L_TwainSetImageUnit

#include "lttwn.h"

L_LTTWN_API L_INT L_TwainSetImageUnit(hSession, nUnit)

HTWAINSESSION hSession;	handle to an existing TWAIN session
L_INT nUnit;	image unit

Sets the image unit value used to transfer images from the current TWAIN source.

Parameter	Description
hSession	Handle to an existing TWAIN session. This handle is obtained by calling the L_TwainInitSession or L_TwainInitSession2 function.
nUnit	Specifies the unit value to set. For more information on possible values, refer to http://www.twain.org/ and click on TWAIN Specification (Version 1.9).

Returns

SUCCESS	The function was successful.
< 1	An error occurred. Refer to Return Codes.

Comments

This function internally sets the image unit capability ICAP_UNITS. For more information on this capability, refer to www.twain.org/download.htm and click on TWAIN Specification (Version 1.9).

To obtain the current image unit value, call the L_TwainGetImageUnit function

This function should be called after calling the L_TwainStartCapsNeg function and before calling the L_TwainEndCapsNeg function.

Required DLLs and Libraries

LTTWN

For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files to be Included with your Application.

Example

L_INT TwainSetImageUnitExample(HTWAINSESSION hSession) 
{ 
   L_INT nRet = SUCCESS; 
   nRet = L_TwainStartCapsNeg (hSession); 
   if(nRet != SUCCESS) 
      return nRet; 
   L_INT nUnit; 
   nRet = L_TwainGetImageUnit (hSession, &nUnit); 
   if (nRet == SUCCESS) 
   { 
      if (nUnit != TWUN_INCHES) 
      { 
         nRet = L_TwainSetImageUnit(hSession, TWUN_INCHES); 
         if(nRet != SUCCESS) 
            return nRet; 
      } 
   } 
   else 
      return nRet; 
   L_INT nBPP; 
   nRet = L_TwainGetImageBitsPerPixel (hSession, &nBPP); 
   if (nRet == SUCCESS) 
   { 
      if (nBPP != 24) 
      { 
         nRet = L_TwainSetImageBitsPerPixel (hSession, 24); 
         if(nRet != SUCCESS) 
            return nRet; 
      } 
   } 
   else 
      return nRet; 
   nRet = L_TwainEndCapsNeg (hSession); 
   if(nRet != SUCCESS) 
      return nRet; 
   return SUCCESS; 
}

Help Version 19.0.2017.10.27

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Function References

Functions:	L_TwainSetTransferOptions, L_TwainGetTransferOptions, L_TwainGetSupportedTransferMode, L_TwainSetResolution, L_TwainGetResolution, L_TwainSetImageFrame, L_TwainGetImageFrame, L_TwainGetImageUnit, L_TwainSetImageBitsPerPixel, L_TwainGetImageBitsPerPixel, L_TwainSetImageEffects, L_TwainGetImageEffects, L_TwainSetAcquirePageOptions, L_TwainGetAcquirePageOptions, L_TwainSetRGBResponse, L_TwainShowProgress, L_TwainEnableDuplex, L_TwainGetDuplexOptions, L_TwainSetMaxXferCount, L_TwainGetMaxXferCount
Topics:	Getting and Setting Capabilities
	TWAIN Functionality: Capability Functions