unit filterAdjust;
(* ***** BEGIN LICENSE BLOCK *****
 * Copyright (C) 2004 Durand Emmanuel
 * Copyright (C) 2004 Burgel Eric
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Contact :
 *   filters@edurand.com
 *   filters@burgel.com
 *
 * ***** END LICENSE BLOCK ***** *)

{
 edurand (filters@edurand.com)
 eburgel (filters@burgel.com)
}

interface
uses
  filter, fparameters, image;

type
  TFilterAdjust = class(TFilter)
  public
    constructor Create; override;
    procedure Run(); override;
  private
    parameterImageIn, parameterImageOut : TParameterImage;
    parameterBrightness : TParameterInteger ;
    parameterContrast : TParameterInteger ;
    parameterAutoAdjust : TParameterBoolean ;
    imgIn, imgOut : PBitmap32 ;
    procedure _run();
  end;

implementation
uses
  imageIO;

constructor TFilterAdjust.Create;
begin
  inherited;
  parameterImageIn:= addParameterImage('inImage', 'input image to invert');
  parameterImageOut:= addParameterImage('outImage', 'result image of invertion');
  parameterBrightness := addParameterInteger('Brightness', 'Brightness', -10000, 10000, 0) ;
  parameterContrast := addParameterInteger('Contrast', 'Contrast', 0, 20000, 10000) ;
  parameterAutoAdjust := addParameterBoolean('AutoAdjust', 'Automatic bright and contrast', false) ;
end;

procedure TFilterAdjust.Run();
begin
  imgIn  := parameterImageIn.Image ;
  imgOut := parameterImageOut.Image ;
  if (imgIn<>nil) and (imgOut<>nil) then begin
    _run();
  end;
end;

procedure TFilterAdjust._run();
var
  pSrc, PDest : PColor32Array;
  x, y, maxX, maxY : Integer ;
  color : integer ;
  red, green, blue : integer ;
  newRed, newGreen, newBlue, newColor : Integer ;
  a, b : integer ;
begin
  maxX := scanWidth(imgIn)-1 ;
  maxY := scanHeight(imgIn)-1 ;
  eraseImage(imgOut);
  a := parameterContrast.Value ;
  b := parameterBrightness.Value ;
  for y:=0 to maxY do begin
    pSrc := scanLine(imgIn, y) ;
    pDest := scanLine(imgOut, y) ;
    for x:=0 to maxX do begin
      color := pSrc^[0] and $00FFFFFF ;
      red := color shr 16 ;
      green := (color shr 8) and $FF ;
      blue := color and $FF ;
      // Red
      newRed := ((red-$80)*a) div $80 + $80 + b ;
      if newRed>255 then newRed := 255 else if newRed<0 then newRed := 0 ;
      // Green
      newGreen := ((green-$80)*a) div $80 + $80 + b ;
      if newGreen>255 then newGreen := 255 else if newGreen<0 then newGreen := 0 ;
      // Blue
      newBlue := ((blue-$80)*a) div $80 + $80 + b ;
      if newBlue>255 then newBlue := 255 else if newBlue<0 then newBlue := 0 ;
      
      newColor := (newRed shl 16) or (newGreen shl 8) or newBlue ;
      pDest^[0] :=
        (pSrc^[0] and $FF000000) +
        (newColor and $00FFFFFF);
      inc(pDest) ;
      inc(pSrc) ;
    end ;
  end ;
end;

end.