C#：根据系统颜色创建更浅/更深的颜色[重复]

Question

复制

How do I adjust the brightness of a color?
How do I determine darker or lighter color variant of a given color?
Programmatically Lighten a Color

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说我有

var c = Color.Red;

现在我想创建一个新的Color，它比那个颜色更亮或更暗。我怎样才能不费力气地做到这一点？

Answer 1

ControlPaint.Light .Dark .DarkDark 等

Color lightRed = ControlPaint.Light( Color.Red );

Answer 2

我最近blogged about this。主要思想是将给定的校正因子应用于每个颜色分量。以下静态方法使用指定的校正因子修改给定颜色的亮度，并生成该颜色的更暗或更亮变体：

/// <summary>
/// Creates color with corrected brightness.
/// </summary>
/// <param name="color">Color to correct.</param>
/// <param name="correctionFactor">The brightness correction factor. Must be between -1 and 1. 
/// Negative values produce darker colors.</param>
/// <returns>
/// Corrected <see cref="Color"/> structure.
/// </returns>
public static Color ChangeColorBrightness(Color color, float correctionFactor)
{
    float red = (float)color.R;
    float green = (float)color.G;
    float blue = (float)color.B;

    if (correctionFactor < 0)
    {
        correctionFactor = 1 + correctionFactor;
        red *= correctionFactor;
        green *= correctionFactor;
        blue *= correctionFactor;
    }
    else
    {
        red = (255 - red) * correctionFactor + red;
        green = (255 - green) * correctionFactor + green;
        blue = (255 - blue) * correctionFactor + blue;
    }

    return Color.FromArgb(color.A, (int)red, (int)green, (int)blue);
}

Answer 3

您也可以使用Lerp 函数来执行此操作。 XNA 里有，不过自己写很容易。

有关 C# 实现，请参阅 my answer to this similar question。

该函数允许您这样做：

// make red 50% lighter:
Color.Red.Lerp( Color.White, 0.5 );

// make red 75% darker:
Color.Red.Lerp( Color.Black, 0.75 );

// make white 10% bluer:
Color.White.Lerp( Color.Blue, 0.1 );

Answer 4

这些方法中的大多数确实会使颜色变暗，但它们会调整色调方式，因此结果看起来不太好。最佳答案是使用Rich Newman's HSLColor 类并调整亮度。

public Color Darken(Color color, double darkenAmount) {
    HSLColor hslColor = new HSLColor(color);
    hslColor.Luminosity *= darkenAmount; // 0 to 1
    return hslColor;
}

Answer 5

采用@Pavel's answer的核心方法，我准备了以下两个小扩展方法，以便更直观（至少对我而言）签名。

public static Color LightenBy(this Color color, int percent)
{
    return ChangeColorBrightness(color, percent/100.0);
}

public static Color DarkenBy(this Color color, int percent)
{
    return ChangeColorBrightness(color, -1 * percent / 100.0); 
}

Answer 6

这里有一些 javascript 代码，用于使给定颜色变亮/变暗。您可以将其用作等效 C# 函数的基础

它的工作原理是计算每个 RGB 分量与纯白色的距离，然后通过提供的因子调整该距离。新距离用于计算新颜色。 0到1之间的因子变暗，大于1的因子变亮

function Darken( hexColor, factor )
    {   
        if ( factor < 0 ) factor = 0;

        var c = hexColor;
        if ( c.substr(0,1) == "#" )
        {
            c = c.substring(1);
        }

        if ( c.length == 3 || c.length == 6 )
        {
            var i = c.length / 3;

            var f;  // the relative distance from white

            var r = parseInt( c.substr(0, i ), 16 );
            f = ( factor * r / (256-r) );
            r = Math.floor((256 * f) / (f+1));

            r = r.toString(16);
            if ( r.length == 1 ) r = "0" + r;

            var g = parseInt( c.substr(i, i), 16);
            f = ( factor * g / (256-g) );
            g = Math.floor((256 * f) / (f+1));
            g = g.toString(16);
            if ( g.length == 1 ) g = "0" + g;

            var b = parseInt( c.substr( 2*i, i),16 );
            f = ( factor * b / (256-b) );
            b = Math.floor((256 * f) / (f+1));
            b = b.toString(16);
            if ( b.length == 1 ) b = "0" + b;

            c =  r+g+b;
         }   

         return "#" + c;

