В-сплайновые кривые - C++ Builder - Ответ 9137636

//---------------------------------------------------------------------------
 
#include <vcl.h>
#pragma hdrstop
 
#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
    : TForm(Owner)
{
}
//---------------------------------------------------------------------------
const count = 4;
TPoint point[count];
double tmin = 0., tmax = 6.;
double step = (tmax-tmin) / (count-1 + count-1);
 
double N(UINT q, UINT k, double t)
{
  if (q == 1)
  {
    if (t >= tmin + step * k && t <= tmin + step * (k + 1))
      return 1;
    else
      return 0;
  }
  else
    return (t - tmin - step * k) / (tmin + step * (k + q + 1) - tmin - step * k) * N(q-1, k, t) +
           (tmin + step * (k + q) - t) / (tmin + step * (k + q) - tmin - step * (k + 1)) * N(q-1, k+1, t);
}
//---------------------------------------------------------------------------
TPoint R(UINT q, double t)
{
  TPoint b = TPoint(0, 0);
  double temp;
  for (UINT i = 0; i < count; i++)
  {
    temp = N(q, i, t);
    b.x += point[i].x * temp;
    b.y += point[i].y * temp;
  }
  return b;
}
//---------------------------------------------------------------------------
void __fastcall TForm1::ButtonClick(TObject *Sender)
{
  Refresh();
  UINT n = count-1, q = n, offset = 500, r = 3;
  TPoint a;
  TColor color = clRed;
  TColor color2 = clBlack;
  double st = 0.00001*1;
  randomize();
  for (UINT i = 0; i < count; i++)
    point[i] = TPoint(random(offset), random(offset));
 
  Canvas->Pen->Color = color2;
  Canvas->TextOutW(point[0].x, point[0].y, 1);
  Canvas->Ellipse(point[0].x - r, point[0].y - r, point[0].x + r, point[0].y + r);
  for (UINT i = 1; i <= n; i++)
  {
    Canvas->TextOutW(point[i].x, point[i].y, i+1);
    Canvas->MoveTo(point[i-1].x, point[i-1].y);
    Canvas->LineTo(point[i].x, point[i].y);
    Canvas->Ellipse(point[i].x - r, point[i].y - r, point[i].x + r, point[i].y + r);
  }
 
  Canvas->Pen->Color = color;
  for(double t = tmin + 0*step; t <= tmax - 0*step; t += st)
  {
    a = R(q, t);
    if (t <= tmin + 2*step || t > tmax - 2*step)
    {
      Canvas->MoveTo(a.x, a.y);
//    Canvas->Pen->Color = color2;
    }
    else
    {
      Canvas->LineTo(a.x, a.y);
//    Canvas->Pen->Color = color;
    }
  }
}
//---------------------------------------------------------------------------