再學GDI+[52]: 路徑 - Reverse、Reset

本例效果圖:

代碼文件:unit Unit1;
interface
uses
　Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
　Dialogs, StdCtrls;
type
　TForm1 = class(TForm)
　　CheckBox1: TCheckBox;
　　CheckBox2: TCheckBox;
　　procedure FormCreate(Sender: TObject);
　　procedure FormPaint(Sender: TObject);
　　procedure CheckBox1Click(Sender: TObject);
　　procedure CheckBox2Click(Sender: TObject);
　end;
var
　Form1: TForm1;
implementation
{$R *.dfm}
uses GDIPOBJ, GDIPAPI;
var pts: array[0..6] of TGPPoint;
procedure TForm1.FormCreate(Sender: TObject);
begin
　pts[0].X := 10;　pts[0].Y := 50;
　pts[1].X := 40;　pts[1].Y := 90;
　pts[2].X := 80;　pts[2].Y := 10;
　pts[3].X := 110;　pts[3].Y := 50;
　pts[4].X := 140;　pts[4].Y := 10;
　pts[5].X := 180; pts[5].Y := 90;
　pts[6].X := 210; pts[6].Y := 50;
　CheckBox1.Caption := '翻轉路徑中的點';
　CheckBox2.Caption := '清空路徑中的點';
end;
procedure TForm1.FormPaint(Sender: TObject);
var
　g: TGPGraphics;
　p: TGPPen;
　path: TGPGraphicsPath;
　PathPts: array of TGPPoint;
　i: Integer;
begin
　g := TGPGraphics.Create(Canvas.Handle);
　p := TGPPen.Create(aclRed, 2);
　path := TGPGraphicsPath.Create;
　path.AddBeziers(PGPPoint(@pts), Length(pts));
　if CheckBox1.Checked then path.Reverse;
　if CheckBox2.Checked then path.Reset;
　{Reset 時, 會清空 PathPoints 和 PathTypes 數組並將 FillMode 設置為 FillModeAlternate}
　SetLength(PathPts, path.GetPointCount);
　path.GetPathPoints(PGPPoint(PathPts), Length(PathPts));
　Canvas.Pen.Color := clGray;
　for i := Low(PathPts) to High(PathPts) do
　　Canvas.TextOut(PathPts[i].X, PathPts[i].Y, IntToStr(i+1));
　g.DrawPath(p, path);
　path.Free;
　p.Free;
　g.Free;
end;
procedure TForm1.CheckBox1Click(Sender: TObject);
begin
　Repaint;
end;
procedure TForm1.CheckBox2Click(Sender: TObject);
begin
　Repaint;
end;
end.