Hex-to-RGB Conversion

Hex-to-RGB Conversion

• CommanderG

  Here is a C# implementation of the convertion:

  private string HexToRgb(string hex)

  {

  int r, g, b;

  int num = (int) long.Parse(hex, NumberStyles.HexNumber);

  r = (num & 0xFF0000) >> 16;

  g = (num & 0xFF00) >> 8;

  b = num & 0xFF;

  return string.Format("{0}, {1}, {2}", r, g, b);

  }

  
  
  

• AlBriggs

  Is #FFFF00 a string Is the output again a string String to COLORREF
  

  Give us more information what kind of conversion do you need.

  And no! There is no such class or function. You can convert a hex string into a long with strtol. The lower 3 bytes are than the COLORREF value.

  
  
  

• dotnetwizkid

  Yours is better Nishant! :-)
  
  

• zetto

  Ok, yes #FFFF00 is a string and i would like to run a conversion method on it that will return a string looking like this "255,255,0"

  Is there no conversion even in the .net framework

  Thanks Martin

  Will

  
  

• BatDeveloper

  wdhough wrote:

  Yeah i know i just want to understand is all. I do know how to split a string! so for the string "#FFFF00" The rgb values, still in string form would be this R = "FF" G = "FF" B = "00" and so strtol method is the converter method Why are you using 16 as the base out of curiosity Thanks

  Because hexadecimal uses base-16. And the third parameter to strtol is the base. Honestly, you should just look up these functions on MSDN, they are very well documented.

  
  
  

• Sergey Bereznikov

  Will, it can't be a problem to splitt a string! This group does not exist to tell you the most basics of programming!

  CString strColor(_T(#ffff00");
  
  // Get in groups of 2 hex chars, and for get the leadin #
  DWORD dwColor = 0;
  for (int i=0; i<3; ++i)
  {
   dwColor << 8;
   dwColor |= strtol(strColor.Mid(i*2+1,2),NULL,16);
  }

  ASSERT(dwColor==0xffff00);

  CString strOut;
  strOut.Format(_T("%d,%d,%d"),
    LOBYTE(HIWORD(dwColor)),
    HIBYTE(LOWORD(dwColor)),
    LOBYTE(LOWORD(dwColor)));

  
  
  

• NetSoft

  wdhough wrote:

  Ok how do you strip out the three hex bytes With the exception of the "#" is it a case of the first 2 letters, then the middle two and then the last two And once you've done this how do you convert the hex byte strings to integers Is there a method for this Thanks Will

  Try something like this :-

  void Convert(LPCTSTR input, LPTSTR output)
  {
  LPTSTR pStop;
  int num = _tcstol(input + 1, &pStop, 16);
  int b1 = (num & 0xFF0000) >> 16;
  int b2 = (num & 0xFF00) >> 8;
  int b3 = num & 0xFF;
  _stprintf(output, _T("%d, %d, %d"), b1, b2, b3);
  }

  
  LPCTSTR input = _T("#FF1B2C");
  TCHAR output[12] = {0};
  Convert(input, output);

  
  
  

• tomtodd

  wdhough wrote:

  Ok, yes #FFFF00 is a string and i would like to run a conversion method on it that will return a string looking like this "255,255,0" Is there no conversion even in the .net framework Thanks Martin Will

  Your input string contains hex, and you want an output string containing decimal equivalents. There's no direct function to do that - you'll have to write your own.

  Strip out the three Hex bytes from the input string, convert the hex byte strings to integers, and then use sprintf or CString::Format to write those integers to the output string.

  
  
  

• Mick Lang

  Ok how do you strip out the three hex bytes With the exception of the "#" is it a case of the first 2 letters, then the middle two and then the last two

  And once you've done this how do you convert the hex byte strings to integers Is there a method for this

  Thanks

  Will

  
  

• Rod77

  Yeah i know i just want to understand is all. I do know how to split a string!

  so for the string "#FFFF00"

  The rgb values, still in string form would be this

  R = "FF"

  G = "FF"

  B = "00"

  and so strtol method is the converter method Why are you using 16 as the base out of curiosity

  Thanks

  
  

• HerbD

  Ok thank you fellas

  Will

  
  
• Hex-to-RGB Conversion