逐行加载图像 Java

Question

所以这听起来很荒谬，但我正在做一个项目，我故意想减慢图像的加载速度，以便逐行加载。无论如何我可以做到这一点吗？我目前在 ImagePane 中有图像，它只是 JPanel 的扩展：

public ImagePane() {
        initComponents();
        image = null;
        //this.setAutoscrolls(true);
    }
    public void setImage(String path) throws IOException {
        image = ImageIO.read(getClass().getResource(path));
    }

    @Override
    public void paintComponent(Graphics g)
    {
        //Graphics2D g2 = (Grahpics2D)g;
        g.drawImage(image, 0,0, this);
    }

在我试图将其显示为的窗口中：

ImagePane image = new ImagePane();
try {
    image.setImage("netscapelogo2.png");
}
catch (IOException e) {
    System.out.print("Failed to Set");
    e.printStackTrace();
}
//jScrollPane1.add(image);
jScrollPane1.setViewportView(image);

我想我需要有人更改我的 paintComponent 方法才能做到这一点，但我不确定具体该怎么做。

Answer 1

此解决方案使用前提I would simulate that the image is loading line by line by uncovering it gradually. – rodrigoap，因此图像会立即加载并且仅显示，因为它将逐行读取！

一个解决方案是创建一个线程并让线程工作......

Runnable r = new Runnable(){

    @Override
    run(){
        for(int i = 0; i < image.getHeight(); i++){
            // wait 100ms to 'slow down'
            Thread.sleep(100)// surround with try/catch, it may throw an exception
            line = line + 1; //increase amount of visible lines
            repaint(); //update the panel
        }
    }
}

//i don't know when you want to start the animation
new Thead(r).start(); //so trigger at free will

当您绘制图像时，您只是绘制线条的数量，而不是整个图像......

@Override
public void paintComponent(Graphics g)
{
    super(g);
    int w = image.getWidth();
    int h = image.getHeight();
    g.drawImage(image, 0,0, w, line, 0,0,w,h,this);
}

drawImage 方法有点奇怪，请参阅docu 以获得更多帮助

当然你需要在某个地方定义private int line = 0;