如何防止JInternalFrame重新绘制重叠的JInternalFrame

Question

我有两个JInternalFrames，每个都包含一个JPanel。一个JPanel (源)更新它的图形用户界面和响应鼠标事件的一些数据。另一个JPanel (目标)接收指示数据已更改的事件并相应地更新其外观。

如果源面板与目标面板重叠，则目标面板中的重绘将触发源面板中的重绘。而且，即使对目标面板所需的更改被源面板遮住了，目标面板仍然重新绘制，并且仍然在源面板中触发重绘。

在我的实际应用程序中，这会造成性能问题，因为多个面板正在鼠标拖动上触发重新绘制，源面板有一个复杂的图像要显示。

如何防止目标面板更新触发源面板中的重新绘制？

我尝试过的事情：

• 给出参数来重新绘制，这意味着只有目标面板的一个不重叠的位被重新绘制，停止了问题，但在我的例子中，我不知道目标面板的哪个部分是可见的(我尝试了getVisibleRect和getClipBounds，但它们只是返回整个面板大小)。在我的实际应用程序中，整个目标面板是更新的，而不仅仅是它的一部分，所以我也不能以这种方式限制重绘。
• 基于现有的InternalFrameDemo创建了一个最小的示例:相同的问题，参见下面的代码。该示例有两个面板，如我所描述的，单击源面板(标记为Document 1)在该位置绘制一个红色框，并更新DataModel对象，该对象将触发目标面板(标记为Document2)接收的事件，该事件本身在同一位置绘制一个红色框。在源paintComponent方法中设置一个断点，您可以看到有两个更新，一个来自SourcePanel重绘，一个来自TargetPanel重绘。 公共类InternalFrameDemo扩展JFrame实现ActionListener { JDesktopPane桌面；DataModel model =新DataModel()；public InternalFrameDemo() { super("InternalFrameDemo")；//使大窗口从屏幕的每边//缩进50个像素。int inset = 50；维度screenSize = Toolkit.getDefaultToolkit().getScreenSize()；setBounds(inset，inset，screenSize.width - inset*2，screenSize.height - inset*2)；//设置GUI。桌面=新的JDesktopPane()；//一个专门的分层窗格MyInternalFrame frame1 = createFrame()；//创建第一个“窗口”MyInternalFrame frame2 = createFrame()；setContentPane(桌面)；SourcePanel sp =新SourcePanel(模型)；Fra1.add(Sp)；TargetPanel tp =新TargetPanel(模型)；Fra2.add(Tp)；//使拖动速度更快，但可能更丑。desktop.setDragMode(JDesktopPane.OUTLINE_DRAG_MODE)；} actionPerformed(ActionEvent e) {}//创建一个新的内部框架。受保护的MyInternalFrame createFrame() { MyInternalFrame frame =新的MyInternalFrame()；frame.setVisible(真)；//必要的自1.3 frame.setOpaque(真)；desktop.add(frame)；尝试{frame.setSelected(真)；}MyInternalFrame (java.beans.PropertyVetoException e) {}返回帧；}//退出应用程序。受保护的void (){ System.exit(0)；} /** *创建并显示该GUI。为了线程安全，*应该从*事件分派线程调用此方法。*/私有静态空createAndShowGUI() {//创建并设置窗口。frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE)；//显示窗口。frame.setVisible(true)；}公共静态void (String[] args) {//调度一个作业，用于事件分派线程://创建和显示该应用程序的GUI。javax.swing.SwingUtilities.invokeLater(new (){ public void (){ createAndShowGUI()；})；}

    package components;

    import javax.swing.JInternalFrame;

    /* Used by InternalFrameDemo.java. */
    public class MyInternalFrame extends JInternalFrame {
    static int openFrameCount = 0;
    static final int xOffset = 30, yOffset = 30;

    public MyInternalFrame() {
        super("Document #" + (++openFrameCount), 
              true, //resizable
              true, //closable
              true, //maximizable
              true);//iconifiable

        setSize(300,300);
        setLocation(xOffset*openFrameCount, yOffset*openFrameCount);
    }
}

package components;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class SourcePanel extends JPanel {

    int boxX, boxY;
    int boxWidth = 10;
    int boxHeight = 10;

    public SourcePanel(DataModel data) {

        addMouseListener(new MouseAdapter()
        {
          @Override
          public void mousePressed(MouseEvent evt)
          {
            if (!SwingUtilities.isRightMouseButton(evt))
            {
              boxX = evt.getX();
              boxY = evt.getY();
              data.update(boxX,boxY);
              repaint();
            }
          }
        });
    }

    @Override
    public void paintComponent(Graphics g)
    {
        super.paintComponent(g);
        g.setColor(Color.RED);
        int x = Math.min(boxX, this.getWidth()-boxWidth);
        int y = Math.min(boxY,  this.getHeight()-boxHeight);
        g.drawRect(x, y, boxWidth, boxHeight);
        g.drawRect(x + 1, y + 1, boxWidth - 2, boxHeight - 2);
    }
}

package components;

import java.awt.Color;
import java.awt.Graphics;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;

import javax.swing.JPanel;

public class TargetPanel extends JPanel implements PropertyChangeListener {

    int boxX, boxY;
    int boxWidth = 10;
    int boxHeight = 10;

    public TargetPanel(DataModel data) {
        data.addPropertyChangeListener(this);
    }

    @Override
    public void propertyChange(PropertyChangeEvent evt)
    {
      //draw something in response to the data change
      boxX = ((int[])evt.getNewValue())[0];
      boxY = ((int[])evt.getNewValue())[1];
      repaint();
    }

    @Override
    public void paintComponent(Graphics g)
    {
        super.paintComponent(g);
        g.setColor(Color.BLUE);
        g.fillRect(0, 0, getWidth(), getHeight());
        g.setColor(Color.RED);
        int x = Math.min(boxX, this.getWidth()-boxWidth);
        int y = Math.min(boxY,  this.getHeight()-boxHeight);
        g.fillRect(x, y, boxWidth, boxHeight);
    }
}

package components;

import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeSupport;

public class DataModel {

    int datax = 10;
    int datay = 10;

    public DataModel()
    {
    }

    public void update(int x, int y)
    {
        int[] olddata = new int[]{datax,datay};
        datax = x;
        datay = y;
        int[] newdata = new int[]{datax,datay};
        changeSupport.firePropertyChange("DataChange", olddata, newdata);
    }

    protected PropertyChangeSupport changeSupport = new PropertyChangeSupport(
              this);

    public void addPropertyChangeListener(PropertyChangeListener listener)
    {
        changeSupport.addPropertyChangeListener(listener);
    }

    public void removePropertyChangeListener(PropertyChangeListener listener)
    {
        changeSupport.removePropertyChangeListener(listener);
    }

}

(原始JInternalFrame示例代码的版权通知：)

/*
 * Copyright (c) 1995, 2008, Oracle and/or its affiliates. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Oracle or the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */ 

Answer 1

您可以缓存鼠标更改，并按间隔执行，或在鼠标跟踪结束时执行。

最简单的办法可能是尝试一次延期的重新油漆。

@Override
public void propertyChange(PropertyChangeEvent evt)
{
  //draw something in response to the data change
  boxX = ((int[])evt.getNewValue())[0];
  boxY = ((int[])evt.getNewValue())[1];
  repaint(200L);
}

实际上，在几次调用repaint(200L);之后重新绘制。(就我的感觉而言，我已经选择了5秒的高价值。)