I wrote the two methods below to automatically select N distinct colors. It works by defining a piecewise linear function on the RGB cube. The benefit of this is you can also get a progressive scale if that's what you want, but when N gets large the colors can start to look similar. I can also imagine evenly subdividing the RGB cube into a lattice and then drawing points. Does anyone know any other methods? I'm ruling out defining a list and then just cycling through it. I should also say I don't generally care if they clash or don't look nice, they just have to be visually distinct.

public static List<Color> pick(int num) {
    List<Color> colors = new ArrayList<Color>();
    if (num < 2)
        return colors;
    float dx = 1.0f / (float) (num - 1);
    for (int i = 0; i < num; i++) {
        colors.add(get(i * dx));
    }
    return colors;
}

public static Color get(float x) {
    float r = 0.0f;
    float g = 0.0f;
    float b = 1.0f;
    if (x >= 0.0f && x < 0.2f) {
        x = x / 0.2f;
        r = 0.0f;
        g = x;
        b = 1.0f;
    } else if (x >= 0.2f && x < 0.4f) {
        x = (x - 0.2f) / 0.2f;
        r = 0.0f;
        g = 1.0f;
        b = 1.0f - x;
    } else if (x >= 0.4f && x < 0.6f) {
        x = (x - 0.4f) / 0.2f;
        r = x;
        g = 1.0f;
        b = 0.0f;
    } else if (x >= 0.6f && x < 0.8f) {
        x = (x - 0.6f) / 0.2f;
        r = 1.0f;
        g = 1.0f - x;
        b = 0.0f;
    } else if (x >= 0.8f && x <= 1.0f) {
        x = (x - 0.8f) / 0.2f;
        r = 1.0f;
        g = 0.0f;
        b = x;
    }
    return new Color(r, g, b);
}

当前回答

如果N足够大,你会得到一些相似的颜色。世界上只有这么多。

为什么不把它们均匀地分布在光谱中,像这样:

IEnumerable<Color> CreateUniqueColors(int nColors)
{
    int subdivision = (int)Math.Floor(Math.Pow(nColors, 1/3d));
    for(int r = 0; r < 255; r += subdivision)
        for(int g = 0; g < 255; g += subdivision)
            for(int b = 0; b < 255; b += subdivision)
                yield return Color.FromArgb(r, g, b);
}

如果您想混合序列,以便相似的颜色不在彼此旁边,您可能会打乱结果列表。

是我想得不够周全吗?

其他回答

这个问题出现在相当多的SO讨论中:

生成独特颜色的算法 生成独特的颜色 在图形中生成明显不同的RGB颜色 如何为任意自然数n生成n种不同的颜色?

提出了不同的解决方案,但没有一个是最优的。幸运的是,科学来拯救我们

任意N

彩色显示分类图像(免费下载) 一个个性化地图着色的网络服务(免费下载,一个网络服务解决方案应该在下个月可用) 选择高对比度颜色集的算法(作者提供了一个免费的c++实现) 高对比度的颜色集(问题的第一个算法)

最后两本将通过大多数大学图书馆/代理免费提供。

N是有限且相对较小的

在这种情况下,可以使用列表解决方案。关于这个主题,有一篇非常有趣的文章是免费的:

《彩色字母表和彩色编码的局限性》

有几个颜色列表可以考虑:

Boynton列出了11种几乎不会被混淆的颜色(可在前一节的第一篇论文中找到) Kelly的22种最大对比度的颜色(可以在上面的论文中找到)

我还遇到了一个麻省理工学院学生的这个调色板。 最后,下面的链接在不同颜色系统/坐标之间的转换可能是有用的(例如,文章中的一些颜色没有在RGB中指定):

http://chem8.org/uch/space-55036-do-blog-id-5333.html https://metacpan.org/pod/Color::Library::Dictionary::NBS_ISCC 色彩理论:如何将孟塞尔HVC转换为RGB/HSB/HSL

