Delphi自绘网格坐标系正弦波演示

刺骨的言语ヽ痛彻心扉 2023-10-08 10:41 24阅读 0赞

procedure TForm1.Button1Click(Sender: TObject);
    var
      x, l,i,j: 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;
    
      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，这里将振幅设为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;
    
    // 绘制直角坐标系上显示的字符
      with Image1.Canvas do
      begin
        Font.Name    := 'Symbol';
        Font.Size    := 8;
        Font.Color   := clBlack;
        TextOut(2,Image1.Height div 2+1, '-2p');
        TextOut(Image1.Width div 4,Image1.Height div 2+1, '-p');
        TextOut(Image1.Width-20,Image1.Height div 2+1, '2p');
        TextOut(Image1.Width div 2+(Image1.Width div 4),Image1.Height div 2+1, 'p');
        TextOut(Image1.Width div 2+5,0, '2');
        TextOut(Image1.Width div 2+5,Image1.Height div 4+1, '1');
        TextOut(Image1.Width div 2+2,Image1.Height-12, '-2');
        TextOut(Image1.Width div 2+2,Image1.Height div 2+Image1.Height div 4-12, '-1');
      end;
    
    
      //画竖网格线
       j:=0;
      for I := 0 to Image1.Width div 15 do
      begin
        with Image1.Canvas do
        begin
          Pen.Color := clLtGray;
          Brush.Style := bsSolid;
          MoveTo(j,0 );
          LineTo(j,Image1.Height);
          {画上坐标数字}
         // TextOut(j-5,Image1.Height-13, IntToStr(i));
        end;
        Form1.Canvas.TextOut(Image1.Left+j-5,Image1.Top+Image1.Height+5, IntToStr(i));   {把坐标数字画到窗体上相应位置，以免影响正弦波显示}
        Inc(j,15);
      end;
       //画横网格线
       j:=15;
      for I := 0 to Image1.Height div 15 do
      begin
        with Image1.Canvas do
        begin
          Pen.Color := clLtGray;
          Brush.Style := bsSolid;
          MoveTo(0,j );
          LineTo(Image1.Width,j);
        end;
        Form1.Canvas.TextOut(Image1.Left-15,Image1.Top+j-8, IntToStr(i+1));   {把坐标数字画到窗体上相应位置}
        Inc(j,15);
      end;
    
      {下面的语句用于绘制直角坐标系x,y轴,后画x,y axis的原因是部分线条会被画网格线条覆盖}
      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); {留下底部15像素做为坐标文字位置 }
      Image1.Canvas.LineTo((Image1.Width div 2), 0); {绘制函数图像Y轴}
    
    end;

效果截图

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3doNDQ1MzA2_size_16_color_FFFFFF_t_70][]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3doNDQ1MzA2_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20191212135557204.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3doNDQ1MzA2,size_16,color_FFFFFF,t_70