GDI+ 学习记录(16): 贝塞尔曲线 Bezier、Beziers

//画贝塞尔曲线
var
  g: TGPGraphics;
  p: TGPPen;
begin
  g := TGPGraphics.Create(Canvas.Handle);
  p := TGPPen.Create(MakeColor(255,0,0),2);

  g.DrawBezier(p, 11,11, 88,333, 99,0, 222,111); {参数是画笔与 4 个点的坐标}

  p.Free;
  g.Free;
end;


//使用 TGPPoint 或 TGPPointF
var
  g: TGPGraphics;
  p: TGPPen;
const
  points: array[0..3] of TGPPoint = ((x:11;  y:11),
                                     (x:88;  y:333),
                                     (x:99;  y:0),
                                     (x:222; y:111));
begin
  g := TGPGraphics.Create(Canvas.Handle);
  p := TGPPen.Create(MakeColor(255,0,0),2);

  g.DrawBezier(p, points[0], points[1], points[2], points[3]); {用了 4 个常数点}

  p.Free;
  g.Free;
end;


//连续 Bezier 线
var
  g: TGPGraphics;
  p: TGPPen;
  pts: array[0..6] of TGPPoint; //数组元素必须是 3 的倍数加 1
begin
  g := TGPGraphics.Create(Canvas.Handle);
  p := TGPPen.Create(MakeColor(255,0,0),4);

  pts[0].X := 77;  pts[0].Y := 44;
  pts[1].X := 66;  pts[1].Y := 111;
  pts[2].X := 88;  pts[2].Y := 222;
  pts[3].X := 111; pts[3].Y := 88;
  pts[4].X := 132; pts[4].Y := 222;
  pts[5].X := 222; pts[5].Y := 111;
  pts[6].X := 256; pts[6].Y := 11;

  g.DrawBeziers(p, PGPPoint(@pts), Length(pts));

  p.Free;
  g.Free;
end;