对于Kelly和Boynton的列表,我已经将其转换为RGB(除了白色和黑色,这应该很明显)。一些c#代码:

public static ReadOnlyCollection<Color> KellysMaxContrastSet
{
    get { return _kellysMaxContrastSet.AsReadOnly(); }
}

private static readonly List<Color> _kellysMaxContrastSet = new List<Color>
{
    UIntToColor(0xFFFFB300), //Vivid Yellow
    UIntToColor(0xFF803E75), //Strong Purple
    UIntToColor(0xFFFF6800), //Vivid Orange
    UIntToColor(0xFFA6BDD7), //Very Light Blue
    UIntToColor(0xFFC10020), //Vivid Red
    UIntToColor(0xFFCEA262), //Grayish Yellow
    UIntToColor(0xFF817066), //Medium Gray

    //The following will not be good for people with defective color vision
    UIntToColor(0xFF007D34), //Vivid Green
    UIntToColor(0xFFF6768E), //Strong Purplish Pink
    UIntToColor(0xFF00538A), //Strong Blue
    UIntToColor(0xFFFF7A5C), //Strong Yellowish Pink
    UIntToColor(0xFF53377A), //Strong Violet
    UIntToColor(0xFFFF8E00), //Vivid Orange Yellow
    UIntToColor(0xFFB32851), //Strong Purplish Red
    UIntToColor(0xFFF4C800), //Vivid Greenish Yellow
    UIntToColor(0xFF7F180D), //Strong Reddish Brown
    UIntToColor(0xFF93AA00), //Vivid Yellowish Green
    UIntToColor(0xFF593315), //Deep Yellowish Brown
    UIntToColor(0xFFF13A13), //Vivid Reddish Orange
    UIntToColor(0xFF232C16), //Dark Olive Green
};

public static ReadOnlyCollection<Color> BoyntonOptimized
{
    get { return _boyntonOptimized.AsReadOnly(); }
}

private static readonly List<Color> _boyntonOptimized = new List<Color>
{
    Color.FromArgb(0, 0, 255),      //Blue
    Color.FromArgb(255, 0, 0),      //Red
    Color.FromArgb(0, 255, 0),      //Green
    Color.FromArgb(255, 255, 0),    //Yellow
    Color.FromArgb(255, 0, 255),    //Magenta
    Color.FromArgb(255, 128, 128),  //Pink
    Color.FromArgb(128, 128, 128),  //Gray
    Color.FromArgb(128, 0, 0),      //Brown
    Color.FromArgb(255, 128, 0),    //Orange
};

static public Color UIntToColor(uint color)
{
    var a = (byte)(color >> 24);
    var r = (byte)(color >> 16);
    var g = (byte)(color >> 8);
    var b = (byte)(color >> 0);
    return Color.FromArgb(a, r, g, b);
}

下面是十六进制和每通道8位的RGB值:

kelly_colors_hex = [
    0xFFB300, # Vivid Yellow
    0x803E75, # Strong Purple
    0xFF6800, # Vivid Orange
    0xA6BDD7, # Very Light Blue
    0xC10020, # Vivid Red
    0xCEA262, # Grayish Yellow
    0x817066, # Medium Gray

    # The following don't work well for people with defective color vision
    0x007D34, # Vivid Green
    0xF6768E, # Strong Purplish Pink
    0x00538A, # Strong Blue
    0xFF7A5C, # Strong Yellowish Pink
    0x53377A, # Strong Violet
    0xFF8E00, # Vivid Orange Yellow
    0xB32851, # Strong Purplish Red
    0xF4C800, # Vivid Greenish Yellow
    0x7F180D, # Strong Reddish Brown
    0x93AA00, # Vivid Yellowish Green
    0x593315, # Deep Yellowish Brown
    0xF13A13, # Vivid Reddish Orange
    0x232C16, # Dark Olive Green
    ]

kelly_colors = dict(vivid_yellow=(255, 179, 0),
                    strong_purple=(128, 62, 117),
                    vivid_orange=(255, 104, 0),
                    very_light_blue=(166, 189, 215),
                    vivid_red=(193, 0, 32),
                    grayish_yellow=(206, 162, 98),
                    medium_gray=(129, 112, 102),

                    # these aren't good for people with defective color vision:
                    vivid_green=(0, 125, 52),
                    strong_purplish_pink=(246, 118, 142),
                    strong_blue=(0, 83, 138),
                    strong_yellowish_pink=(255, 122, 92),
                    strong_violet=(83, 55, 122),
                    vivid_orange_yellow=(255, 142, 0),
                    strong_purplish_red=(179, 40, 81),
                    vivid_greenish_yellow=(244, 200, 0),
                    strong_reddish_brown=(127, 24, 13),
                    vivid_yellowish_green=(147, 170, 0),
                    deep_yellowish_brown=(89, 51, 21),
                    vivid_reddish_orange=(241, 58, 19),
                    dark_olive_green=(35, 44, 22))

