Java Graphics 图像刷新率

Question

我正在制作一个 JFrame，其中包含使用 repaint() 刷新的多个图像。然而，问题是，我添加的图像越多(或者随着渲染区域的增加)，帧速率就会急剧下降。

我最初试图减少 Swing 不可预测的计时器所经历的延迟，但没有成功。这次，我尝试打电话

repaint()

根据系统时间每 10 毫秒一次。 (为了绕过计时器，调用desktop.screenPaint.drawWindow();而不是repaint())

while(true)
  {
     long starttime = System.currentTimeMillis();
     while(System.currentTimeMillis()-starttime < 10)
     {
     }
     desktop.screenPaint.drawWindow();
     desktop2.screenPaint.drawWindow();
  }

每个“桌面”只是运行下面的代码时看到的可拖动窗口之一。我注意到，当仅将“桌面”添加到“框架”时，没有闪烁。然而，当还添加“desktop2”时，闪烁不会消失，直到每次刷新的时间设置为 20 或更多毫秒。这很奇怪，因为当我还在使用定时器时，即使等待设置为10毫秒，帧率也会降低到每20毫秒一帧!我测试了一下，发现了一个趋势:你会一直闪烁，直到等待时间达到 10 毫秒计时器滞后的时间量。我的问题:为什么会发生这种情况？除了返回计时器之外，还有什么方法可以防止闪烁吗？

import javax.swing.JFrame;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import javax.swing.SwingUtilities.*;
import static java.awt.GraphicsDevice.WindowTranslucency.*;
import java.io.File;
import java.io.IOException;
public class Display extends JPanel
{
   public static int width, height;
   public static JFrame frame = new JFrame("");
   private static int rh = 10;
   public static Display desktop = new Display();
   public static Display desktop2 = new Display();
   public static void main(String[] args)
   {
      Dimension screen = new Dimension();
      screen = java.awt.Toolkit.getDefaultToolkit().getScreenSize();
      width = (int)screen.getWidth();
      height = (int)screen.getHeight();
      frame.setLayout(null);
      frame.setLocation(0, 0);
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.setLayout(null);
      desktop.setBounds(0, 0, 620, 500+rh);
      desktop2.setBounds(1000, 200, 620, 500+rh);
      frame.add(desktop);
      frame.add(desktop2);
      frame.setUndecorated(true);
      frame.setSize(width, height);
      frame.setVisible(true);
      while(true)
      {
         long starttime = System.currentTimeMillis();
         while(System.currentTimeMillis()-starttime < 10)
         {
         }
         desktop.screenPaint.drawWindow();
         //desktop2.screenPaint.drawWindow();
      }
   }
   private BufferedImage image;
   private Graphics2D g;
   public Listener screenPaint = new Listener();
   private Display identify;
   public Display()
   {
      identify = this;
      image = new BufferedImage(620, 500+rh, BufferedImage.TYPE_INT_RGB);
      g = (Graphics2D)image.getGraphics();
      Timer timer = new Timer(1, screenPaint);
      timer.start();
      addMouseListener(new mMouse());
      addMouseWheelListener(new wWheel());
      setFocusable(true);
   }
   private BufferedImage toCompatibleImage(BufferedImage image)
   {
      GraphicsConfiguration gfx_config = GraphicsEnvironment.
         getLocalGraphicsEnvironment().getDefaultScreenDevice().
         getDefaultConfiguration();
      if (image.getColorModel().equals(gfx_config.getColorModel()))
         return image;
      BufferedImage new_image = gfx_config.createCompatibleImage(
         image.getWidth(), image.getHeight(), image.getTransparency());
   }
   public void paint(Graphics view)
   {
      g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
      view.drawImage(toCompatibleImage(image), 0, 0, 620, 500+rh, null);
      view.dispose();
   }
   private class Listener implements ActionListener
   {
      int y = 0;
      int wy = 0;
      int b = 500;
      int c = 1500;
      int iy = (int)(wy/(c/(double)b));
      int a = -1;
      int i = -1;
      int j = -1;
      boolean d = false;
      boolean u = false;
      int f = 0;
      public void moveY(int sy)
      {
         f += sy;
      }
      public void actionPerformed(ActionEvent e)
      {
         //drawWindow();
      }
      public void drawWindow()
      {
         int lx = (int)(identify.getLocation().getX());
         int ly = (int)(identify.getLocation().getY());
         g.setColor(Color.white);
         g.fillRect(0, 0, 620, 500+rh);
         g.drawImage(new ImageIcon("image.png").getImage(), 0, wy+rh, 610, c, null);
         if(c > b)
         {
            if(d || Mouse.withinRect(610+lx, (int)(-wy/(c/(double)b))+rh+ly, 10, (int)Math.ceil(Math.pow(b, 2)/(double)c)))
            {
               if(Mouse.pressLeft())
               {
                  if(!d)d = true;
                  if(a == -1)a = Mouse.y()-(int)(-wy/(c/(double)b));
                  y = (int)((Mouse.y()-a)*(c/(double)b));
                  f = y;
                  g.setColor(Color.black);
               }
               else
               {  
                  if(d)d = false;
                  if(a != -1)a = -1;
                  g.setColor(new Color(60, 60, 60));
               }
            }
            else
            {
               g.setColor(Color.gray);
               if(a != -1)a = -1;
            }
            if(y == f){}
            else if(y < f)
            {
               y += (int)((f-y)*0.1);
               if(y < f)y++;
            }
            else
            {
               y -= (int)((y-f)*0.1);
               if(y > f)y--;
            }
            if(y < 0)
            {
               y = 0;
               f = 0;
            }
            else if(y > c-b)
            {
               y = c-b;
               f = y;
            }
            wy = -y;
            if(u || Mouse.withinRect(lx, ly, 620, 10))
            {
               if(Mouse.pressLeft())
               {
                  if(!u)u = true;
                  if(i == -1)i = Mouse.x()-lx;
                  if(j == -1)j = Mouse.y()-ly;
                  identify.setLocation(Mouse.x()-i, Mouse.y()-j);
               }
               else
               {  
                  if(u)u = false;
                  if(i != -1)i = -1;
                  if(j != -1)j = -1;
               }
            }
            else
            {
               if(u)u = false;
               if(i != -1)i = -1;
               if(j != -1)j = -1;
            }
            int scrollBarLength = (int)Math.ceil(Math.pow(b, 2)/(double)c);
            g.fillRect(610, (int)(-wy/(c/(double)b))+rh, 10, scrollBarLength);
         }
         else
         {
            g.setColor(new Color(200, 200, 200));
            g.fillRect(610, rh, 10, b);
         }
         g.setColor(new Color(50, 50, 50));
         g.fillRect(0, 0, 620, rh);
         if(identify == desktop)
            repaint();
         else if(false)
         {}
         }
      }
   }
   public static boolean LMPress, LMRelease = false;
   public static boolean LMRight, LMLeft = false;
   private class mMouse extends MouseAdapter
   {
      public void mousePressed(MouseEvent e)
      {
         LMPress = true; LMRelease = false;
         if(SwingUtilities.isRightMouseButton(e))
         {
            LMRight = true;
            LMLeft = false;
         }
         else if(SwingUtilities.isLeftMouseButton(e))
         {
            LMLeft = true;
            LMRight = false;
         }
      }
      public void mouseReleased(MouseEvent e)
      {
         LMRelease = true; LMPress = false;
         if(SwingUtilities.isRightMouseButton(e))
         {
            LMRight = true;
            LMLeft = false;
         }
         else if(SwingUtilities.isLeftMouseButton(e))
         {
            LMLeft = true;
            LMRight = false;
         }
      }
   }
   private class wWheel implements MouseWheelListener
   {
      public void mouseWheelMoved(MouseWheelEvent e)
      {
         int notches = e.getWheelRotation();
         if (e.getScrollType() == MouseWheelEvent.WHEEL_UNIT_SCROLL) {}
         e.getScrollAmount();
         screenPaint.moveY(e.getUnitsToScroll()*60); //desired pixel jump: 120
      }
   }
}

