my-jdk/jdkSrc/jdk8/javax/swing/text/html/NoFramesView.java

/*
 * Copyright (c) 1998, 2000, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package javax.swing.text.html;

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

/**
 * This is the view associated with the html tag NOFRAMES.
 * This view has been written to ignore the contents of the
 * NOFRAMES tag.  The contents of the tag will only be visible
 * when the JTextComponent the view is contained in is editable.
 *
 * @author  Sunita Mani
 */
class NoFramesView extends BlockView {

    /**
     * Creates a new view that represents an
     * html box.  This can be used for a number
     * of elements.  By default this view is not
     * visible.
     *
     * @param elem the element to create a view for
     * @param axis either View.X_AXIS or View.Y_AXIS
     */
    public NoFramesView(Element elem, int axis) {
        super(elem, axis);
        visible = false;
    }


    /**
     * If this view is not visible, then it returns.
     * Otherwise it invokes the superclass.
     *
     * @param g the rendering surface to use
     * @param allocation the allocated region to render into
     * @see #isVisible
     * @see text.ParagraphView#paint
     */
    public void paint(Graphics g, Shape allocation) {
        Container host = getContainer();
        if (host != null &&
            visible != ((JTextComponent)host).isEditable()) {
            visible = ((JTextComponent)host).isEditable();
        }

        if (!isVisible()) {
            return;
        }
        super.paint(g, allocation);
    }


    /**
     * Determines if the JTextComponent that the view
     * is contained in is editable. If so, then this
     * view and all its child views are visible.
     * Once this has been determined, the superclass
     * is invoked to continue processing.
     *
     * @param p the parent View.
     * @see BlockView#setParent
     */
    public void setParent(View p) {
        if (p != null) {
            Container host = p.getContainer();
            if (host != null) {
                visible = ((JTextComponent)host).isEditable();
            }
        }
        super.setParent(p);
    }

    /**
     * Returns a true/false value that represents
     * whether the view is visible or not.
     */
    public boolean isVisible() {
        return visible;
    }


    /**
     * Do nothing if the view is not visible, otherwise
     * invoke the superclass to perform layout.
     */
    protected void layout(int width, int height) {
        if (!isVisible()) {
            return;
        }
        super.layout(width, height);
    }

    /**
     * Determines the preferred span for this view.  Returns
     * 0 if the view is not visible, otherwise it calls the
     * superclass method to get the preferred span.
     * axis.
     *
     * @param axis may be either View.X_AXIS or View.Y_AXIS
     * @return   the span the view would like to be rendered into;
     *           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
     * @see text.ParagraphView#getPreferredSpan
     */
    public float getPreferredSpan(int axis) {
        if (!visible) {
            return 0;
        }
        return super.getPreferredSpan(axis);
    }

    /**
     * Determines the minimum span for this view along an
     * axis.  Returns 0 if the view is not visible, otherwise
     * it calls the superclass method to get the minimum span.
     *
     * @param axis may be either <code>View.X_AXIS</code> or
     *          <code>View.Y_AXIS</code>
     * @return  the minimum span the view can be rendered into
     * @see text.ParagraphView#getMinimumSpan
     */
    public float getMinimumSpan(int axis) {
        if (!visible) {
            return 0;
        }
        return super.getMinimumSpan(axis);
    }

    /**
     * Determines the maximum span for this view along an
     * axis.  Returns 0 if the view is not visible, otherwise
     * it calls the superclass method ot get the maximum span.
     *
     * @param axis may be either <code>View.X_AXIS</code> or
     *  <code>View.Y_AXIS</code>
     * @return  the maximum span the view can be rendered into
     * @see text.ParagraphView#getMaximumSpan
     */
    public float getMaximumSpan(int axis) {
        if (!visible) {
            return 0;
        }
        return super.getMaximumSpan(axis);
    }

    boolean visible;
}