AXIS, else 0
/**
     * Determines the resizability of the view along the
     * given axis.  A value of 0 or less is not resizable.
     *
     * @param axis View.X_AXIS or View.Y_AXIS
     * @return the weight -&gt; 1 for View.X_AXIS, else 0
     */
    public int getResizeWeight(int axis) {
        if (axis == View.X_AXIS) {
            return 1;
        }
        return 0;
    }

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

Params:
  • pos – the position to convert >= 0
  • a – the allocated region to render into
Throws:
  • BadLocationException –  if the given position does not
  represent a valid location in the associated document
See Also:
Returns:the bounding box of the given position
/**
     * 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 &gt;= 0
     * @param a the allocated region to render into
     * @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 {
        return super.modelToView(pos, adjustAllocation(a), b);
    }

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

Params:
  • fx – the X coordinate >= 0.0f
  • fy – the Y coordinate >= 0.0f
  • a – the allocated region to render into
See Also:
Returns:the location within the model that best represents the
 given point in the view
/**
     * Provides a mapping from the view coordinate space to the logical
     * coordinate space of the model.
     *
     * @param fx the X coordinate &gt;= 0.0f
     * @param fy the Y coordinate &gt;= 0.0f
     * @param a the allocated region to render into
     * @return the location within the model that best represents the
     *  given point in the view
     * @see View#viewToModel
     */
    public int viewToModel(float fx, float fy, Shape a, Position.Bias[] bias) {
        return super.viewToModel(fx, fy, adjustAllocation(a), bias);
    }

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

Params:
  • changes – the change information from the associated document
  • a – the current allocation of the view
  • f – the factory to use to rebuild if the view has children
See Also:
/**
     * Gives notification that something was inserted into the document
     * in a location that this view is responsible for.
     *
     * @param changes the change information from the associated document
     * @param a the current allocation of the view
     * @param f the factory to use to rebuild if the view has children
     * @see View#insertUpdate
     */
    public void insertUpdate(DocumentEvent changes, Shape a, ViewFactory f) {
        super.insertUpdate(changes, adjustAllocation(a), f);
        updateVisibilityModel();
    }

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

Params:
  • changes – the change information from the associated document
  • a – the current allocation of the view
  • f – the factory to use to rebuild if the view has children
See Also:
/**
     * Gives notification that something was removed from the document
     * in a location that this view is responsible for.
     *
     * @param changes the change information from the associated document
     * @param a the current allocation of the view
     * @param f the factory to use to rebuild if the view has children
     * @see View#removeUpdate
     */
    public void removeUpdate(DocumentEvent changes, Shape a, ViewFactory f) {
        super.removeUpdate(changes, adjustAllocation(a), f);
        updateVisibilityModel();
    }

}