Is there a way to determine the number of lines on a screen for programming BDC? 

Many users have different size fonts and resolutions on each screen. The number of lines vary. 
Many ABAPERS have this problem, if a batch input has a table control, then the font size changes from machine to machine as a result the no of entries keeps changing, so how to determine the number of available lines depending on the font size. 

Here is the solution code for this :-
************************************************************************
* data for controlling paging on screen 0102 
DATA: W_MAXLINES(2) TYPE N, 
W_NEXT_LINE(3) TYPE N, 
W_PAGE(1), "y = page forward, n otherwise 
W_SCRLEN(2) TYPE I, 
W_SCRLINE(2) TYPE I. 
DATA: BEGIN OF W_HDR. 
INCLUDE STRUCTURE D020S. 
DATA: END OF W_HDR. 
DATA: BEGIN OF W_FLD OCCURS 100. 
INCLUDE STRUCTURE D021S. 
DATA: END OF W_FLD. 
DATA: BEGIN OF W_LOG OCCURS 20. 
INCLUDE STRUCTURE D022S. 
DATA: END OF W_LOG. 
DATA: BEGIN OF W_MC OCCURS 20. 
INCLUDE STRUCTURE D023S. 
DATA: END OF W_MC. 
DATA: BEGIN OF W_DYNPRONAME, 
PROGRAM(8) VALUE 'SAPMM60X', 
DYNPRO(4) VALUE '0102', 
END OF W_DYNPRONAME. 

************************************************************************ 
FORM GET_MAX_LINES. 
* set w_maxlines to the number of var-loop occurrences on the screen so 
* that we know when to page forward on screen 0102 
* also initialise w_next_line to zero for GET_NEXT_LINE 
* this subroutine caters for all cases - including screens without loops 
CLEAR: W_MAXLINES, 
W_NEXT_LINE. 
IMPORT DYNPRO W_HDR 
W_FLD 
W_LOG 
W_MC 
ID W_DYNPRONAME. 
LOOP AT W_FLD WHERE LTYP EQ 'L'. 
MOVE W_FLD-LINE TO W_SCRLINE. "first var-loop line 
MOVE W_FLD-LBLK TO W_SCRLEN. "depth of loop block 
EXIT. 
ENDLOOP. 
IF SY-SUBRC EQ 0 
AND W_SCRLEN NE 0. 
* sy-srows = total no of lines on screen 
* w_scrline = actual first line of loop so that 
* w_scrline - 1 = number of heading lines (before loop) 
* 4 = no of lines at top of screen - command line, pushbuttons, 2 ulines 
* 3 = no of lines after loop - uline & Page count 
* w_scrlen = no of lines in loop block 
* w_maxlines = sy-srows - ( wscrline - 1 ) - 4 - 3 
* and then 1 less but not sure why! 
W_MAXLINES = SY-SROWS - W_SCRLINE - 1 - 4 - 3. 
W_MAXLINES = W_MAXLINES - 1.
W_MAXLINES = W_MAXLINES DIV W_SCRLEN. 
ELSE. 
MOVE 99 TO W_MAXLINES. "this required if no screen loop 
ENDIF. 
ENDFORM. 

************************************************************************ 
FORM GET_NEXT_LINE. 
* set w_page if page forward is required 
W_NEXT_LINE = W_NEXT_LINE + 1. 
IF W_NEXT_LINE GT W_MAXLINES. 
W_NEXT_LINE = 1. 
W_PAGE = 'Y'. 
ELSE. 
W_PAGE = 'N'. 
ENDIF. 
ENDFORM. 

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