Delphi 的绘图功能[1] - PolyBezier、PolyBezierTo

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unit Unit1; interface uses 　Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, 　Dialogs, StdCtrls; type 　TForm1 = class(TForm) 　　Button1: TButton; 　　Button2: TButton; 　　procedure Button1Click(Sender: TObject); 　　procedure Button2Click(Sender: TObject); 　end; var 　Form1: TForm1; implementation {$R *.dfm}

{PolyBezier 至少需要四个点做参数; 不改变画笔的当前位置}

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procedure TForm1.Button1Click(Sender: TObject); var 　pts: array[0..3] of TPoint; begin 　Canvas.Pen.Width := 2; 　Canvas.Pen.Color := clRed; 　pts[0].X := 10; pts[0].Y := 10;　{起点} 　pts[1].X := 60; pts[1].Y := 10;　{控制点1} 　pts[2].X := 10; pts[2].Y := 100; {控制点2} 　pts[3].X := 60; pts[3].Y := 100; {终点} 　Canvas.PolyBezier(pts); 　Canvas.Pen.Width := 1; 　Canvas.Pen.Color := clWhite; 　Canvas.LineTo(ClientWidth, ClientHeight); end;

{PolyBezierTo 最少只需要需要三个点, 它把当前位置当作第一点; 会改变画笔的当前位置}

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procedure TForm1.Button2Click(Sender: TObject); var 　pts: array[1..3] of TPoint; {从 1 开始的, 就 3 个元素} begin 　Canvas.Pen.Width := 2; 　Canvas.Pen.Color := clRed; 　Canvas.MoveTo(10 + 82, 10);　　　　　 {起点} 　//pts[0].X := 10; pts[0].Y := 10; 　pts[1].X := 60 + 82; pts[1].Y := 10;　{控制点1} 　pts[2].X := 10 + 82; pts[2].Y := 100; {控制点2} 　pts[3].X := 60 + 82; pts[3].Y := 100; {终点} 　Canvas.PolyBezierTo(pts); 　Canvas.Pen.Width := 1; 　Canvas.Pen.Color := clBlue; 　Canvas.LineTo(ClientWidth, ClientHeight); end; end.

//效果图:

　　//绘制多条贝塞尔线时, 每条线的终点也是下条线的起点.

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unit Unit1; interface uses 　Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, 　Dialogs, StdCtrls; type 　TForm1 = class(TForm) 　　Button1: TButton; 　　Button2: TButton; 　　procedure Button1Click(Sender: TObject); 　　procedure Button2Click(Sender: TObject); 　end; var 　Form1: TForm1; implementation {$R *.dfm}

{PolyBezier 绘制多条线时, 需要 3*x + 1 个点}

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procedure TForm1.Button1Click(Sender: TObject); var 　pts: array[0..6] of TPoint; begin 　Canvas.Pen.Width := 2; 　Canvas.Pen.Color := clRed; 　pts[0].X := 10; pts[0].Y := 10; 　pts[1].X := 60; pts[1].Y := 10; 　pts[2].X := 10; pts[2].Y := 100; 　pts[3].X := 40; pts[3].Y := 100; 　pts[4].X := 100; pts[4].Y := 10; 　pts[5].X := 55; pts[5].Y := 99; 　pts[6].X := 70; pts[6].Y := 10; 　Canvas.PolyBezier(pts); end;

{PolyBezierTo 绘制多条线时, 需要 3*x 个点}

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procedure TForm1.Button2Click(Sender: TObject); var 　pts: array[1..6] of TPoint; begin 　Canvas.Pen.Width := 2; 　Canvas.Pen.Color := clRed; 　Canvas.MoveTo(10 + 82, 10); 　//pts[0].X := 10; pts[0].Y := 10; 　pts[1].X := 60 + 82; pts[1].Y := 10; 　pts[2].X := 10 + 82; pts[2].Y := 100; 　pts[3].X := 40 + 82; pts[3].Y := 100; 　pts[4].X := 100 + 82; pts[4].Y := 10; 　pts[5].X := 55 + 82; pts[5].Y := 99; 　pts[6].X := 70 + 82; pts[6].Y := 10; 　Canvas.PolyBezierTo(pts); end; end.

//效果图: