Calculate AntiAliasing to Image

type
  PixArray = Array [0..2] of Byte;


//


procedure Antialiasing(Bitmap: TBitmap; Rect: TRect; Percent: Integer);
var
  pix, prevscan, nextscan, hpix: ^PixArray;
  l, p: Integer;
  R, G, B: Integer;
  R1, R2, G1, G2, B1, B2: Byte;
begin
  Bitmap.PixelFormat := pf24bit;
  with Bitmap.Canvas do
  begin
    Brush.Style := bsclear;
    for l := Rect.Top to Rect.Bottom - 1 do
    begin
      pix:= Bitmap.ScanLine[l];
      if l <> Rect.Top then prevscan := Bitmap.ScanLine[l-1]
      else prevscan := nil;
      if l <> Rect.Bottom - 1 then nextscan := Bitmap.ScanLine[l+1]
      else nextscan := nil;

      for p := Rect.Left to Rect.Right - 1 do
      begin
        R1 := pix^[2];
        G1 := pix^[1];
        B1 := pix^[0];

        if p <> Rect.Left then
        begin
          //Pixel links
          //Pixel left

          hpix := pix;
          dec(hpix);
          R2 := hpix^[2];
          G2 := hpix^[1];
          B2 := hpix^[0];

          if (R1 <> R2) or (G1 <> G2) or (B1 <> B2) then
          begin
            R := R1 + (R2 - R1) * 50 div (Percent + 50);
            G := G1 + (G2 - G1) * 50 div (Percent + 50);
            B := B1 + (B2 - B1) * 50 div (Percent + 50);
            hpix^[2] := R;
            hpix^[1] := G;
            hpix^[0] := B;
          end;
        end;

        if p <> Rect.Right - 1 then
        begin
          //Pixel rechts
          //Pixel right
          hpix := pix;
          inc(hpix);
          R2 := hpix^[2];
          G2 := hpix^[1];
          B2 := hpix^[0];

          if (R1 <> R2) or (G1 <> G2) or (B1 <> B2) then
          begin
            R := R1 + (R2 - R1) * 50 div (Percent + 50);
            G := G1 + (G2 - G1) * 50 div (Percent + 50);
            B := B1 + (B2 - B1) * 50 div (Percent + 50);
            hpix^[2] := R;
            hpix^[1] := G;
            hpix^[0] := B;
          end;
        end;

        if prevscan <> nil then
        begin
          //Pixel oben
          //Pixel up
          R2 := prevscan^[2];
          G2 := prevscan^[1];
          B2 := prevscan^[0];

          if (R1 <> R2) or (G1 <> G2) or (B1 <> B2) then
          begin
            R := R1 + (R2 - R1) * 50 div (Percent + 50);
            G := G1 + (G2 - G1) * 50 div (Percent + 50);
            B := B1 + (B2 - B1) * 50 div (Percent + 50);
            prevscan^[2] := R;
            prevscan^[1] := G;
            prevscan^[0] := B;
          end;
          Inc(prevscan);
        end;

        if nextscan <> nil then
        begin
          //Pixel unten
          //Pixel down
          R2 := nextscan^[2];
          G2 := nextscan^[1];
          B2 := nextscan^[0];

          if (R1 <> R2) or (G1 <> G2) or (B1 <> B2) then
          begin
            R := R1 + (R2 - R1) * 50 div (Percent + 50);
            G := G1 + (G2 - G1) * 50 div (Percent + 50);
            B := B1 + (B2 - B1) * 50 div (Percent + 50);
            nextscan^[2] := R;
            nextscan^[1] := G;
            nextscan^[0] := B;
          end;
          Inc(nextscan);
        end;
        Inc(pix);
      end;
    end;
  end;
end;

Beispiel :

procedure TForm1.Button1Click(Sender: TObject);
begin
  Antialiasing(Image1.Picture.Bitmap,
               Rect(
               0,      // HIER KANN DER BEREICH FÜR DIE HÖHE INERHALB DES BILDES ANGEGEBEN WERDEN
               0,      // HIER KANN DER BEREICH FÜR DIE BREITE INERHALB DES BILDES ANGEGEBEN WERDEN
               Image1.Picture.Bitmap.Width, Image1.Picture.Bitmap.Height), 
               15);    // HIER WIRD PROZENTUAL DIE ANTIALIASING BERECHNUNG DEFINIERT
end;