Converting CSS colors from RGBA to hexadecimal format: A step-by-step guide

Within my selenium code, I am faced with the challenge of verifying that the background color code is #192856. However, when obtaining the CSS property of the element, it returns the color in rgba format. How can I retrieve the values in hex format?

quickLinkstab.GetCssValue("background-color")

The above line provides me with the value "rgba(25, 40, 86, 1)" which is in the rgba format. Is there a method to convert this back to Hex or obtain the value in Hex directly?

I have also attempted the following code snippet:

string colorcode = menuColor;
int argb = Int32.Parse(colorcode.Replace("#", ""), NumberStyles.HexNumber);
Color clr = Color.FromArgb(argb);

int r = Convert.ToInt16(clr.R);
int g = Convert.ToInt16(clr.G);
int b = Convert.ToInt16(clr.B);
int a = Convert.ToInt16(clr.A);
string x = string.Format("rgba({0}, {1}, {2}, {3});", r, g, b,a);

However, this code snippet yields a result like "rgba(25, 40, 86, 0);" The difference lies in the "a" value where my code produces 0 and the cssvalue shows 1.

My focus is on finding a solution to retrieve the Hex value directly, or if not feasible, then converting the rgba to Hex.

Answer №1

This code snippet deals with color parsing in various formats such as hexadecimal, rgb, and rgba.

public static class ColorUtil
{
    public static Color ParseColor(string inputColor)
    {
        inputColor = inputColor.Trim();

        if (inputColor.StartsWith("#"))
        {
            return ColorTranslator.FromHtml(inputColor);
        }
        else if (inputColor.StartsWith("rgb")) //rgb or argb
        {
            int startIndex = inputColor.IndexOf('(');
            int endIndex = inputColor.IndexOf(')');

            if (startIndex < 0 || endIndex < 0)
                throw new FormatException("rgba format error");
            string noBrackets = inputColor.Substring(startIndex + 1, endIndex - startIndex - 1);

            string[] components = noBrackets.Split(',');

            int red = int.Parse(components[0], CultureInfo.InvariantCulture);
            int green = int.Parse(components[1], CultureInfo.InvariantCulture);
            int blue = int.Parse(components[2], CultureInfo.InvariantCulture);

            if (components.Length == 3)
            {
                return Color.FromArgb(red, green, blue);
            }
            else if (components.Length == 4)
            {
                float alpha = float.Parse(components[3], CultureInfo.InvariantCulture);
                return Color.FromArgb((int)(alpha * 255), red, green, blue);
            }
        }
        throw new FormatException("Input color does not match rgb, rgba, or hexa format");
    }
}

Expected outcomes:

[TestClass]
public class ColorParserTest
{
    [TestMethod]
    public void TestParseRGBColor()
    {
        Color result = ColorUtil.ParseColor("rgb(110,120,130)");

        Assert.AreEqual(110, result.R);
        Assert.AreEqual(120, result.G);
        Assert.AreEqual(130, result.B);
        Assert.AreEqual(255, result.A);
    }

    [TestMethod]
    public void TestParseRGBAColor()
    {
        Color result = ColorUtil.ParseColor("rgba(110,120,130,0.5)");

        Assert.AreEqual(110, result.R);
        Assert.AreEqual(120, result.G);
        Assert.AreEqual(130, result.B);
        Assert.AreEqual(127, result.A);
    }

    [TestMethod]
    public void TestParseHexaColor()
    {
        Color result = ColorUtil.ParseColor("#192856");

        Assert.AreEqual(25, result.R);
        Assert.AreEqual(40, result.G);
        Assert.AreEqual(86, result.B);
        Assert.AreEqual(255, result.A);
    }
}

Answer №2

Learn how to convert color values in C#

// Convert color to HTML format
string htmlColor = ColorTranslator.ToHtml(myColor);

