Someone

 alpha = 0xFF; 

   for (i = 0; i < h; i++)
     {
        for (j = 0; j < w; j++)
          {
             new_pixels[i * w + j] = (0x00FFFFFF & old_pixels[i*w + j]) | (alpha << 24) ;
          }
        alpha -= 1; 
 
        printf("alpha : %X %X\n", alpha,   (alpha << 24));
        
     }   
   evas_object_image_data_set(reflection, new_pixels);