September 9, 2008 at 4:08 pm #22403
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I’m trying to make a Delphi program scan without showing the UI using Gustavo Daud’s Delphi Twain component. If I use the HP Twain Driver the page is scanned, but when I try to scan a second page, the scanner does not re-scan but simply downloads the first page the I scanned from some place it’s stored it in memory. This does not happen if the UI is enabled, but I want to disable it as it’s so ?#!@@!! slow!
However, if I use the WIA driver the problem with the scanning tow pages does not happen, but the scanned picture is distorted such that each row is offset from the previous row.
Anyone any suggestions?September 9, 2008 at 7:52 pm #24648
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I accidentally deleted your user while cleaning the *pammers.
I’m really sorry!
Hilary – TWAIN AdminSeptember 15, 2008 at 8:08 am #24649
Still having problems with this. Please can anyone help.September 15, 2008 at 8:00 pm #24650
does this happen with only your program or do other (Ui-less) programs exhibit the same behavior?
.September 17, 2008 at 8:16 am #24651
The test program provided with delphitwain does the same thing.September 17, 2008 at 8:39 am #24652
lets try this another way, do programs not using that library work exhibit the same behavior?
.September 22, 2008 at 12:37 pm #24653
Sorry, being dense!
I’ve downloaded a couple of other programs and tested these. One of them cannot be made to do this at all, but it always unloads the source after scanning, which I can tell because loading the source causes its splash screen to display. The other program can be made to do this as it only unloads the source when told to do so.
What I don’t understand is that if I send the command enable source to the scanner using the WIA-HP Scanjet 4800 driver, a scan is produced and the source’s status is set to disabled. If I then set the source to enabled again, a second scan is produced. Using the same procedure with the HP 4800 Series Twain driver, the first scan is produced as before, but setting the scanner to enabled a secod time, does not cause the scanning process to take place with the previous scan simply being downloaded again. With this driver, the scanner must be unloaded and re-loaded between scans. I assum this is a solution, but I’d like to know why this happens. The HP UI does not unload the scanner between scans, as the splash screen does not display between scans.September 22, 2008 at 3:38 pm #24654
but the Hp Ui doesn’t have to play by the rules – it could be using Custom triplets or even non-twain functions.
The twain.log in %temp% should tell you what it happening, look thru the %temp%twain.log when you control the device and look at it when the Hp Ui does. What is different?