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 * Copyright (c) 1997, 2019, 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).
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 * 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,
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 *
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package javax.swing.plaf.basic;

import sun.swing.SwingUtilities2;
import sun.swing.DefaultLookup;
import sun.swing.UIAction;
import sun.awt.AppContext;

import javax.swing.*;
import javax.swing.plaf.*;
import javax.swing.text.View;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.InputEvent;
import java.awt.event.KeyEvent;
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Rectangle;
import java.awt.Insets;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Font;
import java.awt.FontMetrics;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;

A Windows L&F implementation of LabelUI.  This implementation
is completely static, i.e. there's only one UIView implementation
that's shared by all JLabel objects.
Author:
Hans Muller/**
 * A Windows L&F implementation of LabelUI.  This implementation
 * is completely static, i.e. there's only one UIView implementation
 * that's shared by all JLabel objects.
 *
 * @author Hans Muller
 */
public class BasicLabelUI extends LabelUI implements  PropertyChangeListener
{
   
The default BasicLabelUI instance. This field might
not be used. To change the default instance use a subclass which
overrides the createUI method, and place that class
name in defaults table under the key "LabelUI".
/**
    * The default <code>BasicLabelUI</code> instance. This field might
    * not be used. To change the default instance use a subclass which
    * overrides the <code>createUI</code> method, and place that class
    * name in defaults table under the key "LabelUI".
    */
    protected static BasicLabelUI labelUI = new BasicLabelUI();
    private static final Object BASIC_LABEL_UI_KEY = new Object();

    private Rectangle paintIconR = new Rectangle();
    private Rectangle paintTextR = new Rectangle();

    static void loadActionMap(LazyActionMap map) {
        map.put(new Actions(Actions.PRESS));
        map.put(new Actions(Actions.RELEASE));
    }

    
Forwards the call to SwingUtilities.layoutCompoundLabel().
This method is here so that a subclass could do Label specific
layout and to shorten the method name a little.
Params:
label – an instance of JLabel
fontMetrics – a font metrics
text – a text
icon – an icon
viewR – a bounding rectangle to lay out label
iconR – a bounding rectangle to lay out icon
textR – a bounding rectangle to lay out text
See Also:
SwingUtilities.layoutCompoundLabel
Returns:
a possibly clipped version of the compound labels string/**
     * Forwards the call to SwingUtilities.layoutCompoundLabel().
     * This method is here so that a subclass could do Label specific
     * layout and to shorten the method name a little.
     *
     * @param label an instance of {@code JLabel}
     * @param fontMetrics a font metrics
     * @param text a text
     * @param icon an icon
     * @param viewR a bounding rectangle to lay out label
     * @param iconR a bounding rectangle to lay out icon
     * @param textR a bounding rectangle to lay out text
     * @return a possibly clipped version of the compound labels string
     * @see SwingUtilities#layoutCompoundLabel
     */
    protected String layoutCL(
        JLabel label,
        FontMetrics fontMetrics,
        String text,
        Icon icon,
        Rectangle viewR,
        Rectangle iconR,
        Rectangle textR)
    {
        return SwingUtilities.layoutCompoundLabel(
            (JComponent) label,
            fontMetrics,
            text,
            icon,
            label.getVerticalAlignment(),
            label.getHorizontalAlignment(),
            label.getVerticalTextPosition(),
            label.getHorizontalTextPosition(),
            viewR,
            iconR,
            textR,
            label.getIconTextGap());
    }

