Themes.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.themes;

import com.google.common.base.Preconditions;
import net.bither.languages.LanguageKey;

import javax.swing.*;
import javax.swing.plaf.ColorUIResource;
import javax.swing.plaf.FontUIResource;
import java.awt.*;
import java.util.Enumeration;

/**
 * <p>utility to provide the following to Views:</p>
 * <ul>
 * <li>Provision of a UI theme</li>
 * </ul>
 *
 * @since 0.0.1
 */
public class Themes {

    // Always start with the Bootstrap theme and switch during startup if required
    public static Theme currentTheme = new BootstrapTheme();

    /**
     * Utilities do not have public constructors
     */
    private Themes() {
    }

    public static synchronized void switchTheme(Theme newTheme) {

        Preconditions.checkNotNull(newTheme, "'newTheme' must be present");

        currentTheme = newTheme;

        // Gets used in combo box borders and provides the basis for a "default button"
        UIManager.put("nimbusBase", currentTheme.readOnlyComboBox());

        // Provides basis for text
        UIManager.put("nimbusBlueGrey", currentTheme.fadedText());

        UIManager.put("nimbusBorder", currentTheme.text());
        UIManager.put("nimbusDisabledText", currentTheme.fadedText());

        UIManager.put("nimbusLightBackground", currentTheme.sidebarPanelBackground());

        UIManager.put("nimbusFocus", currentTheme.infoAlertBorder());

        UIManager.put("nimbusSelectedText", currentTheme.infoAlertText());
        UIManager.put("nimbusSelection", currentTheme.infoAlertBackground());
        UIManager.put("nimbusSelectionBackground", currentTheme.infoAlertBackground());

        // Scrollbar UI
        Color scrollBarThumb = currentTheme.infoAlertBackground();
        UIManager.put("ScrollBar.thumb", scrollBarThumb);
        UIManager.put("ScrollBar.thumbDarkShadow", scrollBarThumb);
        UIManager.put("ScrollBar.thumbShadow", scrollBarThumb.darker());
        UIManager.put("ScrollBar.thumbHighlight", scrollBarThumb.darker());

        Color scrollBarTrack = currentTheme.detailPanelBackground();
        UIManager.put("ScrollBar.background", new ColorUIResource(Color.RED));
        UIManager.put("ScrollBar.foreground", new ColorUIResource(Color.BLUE));
        UIManager.put("ScrollBar.track", scrollBarTrack);
        UIManager.put("ScrollBar.trackHighlight", new ColorUIResource(Color.YELLOW));

        // Ensure the language icons match the colour scheme
        LanguageKey.resetIcons();

        // Adjust the font size
        initializeFontSize();

    }

    /**
     * @param color The color
     * @return A hex representation of the RGB values (e.g. "abcdef")
     */
    public static String toHexString(Color color) {
        return Integer.toHexString(color.getRGB());
    }

    /**
     * <p>Apply a default font size modifier</p>
     */
    public static void initializeFontSize() {

        // TODO Introduce a theme-aware font factory for components to use

        // TODO Add this to the configuration in appearance for visually impaired users
        float multiplier = 1.0f;
        UIDefaults defaults = UIManager.getDefaults();

        for (Enumeration e = defaults.keys(); e.hasMoreElements(); ) {

            Object key = e.nextElement();
            Object value = defaults.get(key);

            if (value instanceof Font) {

                Font font = (Font) value;
                int newSize = Math.round(font.getSize() * multiplier);

                if (value instanceof FontUIResource) {
                    defaults.put(key, new FontUIResource(font.getName(), font.getStyle(), newSize));
                } else {
                    defaults.put(key, new Font(font.getName(), font.getStyle(), newSize));
                }

            }

        }

    }
}