    }

Answer 7

您也可以根据需要简单地处理 RGB 百分比以使其更亮或更暗，下面是一个示例，说明如何使颜色比它更暗 x%：

//_correctionfactory in percentage, e.g 50 = make it darker 50%
    private Color DarkerColor(Color color, float correctionfactory = 50f)
    {
        const float hundredpercent = 100f;                        
        return Color.FromArgb((int)(((float)color.R / hundredpercent) * correctionfactory),
            (int)(((float)color.G / hundredpercent) * correctionfactory), (int)(((float)color.B / hundredpercent) * correctionfactory));
    }

还有一件事，我们还可以将过程反转为更轻，只是我们得到 255 - RGB 的结果，然后将其乘以我们想要的百分比，如下例所示：

private Color LighterColor(Color color, float correctionfactory = 50f)
    {
        correctionfactory = correctionfactory / 100f;
        const float rgb255 = 255f;
        return Color.FromArgb((int)((float)color.R + ((rgb255 - (float)color.R) * correctionfactory)), (int)((float)color.G + ((rgb255 - (float)color.G) * correctionfactory)), (int)((float)color.B + ((rgb255 - (float)color.B) * correctionfactory))
            );
    }

希望对您有所帮助。

Answer 8

我创建了一个这样做的网站colorglower.com您可以查看它以查看演示。

这是我使用的 javascript 代码。

function lighten(color) {

// convert to decimal and change luminosity
var luminosity = 0.01
var computedColors = new Array();
var newColor = "#",
    c, i, n, black = 0,
    white = 255;
for (n = 0; n < 10; n++) {
    for (i = 0; i < 3; i++) {
        c = parseInt(color.substr(i * 2, 2), 16);
        c = Math.round(Math.min(Math.max(black, c + (luminosity * white)), white)).toString(16);
        newColor += ("00" + c).substr(c.length);
    }

    computedColors[n] = newColor;
    var arrayUnique = checkIfArrayIsUnique(computedColors);
    if (arrayUnique == false) {
        computedColors.pop();
        break;
    }

    computedColors[n] = newColor;
    newColor = "#";
    luminosity += calcPercentage();
}

return computedColors;

}

此代码的作用是接收十六进制颜色，然后输出 10 个最浅的颜色版本并放入数组中。您可以将亮度更改为您喜欢的任何内容，以调整阴影百分比。要使颜色变暗，您只需更改：

luminosity -= calcPercentage();

Answer 9

使用 HSI 转换器库（搜索 google）。然后，调整 I 通道以获得更浅/更​​深的颜色。

Answer 10

我更改了 Pavel Vladov 函数以修改甚至 RGB 分量，以获得 R/G/B 方向的任意组合的阴影：

Public Function ChangeColorShades(color As Color, correctionFactor As Single, bR As Boolean, bG As Boolean, bB As Boolean) As Color


    Dim red As Single = CSng(color.R)
    Dim green As Single = CSng(color.G)
    Dim blue As Single = CSng(color.B)

    If (correctionFactor < 0) Then

        correctionFactor = 1 + correctionFactor
        If bR Then
            red *= correctionFactor
        End If
        If bG Then
            green *= correctionFactor
        End If
        If bB Then
            blue *= correctionFactor
        End If


    Else
        If bR Then
            red = (255 - red) * correctionFactor + red
        End If
        If bG Then
            green = (255 - green) * correctionFactor + green
        End If
        If bB Then
            blue = (255 - blue) * correctionFactor + blue
        End If

    End If

    Return color.FromArgb(color.A, CInt(red), CInt(green), CInt(blue))
End Function