再学GDI+[55]: 路径 - Flatten

再学GDI+[55]: 路径 - Flatten2012-05-10 cnblogs 万一通过路径的 Flatten 方法可以把路径中的曲线拉直, 拉直到什么程度是由它的第二个参数（默认0.25）决定的; 它的第一个参数又是一个矩阵变换, 也就是说 Flatten 可以同时进行矩阵变换, 本例没有测试它, 其详情参见:

http://www.cnblogs.com/del/archive/2008/06/20/1226293.html

本例效果图:

代码文件:

unit Unit1;
interface
uses
 Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
 Dialogs, ComCtrls;
type
 TForm1 = class（TForm）
  TrackBar1: TTrackBar;
  procedure FormPaint（Sender: TObject）;
  procedure FormCreate（Sender: TObject）;
  procedure TrackBar1Change（Sender: TObject）;
 end;
var
 Form1: TForm1;
implementation
{$R *.dfm}
uses GDIPOBJ, GDIPAPI;
procedure TForm1.FormCreate（Sender: TObject）;
begin
 TrackBar1.Height := 23;
 TrackBar1.ShowSelRange := False;
 TrackBar1.Min := -5000;
 TrackBar1.Max := 5000;
 TrackBar1.Position := 25;
 TrackBar1.PageSize := 5;
end;
procedure TForm1.FormPaint（Sender: TObject）;
var
 g: TGPGraphics;
 p: TGPPen;
 path: TGPGraphicsPath;
 f: Single;
begin
 g := TGPGraphics.Create（Canvas.Handle）;
 p := TGPPen.Create（aclBlue, 2）;
 path := TGPGraphicsPath.Create;
 path.AddEllipse（20, 20, ClientWidth-40, ClientHeight- 80）;
 f := TrackBar1.Position / 100;
 path.Flatten（nil, f）;
 Text := Format（"%f", [f]）;
 g.DrawPath（p, path）;
 path.Free;
 p.Free;
 g.Free;
end;
procedure TForm1.TrackBar1Change（Sender: TObject）;
begin
 Repaint;
end;
end.