SystemCos (Delphi)
Description
This example displays the cosine of any value between 0 and 12. Since the scrollbar position is an integer between the scrollbar min and max, multiply the range and divide the position to regulate it. With the scrollbar selected, use the left and right buttons to change the position by 1E-6. You can also use the Dec function to decrement (or increment) by a specific amount.
Code
procedure TForm1.Button1Click(Sender: TObject);
var
new : Integer;
begin
new := ScrollBar1.Position;
System.Dec(new, Round(StrToFloat(Edit3.Text)*1000000));
ScrollBar1.Position := new;
Edit1.Text := FloatToStr(ScrollBar1.Position/1000000);
Edit2.Text := FloatToStr(Cos(ScrollBar1.Position/1000000));
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
ScrollBar1.Max := Round(Pi * 4000000); // 4 * Pi
end;
procedure TForm1.ScrollBar1Scroll(Sender: TObject; ScrollCode: TScrollCode;
var ScrollPos: Integer);
begin
Edit1.Text := FloatToStr(ScrollPos/1000000);
Edit2.Text := FloatToStr(Cos(ScrollPos/1000000));
end;
Uses
- System.Cos ( fr | de | ja )
- System.Round ( fr | de | ja )
- System.Dec ( fr | de | ja )