对于所有Java开发人员,以下是JavaFX的颜色:

// Don't forget to import javafx.scene.paint.Color;

private static final Color[] KELLY_COLORS = {
    Color.web("0xFFB300"),    // Vivid Yellow
    Color.web("0x803E75"),    // Strong Purple
    Color.web("0xFF6800"),    // Vivid Orange
    Color.web("0xA6BDD7"),    // Very Light Blue
    Color.web("0xC10020"),    // Vivid Red
    Color.web("0xCEA262"),    // Grayish Yellow
    Color.web("0x817066"),    // Medium Gray

    Color.web("0x007D34"),    // Vivid Green
    Color.web("0xF6768E"),    // Strong Purplish Pink
    Color.web("0x00538A"),    // Strong Blue
    Color.web("0xFF7A5C"),    // Strong Yellowish Pink
    Color.web("0x53377A"),    // Strong Violet
    Color.web("0xFF8E00"),    // Vivid Orange Yellow
    Color.web("0xB32851"),    // Strong Purplish Red
    Color.web("0xF4C800"),    // Vivid Greenish Yellow
    Color.web("0x7F180D"),    // Strong Reddish Brown
    Color.web("0x93AA00"),    // Vivid Yellowish Green
    Color.web("0x593315"),    // Deep Yellowish Brown
    Color.web("0xF13A13"),    // Vivid Reddish Orange
    Color.web("0x232C16"),    // Dark Olive Green
};

以下是根据上面的顺序未排序的凯利颜色。

以下是按色调排序的方凯利颜色(注意一些黄色的对比不是很明显)

这产生了与Janus Troelsen的溶液相同的颜色。但是它使用的不是生成器,而是开始/停止语义。它也是完全向量化的。

import numpy as np
import numpy.typing as npt
import matplotlib.colors

def distinct_colors(start: int=0, stop: int=20) -> npt.NDArray[np.float64]:
    """Returns an array of distinct RGB colors, from an infinite sequence of colors
    """
    if stop <= start: # empty interval; return empty array
        return np.array([], dtype=np.float64)
    sat_values = [6/10]         # other tones could be added
    val_values = [8/10, 5/10]   # other tones could be added
    colors_per_hue_value = len(sat_values) * len(val_values)
    # Get the start and stop indices within the hue value stream that are needed
    # to achieve the requested range
    hstart = start // colors_per_hue_value
    hstop = (stop+colors_per_hue_value-1) // colors_per_hue_value
    # Zero will cause a singularity in the caluculation, so we will add the zero
    # afterwards
    prepend_zero = hstart==0 

    # Sequence (if hstart=1): 1,2,...,hstop-1
    i = np.arange(1 if prepend_zero else hstart, hstop) 
    # The following yields (if hstart is 1): 1/2,  1/4, 3/4,  1/8, 3/8, 5/8, 7/8,  
    # 1/16, 3/16, ... 
    hue_values = (2*i+1) / np.power(2,np.floor(np.log2(i*2))) - 1
    
    if prepend_zero:
        hue_values = np.concatenate(([0], hue_values))

    # Make all combinations of h, s and v values, as if done by a nested loop
    # in that order
    hsv = np.array(np.meshgrid(hue_values, sat_values, val_values, indexing='ij')
                    ).reshape((3,-1)).transpose()

    # Select the requested range (only the necessary values were computed but we
    # need to adjust the indices since start & stop are not necessarily multiples
    # of colors_per_hue_value)
    hsv = hsv[start % colors_per_hue_value : 
                start % colors_per_hue_value + stop - start]
    # Use the matplotlib vectorized function to convert hsv to rgb
    return matplotlib.colors.hsv_to_rgb(hsv)

样品:

from matplotlib.colors import ListedColormap
ListedColormap(distinct_colors(stop=20))

ListedColormap(distinct_colors(start=30, stop=50))

