Add Button in Report and Change Icon Image

REPORT ZRR_SAMPLE.

TYPE-POOLS: icon.

TABLES: sscrfields.

CONSTANTS:  true   TYPE true    VALUE 'T',
            false  TYPE false   VALUE 'F'.

DATA:  g_use_pipe  TYPE boole_d, 
       sc_functxt  TYPE smp_dyntxt.

PARAMETERS: p_carrid TYPE s_carr_id,
            p_cityfr TYPE s_from_cit.

SELECTION-SCREEN FUNCTION KEY 1.

INITIALIZATION.
  
  g_use_pipe  =  true.

AT SELECTION-SCREEN.
  
  CASE sscrfields-ucomm.
    WHEN 'FC01'.
      IF  g_use_pipe  =  true.
        
        g_use_pipe  =  false.
      
      ELSE.
        
        g_use_pipe  =  true.
      
      ENDIF.
    WHEN OTHERS.
  ENDCASE.

AT SELECTION-SCREEN  OUTPUT.
  
  IF  g_use_pipe  =  true.
    
    sc_functxt-icon_id     =  icon_view_expand_horizontal.
    sc_functxt-quickinfo   =  'Change field separator'.
    sc_functxt-icon_text   =  'Use Tab delimiter'.
    sscrfields-functxt_01  =  sc_functxt.
    
  ELSE.
    
    sc_functxt-icon_id     =  icon_view_expand_vertical.
    sc_functxt-quickinfo   =  'Change field separator'.
    sc_functxt-icon_text   =  'Use PIPE delimiter'.
    sscrfields-functxt_01  =  sc_functxt.
    
  ENDIF.