L_TwainSetImageEffects

#include "lttwn.h"

L_LTTWN_API L_INT L_TwainSetImageEffects(hSession, ulFlags, pBrightness, pContrast, pHighlight)

Sets the brightness, highlight, and contrast values to be used when transferring images from the current TWAIN source.

Parameters

HTWAINSESSION hSession

Handle to an existing TWAIN session. This handle is obtained by calling the L_TwainInitSession or L_TwainInitSession2 function.

L_UINT32 ulFlags

Flags that indicate which value(s) to set. You can combine values when appropriate by using a bitwise OR ( | ). Possible values are:

pTW_FIX32 pBrightness

Pointer to a variable that contains the brightness value to set. Possible values range from -1000 to 1000.

pTW_FIX32 pContrast

Pointer to a variable that contains the contrast value to set. Possible values range from -1000 to 1000.

pTW_FIX32 pHighlight

Pointer to a variable that contains the highlight value to set. Possible values range from 0 to 255.

Returns

Comments

This function internally sets the brightness capability ICAP_BRIGHTNESS, the highlight capability ICAP_HIGHLIGHT, and the contrast capability ICAP_CONTRAST. For more information on these capabilities, refer to the TWAIN specification.

To get the current brightness, highlight, and contrast capability values, call the L_TwainGetImageEffects 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.

L_INT TwainSetImageEffectsExample(HTWAINSESSION hSession)  
{ 
   L_INT nRet = SUCCESS; 
 
   nRet = L_TwainStartCapsNeg(hSession); 
   if(nRet != SUCCESS) 
      return nRet; 
 
   TW_FIX32 Brightness; 
   nRet = L_TwainGetImageEffects (hSession, TWAIN_NEGOTIATE_BRIGHTNESS, &Brightness, NULL, NULL); 
   if (nRet == SUCCESS) 
   { 
      if (L_TwainFix32ToFloat(&Brightness) != 100.0f) 
      { 
         Brightness = L_TwainFloatToFix32(100.0f); 
         nRet = L_TwainSetImageEffects(hSession, TWAIN_NEGOTIATE_BRIGHTNESS, &Brightness, NULL, NULL); 
         if(nRet != SUCCESS) 
            return nRet; 
      } 
   } 
   else 
      return nRet; 
 
   L_INT nPaperSize, nPaperDirection; 
   nRet = L_TwainGetAcquirePageOptions (hSession, &nPaperSize, &nPaperDirection); 
   if (nRet == SUCCESS) 
   { 
      if (nPaperDirection != TWOR_LANDSCAPE) 
      { 
         nRet = L_TwainSetAcquirePageOptions (hSession, TWSS_A4, TWOR_LANDSCAPE); 
         if(nRet != SUCCESS) 
            return nRet; 
      } 
   } 
   else  
      return nRet; 
 
   nRet = L_TwainEndCapsNeg (hSession); 
   if(nRet != SUCCESS) 
      return nRet; 
   return SUCCESS; 
}