XCanvasPeer.java

/*
 * Copyright 2002-2007 Sun Microsystems, Inc.  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.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */
package sun.awt.X11;

import java.awt.*;
import java.awt.peer.*;

import sun.awt.ComponentAccessor;
import sun.awt.SunToolkit;

import sun.awt.X11GraphicsConfig;
import sun.awt.X11GraphicsDevice;

class XCanvasPeer extends XComponentPeer implements CanvasPeer {

    private boolean eraseBackgroundDisabled;

    XCanvasPeer() {}

    XCanvasPeer(XCreateWindowParams params) {
        super(params);
    }

    XCanvasPeer(Component target) {
        super(target);
    }

    void preInit(XCreateWindowParams params) {
        super.preInit(params);
        if (SunToolkit.getSunAwtNoerasebackground()) {
            disableBackgroundErase();
        }
    }

    void resetTargetGC(Component target) {
        ComponentAccessor.resetGC(target);
    }

    /*
     * Called when the Window this
     * Canvas is on is moved onto another Xinerama screen.
     *
     * Canvases can be created with a non-defulat GraphicsConfiguration.  The
     * GraphicsConfiguration needs to be changed to one on the new screen,
     * preferably with the same visual ID.
     *
     * Up-called for other windows peer instances (XPanelPeer, XWindowPeer).
     *
     * Should only be called from the event thread.
     */
    public void displayChanged(int screenNum) {
        resetLocalGC(screenNum);
        resetTargetGC(target);
    }

    /* Set graphicsConfig to a GraphicsConfig with the same visual on the new
     * screen, which should be easy in Xinerama mode.
     *
     * Should only be called from displayChanged(), and therefore only from
     * the event thread.
     */
    void resetLocalGC(int screenNum) {
        // Opt: Only need to do if we're not using the default GC
        if (graphicsConfig != null) {
            X11GraphicsConfig parentgc;
            // save vis id of current gc
            int visual = graphicsConfig.getVisual();

            X11GraphicsDevice newDev = (X11GraphicsDevice) GraphicsEnvironment.
                getLocalGraphicsEnvironment().
                getScreenDevices()[screenNum];

            for (int i = 0; i < newDev.getNumConfigs(screenNum); i++) {
                if (visual == newDev.getConfigVisualId(i, screenNum)) {
                    // use that
                    graphicsConfig = (X11GraphicsConfig)newDev.getConfigurations()[i];
                    break;
                }
            }
            // just in case...
            if (graphicsConfig == null) {
                graphicsConfig = (X11GraphicsConfig) GraphicsEnvironment.
                    getLocalGraphicsEnvironment().
                    getScreenDevices()[screenNum].
                    getDefaultConfiguration();
            }
        }
    }
    protected boolean shouldFocusOnClick() {
        // Canvas should always be able to be focused by mouse clicks.
        return true;
    }

    public void disableBackgroundErase() {
        eraseBackgroundDisabled = true;
    }
    protected boolean doEraseBackground() {
        return !eraseBackgroundDisabled;
    }
    public void setBackground(Color c) {
        boolean doRepaint = false;
        if( getPeerBackground() == null ||
           !getPeerBackground().equals( c ) ) {
            doRepaint = true;
        }
        super.setBackground(c);
        if( doRepaint ) {
            target.repaint();
        }
    }
}