循环 256*256*256 颜色,这样颜色会逐渐变化,并且类似的阴影不会在以后的循环迭代中重复?

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【中文标题】循环 256*256*256 颜色,这样颜色会逐渐变化,并且类似的阴影不会在以后的循环迭代中重复?【英文标题】:Loop for 256*256*256 colors such that colors are gradually changing and similar shades don't repeat in later iterations of loop? 【发布时间】:2019-01-17 16:15:30 【问题描述】:

当您使用以下循环生成所有可能的颜色时。

for (int red = 0; red < 256; red++) 
  for (int green = 0; green < 256; green++) 
    for (int blue = 0; blue < 256; blue++) 
    
  

它会生成类似这样的东西

我想要一个循环,使颜色逐渐变化(即渐变不能重复。例如,所有可能的绿色阴影都在一起,然后所有可能的蓝色阴影等等)和所有可能的颜色被循环覆盖。

【问题讨论】:

LinearGradientPaint 将是我的第一个停靠港,如果这不能完全满足您的要求,那么可能像 this 这样的东西会更适合 【参考方案1】:

这是我使用了一段时间的“颜色混合”算法的一部分。它基本上采用一系列颜色和一系列归一化点,并自动计算这些颜色/点之间的“混合”

因此,在解决方案的核心,我们拥有从黑色到完全“彩色”(即绿色/蓝色/红色)的颜色

private Color[] colors = new Color[]
    new Color(0, 0, 0), new Color(0, 255, 0), // Green
    new Color(0, 0, 0), new Color(0, 0, 255), // Blue
    new Color(0, 0, 0), new Color(255, 0, 0), // Red
;

然后我们有我们希望这些颜色覆盖的区域的一部分,注意,每次颜色变化都有一个点,然后算法会自动混合从起点到终点的颜色。

private float[] fractions = new float[]
    0f, 0.33f, 
    0.34f, 0.66f,
    0.67f,1f;

该示例然后简单地生成多个波段(在本例中为 100 个)来“伪造”混合效果

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.text.NumberFormat;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class ColorFade 

    public static void main(String[] args) 
        new ColorFade();
    

    public ColorFade() 
        EventQueue.invokeLater(new Runnable() 
            @Override
            public void run() 
                try 
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                 catch (ClassNotFoundException ex) 
                 catch (InstantiationException ex) 
                 catch (IllegalAccessException ex) 
                 catch (UnsupportedLookAndFeelException ex) 
                

                JFrame frame = new JFrame();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new BorderLayout());
                frame.add(new ColorFadePane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            
        );
    

    public class ColorFadePane extends JPanel 

        private float[] fractions = new float[]
            0f, 0.33f, 
            0.34f, 0.66f,
            0.67f,1f;
        private Color[] colors = new Color[]
            new Color(0, 0, 0), new Color(0, 255, 0),
            new Color(0, 0, 0), new Color(0, 0, 255),
            new Color(0, 0, 0), new Color(255, 0, 0),
        ;

        public ColorFadePane() 
        

        @Override
        public Dimension getPreferredSize() 
            return new Dimension(200, 100);
        

        @Override
        protected void paintComponent(Graphics g) 
            super.paintComponent(g);

            Graphics2D g2d = (Graphics2D) g.create();
            int width = getWidth();
            int height = getHeight();
            int bandWidth = width / 100;
            for (int index = 0; index < 100; index++) 
                float progress = (float) index / (float) 100;
                Color color = blendColors(fractions, colors, progress);

                int x = bandWidth * index;
                int y = 0;
                g2d.setColor(color);
                g2d.fillRect(x, y, bandWidth, height);
            
            g2d.dispose();
        
    

    public static Color blendColors(float[] fractions, Color[] colors, float progress) 
        Color color = null;
        if (fractions != null) 
            if (colors != null) 
                if (fractions.length == colors.length) 
                    int[] indicies = getFractionIndicies(fractions, progress);

                    float[] range = new float[]fractions[indicies[0]], fractions[indicies[1]];
                    Color[] colorRange = new Color[]colors[indicies[0]], colors[indicies[1]];

                    float max = range[1] - range[0];
                    float value = progress - range[0];
                    float weight = value / max;

                    color = blend(colorRange[0], colorRange[1], 1f - weight);
                 else 
                    throw new IllegalArgumentException("Fractions and colours must have equal number of elements");
                
             else 
                throw new IllegalArgumentException("Colours can't be null");
            
         else 
            throw new IllegalArgumentException("Fractions can't be null");
        
        return color;
    

    public static int[] getFractionIndicies(float[] fractions, float progress) 
        int[] range = new int[2];

        int startPoint = 0;
        while (startPoint < fractions.length && fractions[startPoint] <= progress) 
            startPoint++;
        

        if (startPoint >= fractions.length) 
            startPoint = fractions.length - 1;
        

        range[0] = startPoint - 1;
        range[1] = startPoint;

        return range;
    

    public static Color blend(Color color1, Color color2, double ratio) 
        float r = (float) ratio;
        float ir = (float) 1.0 - r;

        float rgb1[] = new float[3];
        float rgb2[] = new float[3];

        color1.getColorComponents(rgb1);
        color2.getColorComponents(rgb2);

        float red = rgb1[0] * r + rgb2[0] * ir;
        float green = rgb1[1] * r + rgb2[1] * ir;
        float blue = rgb1[2] * r + rgb2[2] * ir;

        if (red < 0) 
            red = 0;
         else if (red > 255) 
            red = 255;
        
        if (green < 0) 
            green = 0;
         else if (green > 255) 
            green = 255;
        
        if (blue < 0) 
            blue = 0;
         else if (blue > 255) 
            blue = 255;
        

        Color color = null;
        try 
            color = new Color(red, green, blue);
         catch (IllegalArgumentException exp) 
            NumberFormat nf = NumberFormat.getNumberInstance();
            System.out.println(nf.format(red) + "; " + nf.format(green) + "; " + nf.format(blue));
            exp.printStackTrace();
        
        return color;
    

LinearGradientPaint

现在,如果你真的很无聊,你可以改用LinearGradientPaint...

public class ColorFadePane extends JPanel 

    private float[] fractions = new float[]
        0f, 0.33f,
        0.34f, 0.66f,
        0.67f, 1f;
    private Color[] colors = new Color[]
        new Color(0, 0, 0), new Color(0, 255, 0),
        new Color(0, 0, 0), new Color(0, 0, 255),
        new Color(0, 0, 0), new Color(255, 0, 0),;

    public ColorFadePane() 
    

    @Override
    public Dimension getPreferredSize() 
        return new Dimension(200, 100);
    

    @Override
    protected void paintComponent(Graphics g) 
        super.paintComponent(g);

        Graphics2D g2d = (Graphics2D) g.create();
        int width = getWidth();
        int height = getHeight();
        LinearGradientPaint lgp = new LinearGradientPaint(new Point(0, 0), new Point(width, 0), fractions, colors);
        g2d.setPaint(lgp);
        g2d.fillRect(0, 0, width, height);
        g2d.dispose();
    

但我需要将结果生成为图像/文件

好的,好的,所以,创建一个 BufferedImage 并对其进行绘制,然后使用 ImageIO.write 保存它

【讨论】:

【参考方案2】:

如果你真的想展示总共 1600 万种颜色,那么你必须放弃一些标准。你不能拥有所有的红色阴影,然后是所有的绿色阴影,然后是所有的蓝色阴影,因为这并不能解释颜色的混合。所有深浅不一的红色和绿色混合在一起——就是所有深浅不一的红色或所有深浅不一的绿色。特别是因为现在您要添加一些蓝色。

你也说过你希望它逐渐改变,所以你可以做的是(在元代码中):

for (int red = 0; red < 256; ++red) 
    bool redIsEven = (red % 2) == 0;
    int greenStart = redIsEven ? 0 : 255;
    int greenEnd = redIsEven ? 256 : -1;
    int greenDirection = redIsEven ? 1 : -1;
    for (int green = greenStart; green != greenEnd; green += greenDirection) 
         ... similar code for blue, but based on green, not red
    

也就是说...您将执行红色 = 0,绿色将从 0 变为 255。对于绿色 = 0,蓝色也变为 0...255,但当它为 1 时,它会向后移动,所以它在流动均匀。然后绿色向下计数,然后向上,然后向下......

因此,您可以顺利完成 1600 万个选择中的任何一个选择。

这就是你想要做的吗?

【讨论】:

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