使用Java有效地对图像进行颜色循环

Question

我正在写一个Mandelbrot分形观察器，我想以聪明的方式实现色彩循环。 给定一个图像，我想修改它的IndexColorModel。

据我所知，没有办法修改IndexColorModel，并且无法为图像提供新的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持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，然后从数据创建一个全新的图像和新的颜色模型。

这一切似乎都是太多的工作。 有更简单快捷的方式吗？

这是我能想到的最佳解决方案。 此代码创建一个1000x1000像素的图像，并显示以每秒约30帧的速度循环的颜色动画。

（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。

（我也注意到在我的分形探测器中，我可以在我生成的每个图像上重复使用单组预先计算的IndexColorModel。这意味着140K的一次性成本让我可以实时地对所有内容进行颜色循环。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）

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。 在每个帧上，我创建一个新的IndexColorModel并更新MemoryImageSource。

这是更新的代码:( 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;
    }
}

Answer 1

除了预先计算周期之外，作为@Thomas注释，将幻数1000分解出来。这是更改BufferedImage的ColorModel和您可能喜欢的项目的相关示例。

附录：分析幻数将允许您在分析时可靠地更改它们，这是查看您是否正在取得进展所必需的。

附录：虽然我每帧建议三个颜色查找表，但您预先计算IndexColorModel实例的想法更好。 作为数组的替代方法，请考虑Queue<IndexColorModel> ，将LinkedList<IndexColorModel>作为具体实现。 这简化了模型旋转，如下所示。

@Override
public void actionPerformed(ActionEvent e) { // Called by Timer.
    imageSource.newPixels(imageData, models.peek(), 0, N);
    models.add(models.remove());
    repaint();
}

附录：动态改变颜色模型和显示时间的另一种变化。

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.IndexColorModel;
import java.awt.image.MemoryImageSource;
import java.util.LinkedList;
import java.util.Queue;
import javax.swing.*;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

/** @see http://stackoverflow.com/questions/7546025 */
public class ColorCycler {

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                new ColorCycler().create();
            }
        });
    }

    private void create() {
        JFrame jFrame = new JFrame("Color Cycler");
        jFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        final ColorPanel cp = new ColorPanel();
        JPanel control = new JPanel();
        final JSpinner s = new JSpinner(
            new SpinnerNumberModel(cp.colorCount, 2, 256, 1));
        s.addChangeListener(new ChangeListener() {

            @Override
            public void stateChanged(ChangeEvent e) {
                cp.setColorCount(((Integer) s.getValue()).intValue());
            }
        });
        control.add(new JLabel("Shades:"));
        control.add(s);
        jFrame.add(cp, BorderLayout.CENTER);
        jFrame.add(control, BorderLayout.SOUTH);
        jFrame.pack();
        jFrame.setLocationRelativeTo(null);
        jFrame.setVisible(true);
    }

    private static class ColorPanel extends JPanel implements ActionListener {

        private static final int WIDE = 256;
        private static final int PERIOD = 40; // ~25 Hz
        private final Queue<IndexColorModel> models =
            new LinkedList<IndexColorModel>();
        private final MemoryImageSource imageSource;
        private final byte[] imageData = new byte[WIDE * WIDE];
        private final Image image;
        private int colorCount = 128;

        public ColorPanel() {
            generateColorModels();
            generateImageData();
            imageSource = new MemoryImageSource(
                WIDE, WIDE, models.peek(), imageData, 0, WIDE);
            imageSource.setAnimated(true);
            image = createImage(imageSource);
            (new Timer(PERIOD, this)).start();
        }

        // The preferred size is NxN pixels.
        @Override
        public Dimension getPreferredSize() {
            return new Dimension(WIDE, WIDE);
        }

        public void setColorCount(int colorCount) {
            this.colorCount = colorCount;
            generateColorModels();
            generateImageData();
            repaint();
        }

        // Generate MODEL_SIZE unique color models.
        private void generateColorModels() {
            byte[] reds = new byte[colorCount];
            byte[] greens = new byte[colorCount];
            byte[] blues = new byte[colorCount];
            for (int i = 0; i < colorCount; i++) {
                reds[i] = (byte) (i * 256 / colorCount);
                greens[i] = (byte) (i * 256 / colorCount);
                blues[i] = (byte) (i * 256 / colorCount);
            }
            models.clear();
            for (int i = 0; i < colorCount; i++) {
                reds = rotateColors(reds);
                greens = rotateColors(greens);
                blues = rotateColors(blues);
                models.add(new IndexColorModel(
                    8, colorCount, reds, greens, blues));
            }
        }

        // Rotate colors to the right by one.
        private byte[] rotateColors(byte[] colors) {
            byte[] newColors = new byte[colors.length];
            newColors[0] = colors[colors.length - 1];
            System.arraycopy(colors, 0, newColors, 1, colors.length - 1);
            return newColors;
        }

        // Create some data for the MemoryImageSource.
        private void generateImageData() {
            for (int i = 0; i < imageData.length; i++) {
                imageData[i] = (byte) (i % colorCount);
            }
        }

        // Draw the image.
        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            long start = System.nanoTime();
            imageSource.newPixels(imageData, models.peek(), 0, WIDE);
            models.add(models.remove());
            double delta = (System.nanoTime() - start) / 1000000d;
            g.drawImage(image, 0, 0, getWidth(), getHeight(), null);
            g.drawString(String.format("%1$5.3f", delta), 5, 15);
        }

        // Called by the Timer every PERIOD ms.
        @Override
        public void actionPerformed(ActionEvent e) { // Called by Timer.
            repaint();
        }
    }
}

Answer 2

我将LWJGL（Java的OpenGL接口）与Mandelbrot像素着色器一起使用，并在着色器中进行颜色循环。 比使用Java2D更有效。

http://nuclear.mutantstargoat.com/articles/sdr_fract/