Tech Tip: Hex to RGB Color Codes

PRODUCT: 4D | VERSION: 11 | PLATFORM: Mac & Win

Published On: November 19, 2009

It is easy to use and pass hexadecimal values to represent colors in the RGB format. Some situations (such as using SVG) require the extended decimal format for the Red, Green, and Blue values. The following 4D Method, "Hex2RGB" will take a text based Hex value and parse it into three decimal values: R, G, and B.

When calling this method, pass in the Hex value as text and pointers to three numeric variables which will be filled with the R, G, and B values.

` Method: Hex2RGB
`
` Parameters
` $1 - Hex Value
`
` Returns
` $2 - pointer to a numeric (R)
` $3 - pointer to a numeric (G)
` $4 - pointer to a numeric (B)

C_TEXT($1;$hex_t)
C_POINTER($2;$3;$4)
C_POINTER($red_p;$green_p;$blue_p)

If (Count parameters>=4)
$hex_t:=$1

Case of
  :(Not((Type($2->)=Is Integer)|(Type($2->)=Is LongInt)|(Not((Type($2->)=Is Real)))))
  :(Not((Type($3->)=Is Integer)|(Type($3->)=Is LongInt)|(Not((Type($3->)=Is Real)))))
  :(Not((Type($4->)=Is Integer)|(Type($4->)=Is LongInt)|(Not((Type($4->)=Is Real)))))
  Else
   C_LONGINT($len_l;$value_l;$index_l;$dec_l)
   $red_p:=$2
   $green_p:=$3
   $blue_p:=$4

   $len_l:=Length($hex_t)
   For ($index_l;$len_l;1;-1)
    Case of
     : ($hex_t[[$index_l]]="A")
      $value_l:=10
     : ($hex_t[[$index_l]]="B")
      $value_l:=11
     : ($hex_t[[$index_l]]="C")
      $value_l:=12
     : ($hex_t[[$index_l]]="D")
      $value_l:=13
     : ($hex_t[[$index_l]]="E")
      $value_l:=14
     : ($hex_t[[$index_l]]="F")
      $value_l:=15
     Else
      $value_l:=Num($hex_t[[$index_l]])
    End case

    If ($index_l<$len_l)
     $dec_l:=$dec_l+($value_l*(16^($len_l-$index_l)))
    Else
     $dec_l:=$dec_l+$value_l
    End if
   End for

   $red_p->:=0
   $green_p->:=0
   $blue_p->:=0

   If ($dec_l>0)
    $red_p->:=$dec_l >> 16
    $dec_l:=$dec_l-($red_p-> << 16)
    $green_p->:=($dec_l >> 8)
    $blue_p->:=$dec_l-($green_p-> << 8)
   End if
End case
End if