L_ColorThresholdBitmap

#include "l_bitmap.h"

L_LTIMGCLR_API L_INT L_ColorThresholdBitmap (pBitmap, uColorSpace, pCompData)

Using any one of eight color spaces, resets those bitmaps pixel component values that fall inside or outside of a specified range.

Returns

Comments

This function does not support signed data images. It returns the error code ERROR_SIGNED_DATA_NOT_SUPPORTED if a signed data image is passed to this function.

This function is similar to the L_ConvertColorSpace function but provides greater flexibility by allowing the specification of a range and different options for handling those values that fall outside of the range. Please note that every color space component may have a different range.

This function works as follows:

This function works for 1, 2, 3, 8,16, 24, 32, 48 and 64-bit color bitmaps and can support regions for 24 and 48-bit bitmaps. If a 24 or 48-bit bitmap has a region the effect will be applied on the region only.

One structure is used for each color component. The order is considered to be the same as in the CLTH_xxx_SPACE name. For example, for CLTH_RGB_SPACE:

pCompData[0] structure is used for the Blue component

pCompData[1] structure is used for the Green component

pCompData[2] structure is used for the Red component

The pCompData[0].uStructSize must be set to sizeof(COMPDATA) before calling this function. For an array of structures, only the first structure in the array needs to have uStructSize member set.

To update a status bar or detect a user interrupt during execution of this function, refer to L_SetStatusCallback.

This function does not support 32-bit grayscale images. It returns the error code ERROR_GRAY32_UNSUPPORTED if a 32-bit grayscale image is passed to this function.

Required DLLs and Libraries

Platforms

Windows 2000 / XP/Vista.

See Also

Example

 L_INT ColorThresholdBitmapExample(L_VOID)
{
   L_INT nRet;
   BITMAPHANDLE LeadBitmap;   /* Bitmap handle for the image */
   COMPDATA          pCompData[3];
   L_INT                     nI;

   /* Load a bitmap at its own bits per pixel  */
   nRet = L_LoadBitmap(TEXT("C:\\Program Files\\LEAD Technologies\\LEADTOOLS 15\\Images\\IMAGE3.CMP"), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL);
   if(nRet !=SUCCESS)
      return nRet;

   pCompData[0].uStructSize = sizeof(COMPDATA);
   for (nI = 0; nI < 3; nI++)
   {
       pCompData[nI].nMinRange = 128;
       pCompData[nI].nMaxRange = 255; 
       pCompData[nI].uFlags = 0;
   }

   /* Apply color Threshold effect on the image*/
   nRet = L_ColorThresholdBitmap(&LeadBitmap, CLTH_RGB_SPACE,  pCompData);
   if(nRet !=SUCCESS)
      return nRet;
   nRet = L_SaveBitmap(TEXT("C:\\Program Files\\LEAD Technologies\\LEADTOOLS 15\\Images\\Result.BMP"), &LeadBitmap, FILE_BMP, 24, 0, NULL);
   if(nRet !=SUCCESS)
      return nRet;
   //free bitmap 
   if(LeadBitmap.Flags.Allocated)  
      L_FreeBitmap(&LeadBitmap);  
   return SUCCESS;
}