Use String.Format for RGB and RGBA colors

//RGB
String.Format("#{0:X2}{1:X2}{2:X2}", colorValue.R,colorValue.G,colorValue.B);
//RGBA
var strigifiedColor = String.Format("#{0:X2}{1:X2}{2:X2}{3:X2}", colorValue.R, colorValue.G, colorValue.B, colorValue.A);

Create a ColorExtension class for additional functionality

public static class ColorExtension
{
    public static string HexFormat(this Color colorValue)
    {
        return String.Format("#{0:X2}{1:X2}{2:X2}{3:X2}", colorValue.A, colorValue.R, colorValue.G, colorValue.B);
    }
}

Answer №3

I've elaborated on the response provided by Thomas to discuss the #RGBA/#RRGGBBAA formats.

If there are errors during parsing, I personally opt to simply return Color.Empty instead of handling them differently.

(Exploring some C# code after adding unit tests in Typescript led me to realize that ColorTranslator does not consider alpha values - it's crucial to test thoroughly instead of assuming anything!)

public static ColorUtils
{
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Design", "CA1031:Do not catch general exception types", Justification = "ColorTranslator throws System.Exception")]
    public static Color HtmlToColor(string htmlColor)
    {
        Guard.ArgumentIsNotNull(htmlColor, nameof(htmlColor));

        var htmlLowerCase = htmlColor.ToLower().Trim();

        try
        {
            if (htmlLowerCase.StartsWith("rgb"))
            {
                return ArgbToColor(htmlLowerCase);
            }
            else if (htmlLowerCase.StartsWith("#"))
            {
                return HexToColor(htmlLowerCase);
            }
            else
            {
                // Fallback to ColorTranslator for named colors, e.g. "Black", "White" etc.
                return ColorTranslator.FromHtml(htmlLowerCase);
            }
        }
        catch
        {
            // ColorTranslator throws System.Exception, don't really care what the actual error is.
        }

        return Color.Empty;
    }

    private static Color HexToColor(string htmlLowerCase)
    {
        var len = htmlLowerCase.Length;

        // #RGB
        if (len == 4)
        {
            var r = Convert.ToInt32(htmlLowerCase.Substring(1, 1), 16);
            var g = Convert.ToInt32(htmlLowerCase.Substring(2, 1), 16);
            var b = Convert.ToInt32(htmlLowerCase.Substring(3, 1), 16);

            return Color.FromArgb(r + (r * 16), g + (g * 16), b + (b * 16));
        }

        // #RGBA
        else if (len == 5)
        {
            var r = Convert.ToInt32(htmlLowerCase.Substring(1, 1), 16);
            var g = Convert.ToInt32(htmlLowerCase.Substring(2, 1), 16);
            var b = Convert.ToInt32(htmlLowerCase.Substring(3, 1), 16);
            var a = Convert.ToInt32(htmlLowerCase.Substring(4, 1), 16);

            return Color.FromArgb(a + (a * 16), r + (r * 16), g + (g * 16), b + (b * 16));
        }

        // #RRGGBB
        else if (len == 7)
        {
            return Color.FromArgb(
                Convert.ToInt32(htmlLowerCase.Substring(1, 2), 16),
                Convert.ToInt32(htmlLowerCase.Substring(3, 2), 16),
                Convert.ToInt32(htmlLowerCase.Substring(5, 2), 16));
        }

        // #RRGGBBAA
        else if (len == 9)
        {
            return Color.FromArgb(
                Convert.ToInt32(htmlLowerCase.Substring(7, 2), 16),
                Convert.ToInt32(htmlLowerCase.Substring(1, 2), 16),
                Convert.ToInt32(htmlLowerCase.substring(3, 2), 16),
                Convert.ToInt32(htmlLowerCase.substring(5, 2), 16));
        }

        return Color.Empty;
    }

    private static Color ArgbToColor(string htmlLowerCase)
    {
        int left = htmlLowerCase.IndexOf('(');
        int right = htmlLowerCase.IndexOf(')');