    
Paint clippedText at textX, textY with the labels foreground color.
Params:
l – an instance of JLabel
g – an instance of Graphics
s – a text
textX – an X coordinate
textY – an Y coordinate
See Also:
paint
paintDisabledText/**
     * Paint clippedText at textX, textY with the labels foreground color.
     *
     * @param l an instance of {@code JLabel}
     * @param g an instance of {@code Graphics}
     * @param s a text
     * @param textX an X coordinate
     * @param textY an Y coordinate
     * @see #paint
     * @see #paintDisabledText
     */
    protected void paintEnabledText(JLabel l, Graphics g, String s, int textX, int textY)
    {
        int mnemIndex = l.getDisplayedMnemonicIndex();
        g.setColor(l.getForeground());
        SwingUtilities2.drawStringUnderlineCharAt(l, g, s, mnemIndex,
                                                     textX, textY);
    }


    
Paint clippedText at textX, textY with background.lighter() and then
shifted down and to the right by one pixel with background.darker().
Params:
l – an instance of JLabel
g – an instance of Graphics
s – a text
textX – an X coordinate
textY – an Y coordinate
See Also:
paint
paintEnabledText/**
     * Paint clippedText at textX, textY with background.lighter() and then
     * shifted down and to the right by one pixel with background.darker().
     *
     * @param l an instance of {@code JLabel}
     * @param g an instance of {@code Graphics}
     * @param s a text
     * @param textX an X coordinate
     * @param textY an Y coordinate
     * @see #paint
     * @see #paintEnabledText
     */
    protected void paintDisabledText(JLabel l, Graphics g, String s, int textX, int textY)
    {
        int accChar = l.getDisplayedMnemonicIndex();
        Color background = l.getBackground();
        g.setColor(background.brighter());
        SwingUtilities2.drawStringUnderlineCharAt(l, g, s, accChar,
                                                   textX + 1, textY + 1);
        g.setColor(background.darker());
        SwingUtilities2.drawStringUnderlineCharAt(l, g, s, accChar,
                                                   textX, textY);
    }

    
Paints the label text with the foreground color, if the label is opaque then paints the entire background with the background color. The Label text is drawn by paintEnabledText or paintDisabledText. The locations of the label parts are computed by layoutCL. 
See Also:
paintEnabledText
paintDisabledText
layoutCL/**
     * Paints the label text with the foreground color, if the label is opaque
     * then paints the entire background with the background color. The Label
     * text is drawn by {@link #paintEnabledText} or {@link #paintDisabledText}.
     * The locations of the label parts are computed by {@link #layoutCL}.
     *
     * @see #paintEnabledText
     * @see #paintDisabledText
     * @see #layoutCL
     */
    public void paint(Graphics g, JComponent c)
    {
        JLabel label = (JLabel)c;
        String text = label.getText();
        Icon icon = (label.isEnabled()) ? label.getIcon() : label.getDisabledIcon();

        if ((icon == null) && (text == null)) {
            return;
        }

        FontMetrics fm = SwingUtilities2.getFontMetrics(label, g);
        String clippedText = layout(label, fm, c.getWidth(), c.getHeight());

        if (icon != null) {
            icon.paintIcon(c, g, paintIconR.x, paintIconR.y);
        }

        if (text != null) {
            View v = (View) c.getClientProperty(BasicHTML.propertyKey);
            if (v != null) {
                v.paint(g, paintTextR);
            } else {
                int textX = paintTextR.x;
                int textY = paintTextR.y + fm.getAscent();

                if (label.isEnabled()) {
                    paintEnabledText(label, g, clippedText, textX, textY);
                }
                else {
                    paintDisabledText(label, g, clippedText, textX, textY);
                }
            }
        }
    }

    private String layout(JLabel label, FontMetrics fm,
                          int width, int height) {
        Insets insets = label.getInsets(null);
        String text = label.getText();
        Icon icon = (label.isEnabled()) ? label.getIcon() :
                                          label.getDisabledIcon();
        Rectangle paintViewR = new Rectangle();
        paintViewR.x = insets.left;
        paintViewR.y = insets.top;
        paintViewR.width = width - (insets.left + insets.right);
        paintViewR.height = height - (insets.top + insets.bottom);
        paintIconR.x = paintIconR.y = paintIconR.width = paintIconR.height = 0;
        paintTextR.x = paintTextR.y = paintTextR.width = paintTextR.height = 0;
        return layoutCL(label, fm, text, icon, paintViewR, paintIconR,
                        paintTextR);
    }

