WCanvasPeer.java

/*
 * This file is modified by Ivan Maidanski <ivmai@ivmaisoft.com>
 * Project name: JCGO-SUNAWT (http://www.ivmaisoft.com/jcgo/)
 */

/*
 * @(#)WCanvasPeer.java 1.23 03/01/23
 *
 * Copyright 2003 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
package sun.awt.windows;

import java.awt.*;
import java.awt.peer.*;
import java.lang.ref.WeakReference;
import sun.awt.Win32GraphicsDevice;

class WCanvasPeer extends WComponentPeer implements CanvasPeer {

    private static boolean eraseBackgroundDisabled;
    private static boolean eraseBackgroundOnResize;

    static {
        String noerasebackground = (String)java.security.AccessController.doPrivileged(
            new sun.security.action.GetPropertyAction("sun.awt.noerasebackground"));
        eraseBackgroundDisabled = (noerasebackground != null
                                && noerasebackground.length() > 0
                                && noerasebackground.charAt(0) == 't');

        noerasebackground = (String)java.security.AccessController.doPrivileged(
            new sun.security.action.GetPropertyAction("sun.awt.erasebackgroundonresize"));
        eraseBackgroundOnResize = (noerasebackground != null
                                && noerasebackground.length() > 0
                                && noerasebackground.charAt(0) == 't');
    }

    // Toolkit & peer internals

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

    /*
     * From the DisplayChangedListener interface.
     *
     * Overrides WComponentPeer version because Canvases can be created with
     * a non-defulat GraphicsConfiguration, which is no longer valid.
     * Up-called for other windows peer instances (WPanelPeer, WWindowPeer).
     */
    public void displayChanged() {
        clearLocalGC();
        resetTargetGC();
        super.displayChanged();
    }

    /*
     * Reset the graphicsConfiguration member of our target Component.
     * Component.resetGC() is a package-private method, so we have to call it
     * through JNI.
     */
    native void resetTargetGC();

    /*
     * Clears the peer's winGraphicsConfig member.
     * Overridden by WWindowPeer, which shouldn't have a null winGraphicsConfig.
     */
    void clearLocalGC() {
        winGraphicsConfig = null;
    }

    native void create(WComponentPeer parent);

    void initialize() {
        super.initialize();
        Color bg = ((Component)target).getBackground();
        if (bg != null) {
            setBackground(bg);
        }
    }

    public void paint(Graphics g) {
        Dimension d = ((Component)target).getSize();
        if (g instanceof Graphics2D ||
            g instanceof sun.awt.Graphics2Delegate) {
            // background color is setup correctly, so just use clearRect
            g.clearRect(0, 0, d.width, d.height);
        } else {
            // emulate clearRect
            g.setColor(((Component)target).getBackground());
            g.fillRect(0, 0, d.width, d.height);
            g.setColor(((Component)target).getForeground());
        }
        super.paint(g);
    }

    public void print(Graphics g) {
        Dimension d = ((Component)target).getSize();
        if (g instanceof Graphics2D ||
            g instanceof sun.awt.Graphics2Delegate) {
            // background color is setup correctly, so just use clearRect
            g.clearRect(0, 0, d.width, d.height);
        } else {
            // emulate clearRect
            g.setColor(((Component)target).getBackground());
            g.fillRect(0, 0, d.width, d.height);
            g.setColor(((Component)target).getForeground());
        }
        super.print(g);
    }

    public boolean shouldClearRectBeforePaint() {
        return (eraseBackgroundDisabled == false);
    }

}