Java tutorial
/* * Copyright (c) 1996, 2018, 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). * * 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. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package java.awt; import sun.awt.AWTAccessor; import java.io.ObjectStreamException; import java.lang.annotation.Native; /** * A class to encapsulate symbolic colors representing the color of * native GUI objects on a system. For systems which support the dynamic * update of the system colors (when the user changes the colors) * the actual RGB values of these symbolic colors will also change * dynamically. In order to compare the "current" RGB value of a * {@code SystemColor} object with a non-symbolic Color object, * {@code getRGB} should be used rather than {@code equals}. * <p> * Note that the way in which these system colors are applied to GUI objects * may vary slightly from platform to platform since GUI objects may be * rendered differently on each platform. * <p> * System color values may also be available through the {@code getDesktopProperty} * method on {@code java.awt.Toolkit}. * * @see Toolkit#getDesktopProperty * * @author Carl Quinn * @author Amy Fowler */ public final class SystemColor extends Color implements java.io.Serializable { /** * The array index for the * {@link #desktop} system color. * @see SystemColor#desktop */ @Native public static final int DESKTOP = 0; /** * The array index for the * {@link #activeCaption} system color. * @see SystemColor#activeCaption */ @Native public static final int ACTIVE_CAPTION = 1; /** * The array index for the * {@link #activeCaptionText} system color. * @see SystemColor#activeCaptionText */ @Native public static final int ACTIVE_CAPTION_TEXT = 2; /** * The array index for the * {@link #activeCaptionBorder} system color. * @see SystemColor#activeCaptionBorder */ @Native public static final int ACTIVE_CAPTION_BORDER = 3; /** * The array index for the * {@link #inactiveCaption} system color. * @see SystemColor#inactiveCaption */ @Native public static final int INACTIVE_CAPTION = 4; /** * The array index for the * {@link #inactiveCaptionText} system color. * @see SystemColor#inactiveCaptionText */ @Native public static final int INACTIVE_CAPTION_TEXT = 5; /** * The array index for the * {@link #inactiveCaptionBorder} system color. * @see SystemColor#inactiveCaptionBorder */ @Native public static final int INACTIVE_CAPTION_BORDER = 6; /** * The array index for the * {@link #window} system color. * @see SystemColor#window */ @Native public static final int WINDOW = 7; /** * The array index for the * {@link #windowBorder} system color. * @see SystemColor#windowBorder */ @Native public static final int WINDOW_BORDER = 8; /** * The array index for the * {@link #windowText} system color. * @see SystemColor#windowText */ @Native public static final int WINDOW_TEXT = 9; /** * The array index for the * {@link #menu} system color. * @see SystemColor#menu */ @Native public static final int MENU = 10; /** * The array index for the * {@link #menuText} system color. * @see SystemColor#menuText */ @Native public static final int MENU_TEXT = 11; /** * The array index for the * {@link #text} system color. * @see SystemColor#text */ @Native public static final int TEXT = 12; /** * The array index for the * {@link #textText} system color. * @see SystemColor#textText */ @Native public static final int TEXT_TEXT = 13; /** * The array index for the * {@link #textHighlight} system color. * @see SystemColor#textHighlight */ @Native public static final int TEXT_HIGHLIGHT = 14; /** * The array index for the * {@link #textHighlightText} system color. * @see SystemColor#textHighlightText */ @Native public static final int TEXT_HIGHLIGHT_TEXT = 15; /** * The array index for the * {@link #textInactiveText} system color. * @see SystemColor#textInactiveText */ @Native public static final int TEXT_INACTIVE_TEXT = 16; /** * The array index for the * {@link #control} system color. * @see SystemColor#control */ @Native public static final int CONTROL = 17; /** * The array index for the * {@link #controlText} system color. * @see SystemColor#controlText */ @Native public static final int CONTROL_TEXT = 18; /** * The array index for the * {@link #controlHighlight} system color. * @see SystemColor#controlHighlight */ @Native public static final int CONTROL_HIGHLIGHT = 19; /** * The array index for the * {@link #controlLtHighlight} system color. * @see SystemColor#controlLtHighlight */ @Native public static final int CONTROL_LT_HIGHLIGHT = 20; /** * The array index for the * {@link #controlShadow} system color. * @see SystemColor#controlShadow */ @Native public static final int CONTROL_SHADOW = 21; /** * The array index for the * {@link #controlDkShadow} system color. * @see SystemColor#controlDkShadow */ @Native public static final int CONTROL_DK_SHADOW = 22; /** * The array index for the * {@link #scrollbar} system color. * @see SystemColor#scrollbar */ @Native public static final int SCROLLBAR = 23; /** * The array index for the * {@link #info} system color. * @see SystemColor#info */ @Native public static final int INFO = 24; /** * The array index for the * {@link #infoText} system