[英]Java fade in and out of images
我正在嘗試學習如何將圖像淡入和淡出到另一個圖像或從另一個圖像中。 因此,如果我有 2 張圖像,並且目前正在顯示 1 張圖像,我想在背景中顯示另一張圖像並將第一張圖像淡入第二張圖像。 或者,我想將焦點設置在新圖像上並在第一個圖像上慢慢淡入,然后停止顯示第一個圖像。
我不確定如何:
設置焦點,如果甚至需要。
如果我將 alpha 更改為 0 並遞增並且只繪制一張圖像,我可以淡入,但是我無法使用此代碼的任何變體使其淡出。 (即注釋掉一張要繪制的圖像)。
編輯:真的,我擔心的是能夠擁有 2 張圖像並使當前顯示的圖像慢慢消失在第二張圖像中。 這是如何完成的並不需要與此有關。
這是我弄亂的代碼示例:
import java.awt.AlphaComposite;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
public class FadeIn extends JPanel implements ActionListener {
private Image imagem;
private Image image2;
private Timer timer;
private float alpha = 1f;
public FadeIn() {
imagem = (new ImageIcon(getClass().getResource(
"/resources/1stImage.jpg"))).getImage();
image2 = (new ImageIcon(getClass().getResource(
"/resources/2ndImage.jpg"))).getImage();
timer = new Timer(20, this);
timer.start();
}
// here you define alpha 0f to 1f
public FadeIn(float alpha) {
imagem = (new ImageIcon(getClass().getResource(
"/resources/1stImage.jpg"))).getImage();
this.alpha = alpha;
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
g2d.drawImage(imagem, 0, 0, 400, 300, null);
g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER,
alpha));
g2d.drawImage(image2, 0, 0, 400, 300, null);
}
public static void main(String[] args) {
JFrame frame = new JFrame("Fade out");
frame.add(new FadeIn());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(420, 330);
// frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
@Override
public void actionPerformed(ActionEvent e) {
alpha += -0.01f;
if (alpha <= 0) {
alpha = 0;
timer.stop();
}
repaint();
}
}
基本上,這樣做是使用相同的 alpha 值,從 0-1 淡入,然后使用相同的 alpha,從 1-0 開始,允許兩個圖像相互淡入淡出......
魔法基本上發生在paintComponent
,其中使用alpha
值傳入的圖像和傳出圖像使用1f - alpha
。
在兩個圖像之間切換實際上是一個相同的過程,期望將inImage
交換為outImage
時間略有不同。 這不是使用標准增量(例如0.01
)從0-1
的直線移動,而是使用基於時間的算法。
也就是說,我使用一個計時器,它每 40 毫秒左右滴答一次,然后根據計時器運行的時間進行計算,並相應地計算alpha
值......
這允許您更改動畫將花費的時間量,但也提供了一個稍微更好的算法,該算法考慮了 Swings 渲染引擎的被動性質......