    public Dimension getPreferredSize(JComponent c)
    {
        JLabel label = (JLabel)c;
        String text = label.getText();
        Icon icon = (label.isEnabled()) ? label.getIcon() :
                                          label.getDisabledIcon();
        Insets insets = label.getInsets(null);
        Font font = label.getFont();

        int dx = insets.left + insets.right;
        int dy = insets.top + insets.bottom;

        if ((icon == null) &&
            ((text == null) ||
             ((text != null) && (font == null)))) {
            return new Dimension(dx, dy);
        }
        else if ((text == null) || ((icon != null) && (font == null))) {
            return new Dimension(icon.getIconWidth() + dx,
                                 icon.getIconHeight() + dy);
        }
        else {
            FontMetrics fm = label.getFontMetrics(font);
            Rectangle iconR = new Rectangle();
            Rectangle textR = new Rectangle();
            Rectangle viewR = new Rectangle();

            iconR.x = iconR.y = iconR.width = iconR.height = 0;
            textR.x = textR.y = textR.width = textR.height = 0;
            viewR.x = dx;
            viewR.y = dy;
            viewR.width = viewR.height = Short.MAX_VALUE;

            layoutCL(label, fm, text, icon, viewR, iconR, textR);
            int x1 = Math.min(iconR.x, textR.x);
            int x2 = Math.max(iconR.x + iconR.width, textR.x + textR.width);
            int y1 = Math.min(iconR.y, textR.y);
            int y2 = Math.max(iconR.y + iconR.height, textR.y + textR.height);
            Dimension rv = new Dimension(x2 - x1, y2 - y1);

            rv.width += dx;
            rv.height += dy;
            return rv;
        }
    }


    
Returns:
getPreferredSize(c)/**
     * @return getPreferredSize(c)
     */
    public Dimension getMinimumSize(JComponent c) {
        Dimension d = getPreferredSize(c);
        View v = (View) c.getClientProperty(BasicHTML.propertyKey);
        if (v != null) {
            d.width -= v.getPreferredSpan(View.X_AXIS) - v.getMinimumSpan(View.X_AXIS);
        }
        return d;
    }

    
Returns:
getPreferredSize(c)/**
     * @return getPreferredSize(c)
     */
    public Dimension getMaximumSize(JComponent c) {
        Dimension d = getPreferredSize(c);
        View v = (View) c.getClientProperty(BasicHTML.propertyKey);
        if (v != null) {
            d.width += v.getMaximumSpan(View.X_AXIS) - v.getPreferredSpan(View.X_AXIS);
        }
        return d;
    }

    
Returns the baseline.
Throws:
NullPointerException – {@inheritDoc}
IllegalArgumentException – {@inheritDoc}
See Also:
JComponent.getBaseline(int, int)
Since:
1.6/**
     * Returns the baseline.
     *
     * @throws NullPointerException {@inheritDoc}
     * @throws IllegalArgumentException {@inheritDoc}
     * @see javax.swing.JComponent#getBaseline(int, int)
     * @since 1.6
     */
    public int getBaseline(JComponent c, int width, int height) {
        super.getBaseline(c, width, height);
        JLabel label = (JLabel)c;
        String text = label.getText();
        if (text == null || text.isEmpty() || label.getFont() == null) {
            return -1;
        }
        FontMetrics fm = label.getFontMetrics(label.getFont());
        layout(label, fm, width, height);
        return BasicHTML.getBaseline(label, paintTextR.y, fm.getAscent(),
                                     paintTextR.width, paintTextR.height);
    }

