saraff-9EB1047A4BEB4cef8506B29BA325BD5A
commented
7 years ago Hello, @nhan3bin Likely, your a Data Source is not fully compliant to the TWAIN Specification. In a sample you use the Buffered Memory transfer mechanism. The Twain32._GetImageInfo method invoke a DG_IMAGE / DAT_IMAGEINFO / MSG_GET triplet. All the Data Sources must support this triples when processing image data transfer. You may try use the Native or Disk File (except the Buffered Memory) transfer mechanism (see Native Mode Transfer and Disk File Mode Transfer)
For resolve this problem you may contact with a customer service of manufacturer your scanner. Also you can see the TWAIN Specification:
Call
DSM_Entry(pOrigin, pDest, DG_IMAGE, DAT_IMAGEINFO, MSG_GET,pImageInfo);
pImageInfo = A pointer to a TW_IMAGEINFO structure.
Valid States
6 and 7 (State 7 only after receiving TWRC_XFERDONE)
Description
When called in State 6, this operation provides to the application general image description information about the image about to be transferred. When called in State 7, this operation provides the Application with specific image description information about the current image that has just been transferred. It is important during a Memory transfer to call this triplet only after TWRC_XFERDONE is received, since that is the only time the Source will know all the final image information. The same data structure type is used regardless of the mechanism used to transfer the image (Native, Disk File, or Buffered Memory transfer).
Application
The Application can use this operation to check the parameters of the image before initiating the transfer during State 6, or to clarify image parameters during State 7 after the transfer is complete. Applications may inform Sources that they accept -1 value for ImageHeight/ImageWidth by setting the ICAP_UNDEFINEDIMAGESIZE capability to TRUE. Should the Application decide to invoke any Source features that allow the image description information to change during scanning (such as ICAP_UNDEFINEDIMAGESIZE) and still wish to transfer in Buffered memory mode, a DG_CONTROL/DAT_IMAGEINFO/MSG_GET call must be made in State 7 after receiving TWRC_XFERDONE to properly interpret the image data. This is not the default behavior of the Source. Note that the speed at which the Application supplies buffers may determine the scanning speed.
Source
For maximum compatibility with applications, Data Source writers are strongly encouraged to report back finished image values in State 6. In other words, calls to DAT_IMAGEINFO should return the same identical values in State 6, and in State 7 after TWRC_XFERDONE has been issued to the application. During State 6 - Fills in all fields in pImageInfo. All fields are filled in as you would expect with the following exceptions:
- XResolution or YResolution Set to -1 if the device creates data with no inherent resolution (such as a digital camera).
- ImageWidth Set to -1 if the image width to be acquired is unknown (such as when using a hand-held scanner and dragging left-to-right) , and the Application has set ICAP_UNDEFINEDIMAGESIZE to TRUE. In this case the Source must transfer the image in tiles.
- ImageLength ImageLength—Set to -1 if the image length to be acquired is unknown (such as when using a hand-held scanner and dragging top-to-bottom), and the Application has set ICAP_UNDEFINEDIMAGESIZE to TRUE. During State 7 - Fills in all fields in pImageInfo. All fields are filled in as during State 6, except ImageWidth and ImageLength MUST be valid. Source shall return TWRC_SEQERROR if call is made before TWRC_XFERDONE is sent.
7-120 TWAIN 2.3 Specification
nhan3bin
Dir Mr Saraff, Thank you so much for your project. My issue is when I compile and execute your Saraff.Twain.Sample3, it works fine, but in command line mode, the example shows error and halt.
My platform: windows 10 64bit, Visual studio 2015 and had installed Package Saraff.Twain -Version 1.0.27.606 via NUGet Package Manager.
How can I resolve the problem?
Thank for your help.