Работа с графикой

#include <vcl.h>
#pragma hdrstop
 
#include "Unit1.h"
#include <math.h>
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
    : TForm(Owner)
{
}
 float f(float x)
{
    return pow(x,5)-x-0.2;
}
//---------------------------------------------------------------------------
    void TForm1::Grafik()
  {
    Image1->Canvas->FillRect(Rect(0,0,Image1->Width,Image1->Height));
      float x1,x2;
      float y1,y2;
      float x;
      float y;
      float dx;
      int l,b;
      int w,h;
      float mx,my;
      int x0,y0;
      l=10;
      b=Image1->ClientHeight-20;
      h=Image1->ClientHeight-40;
      w=Width-20;
      x1=StrToInt(Edit1->Text);
      x2=StrToFloat(Edit2->Text);
      dx=0.0001;
      x=x1;
      y1=f(x);
      y2=f(x);
      do
      {
          y=f(x);
          if (y<y1)y1=y;
          if (y>y2)y2=y;
          x+=dx;
      }
      while(x<=x2);
      my=(float)h/abs(y2-y1);
      mx=w/abs(x2-x1);
      x0=l+abs(x1*mx);
      y0=b-abs(y1*my);
      Image1->Canvas->MoveTo(x0,b);
      Image1->Canvas->LineTo(x0,b-h);
      Image1->Canvas->MoveTo(1,y0);
      Image1->Canvas->LineTo(1+w,y0);
      Image1->Canvas->TextOutA(x0+5,b-h,FormatFloat("0.000",y2));
      Image1->Canvas->TextOutA(x0+5,b,FormatFloat("0.000",y1));
      Image1->Canvas->TextOutA(280,180,"f(x)");
      x=x1;
      do
      {
          y=f(x);
          Image1->Canvas->Pixels[x0+x*mx][y0-y*my]=clBlue;
          x+=dx;
      }
      while(x<=x2);
  }
 
 
void __fastcall TForm1::Button2Click(TObject *Sender)
{
    Edit1->Text="";
    Edit2->Text="";
    Image1->Canvas->FillRect(Rect(0,0,Image1->Width,Image1->Height));
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Button1Click(TObject *Sender)
{
    Grafik();
 
}
//---------------------------------------------------------------------------