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Date Posted: 17:55:31 02/20/01 Tue
Author: Michel
Subject: Re: Keeping TWAIN interface loaded
In reply to: Michael Mount 's message, "Keeping TWAIN interface loaded" on 11:58:00 02/20/01 Tue


Hi Mike,

Envision is currently not implemented that way. The TScanner.Acquire method, opens the user interface, scans the image (or images on multipage scanners or cameras), then closes the user interface. Here is the section of code in .Acquire (the formatting is quite bad on the forum):

if not CallTriplet( @FTwainData.SourceId, @FTwainData.AppId,
DG_CONTROL, DAT_USERINTERFACE,
MSG_ENABLEDS, @TwainUI, nil, FTwainData.DsmEntry) then
raise ETwainError.Create('Unable to enable twain source.');

try
ProcessImages( AcquireEvent,
@FTwainData.SourceId, @FTwainData.AppId,
FTwainData.DsmEntry, CallBackData);
finally
CallTriplet(
@FTwainData.SourceId, @FTwainData.AppId,
DG_CONTROL, DAT_USERINTERFACE, MSG_DISABLEDS, @TwainUI,
nil, FTwainData.DsmEntry);
end;

If this is very urgent for you and you have the registered version with source, you can try adding three methods:

BeginAcquire;

AcquireWithSourceOpen;

EndAcquire;

BeginAcquire could do everything before ProcesImages in the current .Acquire method.

Then, AcquireWithSourceOpen would simply call ProcessImages, and EndAcquire would close the user interface. This requires splitting the current .Acquire method into three methods.

I'll add this to the todo list. Let me know if you try this out.

Best regards,

Michel


>Hello,
>I'm using a Canon scanner with Ulead iPhotoPlus to
>scan photos for my company. I want to simplify the
>scan process using D5 and the envision library.
>However, iPhotoPlus keeps the Canon interface loaded
>between scans which saves considerable time when
>scanning multiple photos, where envision seems to
>unload and reload it after each call to Acquire. Is
>there a setting or code change I can make to allow my
>program to work like iPhotoPlus in this regard?
>TIA - Mike

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