就像Uri Cohen的答案,但它是一个生成器。首先要把颜色分开。确定的。

样品,左边颜色先:

#!/usr/bin/env python3
from typing import Iterable, Tuple
import colorsys
import itertools
from fractions import Fraction
from pprint import pprint

def zenos_dichotomy() -> Iterable[Fraction]:
    """
    http://en.wikipedia.org/wiki/1/2_%2B_1/4_%2B_1/8_%2B_1/16_%2B_%C2%B7_%C2%B7_%C2%B7
    """
    for k in itertools.count():
        yield Fraction(1,2**k)

def fracs() -> Iterable[Fraction]:
    """
    [Fraction(0, 1), Fraction(1, 2), Fraction(1, 4), Fraction(3, 4), Fraction(1, 8), Fraction(3, 8), Fraction(5, 8), Fraction(7, 8), Fraction(1, 16), Fraction(3, 16), ...]
    [0.0, 0.5, 0.25, 0.75, 0.125, 0.375, 0.625, 0.875, 0.0625, 0.1875, ...]
    """
    yield Fraction(0)
    for k in zenos_dichotomy():
        i = k.denominator # [1,2,4,8,16,...]
        for j in range(1,i,2):
            yield Fraction(j,i)

# can be used for the v in hsv to map linear values 0..1 to something that looks equidistant
# bias = lambda x: (math.sqrt(x/3)/Fraction(2,3)+Fraction(1,3))/Fraction(6,5)

HSVTuple = Tuple[Fraction, Fraction, Fraction]
RGBTuple = Tuple[float, float, float]

def hue_to_tones(h: Fraction) -> Iterable[HSVTuple]:
    for s in [Fraction(6,10)]: # optionally use range
        for v in [Fraction(8,10),Fraction(5,10)]: # could use range too
            yield (h, s, v) # use bias for v here if you use range

def hsv_to_rgb(x: HSVTuple) -> RGBTuple:
    return colorsys.hsv_to_rgb(*map(float, x))

flatten = itertools.chain.from_iterable

def hsvs() -> Iterable[HSVTuple]:
    return flatten(map(hue_to_tones, fracs()))

def rgbs() -> Iterable[RGBTuple]:
    return map(hsv_to_rgb, hsvs())

def rgb_to_css(x: RGBTuple) -> str:
    uint8tuple = map(lambda y: int(y*255), x)
    return "rgb({},{},{})".format(*uint8tuple)

def css_colors() -> Iterable[str]:
    return map(rgb_to_css, rgbs())

if __name__ == "__main__":
    # sample 100 colors in css format
    sample_colors = list(itertools.islice(css_colors(), 100))
    pprint(sample_colors)

我为R写了一个名为qualpalr的包,它是专门为此目的设计的。我建议你看看小插图,看看它是如何工作的,但我会尽量总结要点。

qualpalr在HSL颜色空间(前面在这个线程中描述过)中获取一个颜色规范,将其投射到DIN99d颜色空间(感知上是均匀的),并找到使它们之间的最小距离最大化的n。

# Create a palette of 4 colors of hues from 0 to 360, saturations between
# 0.1 and 0.5, and lightness from 0.6 to 0.85
pal <- qualpal(n = 4, list(h = c(0, 360), s = c(0.1, 0.5), l = c(0.6, 0.85)))

# Look at the colors in hex format
pal$hex
#> [1] "#6F75CE" "#CC6B76" "#CAC16A" "#76D0D0"

# Create a palette using one of the predefined color subspaces
pal2 <- qualpal(n = 4, colorspace = "pretty")

# Distance matrix of the DIN99d color differences
pal2$de_DIN99d
#>        #69A3CC #6ECC6E #CA6BC4
#> 6ECC6E      22                
#> CA6BC4      21      30        
#> CD976B      24      21      21

plot(pal2)

对于Python用户来说,seaborn非常简洁:

>>> import seaborn as sns
>>> sns.color_palette(n_colors=4)

它返回RGB元组列表:

[(0.12156862745098039, 0.4666666666666667, 0.7058823529411765),
(1.0, 0.4980392156862745, 0.054901960784313725),
(0.17254901960784313, 0.6274509803921569, 0.17254901960784313),
(0.8392156862745098, 0.15294117647058825, 0.1568627450980392)]