Acquiring an Image (Delphi 6.0)

Take the following steps to start a project and to add some code that acquires an image from a TWAIN source:

1.	Start Delphi 6.0.
2.	If you didn’t install LEAD RasterView Control, install it as follows:
	On the Component pull-down menu, use Import ActiveX Control… and select the LEAD RasterView Control (14.5). Press install, and then compile and install the package dclusr.dpk.
3.	Select the LEAD RasterView control and add it to your form. Size and position the control, as you want it to appear at run time.
4.	If you didn’t import LEAD Raster Twain before, import it as follows:
	On the Project pull-down menu, use Import Type library… and select the LEAD RasterTwain Object Library (14.5). Press install, and then compile and install the package dclusr.dpk.
5.	From the ActiveX controls tab, add the LEAD Raster Twain control and the LEAD Twain Capability control to your form.
6.	If you didn’t import LEAD Raster Variant before, import it as follows:
7.	On the Project pull-down menu, use the Import Type library… and select the LEAD Raster Variant Object Library (14.5). Press install, and then compile and install the package dclusr.dpk.
8.	From the ActiveX controls tab, add the LEAD Raster Variant control to your form.
9.	At the top of your form, add 9 Buttons and name them as follows:
	Name	Caption
	btnOK	OK
	btnCancel	Cancel
	btnAcquire	Acquire
	btnSelectSource	Select Source
	btnSaveTemplate	Save Template File
	btnLoadTemplate	Load Template File
	btnNative	Native
	btnMemBuf	Memory Buffered
	btnFile	File
10.	Add the following code to the private section of Unit1:

nXferMode: Integer;
nRet: Integer;
Function TwainSetCapability ( uCapability: Integer;
CapVal: LEADRasterVariant;
uItemType: Integer ): Integer;

11.	Handle the Form1 OnCreate event, and code the FormCreate procedure as follows:

procedure TForm1.FormCreate(Sender: TObject);
begin
LEADRasterTwain1.InitSession ( Handle ) ;
end;

12.	Handle the Form1 OnClose event, and code the FormClose procedure as follows:

procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
begin
LEADRasterTwain1.EndSession ();
end;

13.	Handle the btnOK OnClick event, and code the btnOKClick procedure as follows. In online help, you can use the Edit pull-down menu to copy the block of code.

procedure TForm1.btnOKClick(Sender: TObject);
begin
Close ( ) ;
end;

14.	Handle the btnCancel OnClick event, and code the btnCancelClick procedure as follows. In online help, you can use the Edit pull-down menu to copy the block of code:

procedure TForm1.btnCancelClick(Sender: TObject);
begin
Close ( ) ;
end;

15.	Handle the btnAcquire OnClick event, and code the btnAcquireClick procedure as follows:

procedure TForm1.btnAcquireClick(Sender: TObject);
begin
LEADRasterTwain1.Acquire ( L_LTWAIN_SHOW_USER_INTERFACE ) ;
end;

16.	Handle the btnSelectSource OnClick event, and code the btnSelectSourceClick procedure as follows:

procedure TForm1.btnSelectSourceClick(Sender: TObject);
begin
LEADRasterTwain1.SelectSource ( ) ;
end;

17.	Handle the btnSaveTemplate OnClick event, and code the btnSaveTemplateClick procedure as follows:

procedure TForm1.btnSaveTemplateClick(Sender: TObject);
begin
nRet:= LEADRasterTwain1.SaveTemplate ('c:\test.ltt');
end;

18.	Handle the btnLoadTemplate OnClick event, and code the btnLoadTemplateClick procedure as follows:

procedure TForm1.btnLoadTemplateClick(Sender: TObject);
begin
nRet:= LEADRasterTwain1.LoadTemplate ( 'c:\test.ltt' ) ;
end;

19.	Handle the btnNative button’s OnClick event, and code the btnNativeClick procedure as Follows:

procedure TForm1.btnNativeClick(Sender: TObject);
begin
   nXferMode:= L_TWSX_NATIVE;
   LEADRasterVariant1.Type_:= VALUE_USHORT;
   LEADRasterVariant1.LongValue:= nXferMode;
   TwainSetCapability ( L_ICAP_XFERMECH,
                        LEADRasterVariant1.DefaultInterface,
                        L_TWTY_UINT16 );
end;

20.	Handle the btnMemBuf button’s OnClick event, and code the btnMemBufClick procedure as follows:

procedure TForm1.btnMemBufClick(Sender: TObject);
begin
   nXferMode:= L_TWSX_MEMORY;
   LEADRasterVariant1.Type_:= VALUE_USHORT;
   LEADRasterVariant1.LongValue:= nXferMode;
   TwainSetCapability ( L_ICAP_XFERMECH, LEADRasterVariant1.DefaultInterface, L_TWTY_UINT16 );
end;

21.	Handle the btnFile option OnClick event, and code the btnFileClick procedure as follows:

procedure TForm1.btnFileClick(Sender: TObject);
begin
   nXferMode:= L_TWSX_FILE;
   LEADRasterVariant1.Type_:= VALUE_USHORT;
   LEADRasterVariant1.LongValue:= nXferMode;
   TwainSetCapability ( L_ICAP_XFERMECH, LEADRasterVariant1.DefaultInterface, L_TWTY_UINT16 );
   LEADRasterTwain1.FileTransferName:= 'c:\twain.bmp';
end;

22.	Handle the LEADRasterTwain1 OnAcquirePageEvent event, and code the LEADRasterTwain1AcquirePageEvent procedure as follows:

procedure TForm1.LEADRasterTwain1AcquirePageEvent(Sender: TObject;
  pBitmap: Integer);
begin
   ShowMessage ( 'Acquisition of Image Done' ) ;
   LEADRasterView1.Raster.InsertBitmapListItem ( -1, pBitmap ) ;
end;

23.	Add the TwainSetCapability function body to the Unit1 file.

Function TForm1.TwainSetCapability ( uCapability: Integer; CapVal: LEADRasterVariant; uItemType: Integer): Integer;
var
   iRet: Integer;
begin
   LEADTwainCapability1.EnableMethodErrors:= False;
   LEADTwainCapability1.CapInfo.Capability:= uCapability;
   LEADTwainCapability1.CapInfo.ConType:= L_TWON_ONEVALUE;
   LEADTwainCapability1.CapOneValue.OneValItemType:= uItemType;
   LEADTwainCapability1.CapOneValue.OneValCapValue:= CapVal;

   iRet:= LEADRasterTwain1.SetCapability2 (LEADTwainCapability1.DefaultInterface, L_LTWAIN_CAPABILITY_SET);
   TwainSetCapability:= iRet;
end;

24.	Run your program to test it.