褪色样品

Question

我需要一个用Java编写的颜色渐变示例。 我的要求是我有两个矩形。一个充满了红色，另一个充满了白色。当我点击任何按钮时，我希望红色开始褪色并移动绿色。一旦到达绿色位置，则自动另一个矩形应从黄色蓝色开始。有人可以帮我吗？如果得到任何用Javaswing或SWT编写的例子都会很好。感谢。

Answer 1

Checkout Trident动画库。它允许您轻松地在类中插入属性。另请查看Kirill Grouchnikov（Trident的作者）的these原始教程。

编辑：没有三叉戟的动画示例

以下示例基于Filthy Rich Clients中的AnimatedGraphics示例：

import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
import javax.swing.Timer;

public class AnimatedGraphics extends JComponent implements ActionListener {

    Color startColor = Color.RED;   // where we start
    Color endColor = Color.GREEN;         // where we end
    Color currentColor = startColor;
    int animationDuration = 2000;   // each animation will take 2 seconds
    long animStartTime;         // start time for each animation

    public AnimatedGraphics() {
        Timer timer = new Timer(30, this);
        // initial delay while window gets set up
        timer.setInitialDelay(1000);
        animStartTime = 1000 + System.nanoTime() / 1000000;
        timer.start();
    }

    public void paintComponent(Graphics g) {
        g.setColor(getBackground());
        g.fillRect(0, 0, getWidth(), getHeight());
        g.setColor(currentColor);
        g.fillOval(0, 0, getWidth(), getHeight());
    }

    public void actionPerformed(ActionEvent ae) {
        // calculate elapsed fraction of animation
        long currentTime = System.nanoTime() / 1000000;
        long totalTime = currentTime - animStartTime;
        if (totalTime > animationDuration) {
            animStartTime = currentTime;
        }
        float fraction = (float)totalTime / animationDuration;
        fraction = Math.min(1.0f, fraction);
        // interpolate between start and end colors with current fraction
        int red = (int)(fraction * endColor.getRed() + 
                (1 - fraction) * startColor.getRed());
        int green = (int)(fraction * endColor.getGreen() + 
                (1 - fraction) * startColor.getGreen());
        int blue = (int)(fraction * endColor.getBlue() + 
                (1 - fraction) * startColor.getBlue());
        // set our new color appropriately
        currentColor = new Color(red, green, blue);
        // force a repaint to display our oval with its new color
        repaint();
    }

    private static void createAndShowGUI() {    
        JFrame f = new JFrame("Animated Graphics");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setSize(200, 200);
        f.add(new AnimatedGraphics());
        f.setVisible(true);
    }

    public static void main(String args[]) {
        Runnable doCreateAndShowGUI = new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        };
        SwingUtilities.invokeLater(doCreateAndShowGUI);
    }
}