Delphi实例之绘制正弦函数图像

Delphi实例之绘制正弦函数图像

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, ExtCtrls;

type
TForm1 = class(TForm)
Image1: TImage;
Button1: TButton;
Label1: TLabel;
Label2: TLabel;
Label3: TLabel;
Label4: TLabel;
Label5: TLabel;
Label6: TLabel;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
var
x,l:Integer;
y,a:double;
begin
Image1.Picture.Bitmap:=TBitMap.Create;
Image1.Picture.Bitmap.Width:=Image1.Width;
Image1.Picture.Bitmap.Height:=Image1.Height;
l:=Image1.Picture.Bitmap.Width;
{下面的语句用于绘制直角坐标系}
Image1.Canvas.MoveTo(0,(Image1.Height div 2));
Image1.Canvas.Pen.Color:=clBlue;
Image1.Canvas.LineTo(Image1.Width,(Image1.Height div 2));{绘制函数图像X轴}
Image1.Canvas.MoveTo((Image1.Width div 2),Image1.Height);
Image1.Canvas.LineTo((Image1.Width div 2),0);{绘制函数图像Y轴}
for x:=0 to l do
begin
a:=(x/l)*2*Pi;{角度化弧度}
y:=sin(2*a);{为了加强美观效果，这里讲振幅设为2}
y:=y*(Image1.Picture.Bitmap.Height/2);
y:=y+(Image1.Picture.Bitmap.Height/2);
Image1.Picture.Bitmap.Canvas.Brush.Style:=bsSolid;
Image1.Picture.Bitmap.Canvas.Pixels[Trunc(x),Trunc(y)]:=clRed;{当然也可以用LineTo过程来实现，但是要注意设置Pen.Width到合适的值}
end;
label1.Visible:=true;
Label2.Visible:=true;
label3.Visible:=true;
Label4.Visible:=true;
label5.Visible:=true;
Label6.Visible:=true;
end;

end.