TipUtil.java

/*
 * 08/13/2009
 *
 * TipUtil.java - Utility methods for homemade tool tips.
 * Copyright (C) 2009 Robert Futrell
 * robert_futrell at users.sourceforge.net
 * http://fifesoft.com/rsyntaxtextarea
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA.
 */
package org.fife.ui.rsyntaxtextarea.focusabletip;

import java.awt.Color;
import java.awt.Font;
import java.awt.GraphicsConfiguration;
import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;
import java.awt.Rectangle;
import java.awt.SystemColor;
import javax.swing.BorderFactory;
import javax.swing.JEditorPane;
import javax.swing.UIManager;
import javax.swing.plaf.ColorUIResource;
import javax.swing.text.html.HTMLDocument;

/**
 * Static utility methods for focusable tips.
 * 
 * @author Robert Futrell
 * @version 1.0
 */
class TipUtil {

    private TipUtil() {
    }

    /**
     * Returns the screen coordinates for the monitor that contains the specified point. This is useful for setups with
     * multiple monitors, to ensure that popup windows are positioned properly.
     * 
     * @param x
     *            The x-coordinate, in screen coordinates.
     * @param y
     *            The y-coordinate, in screen coordinates.
     * @return The bounds of the monitor that contains the specified point.
     */
    public static Rectangle getScreenBoundsForPoint(int x, int y) {
        GraphicsEnvironment env = GraphicsEnvironment.
                getLocalGraphicsEnvironment();
        GraphicsDevice[] devices = env.getScreenDevices();
        for (int i = 0; i < devices.length; i++) {
            GraphicsConfiguration[] configs = devices[i].getConfigurations();
            for (int j = 0; j < configs.length; j++) {
                Rectangle gcBounds = configs[j].getBounds();
                if (gcBounds.contains(x, y)) {
                    return gcBounds;
                }
            }
        }
        // If point is outside all monitors, default to default monitor (?)
        return env.getMaximumWindowBounds();
    }

    /**
     * Returns the default background color to use for tool tip windows.
     * 
     * @return The default background color.
     */
    public static Color getToolTipBackground() {

        Color c = UIManager.getColor("ToolTip.background");

        // Tooltip.background is wrong color on Nimbus (!)
        if (c == null || UIManager.getLookAndFeel().getName().equals("Nimbus")) {
            c = UIManager.getColor("info"); // Used by Nimbus (and others)
            if (c == null) {
                c = SystemColor.info; // System default
            }
        }

        // Workaround for a bug (?) with Nimbus - calling JLabel.setBackground()
        // with a ColorUIResource does nothing, must be a normal Color
        if (c instanceof ColorUIResource) {
            c = new Color(c.getRGB());
        }

        return c;

    }

    /**
     * Tweaks a <code>JEditorPane</code> so it can be used to render the content in a focusable pseudo-tool tip. It is
     * assumed that the editor pane is using an <code>HTMLDocument</code>.
     * 
     * @param textArea
     *            The editor pane to tweak.
     */
    public static void tweakTipEditorPane(JEditorPane textArea) {

        // Jump through a few hoops to get things looking nice in Nimbus
        if (UIManager.getLookAndFeel().getName().equals("Nimbus")) {
            Color selBG = textArea.getSelectionColor();
            Color selFG = textArea.getSelectedTextColor();
            textArea.setUI(new javax.swing.plaf.basic.BasicEditorPaneUI());
            textArea.setSelectedTextColor(selFG);
            textArea.setSelectionColor(selBG);
        }

        textArea.setEditable(false); // Required for links to work!
        textArea.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));

        // Make selection visible even though we are not (initially) focusable.
        textArea.getCaret().setSelectionVisible(true);

        // Make it use the "tool tip" background color.
        textArea.setBackground(TipUtil.getToolTipBackground());

        // Force JEditorPane to use a certain font even in HTML.
        // All standard LookAndFeels, even Nimbus (!), define Label.font.
        Font font = UIManager.getFont("Label.font");
        if (font == null) { // Try to make a sensible default
            font = new Font("SansSerif", Font.PLAIN, 12);
        }
        HTMLDocument doc = (HTMLDocument) textArea.getDocument();
        doc.getStyleSheet().addRule(
                "body { font-family: " + font.getFamily() + "; font-size: "
                        + font.getSize() + "pt; }");

    }

}