在 Java 中高效地对图像进行色彩循环
2022-09-04 22:15:04
我正在编写一个曼德布洛特分形查看器，我想以智能方式实现颜色循环。给定一个图像，我想修改它的IndexColorModel。
据我所知，没有办法修改IndexColorModel，也没有办法给图像一个新的IndexColorModel。事实上，我认为没有办法提取其颜色模型或图像数据。
似乎唯一的解决方案是保留用于创建图像的原始图像数据和调色板，手动创建具有旋转颜色的新调色板，创建新的IndexColorModel，然后从数据和新颜色模型创建一个全新的图像。
这一切似乎都太费劲了。有没有更简单，更快捷的方法？
这是我能想到的最好的解决方案。此代码创建一个 1000x1000 像素的图像，并显示颜色以每秒约 30 帧的速度循环的动画。
（旧）
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import javax.swing.*;
public class ColorCycler {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
private static void createAndShowGUI() {
JFrame jFrame = new JFrame("Color Cycler");
jFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jFrame.add(new MyPanel());
jFrame.pack();
jFrame.setVisible(true);
}
}
class MyPanel extends JPanel implements ActionListener {
private byte[] reds = new byte[216];
private byte[] greens = new byte[216];
private byte[] blues = new byte[216];
private final byte[] imageData = new byte[1000 * 1000];
private Image image;
public MyPanel() {
generateColors();
generateImageData();
(new Timer(35, this)).start();
}
// The window size is 1000x1000 pixels.
public Dimension getPreferredSize() {
return new Dimension(1000, 1000);
}
// Generate 216 unique colors for the color model.
private void generateColors() {
int index = 0;
for (int i = 0; i < 6; i++) {
for (int j = 0; j < 6; j++) {
for (int k = 0; k < 6; k++, index++) {
reds[index] = (byte) (i * 51);
greens[index] = (byte) (j * 51);
blues[index] = (byte) (k * 51);
}
}
}
}
// Create the image data for the MemoryImageSource.
// This data is created once and never changed.
private void generateImageData() {
for (int i = 0; i < 1000 * 1000; i++) {
imageData[i] = (byte) (i % 216);
}
}
// Draw the image.
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(image, 0, 0, 1000, 1000, null);
}
// This method is called by the timer every 35 ms.
// It creates the modified image to be drawn.
@Override
public void actionPerformed(ActionEvent e) { // Called by Timer.
reds = cycleColors(reds);
greens = cycleColors(greens);
blues = cycleColors(blues);
IndexColorModel colorModel = new IndexColorModel(8, 216, reds, greens, blues);
image = createImage(new MemoryImageSource(1000, 1000, colorModel, imageData, 0, 1000));
repaint();
}
// Cycle the colors to the right by 1.
private byte[] cycleColors(byte[] colors) {
byte[] newColors = new byte[216];
newColors[0] = colors[215];
System.arraycopy(colors, 0, newColors, 1, 215);
return newColors;
}
}
编辑 2：
现在我预先计算了IndexColorModels。这意味着在每个帧上，我只需要使用新的IndexColorModel更新MemoryImageSource。这似乎是最好的解决方案。
（我还注意到，在我的分形资源管理器中，我可以在我生成的每个图像上重用一组预先计算的IndexColorModels。这意味着140K的一次性成本让我能够实时循环所有内容。这很棒。
代码如下：
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import javax.swing.*;
public class ColorCycler {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
private static void createAndShowGUI() {
JFrame jFrame = new JFrame("Color Cycler");
jFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jFrame.add(new MyPanel());
jFrame.pack();
jFrame.setVisible(true);
}
}
class MyPanel extends JPanel implements ActionListener {
private final IndexColorModel[] colorModels = new IndexColorModel[216];
private final byte[] imageData = new byte[1000 * 1000];
private final MemoryImageSource imageSource;
private final Image image;
private int currentFrame = 0;
public MyPanel() {
generateColorModels();
generateImageData();
imageSource = new MemoryImageSource(1000, 1000, colorModels[0], imageData, 0, 1000);
imageSource.setAnimated(true);
image = createImage(imageSource);
(new Timer(35, this)).start();
}
// The window size is 1000x1000 pixels.
public Dimension getPreferredSize() {
return new Dimension(1000, 1000);
}
// Generate 216 unique colors models, one for each frame.
