再学GDI+[58]: 路径

本例演示了把路径中的数据保存到一个文本文件, 然后再读出的过程.

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)
　　Button1: TButton;
　　Button2: TButton;
　　procedure FormCreate(Sender: TObject);
　　procedure FormDestroy(Sender: TObject);
　　procedure FormPaint(Sender: TObject);
　　procedure Button1Click(Sender: TObject);
　　procedure Button2Click(Sender: TObject);
　end;
var
　Form1: TForm1;
implementation
{$R *.dfm}
uses GDIPOBJ, GDIPAPI;
const
　FilePath = 'c:\temp\path.txt';
var
　path: TGPGraphicsPath;
　p: TGPPen;
procedure TForm1.FormCreate(Sender: TObject);
var
　pts: array[0..6] of TGPPoint;
　rect: TGPRect;
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;
　path := TGPGraphicsPath.Create;
　path.AddBeziers(PGPPoint(@pts), Length(pts));
　path.GetBounds(rect);
　path.AddEllipse(rect);
　p := TGPPen.Create(aclBlue, 2);
　Button1.Caption := '保存路径数据';
　Button2.Caption := '读取路径数据';
end;
procedure TForm1.FormDestroy(Sender: TObject);
begin
　path.Free;
　p.Free;
end;
procedure TForm1.FormPaint(Sender: TObject);
var
　g: TGPGraphics;
begin
　g := TGPGraphics.Create(Canvas.Handle);
　g.DrawPath(p, path);
　g.Free;
end;
procedure TForm1.Button1Click(Sender: TObject);
var
　points: array of TGPPoint;
　types: array of Byte;
　List: TStringList;
　i: Integer;
begin
　SetLength(points, path.GetPointCount);
　SetLength(types, path.GetPointCount);
　path.GetPathPoints(PGPPoint(points), Length(points));
　path.GetPathTypes(PByte(types), Length(types));
　List := TStringList.Create;
　for i := 0 to Length(points) - 1 do
　　List.Add(Format('%d,%d,%d', [points[i].X, points[i].Y, types[i]]));
　List.SaveToFile(FilePath);
　List.Free;
　Text := FilePath;
end;
procedure TForm1.Button2Click(Sender: TObject);
var
　points: array of TGPPoint;
　types: array of Byte;
　List1,List2: TStringList;
　i: Integer;
begin
　List1 := TStringList.Create;
　List2 := TStringList.Create;
　if not FileExists(FilePath) then Exit;
　List1.LoadFromFile(FilePath);
　SetLength(points, List1.Count);
　SetLength(types, List1.Count);
　for i := 0 to List1.Count - 1 do
　begin
　　if List1[i] = '' then Break;
　　List2.CommaText := List1[i];
　　points[i].X := StrToIntDef(List2[0], 0);
　　points[i].Y := StrToIntDef(List2[1], 0);
　　types[i] := StrToIntDef(List2[2], 0);
　end;
　path.Reset;
　path.Free;
　path := TGPGraphicsPath.Create(PGPPoint(points), PByte(types), List1.Count);
　p.SetColor(aclRed);
　Repaint;
　List1.Free;
　List2.Free;
end;
end.