我正在编写一个曼德勃罗特分形查看器,并希望以聪明的方式实现颜色循环。给定一张图像,我想修改它的IndexColorModel。
据我所知,没有办法修改IndexColorModel,也没有办法为图像提供新的IndexColorModel。事实上,我认为没有办法提取它的颜色模型或图像数据。
似乎唯一的解决办法是保留用于创建图像的原始图像数据和调色板,手动创建一个具有旋转颜色的新调色板,创建一个新的IndexColorModel,然后从数据和新调色板创建全新的图像。
这一切看起来太麻烦了。有更简单、更快速的方法吗?
这是我能想到的最好的解决方案。这段代码创建了一个1000x1000像素的图像,并显示了每秒约30帧的颜色循环动画。
(old)
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:
现在我预计算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。
(我还刚注意到,在我的分形浏览器中,我可以重复使用单个预计算的IndexColorModels来生成每个图像。这意味着140K的一次性成本让我能够实时地循环颜色。这很棒。)
这是代码:
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:(旧版)
Heisenbug建议我使用MemoryImageSource的newPixels()方法。答案已被删除,但这是个好主意。现在我只创建一个MemoryImageSource和一个Image。每帧我都会创建一个新的IndexColorModel并更新MemoryImageSource。
以下是更新后的代码:(旧版)
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;
}
}