鼠标类:

import java.awt.*;
import java.awt.event.*;

public class Mouse {
    public static int x() {
        PointerInfo a = MouseInfo.getPointerInfo();
        Point b = a.getLocation();
        return (int) b.getX();
    }

    public static int y() {
        PointerInfo a = MouseInfo.getPointerInfo();
        Point b = a.getLocation();
        return (int) b.getY();
    }

    public static boolean withinRect(int x, int y, int w, int h) {
        if (x() >= x && x() < x + w && y() >= y && y() < y + h) return true;
        else return false;
    }

    public static boolean press() {
        return Display.LMPress;
    }

    public static boolean release() {
        return Display.LMRelease;
    }

    public static boolean pressLeft() {
        if (Display.LMPress && Display.LMLeft)
            return true;
        else return false;
    }

    public static boolean releaseLeft() {
        if (Display.LMRelease && Display.LMLeft)
            return true;
        else return false;
    }

    public static boolean pressRight() {
        if (Display.LMPress && Display.LMRight)
            return true;
        else return false;
    }

    public static boolean releaseRight() {
        if (Display.LMRelease && Display.LMRight)
            return true;
        else return false;
    }
}

Answer 1

以 1 kHz 的频率更新 View 是不现实的；相反，请考虑引用的替代方案 here 。看这个AnimationTest有关自行计时以确定动画预算的示例。

附录: while(true) 顶部循环以 100 Hz 运行。

System.currentTimeMillis() 的可用分辨率可能 vary by platform .

附录:我正在重新打开这个问题，因为我无法解决它。还有更多帮助吗？

缺少 Minimal, Complete, Tested and Readable Example ，很难说。您似乎正在覆盖 paint();已在 Painting in AWT and Swing: The Paint Methods 中注明，“Swing 程序应该重写 paintComponent()。”此外，您还需要调用super.paintComponent()，如图here ，以避免视觉伪影。