    
Returns an enum indicating how the baseline of the component
changes as the size changes.
Throws:
NullPointerException – {@inheritDoc}
See Also:
JComponent.getBaseline(int, int)
Since:
1.6/**
     * Returns an enum indicating how the baseline of the component
     * changes as the size changes.
     *
     * @throws NullPointerException {@inheritDoc}
     * @see javax.swing.JComponent#getBaseline(int, int)
     * @since 1.6
     */
    public Component.BaselineResizeBehavior getBaselineResizeBehavior(
            JComponent c) {
        super.getBaselineResizeBehavior(c);
        if (c.getClientProperty(BasicHTML.propertyKey) != null) {
            return Component.BaselineResizeBehavior.OTHER;
        }
        switch(((JLabel)c).getVerticalAlignment()) {
        case JLabel.TOP:
            return Component.BaselineResizeBehavior.CONSTANT_ASCENT;
        case JLabel.BOTTOM:
            return Component.BaselineResizeBehavior.CONSTANT_DESCENT;
        case JLabel.CENTER:
            return Component.BaselineResizeBehavior.CENTER_OFFSET;
        }
        return Component.BaselineResizeBehavior.OTHER;
    }


    public void installUI(JComponent c) {
        installDefaults((JLabel)c);
        installComponents((JLabel)c);
        installListeners((JLabel)c);
        installKeyboardActions((JLabel)c);
    }


    public void uninstallUI(JComponent c) {
        uninstallDefaults((JLabel) c);
        uninstallComponents((JLabel) c);
        uninstallListeners((JLabel) c);
        uninstallKeyboardActions((JLabel) c);
    }

    
Installs default properties.
Params:
c – an instance of JLabel/**
     * Installs default properties.
     *
     * @param c an instance of {@code JLabel}
     */
    protected void installDefaults(JLabel c){
        LookAndFeel.installColorsAndFont(c, "Label.background", "Label.foreground", "Label.font");
        LookAndFeel.installProperty(c, "opaque", Boolean.FALSE);
    }

    
Registers listeners.
Params:
c – an instance of JLabel/**
     * Registers listeners.
     *
     * @param c an instance of {@code JLabel}
     */
    protected void installListeners(JLabel c){
        c.addPropertyChangeListener(this);
    }

    
Registers components.
Params:
c – an instance of JLabel/**
     * Registers components.
     *
     * @param c an instance of {@code JLabel}
     */
    protected void installComponents(JLabel c){
        BasicHTML.updateRenderer(c, c.getText());
        c.setInheritsPopupMenu(true);
    }

    
Registers keyboard actions.
Params:
l – an instance of JLabel/**
     * Registers keyboard actions.
     *
     * @param l an instance of {@code JLabel}
     */
    protected void installKeyboardActions(JLabel l) {
        int dka = l.getDisplayedMnemonic();
        Component lf = l.getLabelFor();
        if ((dka != 0) && (lf != null)) {
            LazyActionMap.installLazyActionMap(l, BasicLabelUI.class,
                                               "Label.actionMap");
            InputMap inputMap = SwingUtilities.getUIInputMap
                            (l, JComponent.WHEN_IN_FOCUSED_WINDOW);
            if (inputMap == null) {
                inputMap = new ComponentInputMapUIResource(l);
                SwingUtilities.replaceUIInputMap(l,
                                JComponent.WHEN_IN_FOCUSED_WINDOW, inputMap);
            }
            inputMap.clear();
            inputMap.put(KeyStroke.getKeyStroke(dka, BasicLookAndFeel.getFocusAcceleratorKeyMask(), false), "press");
            inputMap.put(KeyStroke.getKeyStroke(dka,
                    SwingUtilities2.setAltGraphMask (
                            BasicLookAndFeel.getFocusAcceleratorKeyMask()),
                    false), "press");
        }
        else {
            InputMap inputMap = SwingUtilities.getUIInputMap
                            (l, JComponent.WHEN_IN_FOCUSED_WINDOW);
            if (inputMap != null) {
                inputMap.clear();
            }
        }
    }