        if (left < 0 || right < 0)
        {
            return Color.Empty;
        }

        string noBrackets = htmlLowerCase.Substring(left + 1, right - left - 1);

        string[] parts = noBrackets.Split(',');

        int r = int.Parse(parts[0], CultureInfo.InvariantCulture);
        int g = int.Parse(parts[1], CultureInfo.InvariantCulture);
        int b = int.Parse(parts[2], CultureInfo.InvariantCulture);

        if (parts.Length == 3)
        {
            return Color.FromArgb(r, g, b);
        }
        else if (parts.Length == 4)
        {
            float a = float.Parse(parts[3], CultureInfo.InvariantCulture);

            return Color.FromArgb((int)(a * 255), r, g, b);
        }

        return Color.Empty;
    }
}

Tests:

    [TestMethod]
    public void ColorUtils_HtmlToColor()
    {
        Assert.AreEqual(Color.FromArgb(0x11, 0x22, 0x33), ColorUtils.HtmlToColor("#123"), "#123 (without alpha channel)");
        Assert.AreEqual(Color.FromArgb(0x11, 0x22, 0x33), ColorUtils.HtmlToColor("#112233"), "#112233 (without alpha channel)");
        Assert.AreEqual(Color.FromArgb(0x44, 0x11, 0x22, 0x33), ColorUtils.HtmlToColor("#1234"), "#1234 (alpha channel)");
        Assert.AreEqual(Color.FromArgb(0x44, 0x11, 0x22, 0x33), ColorUtils.HtmlToColor("#11223344"), "#11223344 (alpha channel)");
        Assert.AreEqual(Color.FromArgb(127, 11, 22, 33), ColorUtils.HtmlToColor("rgba(11,22,33,0.5)"), "rgba(11,22,33,0.5) (alpha channel)");
        Assert.AreEqual(Color.FromArgb(11, 22, 33), ColorUtils.HtmlToColor("rgb(11,22,33)"), "rgb(11,22,33) (alpha channel)");
        Assert.AreEqual(Color.Red, ColorUtils.HtmlToColor("red"), "red (named color)");
        Assert.AreEqual(Color.White, ColorUtils.HtmlToColor("white"), "white (named color)");
        Assert.AreEqual(Color.Blue, ColorUtils.HtmlToColor("blue"), "blue (named color)");
        Assert.AreEqual(Color.Empty, ColorUtils.HtmlToColor("invalid"), "invalid");
        Assert.AreEqual(Color.Empty, ColorUtils.HtmlToColor("#invalid"), "#invalid");
        Assert.AreEqual(Color.Empty, ColorUtils.HtmlToColor("rgb(invalid)"), "rgb(invalid)");
        Assert.AreEqual(Color.Empty, ColorUtils.HtmlToColor("rgba(invalid)"), "rgba(invalid)");
        Assert.AreEqual(Color.Empty, ColorUtils.HtmlToColor("rgba(invalid,invalid)"), "rgba(invalid,invalid)");
        Assert.AreEqual(Color.Empty, ColorUtils.HtmlToColor("rgb(11,22,333)"), "rgb(11,22,333) (value out of range)");
        Assert.AreEqual(Color.Empty, ColorUtils.HtmlToColor("rgba(11,22,333,0.5)"), "rgb(11,22,333,0.5) (value out of range)");
    }

Answer №4

A simple solution to the problem.

public static string ConvertRgbaToHex(string rgba)
{
    if (!Regex.IsMatch(rgba, @"rgba\((\d{1,3},\s*){3}(0(\.\d+)?|1)\)"))
            throw new FormatException("Invalid format for rgba string");

    var matches = Regex.Matches(rgba, @"\d+");
    StringBuilder hexaString = new StringBuilder("#");

    for(int i = 0; i < matches.Count - 1; i++)
    {
        int value = Int32.Parse(matches[i].Value);

        hexaString.Append(value.ToString("X"));
    }

    return hexaString.ToString();
}

Example:

public class Program
{
    static void Main(string[] args)
    {
        // Output: #192856
        Console.WriteLine(ConvertRgbaToHex("rgba(25, 40, 86, 1)"));

