Построение графика

setviewport

program lb10;
uses graph, crt;
const a=0; b=2*pi; h=0.1; h1=20; x0=60; y0=240; m=50;
var driver, d2, mode, x1, y1: integer;
    x,y:real;
 function f(x:real):real;
 begin
 f:=exp(-x)*sin(8*x)+1;
 end;
begin clrscr;
driver:=detect;
initgraph(driver,mode,'C:\TP7\TP\BGI');
setviewport(600,600,800,800,clipoff);
setcolor(5);
line(20,y0,600,y0);
line(x0,440,x0,20);
x:=a; x1:=x0+trunc(m*x);
y:=f(x); y1:=y0-trunc(m*y);
moveto(x1,y1);
while x<=6 do begin
y:=f(x); y1:=y0-trunc(m*y);
lineto(x1,y1);
x1:=x1+h1; x:=x+h;
end;
outtextxy(200,320,'GRAFIK ');
end.

uses graph;
type
  TViewArea = record
    sxc, syc: Integer;
    xc, yc, mx, my: Real;
    xlg, ylg: Boolean;
  end;
function Lg(x: Real): Real;
const Ln10=2.302585099405;
begin
  Lg:=Ln(x)/Ln10;
end;
procedure InitVU(var v: TViewArea;
  xmin, ymin, xmax, ymax: Real;
  sxmin, symin, sxmax, symax: Integer;
  xlog, ylog: Boolean);
var t: Real;
begin
  with v do begin
    xlg:=xlog; ylg:=ylog;
    sxc:=sxmin+(sxmax-sxmin) div 2;
    syc:=symin+(symax-symin) div 2;
    if xlg then begin
      xmin:=Lg(xmin); xmax:=Lg(xmax);
    end;
    if ylg then begin
      ymin:=Lg(ymin); ymax:=Lg(ymax);
    end;
    t:=xmax-xmin; xc:=xmin+t/2; mx:=(sxmax-sxmin)/t;
    t:=ymax-ymin; yc:=ymin+t/2; my:=(symin-symax)/t; 
  end;
end;
function GetSX(const v: TViewArea; x: Real): Integer;
begin
  with v do begin if xlg then x:=Lg(x); GetSX:=sxc+Trunc(mx*(x-xc)); end;
end;
function GetSY(const v: TViewArea; y: Real): Integer;
begin
  with v do begin if ylg then y:=Lg(y); GetSY:=syc+Trunc(my*(y-yc)); end;
end;
function f(x: Real): Real;
begin
  f:=exp(-x)*Sin(8*x)+1;
end;
const
  vx1=40; vy1=100; vx2=200; vy2=200; LeftMargin=8*3; vwx=vx2-vx1-LeftMargin;
  xmn=0.1; xmx=2.1; mm=2;
procedure Draw;
var
  i, j, k: Integer;
  x, y, xmin, ymin, xmax, ymax: Real;
  v: TViewArea;
  s: String;
begin
  ymin:=f(xmn); ymax:=ymin;
  for i:=1 to vwx do begin
    y:=f(xmn+i*(xmx-xmn)/vwx);
    if ymin>y then ymin:=y;
    if ymax<y then ymax:=y;
  end;
  xmin:=0; xmax:=2.4;
  InitVU(v,xmin,ymin,xmax,ymax,LeftMargin,2,vx2-vx1,vy2-vy1-2,False,True);
  SetColor(Blue);
  k:=GetSX(v,0);
  i:=GetSY(v,ymin); MoveTo(k-3,i); LineRel(5,0); Str(ymin:3:1,s); OutTextXY(0,i-8,s);
  i:=GetSY(v,ymax); MoveTo(k-3,i); LineRel(5,0); Str(ymax:3:1,s); OutTextXY(0,i,s);
  i:=GetSY(v,1);    MoveTo(k-3,i); LineRel(5,0); OutTextXY(0,i-4,' 1');
  Line(k,0,k,vy2-vy1); Line(k,i,vx2-vx1,i);
  for j:=0 to 2 do begin
    k:=GetSX(v,j);
    MoveTo(k,i-3); LineRel(0,5); MoveRel(2,0); OutText(Chr(Ord('0')+j));
  end;
  SetColor(White);
  MoveTo(GetSX(v,xmn),GetSY(v,f(xmn)));
  for i:=1 to Trunc(vwx*mm) do begin
    x:=xmn+i*(xmx-xmn)/vwx/mm;
    LineTo(GetSX(v,x),GetSY(v,f(x)));
  end;
end;
var gd, gm, gr: Integer;
begin
  gd:=Detect; InitGraph(gd,gm,''); gr:=GraphResult;
  if gr<>0 then begin
    WriteLn('*** Error: ',GraphErrorMsg(gr)); Halt(1);
  end;
  SetFillStyle(SolidFill,Green);
  Bar(vx1,vy1,vx2,vy2);
  SetViewPort(vx1,vy1,vx2,vy2,ClipOff);
  Draw;
  Write('Press Enter...'); ReadLn;
  CloseGraph;
end.