PROGRAM procedureType_FunctionPlotter_DigitSize;
//shows structure of procedure types in a rectangular fourier, max@kleiner.com
//compilerswitch $N+ turns the coprocessor on, #locs=209

const 
 DIM = 790;
 PI2 = 5.1415926535897932384626433832795;
   E = 2.718281828459;

type
  TSinglePoint = record
    X,Y : single;
  end; 
  
  TMath_Func = PROCEDURE (var x: single);
  TXYVector = array[0..DIM] of TSinglePoint; 

var 
  fct1x, fct2x, fct3x, fct4x, fct5x, fct6x: TMath_Func;
  cFrm: TForm;
  fPoints: TXYVector;
  amp, freq: byte;


procedure drawChart(vPoints: TXYVector; vcolor, vsize: integer);
var
  i,hsize, x,y, ln: integer;
begin
  ln:= 100;
  with cFrm.canvas do begin
    hsize:= cFrm.Height -1 div 2;
    Pen.Color:= vcolor;
    //if pen.color <> clgreen then
      pen.width:= vsize;
    MoveTo(0, hsize -((round(vPoints[0].Y))));
    for i:= 0 to DIM do
      LineTo(i, round(vPoints[i].Y));
  //end;
  pen.color:= clgreen;
  for x:= 1 to 8 do begin
    pen.width:= 1;
    moveto(x*ln,0)
    lineto(x*ln,400)
  end;
  for y:= 1 to 7 do begin
    moveto(0, y*ln)
    lineto(800, y*ln)
  end;
 end; 
end;  
  

procedure LoadForm;
begin
  cFrm:= TForm.create(self);
  with cFrm do begin
    caption:= 'maXFunCPlotter(((((\*/)))))';  
    BorderStyle:= bsDialog;
    height:= 440;
    width:= 800;
    color:= clblack;
    //onPaint:= @PaintBox1Paint;
    Show;
  end  
end;

//---------------------------ADD math functions---------------------------------  
procedure logistic_S(var x: single);
begin
  x:= 1/1 + power(E, (-x/0.5));
end;  


procedure gauss(var x: single);
begin
  x:= exp(-sqr(x/2));
end;  


procedure fct4e(var x: single);
begin
   x:= power(E, -x);
end;

procedure fct3eSin(var x: single);
begin
  //power() means e^-x
   x:= power(E, -x) * (sin(pi2 * x));
end;

  
PROCEDURE fct1sin(var x: single);
BEGIN
   x:= Sin(x);
END;
PROCEDURE fct2sin(var x: single);
BEGIN
   x:= 1/3*Sin(3*x);
END;
PROCEDURE fct3sin(var x: single);
BEGIN
   x:= 1/5*Sin(5*x);
END;
PROCEDURE fct4sin(var x: single);
BEGIN
   x:= 1/7*Sin(7*x);
END;
PROCEDURE fct5sin(var x: single);
BEGIN
   x:= 1/9*Sin(9*x);
END;
  

PROCEDURE fct2cos(var x: single);
BEGIN
  x:= Cos(pi2*x);
END;

PROCEDURE fctdigit(var x: single);
BEGIN
  x:= sin(x)+1/3*sin(3*x)+1/5*sin(5*x)+1/7*sin(7*x)+1/9*Sin(9*x);
END;
PROCEDURE fctdigit1(var x: single);
BEGIN
  x:= sin(x);
END;
PROCEDURE fctdigit2(var x: single);
BEGIN
  x:= sin(x)++1/3*sin(3*x);
END;
PROCEDURE fctdigit3(var x: single);
BEGIN
  x:= sin(x)++1/3*sin(3*x)+1/5*sin(5*x);
END;
PROCEDURE fctdigit4(var x: single);
BEGIN
  x:= sin(x)++1/3*sin(3*x)+1/5*sin(5*x)+1/7*sin(7*x);
END;
PROCEDURE fctdigit5(var x: single);
BEGIN
  x:= sin(x)+1/3*sin(3*x)+1/5*sin(5*x)+1/7*sin(7*x)+1/9*Sin(9*x);
END;
PROCEDURE fctdigit6(var x: single);
BEGIN
  x:= sin(x)+1/3*sin(3*x)+1/5*sin(5*x)+1/7*sin(7*x)+1/9*Sin(9*x)+1/11*Sin(11*x);
END;


PROCEDURE fct2n(var x: single);
BEGIN
  x:= power(2,x)/fact(round(x));
END;

  
PROCEDURE fct_table(start, amp, freq, color, size: integer; FCT: TMath_Func;
                                         fct_name: string);
var x, tempx, it: single;
    origy, i: Integer;
BEGIN
  Writeln('x   |   ' + fct_name);
  origy:= cFrm.Height div 2;
  x:= start;
  for i:= 0 to (DIM) do begin
    it:= i;
    x:= it/freq
    tempx:= x;
    FCT(x);
    fPoints[i].Y:= origy + (x * amp);
   Writeln(floatToStr(x)+' | '+ floatToStr((tempx))); //comment out for speed!
  end;
  DrawChart(fPoints, color, size)
END;
  
//main function_p call  
BEGIN
  //calls the proc with a function var
  amp:= 110;
  freq:= 30;   //> is less freq.
  loadForm
  fct1x:= @fct1sin
  fct2x:= @fct2cos
  fct3x:= @fct3eSin
  fct4x:= @fct4e;
  fct5x:= @gauss;
  fct6x:= @logistic_s;
  (*fct_table(40, amp, freq, clred, fct1x, 'Sin(x)');
  fct_table(50, amp, freq, clyellow, fct2x, 'Cos(x)');
  fct_table(30, amp, freq, cllime, fct3x, 'ESin(x)');
  fct_table(30, amp, freq, clblue, fct4x, 'E(x)');
  fct_table(50, amp, freq, clgreen, fct5x, 'exp(sqr(x))');
  fct_table(40, 74, 200, clpurple, fct6x, 'logistic function');*)
  
  {fct_table(50, amp, freq, clred, @fct1sin, 'sin(x)');
  fct_table(50, amp, freq, clred, @fct2sin, '1/3sin(x)');
  fct_table(50, amp, freq, clred, @fct3sin, '1/5sin(x)');
  fct_table(50, amp, freq, clred, @fct4sin, '1/7sin(x)');
  fct_table(50, amp, freq, clred, @fct5sin, '1/9sin(x)');
  fct_table(40, 110, 30, clyellow, @fctdigit, 'sum square digit function');}
  
  fct_table(40, 110, 30, clred, 1, @fctdigit1, 'sum square digit function');
  fct_table(40, 110, 30, clred, 2, @fctdigit2, 'sum square digit function');
  fct_table(40, 110, 30, clred, 3, @fctdigit3, 'sum square digit function');
  fct_table(40, 110, 30, clred, 4, @fctdigit4, 'sum square digit function');
  fct_table(40, 110, 30, clred, 5, @fctdigit5, 'sum square digit function');
  fct_table(40, 110, 30, clyellow, 3, @fctdigit6, 'sum square digit function');
  
  //fct_table(50, amp, freq, clred, @fct2n, '2^x/x!');
 
END.

ref:

  code snippet
  
  set coordinates
  
  xpos:= X div 16 + 1;
  ypos:= Y div 16 + 1;
  lblcoordinates.caption:= format('%d-%d',[xpos, ypos]);