ScrollBarUIDecorator.java

/*
 *
 *  Copyright 2014 http://Bither.net
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 * /
 */

package net.bither.viewsystem.components;


import net.bither.viewsystem.themes.Themes;

import javax.swing.*;
import javax.swing.plaf.ScrollBarUI;
import javax.swing.plaf.basic.BasicScrollBarUI;
import java.awt.*;
import java.awt.event.HierarchyEvent;
import java.awt.event.HierarchyListener;

/**
 * <p>Decorator to provide the following to UI:</p>
 * <ul>
 * <li>Apply a custom ScrollBarUI to the given components</li>
 * </ul>
 *
 * @since 0.0.1
 */
public class ScrollBarUIDecorator {

    /**
     * Utilities have no public constructor
     */
    private ScrollBarUIDecorator() {
    }

    /**
     * <p>Apply the scroll bar UI to the scroll pane</p>
     *
     * @param scrollPane      The scroll pane
     * @param addVerticalLine True if the scroll pane wraps a flat component (not rounded)
     */
    public static void apply(final JScrollPane scrollPane, boolean addVerticalLine) {

        if (scrollPane.getVerticalScrollBar() != null) {

            scrollPane.getVerticalScrollBar().setUI(newScrollBarUI());
            if (addVerticalLine) {
                // Add a vertical line to the left of scroll bar track for better visual effect
                scrollPane.getVerticalScrollBar().setBorder(BorderFactory.createMatteBorder(0, 1, 0, 0, Themes.currentTheme.text()));
            }
        }
        if (scrollPane.getHorizontalScrollBar() != null) {
            scrollPane.getHorizontalScrollBar().setUI(newScrollBarUI());
        }

    }

    /**
     * <p>Apply the scroll bar UI to a scroll pane wrapping a table</p>
     *
     * @param scrollPane The scroll pane
     * @param table      The table contained within the scroll pane
     */
    public static void apply(final JScrollPane scrollPane, final JTable table) {

        if (scrollPane.getVerticalScrollBar() != null) {
            scrollPane.getVerticalScrollBar().setUI(newScrollBarUI());
            scrollPane.getVerticalScrollBar().addHierarchyListener(new HierarchyListener() {
                @Override
                public void hierarchyChanged(HierarchyEvent e) {

                    if (HierarchyEvent.HIERARCHY_CHANGED == e.getID()
                            && (e.getChangeFlags() & HierarchyEvent.SHOWING_CHANGED) != 0) {
                        // The scroll bar has changed state
                        if (e.getComponent().isShowing()) {
                            // Draw a border to the right of the table
                            table.setBorder(BorderFactory.createMatteBorder(0, 0, 0, 1, Themes.currentTheme.text()));
                        } else {
                            // Remove the table border to avoid a thick black line on the right
                            table.setBorder(BorderFactory.createEmptyBorder());
                        }
                    }

                }
            });
        }
        if (scrollPane.getHorizontalScrollBar() != null) {
            scrollPane.getHorizontalScrollBar().setUI(newScrollBarUI());
        }

    }

    /**
     * @return The ScrollBarUI to use (see Themes for colouring)
     */
    private static ScrollBarUI newScrollBarUI() {

        return new BasicScrollBarUI() {


            public void paintThumb(Graphics g, JComponent c, Rectangle thumbBounds) {
                super.paintThumb(g, c, thumbBounds);
                int tw = thumbBounds.width;
                int th = thumbBounds.height;

                g.translate(thumbBounds.x, thumbBounds.y);

                Graphics2D g2 = (Graphics2D) g;
                Paint gp = null;
                if (this.scrollbar.getOrientation() == JScrollBar.VERTICAL) {
                    gp = new GradientPaint(0, 0, Themes.currentTheme.buttonBackground(), tw, 0, Color.WHITE);
                }
                if (this.scrollbar.getOrientation() == JScrollBar.HORIZONTAL) {
                    gp = new GradientPaint(0, 0, Themes.currentTheme.buttonBackground(), 0, th, Color.WHITE);
                }
                g2.setPaint(gp);
                g2.fillRoundRect(0, 0, tw - 1, th - 1, 5, 5);

                g2.drawRoundRect(0, 0, tw - 1, th - 1, 5, 5);
            }

            @Override
            protected JButton createDecreaseButton(int orientation) {
                return createZeroButton();
            }

            @Override
            protected JButton createIncreaseButton(int orientation) {
                return createZeroButton();
            }

            private JButton createZeroButton() {
                JButton jbutton = new JButton();

                jbutton.setPreferredSize(new Dimension(0, 0));
                jbutton.setMinimumSize(new Dimension(0, 0));
                jbutton.setMaximumSize(new Dimension(0, 0));
                return jbutton;
            }


        };

    }
}