This regular expression matches on a hexadecimal color code (like #ffffff). These are often used in style sheets and HTML code

(regexp can ofcourse be used for other languages as well..)

preg_match('/^([0-9a-f]{1,2}){3}$/i', $color);

procedure ChangeRGB(var Bitmap:TBitmap;R,G,B:integer);
var
H,V:integer;
DstRow:^TRGBTriple; // to jest wskaźnik dopixela
begin
 Bitmap.PixelFormat:=pf24bit;
 for V:=0 to Bitmap.Height -1 do
  begin
      DstRow:=Bitmap.ScanLine[V];
      for H:=0 to Bitmap.Width -1 do
      begin
      DstRow^:=ChangeRGBColor(DStrow^,R,G,B);
       Inc(DstRow);
     end;
  end;
end;

procedure ColorNoise( Bitmap: TBitmap; Amount: Integer);
var
WSK:^Byte;
H,V,a: Integer;
begin
Bitmap.PixelFormat:=pf24bit;
  for V:=0 to Bitmap.Height-1 do
  begin
    Wsk:=Bitmap.ScanLine[V];
    for H:=0 to Bitmap.Width*3-1 do
    begin
    Wsk^:=IntToByte(Wsk^+(Random(Amount)-(Amount shr 1)));
      inc(Wsk);
    end;
  end;
end;

procedure Negative(var Bitmap:TBitmap);
var
H,V:Integer;
WskByte:^Byte; //Wskaźnik do Bajta (nie trzeba do całego pixela bo i tak wszystko odwracamy)
begin
Bitmap.PixelFormat:=pf24bit;
for V:=0 to Bitmap.Height-1 do
  begin
    WskByte:=Bitmap.ScanLine[V]; // V jest to pozycja  danej linii bitmapy (od góry )
    for  H:=0 to (Bitmap.Width *3)-1 do
    begin
      WskByte^:= not WskByte^ ;// (odwracamy wartość na którą pokazuje wskaźnik)
      inc(WskByte);//Przesuwam wskaźnik
    end;
  end;
end;

procedure Saturation(var  Bitmap: TBitmap; Amount: Integer);
var
Wsk:^TRGBTriple;
Gray,H,V: Integer;
begin
  for V:=0 to Bitmap.Height-1 do
  begin
    Wsk:=Bitmap.ScanLine[V];
    for H:=0 to Bitmap.Width-1 do
    begin

    Gray:=(Wsk.rgbtBlue+Wsk.rgbtGreen+Wsk.rgbtRed)div 3;
    Wsk.rgbtRed:=IntToByte(Gray+(((Wsk.rgbtRed-Gray)*Amount)div 255));
    Wsk.rgbtGreen:=IntToByte(Gray+(((Wsk.rgbtGreen-Gray)*Amount)div 255));
    Wsk.rgbtBlue:=IntToByte(Gray+(((Wsk.rgbtBlue-Gray)*Amount)div 255));
    inc(Wsk);
    end;
  end;
end;

procedure Contrast(var Bitmap:TBitmap; Amount: Integer);
var
ByteWsk:^Byte;
H,V:  Integer;
begin
  for V:=0 to Bitmap.Height-1 do
  begin
    ByteWsk:=Bitmap.ScanLine[V];
    for H:=0 to Bitmap.Width*3 -1  do
    begin
      if ByteWsk^>127 then
      ByteWsk^:=IntToByte(ByteWsk^+(Abs(127-ByteWsk^)*Amount)div 255)
      else ByteWsk^:=IntToByte(ByteWsk^-(Abs(127-ByteWsk^)*Amount)div 255);
      Inc(ByteWsk);
    end;
  end;
end;

Funkcja zamienia wartość TColor na TRGBTriple.

function ColorToTriple(Color:TColor):TRGBTriple;
type
Rec=Record
Case TColor of
1:( ColorValue:TColor );
2:(Bytes: array [0..3] of Byte);
end;
var
Col:Rec;
begin
Col.ColorValue:= Color;

Result.rgbtRed :=Col.Bytes[0];
Result.rgbtGreen :=Col.Bytes[1];
Result.rgbtBlue :=Col.Bytes[2];
end ;

function ChangeRGBColor(color:TRGBTriple;R,G,B:integer):TRGBTriple;
begin

if  B+Color.rgbtBlue >255 then Color.rgbtBlue :=255 else
if  B+Color.rgbtBlue <0 then  Color.rgbtBlue :=0 else
inc(Color.rgbtBlue,B) ;


if  G+Color.rgbtGreen >255 then Color.rgbtGreen :=255 else
if  G+Color.rgbtGreen <0 then  Color.rgbtGreen :=0 else
inc(Color.rgbtGreen,G) ;

if  R+Color.rgbtRed >255 then Color.rgbtRed :=255 else
if  R+Color.rgbtRed <0 then  Color.rgbtRed :=0 else
inc(Color.rgbtRed,R) ;
Result:=Color;

end;

// covert a color to hex

function toHex(dec) {
        // create list of hex characters
        var hexCharacters = "0123456789ABCDEF"
        // if number is out of range return limit
        if (dec < 0)
                return "00"
        if (dec > 255)
                return "FF"
        // decimal equivalent of first hex character in converted number
        var i = Math.floor(dec / 16)
        // decimal equivalent of second hex character in converted number
        var j = dec % 16
        // return hexadecimal equivalent
        return hexCharacters.charAt(i) + hexCharacters.charAt(j)
}

//Generates an array of size howMany with colors from start RGB to end RGB
//toHex() function is on my profile.

function generateColors(sred, sgreen, sblue, ered, egreen, eblue, howMany) {
        // loop to create
        var arColors = new Array();
        for(var i = 0; i < howMany; ++i) {
                        // set current red descriptor
                        var red = Math.floor(sred * ((howMany - i) / howMany) + ered * (i / howMany));

                        // set current green descriptor
                        var green = Math.floor(sgreen * ((howMany - i) / howMany) +egreen * (i / howMany));

                        // set current green descriptor
                        var blue = Math.floor(sblue * ((howMany - i) / howMany) + eblue * (i / howMany));
                        
                        arColors[i] = [toHex(red), toHex(green), toHex(blue)];
        }
        return arColors;
}