Jpeg To Grb Convert

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls;

type
TForm1 = class(TForm)
Button1: TButton;
OpenDialog1: TOpenDialog;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var Form1: TForm1;
implementation
uses jpeg;

{$R *.dfm}

function ConvertBitmapToGrayscale(const Bitmap: TBitmap): TBitmap;
var i, j: Integer; Grayshade, Red, Green, Blue: Byte; PixelColor: Longint;
begin
with Bitmap do
for i := 0 to Width - 1 do
for j := 0 to Height - 1 do
begin
PixelColor := ColorToRGB(Canvas.Pixels[i, j]);
Red := PixelColor;
Green := PixelColor shr 8;
Blue := PixelColor shr 16;
Grayshade := Round(0.3 * Red + 0.6 * Green + 0.1 * Blue);
Canvas.Pixels[i, j] := RGB(Grayshade, Grayshade, Grayshade);
end;
Result := Bitmap;
end;

procedure ConvertToBitmap(Source : TGraphic; Bitmap : TBitmap);
begin
try
if Bitmap = nil then
Bitmap := TBitmap.Create
Else Bitmap.FreeImage;
Bitmap.Width := Source.Width;
Bitmap.Height := Source.Height;
Bitmap.Canvas.Draw(0,0,Source);
except
showmessage('No Loaded File');
end;end;

procedure TForm1.Button1Click(Sender: TObject);
var
MyJpeg,OperatedJpeg:TJPEGImage;
MyBitmap,OperatedBitmap:TBitmap;
Begin
if OpenDialog1.Execute then
begin
MyJpeg := TJPEGImage.Create;
MyBitmap := TBitmap.Create;
OperatedBitmap := TBitmap.Create;
OperatedJpeg := TJPEGImage.Create;
try
MyJpeg.LoadFromFile(OpenDialog1.FileName);
ConvertToBitmap(MyJpeg,MyBitmap);
// Do any Bitmap Operation Here
//For Example i Convert Bitmap To GrayScale and perform result into
//operateBitmap
OperatedBitmap := ConvertBitmapToGrayscale(MyBitmap);
//Perform operated bitmap into jpeg
OperatedJpeg.Assign(OperatedBitmap);
OperatedJpeg.SaveToFile(OpenDialog1.FileName+'-Gray.jpeg');
Showmessage('Operation Completed')
finally
MyJpeg.Free;
OperatedJpeg.Free;
end;end;end; end.