    
Uninstalls default properties.
Params:
c – an instance of JLabel/**
     * Uninstalls default properties.
     *
     * @param c an instance of {@code JLabel}
     */
    protected void uninstallDefaults(JLabel c){
    }

    
Unregisters listeners.
Params:
c – an instance of JLabel/**
     * Unregisters listeners.
     *
     * @param c an instance of {@code JLabel}
     */
    protected void uninstallListeners(JLabel c){
        c.removePropertyChangeListener(this);
    }

    
Unregisters components.
Params:
c – an instance of JLabel/**
     * Unregisters components.
     *
     * @param c an instance of {@code JLabel}
     */
    protected void uninstallComponents(JLabel c){
        BasicHTML.updateRenderer(c, "");
    }

    
Unregisters keyboard actions.
Params:
c – an instance of JLabel/**
     * Unregisters keyboard actions.
     *
     * @param c an instance of {@code JLabel}
     */
    protected void uninstallKeyboardActions(JLabel c) {
        SwingUtilities.replaceUIInputMap(c, JComponent.WHEN_FOCUSED, null);
        SwingUtilities.replaceUIInputMap(c, JComponent.WHEN_IN_FOCUSED_WINDOW,
                                       null);
        SwingUtilities.replaceUIActionMap(c, null);
    }

    
Returns an instance of BasicLabelUI. 
Params:
c – a component
Returns:
an instance of BasicLabelUI/**
     * Returns an instance of {@code BasicLabelUI}.
     *
     * @param c a component
     * @return an instance of {@code BasicLabelUI}
     */
    public static ComponentUI createUI(JComponent c) {
        if (System.getSecurityManager() != null) {
            AppContext appContext = AppContext.getAppContext();
            BasicLabelUI safeBasicLabelUI =
                    (BasicLabelUI) appContext.get(BASIC_LABEL_UI_KEY);
            if (safeBasicLabelUI == null) {
                safeBasicLabelUI = new BasicLabelUI();
                appContext.put(BASIC_LABEL_UI_KEY, safeBasicLabelUI);
            }
            return safeBasicLabelUI;
        }
        return labelUI;
    }

    public void propertyChange(PropertyChangeEvent e) {
        String name = e.getPropertyName();
        if (name == "text" || "font" == name || "foreground" == name
                || SwingUtilities2.isScaleChanged(e)) {
            // remove the old html view client property if one
            // existed, and install a new one if the text installed
            // into the JLabel is html source.
            JLabel lbl = ((JLabel) e.getSource());
            String text = lbl.getText();
            BasicHTML.updateRenderer(lbl, text);
        }
        else if (name == "labelFor" || name == "displayedMnemonic") {
            installKeyboardActions((JLabel) e.getSource());
        }
    }

    // When the accelerator is pressed, temporarily make the JLabel
    // focusTraversable by registering a WHEN_FOCUSED action for the
    // release of the accelerator.  Then give it focus so it can
    // prevent unwanted keyTyped events from getting to other components.
    private static class Actions extends UIAction {
        private static final String PRESS = "press";
        private static final String RELEASE = "release";

        Actions(String key) {
            super(key);
        }

        public void actionPerformed(ActionEvent e) {
            JLabel label = (JLabel)e.getSource();
            String key = getName();
            if (key == PRESS) {
                doPress(label);
            }
            else if (key == RELEASE) {
                doRelease(label, e.getActionCommand() != null);
            }
        }

