Set/Get a Twain Capability (Delphi 4.0)
Take the following steps to start a project and to add some code to use the Get/Set capability methods and then acquire your image using the newly set capability:
1. |
Start Delphi. |
2. |
On the Project pull-down menu, use the Import Type library… and select the LEAD Raster Object Library (14.5). Press OK. |
3. |
On the Project pull-down menu, use the Import Type library… and select the LEAD RasterTwain Object Library (14.5). Press OK. |
4. |
If you didn’t import LEAD Raster Variant before, import it as follows: |
5. |
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 dclusr40.dpk. |
6. |
Declare the following variables in the public section of Unit1: |
TwainCap1: LEADTwainCapability;
TwainCap2: LEADTwainCapability;
TwainCap3: LEADTwainCapability;
RasterTwain: LEADRasterTwain;
nRet: Integer;
7. |
Handle the Form1 OnCreate event, and code the FormCreate procedure as follows: |
procedure TForm1.FormCreate(Sender: TObject);
begin
RasterTwain:= coLEADRasterTwain.Create ( );
TwainCap1:= coLEADTwainCapability.Create ( );
TwainCap2:= coLEADTwainCapability.Create ( );
TwainCap3:= coLEADTwainCapability.Create ( );
RasterTwain.InitSession ( Handle ) ;
RasterTwain.EnableMethodErrors:= False;
{ Unlock Document support.
Note that this is a sample key, which will not work in your toolkit. }
RasterTwain.UnlockSupport( L_SUPPORT_DOCUMENT, 'TestKey' ) ;
end;
8. |
Handle the Form1 OnClose event, and code the FormClose procedure as follows: |
procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
begin
RasterTwain.EndSession ( ) ;
RasterTwain:= Nil;
end;
9. |
At the top of Form1, add 4 button controls and name them as follows: |
|
|
Name |
Caption |
|
btnSelectSource |
Select Source |
|
btnUseCapability |
Use Capability |
|
btnSetBrightness |
Set Brightness |
|
btnAcquire |
Acquire |
10. |
Handle the btnSelectSource OnClick event, and code the btnSelectSourceClick procedure as follows. In online help, you can use the Edit pull-down menu to copy the block of code. |
procedure TForm1.btnSelectSourceClick(Sender: TObject);
begin
RasterTwain.SelectSource ( ) ;
end;
11. |
Handle the btnUseCapability OnClick event, and code the btnUseCapabilityClick procedure as follows. In online help, you can use the Edit pull-down menu to copy the block of code. |
procedure TForm1.btnUseCapabilityClick(Sender: TObject);
var
Xfer: LEADRasterVariant;
begin
TwainCap1.EnableMethodErrors:= False;
TwainCap1.CapInfo.ConType:= L_TWON_ONEVALUE;
TwainCap1.CapInfo.Capability:= L_ICAP_XFERMECH;
nRet:= RasterTwain.GetCapability2( TwainCap1, L_LTWAIN_CAPABILITY_GETCURRENT ) ;
if ( nRet = 0 ) then
begin
Xfer:= TwainCap1.CapOneValue.OneValCapValue;
if ( Xfer.LongValue <> L_TWSX_FILE ) then
begin
TwainCap2.EnableMethodErrors:= False;
TwainCap2.CapInfo.Capability:= L_ICAP_XFERMECH;
TwainCap2.CapInfo.ConType:= L_TWON_ONEVALUE;
TwainCap2.CapOneValue.OneValItemType:= L_TWTY_UINT16;
TwainCap2.CapOneValue.OneValCapValue:= Xfer;
nRet:= RasterTwain.SetCapability2( TwainCap2, L_LTWAIN_CAPABILITY_SET );
end
else
ShowMessage ( 'The Transfer mode is File' ) ;
end
else
ShowMessage ( 'Error occurred in GetCapability method' ) ;
end;
12. |
Handle the btnSetBrightness OnClick event, and code the btnSetBrightnessClick procedure as follows. In online help, you can use the Edit pull-down menu to copy the block of code. |
procedure TForm1.btnSetBrightnessClick(Sender: TObject);
var
iRet: Integer;
CapVal: LEADRasterVariant;
begin
TwainCap3.CapInfo.ConType:= L_TWON_ONEVALUE;
TwainCap3.CapInfo.Capability:= L_ICAP_BRIGHTNESS;
TwainCap3.EnableMethodErrors:= False;
CapVal:= coLEADRasterVariant.Create ( );
CapVal.type_:= VALUE_USHORT;
CapVal.LongValue:= 50;
TwainCap3.CapOneValue.OneValItemType:= L_TWTY_FIX32;
TwainCap3.CapOneValue.OneValCapValue:= CapVal;
iRet:= RasterTwain.SetCapability2(TwainCap3, L_LTWAIN_CAPABILITY_SET);
if (iRet <> 0) then
ShowMessage ( 'Error Setting Capability' );
end;
13. |
Handle the btnAcquire OnClick event, and code the btnAcquireClick procedure as follows. In online help, you can use the Edit pull-down menu to copy the block of code. |
procedure TForm1.btnAcquireClick(Sender: TObject);
begin
RasterTwain.FileTransferName:= 'c:\twain.bmp';
nRet:= RasterTwain.Acquire ( L_LTWAIN_SHOW_USER_INTERFACE ) ;
if ( nRet <> 0 ) then
ShowMessage ( 'Error acquiring from source' ) ;
end;
14. |
At the beginning of the Unit1 file, add ComObj, LTRASTERTWAINLib_TLB, LTRASTERVARIANTLib_TLB, LTDLLDef to the uses section. This lets you handle the Com objects, the Raster Twain object library, and use the LEAD Defines. |
15. |
Save your project and run your program to test it. |