Convert System.Drawing.Color to RGB and Hex Value
C#asp.netRgbsystem.drawing.colorC# Problem Overview
Using C# I was trying to develop the following two. The way I am doing it may have some problem and need your kind advice. In addition, I dont know whether there is any existing method to do the same.
private static String HexConverter(System.Drawing.Color c)
{
String rtn = String.Empty;
try
{
rtn = "#" + c.R.ToString("X2") + c.G.ToString("X2") + c.B.ToString("X2");
}
catch (Exception ex)
{
//doing nothing
}
return rtn;
}
private static String RGBConverter(System.Drawing.Color c)
{
String rtn = String.Empty;
try
{
rtn = "RGB(" + c.R.ToString() + "," + c.G.ToString() + "," + c.B.ToString() + ")";
}
catch (Exception ex)
{
//doing nothing
}
return rtn;
}
Thanks.
C# Solutions
Solution 1 - C#
I'm failing to see the problem here. The code looks good to me.
The only thing I can think of is that the try/catch blocks are redundant -- Color is a struct and R, G, and B are bytes, so c can't be null and c.R.ToString()
, c.G.ToString()
, and c.B.ToString()
can't actually fail (the only way I can see them failing is with a NullReferenceException
, and none of them can actually be null).
You could clean the whole thing up using the following:
private static String HexConverter(System.Drawing.Color c)
{
return "#" + c.R.ToString("X2") + c.G.ToString("X2") + c.B.ToString("X2");
}
private static String RGBConverter(System.Drawing.Color c)
{
return "RGB(" + c.R.ToString() + "," + c.G.ToString() + "," + c.B.ToString() + ")";
}
Solution 2 - C#
You could keep it simple and use the native color translator:
Color red = ColorTranslator.FromHtml("#FF0000");
string redHex = ColorTranslator.ToHtml(red);
Then break the three color pairs into integer form:
int value = int.Parse(hexValue, System.Globalization.NumberStyles.HexNumber);
Solution 3 - C#
If you can use C#6 or higher, you can benefit from Interpolated Strings and rewrite @Ari Roth's solution like this:
C# 6:
public static class ColorConverterExtensions
{
public static string ToHexString(this Color c) => $"#{c.R:X2}{c.G:X2}{c.B:X2}";
public static string ToRgbString(this Color c) => $"RGB({c.R}, {c.G}, {c.B})";
}
Also:
- I add the keyword
this
to use them as extensions methods. - We can use the type keyword
string
instead of the class name. - We can use lambda syntax.
- I rename them to be more explicit for my taste.
Edit: If you want to support the alpha channel:
public static class ColorConverterExtensions
{
// #RRGGBB
public static string ToHexString(this Color c) => $"#{c.R:X2}{c.G:X2}{c.B:X2}";
// RGB(R, G, B)
public static string ToRgbString(this Color c) => $"RGB({c.R}, {c.G}, {c.B})";
// #RRGGBBAA
public static string ToHexaString(this Color c) => $"#{c.R:X2}{c.G:X2}{c.B:X2}{c.A:X2}";
public static double ToProportion(byte b) => b / (double)Byte.MaxValue;
// RGBA(R, G, B, A)
public static string ToRgbaString(this Color c) => $"RGBA({c.R}, {c.G}, {c.B}, {ToProportion(c.A):N2})";
}
Fun fact: I have to search about the proportion name, because we want for a value in the interval [0, 1]
not a percent which is in the interval [0, 100]
- https://english.stackexchange.com/a/286524/70403
- https://english.stackexchange.com/questions/218655/a-number-between-0-and-1-like-a-percentage-but-expressed-as-a-decimal
- https://math.stackexchange.com/questions/890617/name-for-percentage-as-a-decimal-between-0-and-1-inclusive
- https://math.stackexchange.com/questions/1626783/is-there-a-name-for-numbers-between-0-and-1
Solution 4 - C#
e.g.
ColorTranslator.ToHtml(Color.FromArgb(Color.Tomato.ToArgb()))
This can avoid the KnownColor trick.
Solution 5 - C#
I found an extension method that works quite well
public static string ToHex(this Color color)
{
return String.Format("#{0}{1}{2}{3}"
, color.A.ToString("X").Length == 1 ? String.Format("0{0}", color.A.ToString("X")) : color.A.ToString("X")
, color.R.ToString("X").Length == 1 ? String.Format("0{0}", color.R.ToString("X")) : color.R.ToString("X")
, color.G.ToString("X").Length == 1 ? String.Format("0{0}", color.G.ToString("X")) : color.G.ToString("X")
, color.B.ToString("X").Length == 1 ? String.Format("0{0}", color.B.ToString("X")) : color.B.ToString("X"));
}
Solution 6 - C#
For hexadecimal code try this
- Get ARGB (Alpha, Red, Green, Blue) representation for the color
- Filter out Alpha channel:
& 0x00FFFFFF
- Format out the value (as hexadecimal "X6" for hex)
For RGB one
- Just format out
Red
,Green
,Blue
values
Implementation
private static string HexConverter(Color c) {
return String.Format("#{0:X6}", c.ToArgb() & 0x00FFFFFF);
}
public static string RgbConverter(Color c) {
return String.Format("RGB({0},{1},{2})", c.R, c.G, c.B);
}