再学GDI+[47]: 路径

本例效果图:

代码文件: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;
procedure TForm1.FormCreate(Sender: TObject);
begin
　CheckBox1.Caption := '闭合路径';
　CheckBox2.Caption := '填充路径';
end;
procedure TForm1.FormPaint(Sender: TObject);
var
　g: TGPGraphics;
　path: TGPGraphicsPath;
　p: TGPPen;
　b: TGPBrush;
　pt1,pt2,pt3: TGPPoint;
begin
　pt1 := MakePoint(0, ClientHeight div 2);
　pt2 := MakePoint(ClientWidth div 2, 0);
　pt3 := MakePoint(ClientWidth, ClientHeight div 2);
　g := TGPGraphics.Create(Canvas.Handle);
　path := TGPGraphicsPath.Create;
　path.AddLine(pt1, pt2);
　path.AddLine(pt2, pt3);
　if CheckBox1.Checked then path.CloseFigure;
　p := TGPPen.Create(aclRed, 2);
　b := TGPSolidBrush.Create(aclYellow);
　if CheckBox2.Checked then g.FillPath(b, path);
　g.DrawPath(p, path);
　b.Free;
　p.Free;
　path.Free;
　g.Free;
end;
procedure TForm1.CheckBox1Click(Sender: TObject);
begin
　Repaint;
end;
procedure TForm1.CheckBox2Click(Sender: TObject);
begin
　Repaint;
end;
end.