画框输出三角函数-白红宇

画框输出三角函数

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发布时间：2019-06-09

本文共 2828 字，大约阅读时间需要 9 分钟。

unit Unit1;interfaceuses  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,  Dialogs, Menus, ExtCtrls;type  TForm1 = class(TForm)    PaintBox1: TPaintBox;    MainMenu1: TMainMenu;    N1: TMenuItem;    N2: TMenuItem;    sin1: TMenuItem;    cos1: TMenuItem;    cls1: TMenuItem;    procedure FormPaint(Sender: TObject);    procedure sin1Click(Sender: TObject);    procedure cos1Click(Sender: TObject);    procedure N2Click(Sender: TObject);    procedure cls1Click(Sender: TObject);  private    { Private declarations }  public    { Public declarations }  end;var  Form1: TForm1;implementation{$R *.dfm}procedure TForm1.cls1Click(Sender: TObject);        //清除sin和cos曲线begin  paintbox1.Refresh;end;procedure TForm1.cos1Click(Sender: TObject);        //画出cos函数曲线var  oldx, oldy, t: integer;  xt, yt: real;begin  oldx := round(form1.ClientWidth / 2);  oldy := round(form1.ClientHeight / 2);  for t := -oldx to oldx do    begin      xt := t / 20;      yt := cos(xt);      paintbox1.Canvas.Pixels[t + oldx, oldy + round(yt * 20)] := clblack;    end;end;procedure TForm1.FormPaint(Sender: TObject);        //当窗体刷新时执行此事件var  oldx, oldy, xt, yt: integer;  st: real;  rect1: trect;begin  with paintbox1 do    begin      top := 0;      left := 0;      width := form1.ClientWidth;      height := form1.ClientHeight;      canvas.Pen.Color := clblack;    end;  oldx := round(form1.ClientWidth / 2);             //获得窗体的原点x坐标  oldy := round(form1.ClientHeight / 2);            //获得窗体的原点y坐标  paintbox1.Canvas.MoveTo(oldx,0);  paintbox1.Canvas.LineTo(oldx,paintbox1.Height);   //画y轴的轴线  paintbox1.Canvas.MoveTo(0,oldy);  paintbox1.Canvas.LineTo(paintbox1.Width,oldy);    //画x轴的轴线  for xt := -9 to 9 do                              //画出x轴的坐标    if xt <> 0 then      begin        st := xt * 10 * pi;        paintbox1.Canvas.MoveTo(oldx + round(st),oldy-1);        paintbox1.Canvas.LineTo(oldx + round(st),oldy);        paintbox1.Canvas.TextOut(oldx + round(st) - 10, oldy + 1, inttostr(xt) + '/2π');      end;  for yt := -9 to 9 do                              //画出y轴的坐标    if yt <> 0 then      begin        st := yt * 20;        paintbox1.Canvas.MoveTo(oldx + 1,oldy + round(st));        paintbox1.Canvas.LineTo(oldx,oldy + round(st));        paintbox1.Canvas.TextOut(oldx - 20, oldy + round(st), inttostr(yt));      end;end;procedure TForm1.N2Click(Sender: TObject);          //退出begin  form1.close;end;procedure TForm1.sin1Click(Sender: TObject);        //画出sin曲线var  oldx, oldy, t: integer;  xt, yt: real;begin  oldx := round(form1.ClientWidth / 2);  oldy := round(form1.ClientHeight / 2);  for t := -oldx to oldx do    begin      xt := t / 20;      yt := sin(xt);      paintbox1.Canvas.Pixels[t + oldx, oldy + round(yt * 20)] := clblack;    end;end;end.