/*

 * 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

 * particular file as subject to the "Classpath" exception as provided

 *

 * 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.

 *

 */

package javax.swing.text;

import java.awt.*;

import javax.swing.event.*;

/**

 * A <code>LabelView</code> is a styled chunk of text

 * that represents a view mapped over an element in the

 * text model.  It caches the character level attributes

 * used for rendering.

 *

 * @author Timothy Prinzing

 */

public class LabelView extends GlyphView implements TabableView {

    /**

     * Constructs a new view wrapped on an element.

     *

     * @param elem the element

     */

    public LabelView(Element elem) {

        super(elem);

    }

    /**

     * Synchronize the view's cached values with the model.

     * This causes the font, metrics, color, etc to be

     * re-cached if the cache has been invalidated.

     */

    final void sync() {

        if (font == null) {

            setPropertiesFromAttributes();

        }

    }

    /**

     * Sets whether or not the view is underlined.

     * Note that this setter is protected and is really

     * only meant if you need to update some additional

     * state when set.

     *

     * @param u true if the view is underlined, otherwise

     *          false

     * @see #isUnderline

     */

    protected void setUnderline(boolean u) {

        underline = u;

    }

    /**

     * Sets whether or not the view has a strike/line

     * through it.

     * Note that this setter is protected and is really

     * only meant if you need to update some additional

     * state when set.

     *

     * @param s true if the view has a strike/line

     *          through it, otherwise false

     * @see #isStrikeThrough

     */

    protected void setStrikeThrough(boolean s) {

        strike = s;

    }

    /**

     * Sets whether or not the view represents a

     * superscript.

     * Note that this setter is protected and is really

     * only meant if you need to update some additional

     * state when set.

     *

     * @param s true if the view represents a

     *          superscript, otherwise false

     * @see #isSuperscript

     */

    protected void setSuperscript(boolean s) {

        superscript = s;

    }

    /**

     * Sets whether or not the view represents a

     * subscript.

     * Note that this setter is protected and is really

     * only meant if you need to update some additional

     * state when set.

     *

     * @param s true if the view represents a

     *          subscript, otherwise false

     * @see #isSubscript

     */

    protected void setSubscript(boolean s) {

        subscript = s;

    }

    /**

     * Sets the background color for the view. This method is typically

     * invoked as part of configuring this <code>View</code>. If you need

     * to customize the background color you should override

     * <code>setPropertiesFromAttributes</code> and invoke this method. A

     * value of null indicates no background should be rendered, so that the

     * background of the parent <code>View</code> will show through.

     *

     * @param bg background color, or null

     * @see #setPropertiesFromAttributes

     * @since 1.5

     */

    protected void setBackground(Color bg) {

        this.bg = bg;

    }

    /**

     * Sets the cached properties from the attributes.

     */

    protected void setPropertiesFromAttributes() {

        AttributeSet attr = getAttributes();

        if (attr != null) {

            Document d = getDocument();

            if (d instanceof StyledDocument) {

                StyledDocument doc = (StyledDocument) d;

                font = doc.getFont(attr);

                fg = doc.getForeground(attr);

                if (attr.isDefined(StyleConstants.Background)) {

                    bg = doc.getBackground(attr);

                } else {

                    bg = null;

                }

                setUnderline(StyleConstants.isUnderline(attr));

                setStrikeThrough(StyleConstants.isStrikeThrough(attr));

                setSuperscript(StyleConstants.isSuperscript(attr));

                setSubscript(StyleConstants.isSubscript(attr));

            } else {

                throw new StateInvariantError("LabelView needs StyledDocument");

            }

        }

     }

    /**

     * Fetches the <code>FontMetrics</code> used for this view.

     * @deprecated FontMetrics are not used for glyph rendering

     *  when running in the JDK.

     */

    @Deprecated

    protected FontMetrics getFontMetrics() {

        sync();

        Container c = getContainer();

        return (c != null) ? c.getFontMetrics(font) :

            Toolkit.getDefaultToolkit().getFontMetrics(font);

    }

    /**

     * Fetches the background color to use to render the glyphs.

     * This is implemented to return a cached background color,

     * which defaults to <code>null</code>.

     *

     * @return the cached background color

     * @since 1.3

     */

    public Color getBackground() {

        sync();

        return bg;

    }

    /**

     * Fetches the foreground color to use to render the glyphs.

     * This is implemented to return a cached foreground color,

     * which defaults to <code>null</code>.

     *

     * @return the cached foreground color

     * @since 1.3

     */

    public Color getForeground() {

        sync();

        return fg;

    }

    /**

     * Fetches the font that the glyphs should be based upon.

     * This is implemented to return a cached font.

     *

     * @return the cached font

     */

     public Font getFont() {

        sync();

        return font;

    }

    /**

     * Determines if the glyphs should be underlined.  If true,

     * an underline should be drawn through the baseline.  This

     * is implemented to return the cached underline property.

     *

     * <p>When you request this property, <code>LabelView</code>

     * re-syncs its state with the properties of the

     * <code>Element</code>'s <code>AttributeSet</code>.

     * If <code>Element</code>'s <code>AttributeSet</code>

     * does not have this property set, it will revert to false.

     *

     * @return the value of the cached

     *     <code>underline</code> property

     * @since 1.3

     */

    public boolean isUnderline() {

        sync();

        return underline;

    }

    /**

     * Determines if the glyphs should have a strikethrough

     * line.  If true, a line should be drawn through the center

     * of the glyphs.  This is implemented to return the

     * cached <code>strikeThrough</code> property.

     *

     * <p>When you request this property, <code>LabelView</code>

     * re-syncs its state with the properties of the

     * <code>Element</code>'s <code>AttributeSet</code>.

     * If <code>Element</code>'s <code>AttributeSet</code>

     * does not have this property set, it will revert to false.

     *

     * @return the value of the cached

     *     <code>strikeThrough</code> property

     * @since 1.3

     */

    public boolean isStrikeThrough() {

        sync();

        return strike;

    }

    /**

     * Determines if the glyphs should be rendered as superscript.

     * @return the value of the cached subscript property

     *

     * <p>When you request this property, <code>LabelView</code>

     * re-syncs its state with the properties of the

     * <code>Element</code>'s <code>AttributeSet</code>.

     * If <code>Element</code>'s <code>AttributeSet</code>

     * does not have this property set, it will revert to false.

     *

     * @return the value of the cached

     *     <code>subscript</code> property

     * @since 1.3

     */

    public boolean isSubscript() {

        sync();

        return subscript;

    }

    /**

     * Determines if the glyphs should be rendered as subscript.

     *

     * <p>When you request this property, <code>LabelView</code>

     * re-syncs its state with the properties of the

     * <code>Element</code>'s <code>AttributeSet</code>.

     * If <code>Element</code>'s <code>AttributeSet</code>

     * does not have this property set, it will revert to false.

     *

     * @return the value of the cached

     *     <code>superscript</code> property

     * @since 1.3

     */

    public boolean isSuperscript() {

        sync();

        return superscript;

    }

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

    /**

     * Gives notification from the document that attributes were changed

     * in a location that this view is responsible for.

     *

     * @param e 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#changedUpdate

     */

    public void changedUpdate(DocumentEvent e, Shape a, ViewFactory f) {

        font = null;

        super.changedUpdate(e, a, f);

    }

    // --- variables ------------------------------------------------

    private Font font;

    private Color fg;

    private Color bg;

    private boolean underline;

    private boolean strike;

    private boolean superscript;

    private boolean subscript;

}