color. * @see SystemColor#infoText */ @Native public static final int INFO_TEXT = 25; /** * The number of system colors in the array. */ @Native public static final int NUM_COLORS = 26; /******************************************************************************************/ /* * System colors with default initial values, overwritten by toolkit if * system values differ and are available. * Should put array initialization above first field that is using * SystemColor constructor to initialize. */ private static int[] systemColors = { 0xFF005C5C, // desktop = new Color(0,92,92); 0xFF000080, // activeCaption = new Color(0,0,128); 0xFFFFFFFF, // activeCaptionText = Color.white; 0xFFC0C0C0, // activeCaptionBorder = Color.lightGray; 0xFF808080, // inactiveCaption = Color.gray; 0xFFC0C0C0, // inactiveCaptionText = Color.lightGray; 0xFFC0C0C0, // inactiveCaptionBorder = Color.lightGray; 0xFFFFFFFF, // window = Color.white; 0xFF000000, // windowBorder = Color.black; 0xFF000000, // windowText = Color.black; 0xFFC0C0C0, // menu = Color.lightGray; 0xFF000000, // menuText = Color.black; 0xFFC0C0C0, // text = Color.lightGray; 0xFF000000, // textText = Color.black; 0xFF000080, // textHighlight = new Color(0,0,128); 0xFFFFFFFF, // textHighlightText = Color.white; 0xFF808080, // textInactiveText = Color.gray; 0xFFC0C0C0, // control = Color.lightGray; 0xFF000000, // controlText = Color.black; 0xFFFFFFFF, // controlHighlight = Color.white; 0xFFE0E0E0, // controlLtHighlight = new Color(224,224,224); 0xFF808080, // controlShadow = Color.gray; 0xFF000000, // controlDkShadow = Color.black; 0xFFE0E0E0, // scrollbar = new Color(224,224,224); 0xFFE0E000, // info = new Color(224,224,0); 0xFF000000, // infoText = Color.black; }; /** * The color rendered for the background of the desktop. */ public static final SystemColor desktop = new SystemColor((byte) DESKTOP); /** * The color rendered for the window-title background of the currently active window. */ public static final SystemColor activeCaption = new SystemColor((byte) ACTIVE_CAPTION); /** * The color rendered for the window-title text of the currently active window. */ public static final SystemColor activeCaptionText = new SystemColor((byte) ACTIVE_CAPTION_TEXT); /** * The color rendered for the border around the currently active window. */ public static final SystemColor activeCaptionBorder = new SystemColor((byte) ACTIVE_CAPTION_BORDER); /** * The color rendered for the window-title background of inactive windows. */ public static final SystemColor inactiveCaption = new SystemColor((byte) INACTIVE_CAPTION); /** * The color rendered for the window-title text of inactive windows. */ public static final SystemColor inactiveCaptionText = new SystemColor((byte) INACTIVE_CAPTION_TEXT); /** * The color rendered for the border around inactive windows. */ public static final SystemColor inactiveCaptionBorder = new SystemColor((byte) INACTIVE_CAPTION_BORDER); /** * The color rendered for the background of interior regions inside windows. */ public static final SystemColor window = new SystemColor((byte) WINDOW); /** * The color rendered for the border around interior regions inside windows. */ public static final SystemColor windowBorder = new SystemColor((byte) WINDOW_BORDER); /** * The color rendered for text of interior regions inside windows. */ public static final SystemColor windowText = new SystemColor((byte) WINDOW_TEXT); /** * The color rendered for the background of menus. */ public static final SystemColor menu = new SystemColor((byte) MENU); /** * The color rendered for the text of menus. */ public static final SystemColor menuText = new SystemColor((byte) MENU_TEXT); /** * The color rendered for the background of text control objects, such as * textfields and comboboxes. */ public static final SystemColor text = new SystemColor((byte) TEXT); /** * The color rendered for the text of text control objects, such as textfields * and comboboxes. */ public static final SystemColor textText = new SystemColor((byte) TEXT_TEXT); /** * The color rendered for the background of selected items, such as in menus, * comboboxes, and text. */ public static final SystemColor textHighlight = new SystemColor((byte) TEXT_HIGHLIGHT); /** * The color rendered for the text of selected items, such as in menus, comboboxes, * and text. */ public static final SystemColor textHighlightText = new SystemColor((byte) TEXT_HIGHLIGHT_TEXT); /** * The color rendered for the text of inactive items, such as in menus. */ public static final SystemColor textInactiveText = new SystemColor((byte) TEXT_INACTIVE_TEXT); /** * The color rendered for the background of control panels and control objects, * such as pushbuttons. */ public static final SystemColor control = new SystemColor((byte) CONTROL); /** * The color rendered for the text of control panels and control objects, * such as pushbuttons. */ public static final SystemColor controlText = new SystemColor((byte) CONTROL_TEXT); /** * The color rendered for light areas of 3D control objects, such as pushbuttons. * This color is typically derived from the {@code control} background color * to provide a 3D effect. */ public static final SystemColor controlHighlight = new SystemColor((byte) CONTROL_HIGHLIGHT); /** * The color rendered for highlight areas of 3D control objects, such as pushbuttons. * This color is typically derived from the {@code control} background color * to provide a 3D effect. */ public static final SystemColor controlLtHighlight = new SystemColor((byte) CONTROL_LT_HIGHLIGHT); /** * The color rendered for shadow areas of 3D control objects, such as pushbuttons. * This color is typically derived from the {@code control} background color * to provide a 3D effect. */ public static final SystemColor controlShadow = new SystemColor((byte) CONTROL_SHADOW); /** * The color rendered for dark shadow areas on 3D control objects, such as pushbuttons. * This color is typically derived from the {@code control} background color * to provide a 3D effect. */ public static final SystemColor controlDkShadow = new SystemColor((byte) CONTROL_DK_SHADOW); /** * The color rendered for the background of scrollbars. */ public static final SystemColor scrollbar = new SystemColor((byte) SCROLLBAR); /** * The color rendered for the background of tooltips or spot help. */ public static final SystemColor info = new SystemColor((byte) INFO); /** * The color rendered for the text of tooltips or spot help. */ public static final SystemColor infoText = new SystemColor((byte) INFO_TEXT); /* * JDK 1.1 serialVersionUID. */ private static final long serialVersionUID = 4503142729533789064L; /* * An index into either array of SystemColor objects or values. */ private transient int index; private static SystemColor[] systemColorObjects = { SystemColor.desktop, SystemColor.activeCaption, SystemColor.activeCaptionText, SystemColor.activeCaptionBorder, SystemColor.inactiveCaption, SystemColor.inactiveCaptionText, SystemColor.inactiveCaptionBorder, SystemColor.window, SystemColor.windowBorder, SystemColor.windowText, SystemColor.menu, SystemColor.menuText, SystemColor.text, SystemColor.textText, SystemColor.textHighlight, SystemColor.textHighlightText, SystemColor.textInactiveText, SystemColor.control, SystemColor.controlText, SystemColor.controlHighlight, SystemColor.controlLtHighlight, SystemColor.controlShadow, SystemColor.controlDkShadow, SystemColor.scrollbar, SystemColor.info, SystemColor.infoText }; static { AWTAccessor.setSystemColorAccessor(SystemColor::updateSystemColors); updateSystemColors(); } /** * Called from {@code <init>} and toolkit to update the above systemColors cache. */ private static void updateSystemColors() { if (!GraphicsEnvironment.isHeadless()) { Toolkit.getDefaultToolkit().loadSystemColors(systemColors); } for (int i = 0; i < systemColors.length; i++) { systemColorObjects[i].value = systemColors[i]; } } /** * Creates a symbolic color that represents an indexed entry into system * color cache. Used by above static system colors. */ private SystemColor(byte index) { super(systemColors[index]); this.index = index; } /** * Returns a string representation of this {@code Color}'s values. * This method is intended to be used only for debugging purposes, * and the content and format of the returned string may vary between * implementations. * The returned string may be empty but may not be {@code null}. * * @return a string representation of this {@code Color} */ public String toString() { return getClass().getName() + "[i=" + (index) + "]"; } /** * The design of the {@code SystemColor} class assumes that * the {@code SystemColor} object instances stored in the * static final fields above are the only instances that can * be used by developers. * This method helps maintain those limits on instantiation * by using the index stored in the value field of the * serialized form of the object to replace the serialized * object with the equivalent static object constant field * of {@code SystemColor}. * See the {@link #writeReplace} method for more information * on the serialized form of these objects. * @return one of the {@code SystemColor} static object * fields that refers to the same system color. */ private Object readResolve() { // The instances of SystemColor are tightly controlled and // only the canonical instances appearing above as static // constants are allowed. The serial form of SystemColor // objects stores the color index as the value. Here we // map that index back into the canonical instance. return systemColorObjects[value]; } /** * Returns a specialized version of the {@code SystemColor} * object for writing to the serialized stream. * @serialData * The value field of a serialized {@code SystemColor} object * contains the array index of the system color instead of the * rgb data for the system color. * This index is used by the {@link #readResolve} method to * resolve the deserialized objects back to the original * static constant versions to ensure unique instances of * each {@code SystemColor} object. * @return a proxy {@code SystemColor} object with its value * replaced by the corresponding system color index. */ private Object writeReplace() throws ObjectStreamException { // we put an array index in the SystemColor.value while serialize // to keep compatibility. SystemColor color = new SystemColor((byte) index); color.value = index; return color; } }