如何在Java Swing应用程序中修改颜色强度

Question

I am using java swing to create an interface where the user draws a couple of points. What I want to do is after those points are drawn to change automatically the intensity of the color from really bright to dark till the point fades. Does anyone know any tutorials on how to change the color intensity because I cannot find something to help me.

EDIT: Thank you for your answers they helped me understand better how to work with Color class. I fixed it so I am uploading the thread part to help if anyone anyone else needs to do something similar... I am working on a black background so I darken the colors instead of lightening them.

public class MyThread extends Thread {

    private Canvas canvas;
    private int sleepingTime = 5000;
    private Color color;
    private int red, green, blue, alpha;

    public MyThread(Canvas canvas) {
        super();
        this.canvas = canvas;
        setDaemon(true);

    }

    public void run(){
        while (true){
            try {
                System.out.println("going to sleep...");
                Thread.sleep(sleepingTime);

            } catch (InterruptedException e) {
                System.out.println("sleep interrupted..");
                return;
            }
            System.out.println("woke up!");
                int size = canvas.points_list.size();
                int i =0;
                while (size > 0) {
                    color = canvas.points_list.get(i).getForeground();

                    red = (int) Math.round(Math.max(0, color.getRed() - 255 * 0.25f));
                    green = (int) Math.round(Math.max(0, color.getGreen() - 255 * 0.25f));
                    blue = (int) Math.round(Math.max(0, color.getBlue() - 255 * 0.25f));

                    alpha = color.getAlpha();

                    canvas.points_list.get(i).setForeground(new Color(red, green, blue, alpha));
                    size--; 
                    i++;
                }

                canvas.repaint();
        }
    }
}

Answer 1

您需要使用RGB形式，通过添加蓝色和绿色并使红色值保持不变，使它成为从明亮到黑暗的渐变，在for循环中连续进行此操作，最后将其设置为背景色，使其不可见。

Answer 2

Take a look at the HSB color model. It allows you to specify a "intensity" (saturation and brightness).

Example (red background becoming black - alternatively, modify the "s" parameter for fading the color to white):

final Frame frame = new Frame();

Timer timer = new Timer(500, new ActionListener() {

    float b = 1.0f;

    @Override
    public void actionPerformed(ActionEvent e) {
        int color = Color.HSBtoRGB(0, 1, b);
        frame.setBackground(new Color(color));

        b -= 0.05f;
    }
});
timer.start();

frame.setSize(200, 200);
frame.setVisible(true);