        private void doPress(JLabel label) {
            Component labelFor = label.getLabelFor();
            if (labelFor != null && labelFor.isEnabled()) {
                InputMap inputMap = SwingUtilities.getUIInputMap(label, JComponent.WHEN_FOCUSED);
                if (inputMap == null) {
                    inputMap = new InputMapUIResource();
                    SwingUtilities.replaceUIInputMap(label, JComponent.WHEN_FOCUSED, inputMap);
                }
                int dka = label.getDisplayedMnemonic();
                putOnRelease(inputMap, dka, BasicLookAndFeel
                        .getFocusAcceleratorKeyMask());
                putOnRelease(inputMap, dka, SwingUtilities2.setAltGraphMask (
                        BasicLookAndFeel.getFocusAcceleratorKeyMask()));
                // Need this when the sticky keys are enabled
                putOnRelease(inputMap, dka, 0);
                // Need this if ALT is released before the accelerator
                putOnRelease(inputMap, KeyEvent.VK_ALT, 0);
                label.requestFocus();
            }
        }

        private void doRelease(JLabel label, boolean isCommand) {
            Component labelFor = label.getLabelFor();
            if (labelFor != null && labelFor.isEnabled()) {
                if (label.hasFocus()) {
                    InputMap inputMap = SwingUtilities.getUIInputMap(label,
                            JComponent.WHEN_FOCUSED);
                    if (inputMap != null) {
                        // inputMap should never be null.
                        int dka = label.getDisplayedMnemonic();
                        removeOnRelease(inputMap, dka, BasicLookAndFeel
                                .getFocusAcceleratorKeyMask());
                        removeOnRelease(inputMap, dka,
                                SwingUtilities2.setAltGraphMask (
                                BasicLookAndFeel.getFocusAcceleratorKeyMask()));
                        removeOnRelease(inputMap, dka, 0);
                        removeOnRelease(inputMap, KeyEvent.VK_ALT, 0);
                    }
                    inputMap = SwingUtilities.getUIInputMap(label,
                            JComponent.WHEN_IN_FOCUSED_WINDOW);
                    if (inputMap == null) {
                        inputMap = new InputMapUIResource();
                        SwingUtilities.replaceUIInputMap(label,
                                JComponent.WHEN_IN_FOCUSED_WINDOW, inputMap);
                    }
                    int dka = label.getDisplayedMnemonic();
                    if (isCommand) {
                        putOnRelease(inputMap, KeyEvent.VK_ALT, 0);
                    } else {
                        putOnRelease(inputMap, dka, BasicLookAndFeel
                                .getFocusAcceleratorKeyMask());
                        putOnRelease(inputMap, dka,
                                SwingUtilities2.setAltGraphMask (
                                BasicLookAndFeel.getFocusAcceleratorKeyMask()));
                        // Need this when the sticky keys are enabled
                        putOnRelease(inputMap, dka, 0);
                    }
                    if (labelFor instanceof Container &&
                            ((Container) labelFor).isFocusCycleRoot()) {
                        labelFor.requestFocus();
                    } else {
                        SwingUtilities2.compositeRequestFocus(labelFor);
                    }
                } else {
                    InputMap inputMap = SwingUtilities.getUIInputMap(label,
                            JComponent.WHEN_IN_FOCUSED_WINDOW);
                    int dka = label.getDisplayedMnemonic();
                    if (inputMap != null) {
                        if (isCommand) {
                            removeOnRelease(inputMap, dka, BasicLookAndFeel
                                    .getFocusAcceleratorKeyMask());
                            removeOnRelease(inputMap, dka,
                                    SwingUtilities2.setAltGraphMask (
                                    BasicLookAndFeel.getFocusAcceleratorKeyMask()));
                            removeOnRelease(inputMap, dka, 0);
                        } else {
                            removeOnRelease(inputMap, KeyEvent.VK_ALT, 0);
                        }
                    }
                }
            }
        }

        private void putOnRelease(InputMap inputMap, int keyCode, int modifiers) {
            inputMap.put(KeyStroke.getKeyStroke(keyCode, modifiers, true),
                    RELEASE);
        }

        private void removeOnRelease(InputMap inputMap, int keyCode, int modifiers) {
            inputMap.remove(KeyStroke.getKeyStroke(keyCode, modifiers, true));
        }

    }
}