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{ Copyright (C) 2004 Mattias Gaertner
Example for loading and saving jpeg images.
Important:
This example uses the JPEGForLazarusPackage (see in the directory above).
You must first open once this package so that the IDE knows, where to find
the lpk file.
See the README.txt.
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the Free
Software Foundation; either version 2 of the License, or (at your option)
any later version.
This program 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 Library General Public License
for more details.
You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place - Suite 330, Boston, MA 02111-1307, USA.
}
unit MainForm;
{$mode objfpc}{$H+}
interface
uses
Classes, SysUtils, LResources, Forms, Controls, Graphics, Dialogs, StdCtrls,
ExtCtrls, Buttons, ExtDlgs;
type
{ TJPEGExampleForm }
TJPEGExampleForm = class(TForm)
LoadImageButton: TButton;
OpenPictureDialog1: TOpenPictureDialog;
SaveImageButton: TButton;
LoadJPEGButton: TButton;
SaveJPEGButton: TButton;
ImageGroupBox: TGroupBox;
Image1: TImage;
SavePictureDialog1: TSavePictureDialog;
procedure LoadJPEGButtonClick(Sender: TObject);
procedure LoadImageButtonClick(Sender: TObject);
procedure SaveJPEGButtonClick(Sender: TObject);
procedure SaveImageButtonClick(Sender: TObject);
private
procedure UpdateInfo(const Filename: string);
end;
var
JPEGExampleForm: TJPEGExampleForm;
implementation
{ TJPEGExampleForm }
procedure TJPEGExampleForm.LoadJPEGButtonClick(Sender: TObject);
var
JPEG: TJPEGImage;
begin
OpenPictureDialog1.Options:=OpenPictureDialog1.Options+[ofFileMustExist];
if not OpenPictureDialog1.Execute then exit;
try
//--------------------------------------------------------------------------
// Create a TJPEGImage and load the file, then copy it to the TImage.
// A TJPEGImage can only load jpeg images.
JPEG:=TJPEGImage.Create;
try
JPEG.LoadFromFile(OpenPictureDialog1.Filename);
// copy jpeg content to a TImage
Image1.Picture.Assign(JPEG);
finally
JPEG.Free;
end;
//--------------------------------------------------------------------------
UpdateInfo(OpenPictureDialog1.Filename);
except
on E: Exception do begin
MessageDlg('Error','Error: '+E.Message,mtError,[mbOk],0);
end;
end;
end;
procedure TJPEGExampleForm.LoadImageButtonClick(Sender: TObject);
begin
OpenPictureDialog1.Options:=OpenPictureDialog1.Options+[ofFileMustExist];
if not OpenPictureDialog1.Execute then exit;
try
//--------------------------------------------------------------------------
// Loading directly into a TImage. This will load any registered image
// format. .bmp, .xpm, .png are the standard LCL formats.
// The jpeg units register .jpeg and .jpg.
Image1.Picture.LoadFromFile(OpenPictureDialog1.Filename);
//--------------------------------------------------------------------------
UpdateInfo(OpenPictureDialog1.Filename);
except
on E: Exception do begin
MessageDlg('Error','Error: '+E.Message,mtError,[mbOk],0);
end;
end;
end;
procedure TJPEGExampleForm.SaveJPEGButtonClick(Sender: TObject);
var
JPEG: TJPEGImage;
begin
if Image1.Picture.Graphic=nil then begin
MessageDlg('No image','Please open an image, before save',mtError,
[mbOk],0);
exit;
end;
SavePictureDialog1.Options:=SavePictureDialog1.Options+[ofPathMustExist];
if not SavePictureDialog1.Execute then exit;
try
//--------------------------------------------------------------------------
// Create a TImage1 and copy the TImage into it. Then save to file.
// This will ignore the file extension. TImage1 will always save as jpeg.
JPEG:=TJPEGImage.Create;
try
// copy content of the TImage to jpeg
JPEG.Assign(Image1.Picture.Graphic);
// save to file
JPEG.SaveToFile(SavePictureDialog1.Filename);
finally
JPEG.Free;
end;
//--------------------------------------------------------------------------
UpdateInfo(SavePictureDialog1.Filename);
except
on E: Exception do begin
MessageDlg('Error','Error: '+E.Message,mtError,[mbOk],0);
end;
end;
end;
procedure TJPEGExampleForm.SaveImageButtonClick(Sender: TObject);
begin
if Image1.Picture.Graphic=nil then begin
MessageDlg('No image','Please open an image, before save',mtError,
[mbOk],0);
exit;
end;
SavePictureDialog1.Options:=SavePictureDialog1.Options+[ofPathMustExist];
if not SavePictureDialog1.Execute then exit;
try
//--------------------------------------------------------------------------
// Saving directly from a TImage to a file. This will save in any registered
// image format. .bmp, .xpm, .png are the standard LCL formats.
// The jpeg units register .jpeg and .jpg.
// So, saving as file1.jpg will save as jpeg, while saving a file1.bmp will
// save as bmp.
Image1.Picture.SaveToFile(SavePictureDialog1.Filename);
//--------------------------------------------------------------------------
UpdateInfo(SavePictureDialog1.Filename);
except
on E: Exception do begin
MessageDlg('Error','Error: '+E.Message,mtError,[mbOk],0);
end;
end;
end;
procedure TJPEGExampleForm.UpdateInfo(const Filename: string);
var
Info: String;
begin
if Image1.Picture.Graphic<>nil then begin
Info:=Image1.Picture.Graphic.ClassName+':'+Filename;
end else begin
Info:=Filename;
end;
ImageGroupBox.Caption:=Info;
end;
initialization
{$I mainform.lrs}
end.
|
