void TForm1::ReSampleEdge(TStringList  *contour_x,TStringList  *contour_y)
{  int i=0;
   int x,y;
   int dx,dy;
   int total_edpt=contour_x->Count;
   double theta=0; //目前所在點的夾角
   double delta_theta=PI/4;//標準夾角差為45
   int n=0;//
   Image1->Canvas->Pen->Color=clRed;
   Image1->Canvas->Pen->Width=1;
    for(i=0;iStrings[i]);
        y=StrToInt(contour_y->Strings[i]);
        if(i==0)
        {
        Image1->Canvas->Pixels[x-1][y-1]=clBlue;
        Image1->Canvas->Pixels[x][y-1]=clBlue;
        Image1->Canvas->Pixels[x 1][y-1]=clBlue;
        Image1->Canvas->Pixels[x-1][y]=clBlue;
        Image1->Canvas->Pixels[x][y]=clBlue;
        Image1->Canvas->Pixels[x 1][y]=clBlue;
        Image1->Canvas->Pixels[x-1][y 1]=clBlue;
        Image1->Canvas->Pixels[x][y 1]=clBlue;
        Image1->Canvas->Pixels[x 1][y 1]=clBlue;
        }            dx=x-cx;
        dy=y-cy;
        theta=(atan2(dx,-dy)>=0)?atan2(dx,-dy):(atan2(dx,-dy) 2*PI);
//        ShowMessage(FloatToStr(theta*180/PI));
//        ShowMessage(FloatToStr(n*delta_theta*180/PI));
        if(fabs(fabs(sin(theta))-fabs(sin(n*delta_theta)))<0.1)
        {
         Image1->Canvas->MoveTo(cx,cy);
         Image1->Canvas->LineTo(x,y);
         ShowMessage(FloatToStr(theta*180/PI));
         ShowMessage(FloatToStr(n*delta_theta*180/PI));
         Sleep(100);
         Application->ProcessMessages();
         n  ;
         }
    }
   ShowMessage("End");    }

比如說:我要取圖形邊緣上取一些點 該點與圖形質心連線的符合某些角度 (ex: 從0、45、90、135、180、225、270、315、360 ) 發現取出來的角度的值會圖形大小改變也就算了 (比如:44.99) 有時候還會取到40度的值 誤差太大了->請問各位大大該如何解決這一個問題

找到問題所在 改為 if((fabs(theta-(n*delta_theta))==0)||(fabs(theta-(n*delta_theta))