import java.awt.AlphaComposite;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class FadeImage {
public static void main(String[] args) {
new FadeImage();
}
public FadeImage() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public static class TestPane extends JPanel {
public static final long RUNNING_TIME = 2000;
private BufferedImage inImage;
private BufferedImage outImage;
private float alpha = 0f;
private long startTime = -1;
public TestPane() {
try {
inImage = ImageIO.read(new File("/path/to/inImage"));
outImage = ImageIO.read(new File("/path/to/outImage"));
} catch (IOException exp) {
exp.printStackTrace();
}
final Timer timer = new Timer(40, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
if (startTime < 0) {
startTime = System.currentTimeMillis();
} else {
long time = System.currentTimeMillis();
long duration = time - startTime;
if (duration >= RUNNING_TIME) {
startTime = -1;
((Timer) e.getSource()).stop();
alpha = 0f;
} else {
alpha = 1f - ((float) duration / (float) RUNNING_TIME);
}
repaint();
}
}
});
addMouseListener(new MouseAdapter() {
@Override
public void mouseClicked(MouseEvent e) {
alpha = 0f;
BufferedImage tmp = inImage;
inImage = outImage;
outImage = tmp;
timer.start();
}
});
}
@Override
public Dimension getPreferredSize() {
return new Dimension(
Math.max(inImage.getWidth(), outImage.getWidth()),
Math.max(inImage.getHeight(), outImage.getHeight()));
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.setComposite(AlphaComposite.SrcOver.derive(alpha));
int x = (getWidth() - inImage.getWidth()) / 2;
int y = (getHeight() - inImage.getHeight()) / 2;
g2d.drawImage(inImage, x, y, this);
g2d.setComposite(AlphaComposite.SrcOver.derive(1f - alpha));
x = (getWidth() - outImage.getWidth()) / 2;
y = (getHeight() - outImage.getHeight()) / 2;
g2d.drawImage(outImage, x, y, this);
g2d.dispose();
}
}
}
這是大多數開發人員使用 java 代碼進行圖像淡入淡出的簡單而簡短的方法。
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.awt.image.RescaleOp;
import java.io.File;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
/**
*
* @author ADMIN
*/
public class ImageFade extends JFrame {
ImageFade() {
setLayout(null);
JLabel l = new JLabel();
l.setBounds(0, 0, 100, 96);
add(l);
Thread tp = new Thread() {
@Override
public void run() {
for (int amp = 0; amp <= 500; amp++) {
try {
sleep(1);
try {
BufferedImage bim = ImageIO.read(new File("src/image/fade/image.png"));
BufferedImage nbim = new BufferedImage(bim.getWidth(), bim.getHeight(), BufferedImage.TYPE_INT_ARGB);
Graphics2D createGraphics = nbim.createGraphics();
createGraphics.drawImage(bim, null, 0, 0);
RescaleOp r = new RescaleOp(new float[]{1f, 1f, 1f, (float) amp / 500}, new float[]{0, 0, 0, 0}, null);
BufferedImage filter = r.filter(nbim, null);
l.setIcon(new ImageIcon(filter));
} catch (Exception ex) {
System.err.println(ex);
}
} catch (InterruptedException ex) {
}
}
}
};
tp.start();
setUndecorated(true);
setBackground(new Color(0, 0, 0, 0));
setSize(100, 96);
setVisible(true);
setLocationRelativeTo(null);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setResizable(false);
setAlwaysOnTop(true);
}
/**
* @param args the command line arguments
*/
public static void main(String[] args) {
ImageFade fr = new ImageFade();
}
}
在此代碼中,您可以看到線程代碼。 在這個圖像將淡入的線程中。
使用的圖像是堆棧溢出網頁的徽標圖像。
只有通過顯示的代碼圖像才會淡入。
Thread tp = new Thread() {
@Override
public void run() {
for (int amp = 0; amp <= 500; amp++) {
try {
sleep(1);
try {
BufferedImage bim = ImageIO.read(new File("src/image/fade/image.png"));
BufferedImage nbim = new BufferedImage(bim.getWidth(), bim.getHeight(), BufferedImage.TYPE_INT_ARGB);
Graphics2D createGraphics = nbim.createGraphics();
createGraphics.drawImage(bim, null, 0, 0);
RescaleOp r = new RescaleOp(new float[]{1f, 1f, 1f, (float) amp / 500}, new float[]{0, 0, 0, 0}, null);
BufferedImage filter = r.filter(nbim, null);
l.setIcon(new ImageIcon(filter));
} catch (Exception ex) {
System.err.println(ex);
}
} catch (InterruptedException ex) {
}
}
}
};
tp.start();
這段代碼使用起來非常簡單。
這不是來自任何書籍、互聯網等。它是由我開發的。
普通圖像無法更改 alpha。 通過代碼: BufferedImage nbim = new BufferedImage(bim.getWidth(), bim.getHeight(), BufferedImage.TYPE_INT_ARGB);
圖像將轉換為 ARGB - Alpha、紅色、綠色、藍色(R、G、B、A)圖像。
因此,您可以更改圖像的 alpha。
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