private void generateColorModels() {
byte[] reds = new byte[216];
byte[] greens = new byte[216];
byte[] blues = new byte[216];
int index = 0;
for (int i = 0; i < 6; i++) {
for (int j = 0; j < 6; j++) {
for (int k = 0; k < 6; k++, index++) {
reds[index] = (byte) (i * 51);
greens[index] = (byte) (j * 51);
blues[index] = (byte) (k * 51);
}
}
}
for (int i = 0; i < 216; i++) {
colorModels[i] = new IndexColorModel(8, 216, reds, greens, blues);
reds = cycleColors(reds);
greens = cycleColors(greens);
blues = cycleColors(blues);
}
}
// Create the image data for the MemoryImageSource.
// This data is created once and never changed.
private void generateImageData() {
for (int i = 0; i < 1000 * 1000; i++) {
imageData[i] = (byte) (i % 216);
}
}
// Draw the image.
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(image, 0, 0, 1000, 1000, null);
}
// This method is called by the timer every 35 ms.
// It updates the ImageSource of the image to be drawn.
@Override
public void actionPerformed(ActionEvent e) { // Called by Timer.
currentFrame++;
if (currentFrame == 216) {
currentFrame = 0;
}
imageSource.newPixels(imageData, colorModels[currentFrame], 0, 1000);
repaint();
}
// Cycle the colors to the right by 1.
private byte[] cycleColors(byte[] colors) {
byte[] newColors = new byte[216];
newColors[0] = colors[215];
System.arraycopy(colors, 0, newColors, 1, 215);
return newColors;
}
}
编辑：（旧）
Heisenbug建议我使用MemoryImageSource的newPixels（）方法。答案已被删除，但事实证明这是一个好主意。现在我只创建一个 MemoryImageSource 和一个 Image。在每一帧上，我都会创建一个新的IndexColorModel并更新MemoryImageSource。
以下是更新的代码：（旧）
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import javax.swing.*;
public class ColorCycler {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
private static void createAndShowGUI() {
JFrame jFrame = new JFrame("Color Cycler");
jFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jFrame.add(new MyPanel());
jFrame.pack();
jFrame.setVisible(true);
}
}
class MyPanel extends JPanel implements ActionListener {
private byte[] reds = new byte[216];
private byte[] greens = new byte[216];
private byte[] blues = new byte[216];
private final byte[] imageData = new byte[1000 * 1000];
private final MemoryImageSource imageSource;
private final Image image;
public MyPanel() {
generateColors();
generateImageData();
IndexColorModel colorModel = new IndexColorModel(8, 216, reds, greens, blues);
imageSource = new MemoryImageSource(1000, 1000, colorModel, imageData, 0, 1000);
imageSource.setAnimated(true);
image = createImage(imageSource);
(new Timer(35, this)).start();
}
// The window size is 1000x1000 pixels.
public Dimension getPreferredSize() {
return new Dimension(1000, 1000);
}
// Generate 216 unique colors for the color model.
private void generateColors() {
int index = 0;
for (int i = 0; i < 6; i++) {
for (int j = 0; j < 6; j++) {
for (int k = 0; k < 6; k++, index++) {
reds[index] = (byte) (i * 51);
greens[index] = (byte) (j * 51);
blues[index] = (byte) (k * 51);
}
}
}
}
// Create the image data for the MemoryImageSource.
// This data is created once and never changed.
private void generateImageData() {
for (int i = 0; i < 1000 * 1000; i++) {
imageData[i] = (byte) (i % 216);
}
}
// Draw the image.
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(image, 0, 0, 1000, 1000, null);
}
// This method is called by the timer every 35 ms.
// It updates the ImageSource of the image to be drawn.
@Override
public void actionPerformed(ActionEvent e) { // Called by Timer.
reds = cycleColors(reds);
greens = cycleColors(greens);
blues = cycleColors(blues);
IndexColorModel colorModel = new IndexColorModel(8, 216, reds, greens, blues);
imageSource.newPixels(imageData, colorModel, 0, 1000);
repaint();
}
// Cycle the colors to the right by 1.
private byte[] cycleColors(byte[] colors) {
byte[] newColors = new byte[216];
newColors[0] = colors[215];
System.arraycopy(colors, 0, newColors, 1, 215);
return newColors;
}
}
