@reanchear wrote:
Now I am closed to crazy. I have completed to get image from usb camera on twain data source based on the twain toolkit demo –twack_32.exe . But when I open the source by Photoshop software, it issues that it can’t complete to import command, because of the scanner’s problem. Then when I debug the ds, I found that when the code complete the DAT_CAPABILITY serial command, the source entered into the CLOSEDS command.
Which capability was specified with DAT_CAPABILITY?
Also, it’s possible that your webcam’s TWAIN driver is incompatible with the Photoshop version you’re using. Have you checked with the maker?
More information on your setup, both hardware and software, would make it easier for others to help you.