#include "lttwn.h"

L_LTTWN_API L_INT L_TwainSetRGBResponse(hSession, pRgbResponse, nBitsPerPixel, uFlag)


handle to an existing TWAIN session


pointer to the RGB response

L_INT nBitsPerPixel;

bits per pixel

L_UINT uFlag;

optional flags

Sets the RGB elements used when transferring data 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.
pRgbResponse Pointer to a TW_RGBRESPONSE structure that references the RGB elements to be set for the TWAIN source. For more information about TW_RGBRESPONSE, http://www.twain.org/ and click on TWAIN Specification (Version 1.9).
nBitsPerPixel Bits per pixel to be set. This is used to determine the number of RGB elements in the TW_RGBRESPONSE structure.
uFlag Flags that indicate whether to set or reset the RGB elements for the TWAIN source. Possible values are:
  Value Meaning
  TWAIN_RGB_RESPONSE_SET [0x0001] Set the RGB elements for the current TWAIN source using the information provided.
  TWAIN_RGB_RESPONSE_RESET [0x0002] Reset the RGB elements for the current TWAIN source to the default values. Please note that defaults vary from TWAIN source to TWAIN source.



The function was successful.

< 1

An error occurred. Refer to Return Codes.


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

Required DLLs and Libraries


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

See Also


L_TwainSetTransferOptions, L_TwainGetTransferOptions, L_TwainGetSupportedTransferMode, L_TwainSetResolution, L_TwainGetResolution, L_TwainSetImageFrame, L_TwainGetImageFrame, L_TwainSetImageUnit, L_TwainGetImageUnit, L_TwainSetImageBitsPerPixel, L_TwainGetImageBitsPerPixel, L_TwainSetImageEffects, L_TwainGetImageEffects, L_TwainSetAcquirePageOptions, L_TwainGetAcquirePageOptions, L_TwainShowProgress, L_TwainEnableDuplex, L_TwainGetDuplexOptions, L_TwainSetMaxXferCount, L_TwainGetMaxXferCount


Getting and Setting Capabilities


TWAIN Functionality: Capability Functions


L_INT TwainSetRGBResponseExample(HTWAINSESSION hSession) 
   L_INT nRet; 
   nRet = L_TwainStartCapsNeg (hSession); 
   if(nRet != SUCCESS) 
      return nRet; 
   pTW_RGBRESPONSE pRgbResponse = NULL; 
   pRgbResponse = (pTW_RGBRESPONSE)GlobalAllocPtr(GHND, sizeof(TW_RGBRESPONSE) + sizeof(TW_ELEMENT8) * 2); 
   if (pRgbResponse) 
      pRgbResponse->Response[0].Index = 0; 
      pRgbResponse->Response[0].Channel1 = 0; 
      pRgbResponse->Response[0].Channel2 = 0; 
      pRgbResponse->Response[0].Channel3 = 0; 
      pRgbResponse->Response[1].Index = 1; 
      pRgbResponse->Response[1].Channel1 = 255; 
      pRgbResponse->Response[1].Channel2 = 255; 
      pRgbResponse->Response[1].Channel3 = 255; 
      nRet = L_TwainSetRGBResponse(hSession, pRgbResponse, 1, TWAIN_RGB_RESPONSE_SET); 
      if(nRet != SUCCESS) 
         return nRet; 
   nRet = L_TwainEndCapsNeg (hSession); 
   if(nRet != SUCCESS) 
      return nRet; 
   return SUCCESS; 

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