        Console.Read();
    }

    public static string ConvertRgbaToHex(string rgba)
    {
        if (!Regex.IsMatch(rgba, @"rgba\((\d{1,3},\s*){3}(0(\.\d+)?|1)\)"))
                throw new FormatException("Incorrect rgba string format");

        var matches = Regex.Matches(rgba, @"\d+");
        StringBuilder hexaString = new StringBuilder("#");

        for(int i = 0; i < matches.Count - 1; i++)
        {
            int value = Int32.Parse(matches[i].Value);

            hexaString.Append(value.ToString("X"));
        }

        return hexaString.ToString();
    }
}

Answer №5

This code snippet extracts the style attribute from an HTML element, converts the RGB value into hexadecimal format, and then compares it with another color code.

string color = GetElement(LocateBy.XPath, "XpathOfTheElement").GetAttribute("style").ToString();
string[] colorvalue1 = color.Split('(');

string[] colorvalue2 = colorvalue1[1].Split(')');

string colorvalue = colorvalue2[0].ToString();
string[] ColorCodeRGBValue = colorvalue.Split(',');
Color myColor = Color.FromArgb(Convert.ToInt32(ColorCodeRGBValue[0]), Convert.ToInt32(ColorCodeRGBValue[1]), Convert.ToInt32(ColorCodeRGBValue[2]));

string hexValue = myColor.R.ToString("X2") + myColor.G.ToString("X2") + myColor.B.ToString("X2");

Assert.AreEqual(hexValue , CsvReader.ColorCode,"Color codes are not equal");

Answer №6

If you're looking to work with colors in Selenium, you can use the Color library:

import org.openqa.selenium.support.Color;

String rgbaValue = "rgba(1,1,1,1)";
Color color = Color.fromString(rgbaValue);
System.out.println("Converted hex value: " + color.asHex());

Answer №7

Developed and tested a two-way conversion method.

public static string RgbaToHex(string value)
{
    if (string.IsNullOrEmpty(value))
        return null;
    Color color;
    value = value.Trim();
    if (value.StartsWith("#"))
        color = ColorTranslator.FromHtml(value);
    else
    {
        if (!value.StartsWith("rgba"))
            throw new FormatException("Not rgba string");
        var left = value.IndexOf('(');
        var right = value.IndexOf(')');
        if (left < 0 || right < 0)
            throw new FormatException("rgba format error");
        var noBrackets = value.Substring(left + 1, right - left - 1);
        var parts = noBrackets.Split(',');
        var r = int.Parse(parts[0], CultureInfo.InvariantCulture);
        var g = int.Parse(parts[1], CultureInfo.InvariantCulture);
        var b = int.Parse(parts[2], CultureInfo.InvariantCulture);
        switch (parts.Length)
        {
            case 3:
                color = Color.FromArgb(r, g, b);
                break;
            case 4:
            {
                var a = float.Parse(parts[3], CultureInfo.InvariantCulture);
                color = Color.FromArgb((int)(a * 255), r, g, b);
                break;
            }
            default:
                throw new FormatException("Not rgba string");
        }
    }

    return "#" + color.A.ToString("X2") + color.R.ToString("X2") + color.G.ToString("X2") + color.B.ToString("X2");
}

public static string HexToRgba(string value)
{
    if (string.IsNullOrEmpty(value))
        return null;
    var argb = int.Parse(value.Replace("#", ""), NumberStyles.HexNumber);
    var clr = Color.FromArgb(argb);
    int r = Convert.ToInt16(clr.R);
    int g = Convert.ToInt16(clr.G);
    int b = Convert.ToInt16(clr.B);
    int a = Convert.ToInt16(clr.A);
    var trans = Math.Round((double)a / 255, 2).ToString("N2").Replace(",", ".");
    return $"rgba({r}, {g}, {b}, {trans})";
}

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