/*

 * Copyright (c) 1997, 2003, 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 java.util.Enumeration;

import java.awt.*;

import javax.swing.*;

import javax.swing.border.*;

import javax.swing.event.*;

import javax.swing.text.*;

/**

 * A view implementation to display an unwrapped

 * preformatted line.<p>

 * This subclasses ParagraphView, but this really only contains one

 * Row of text.

 *

 * @author  Timothy Prinzing

 */

class LineView extends ParagraphView {

    /** Last place painted at. */

    int tabBase;

    /**

     * Creates a LineView object.

     *

     * @param elem the element to wrap in a view

     */

    public LineView(Element elem) {

        super(elem);

    }

    /**

     * Preformatted lines are not suppressed if they

     * have only whitespace, so they are always visible.

     */

    public boolean isVisible() {

        return true;

    }

    /**

     * Determines the minimum span for this view along an

     * axis.  The preformatted line should refuse to be

     * sized less than the preferred size.

     *

     * @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 View#getPreferredSpan

     */

    public float getMinimumSpan(int axis) {

        return getPreferredSpan(axis);

    }

    /**

     * Gets the resize weight for the specified axis.

     *

     * @param axis may be either X_AXIS or Y_AXIS

     * @return the weight

     */

    public int getResizeWeight(int axis) {

        switch (axis) {

        case View.X_AXIS:

            return 1;

        case View.Y_AXIS:

            return 0;

        default:

            throw new IllegalArgumentException("Invalid axis: " + axis);

        }

    }

    /**

     * Gets the alignment for an axis.

     *

     * @param axis may be either X_AXIS or Y_AXIS

     * @return the alignment

     */

    public float getAlignment(int axis) {

        if (axis == View.X_AXIS) {

            return 0;

        }

        return super.getAlignment(axis);

    }

    /**

     * Lays out the children.  If the layout span has changed,

     * the rows are rebuilt.  The superclass functionality

     * is called after checking and possibly rebuilding the

     * rows.  If the height has changed, the

     * <code>preferenceChanged</code> method is called

     * on the parent since the vertical preference is

     * rigid.

     *

     * @param width  the width to lay out against >= 0.  This is

     *   the width inside of the inset area.

     * @param height the height to lay out against >= 0 (not used

     *   by paragraph, but used by the superclass).  This

     *   is the height inside of the inset area.

     */

    protected void layout(int width, int height) {

        super.layout(Integer.MAX_VALUE - 1, height);

    }

    /**

     * Returns the next tab stop position given a reference position.

     * This view implements the tab coordinate system, and calls

     * <code>getTabbedSpan</code> on the logical children in the process

     * of layout to determine the desired span of the children.  The

     * logical children can delegate their tab expansion upward to

     * the paragraph which knows how to expand tabs.

     * <code>LabelView</code> is an example of a view that delegates

     * its tab expansion needs upward to the paragraph.

     * <p>

     * This is implemented to try and locate a <code>TabSet</code>

     * in the paragraph element's attribute set.  If one can be

     * found, its settings will be used, otherwise a default expansion

     * will be provided.  The base location for for tab expansion

     * is the left inset from the paragraphs most recent allocation

     * (which is what the layout of the children is based upon).

     *

     * @param x the X reference position

     * @param tabOffset the position within the text stream

     *   that the tab occurred at >= 0.

     * @return the trailing end of the tab expansion >= 0

     * @see TabSet

     * @see TabStop

     * @see LabelView

     */

    public float nextTabStop(float x, int tabOffset) {

        // If the text isn't left justified, offset by 10 pixels!

        if (getTabSet() == null &&

            StyleConstants.getAlignment(getAttributes()) ==

            StyleConstants.ALIGN_LEFT) {

            return getPreTab(x, tabOffset);

        }

        return super.nextTabStop(x, tabOffset);

    }

    /**

     * Returns the location for the tab.

     */

    protected float getPreTab(float x, int tabOffset) {

        Document d = getDocument();

        View v = getViewAtPosition(tabOffset, null);

        if ((d instanceof StyledDocument) && v != null) {

            // Assume f is fixed point.

            Font f = ((StyledDocument)d).getFont(v.getAttributes());

            Container c = getContainer();

            FontMetrics fm = (c != null) ? c.getFontMetrics(f) :

                Toolkit.getDefaultToolkit().getFontMetrics(f);

            int width = getCharactersPerTab() * fm.charWidth('W');

            int tb = (int)getTabBase();

            return (float)((((int)x - tb) / width + 1) * width + tb);

        }

        return 10.0f + x;

    }

    /**

     * @return number of characters per tab, 8.

     */

    protected int getCharactersPerTab() {

        return 8;

    }

}