在画布上闪烁的白色 [英] Flickering white on canvas

问题描述

我发现一个解决方案分钟后，张贴，但由于低声誉我不能删除的帖子

它我决定开始工作，可能会变成一个游戏在某一点。

我想画一些圆圈，目前在指定的方向移动它们。这导致闪烁。这很可能是我监督一些非常基本的东西，但我不知道为什么它不顺利。

我的板类看起来像（删除我认为不必要）：

  public class Board extends Canvas implements Runnable {
 
 public static void main ] args）{
 Board board = new Board（）; 
 
 board.setPreferredSize（new Dimension（WIDTH * SCALE，HEIGHT * SCALE））; 
 
 JFrame frame = new JFrame（Circles）; 
 frame.setDefaultCloseOperation（WindowConstants.EXIT_ON_CLOSE）; 
 frame.add（board）; 
 frame.pack（）; 
 
 frame.setVisible（true）; 
 
 board.start（）; 
} 
 
 @Override 
 public void run（）{
 while（running）{
 process（）; 
 repaint（）; 
 
 try {
 Thread.sleep（15）; 
} catch（InterruptedException e）{
 e.printStackTrace（）; 
} 
} 
} 
} 
  

paint方法：

  public void paint（Graphics g1）{
 super.paint（g1）; 
 Graphics2D g =（Graphics2D）g1; 
 for（Ball ball：Ball.BALLS）{
 g.drawOval（（int）ball.getLocation（）。getX（），（int）ball.getLocation（）。getY（） addRadius（），ball.getRadius（））; 
} 
} 
  

我的处理方法：

  private void process（）{
 if（utilities.randInt（1，100）< 10&&Ball.getBallCount ; 40）{
 Ball.spawnNew（this）; 
} 
（球球：Ball.BALLS）{
 ball.move（this）; 
} 
 Ball.BALLS.removeAll（Ball.TO_REMOVE）; 
 Ball.TO_REMOVE.clear（）; 
} 
  

move方法基本上将球的x值增加给定值每次它的调用（移动它正确）。

像我说的，我不确定为什么它闪烁，如果你有任何指针，请告诉。

谢谢！

解决方案

为此，您需要创建一个 BufferedImage 并从中获取 Graphics 。

示例：

将所有图像绘制到图像，将图像渲染到屏幕上，然后最终填充图像的背景颜色或图像以重置图像。 >

  //一次实例化
 BufferedImage b = new BufferedImage（width，height，mode）; 
  

在 paint（Graphics g）：

  Graphics buffer = b.getGraphics（）; 
 //将所有的东西渲染到缓冲区
 Graphics2D g =（Graphics2D）buffer; 
 for（Ball ball：Ball.BALLS）{
 g.drawOval（（int）ball.getLocation（）。getX（），（int）ball.getLocation（）。getY（） getRadius（），ball.getRadius（））; 
} 
 g1.drawImage（b，0，0，width，height，null）; 
 g.setColor（Color.BLACK）; 
 //复位图像
 g.drawRect（0，0，width，height）; 
 g.dispose（）; 
  

I figured out a solution minutes after posting, but due to low reputation I couldn't delete the post

For the fun of it I decided to start working on something which might turn into a game at some point.

I'm trying to draw some circles and move them in a given direction currently. This causes flickering. It's very likely that I oversee something very basic but I can't figure out why it doesn't render smoothly.

My board class looks something like (removed what I deemed unnecessary):

public class Board extends Canvas implements Runnable {

    public static void main(String[] args) {
        Board board = new Board();

        board.setPreferredSize(new Dimension(WIDTH * SCALE, HEIGHT * SCALE));

        JFrame frame = new JFrame("Circles");
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        frame.add(board);
        frame.pack();

        frame.setVisible(true);

        board.start();
    }

    @Override
    public void run() {
        while (running) {
            process();
            repaint();

            try {
                Thread.sleep(15);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

The paint method:

    public void paint(Graphics g1) {
        super.paint(g1);
        Graphics2D g = (Graphics2D) g1;
        for (Ball ball : Ball.BALLS) {
            g.drawOval((int) ball.getLocation().getX(), (int) ball.getLocation().getY(), ball.getRadius(),  ball.getRadius());
        }
    }

My process method:

private void process() {
    if (utilities.randInt(1, 100) < 10 && Ball.getBallCount() < 40) {
        Ball.spawnNew(this);
    }
    for (Ball ball : Ball.BALLS) {
        ball.move(this);
    }
    Ball.BALLS.removeAll(Ball.TO_REMOVE);
    Ball.TO_REMOVE.clear();
}

The move method basically increments the x-value of the ball by a given value each time its called (moving it right).

Like I said, I'm unsure why it flickers so if you have any pointers please do tell.

Thanks!

解决方案

You need double buffering. To do this you need to create a BufferedImage and get the Graphics from it. Paint everything to the image, render the image on to the screen, then finally fill the image with a the background color or image to reset it.

Sample:

//one time instantiation
BufferedImage b = new BufferedImage(width, height, mode);

In paint(Graphics g):

Graphics buffer = b.getGraphics();
//render all of the stuff on to buffer
Graphics2D g = (Graphics2D) buffer;
    for (Ball ball : Ball.BALLS) {
        g.drawOval((int) ball.getLocation().getX(), (int) ball.getLocation().getY(), ball.getRadius(),  ball.getRadius());
    }
g1.drawImage(b, 0, 0, width, height, null);
g.setColor(Color.BLACK);
//reset the image
g.drawRect(0, 0, width, height);
g.dispose();

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