再学 GDI+[58]: 路径 - 保存与读取路径数据

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.

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本例效果图:

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代码文件:

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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 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.


 
   

窗体文件:

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object Form1: TForm1

  Left = 0

  Top = 0

  Caption = 'Form1'

  ClientHeight = 147

  ClientWidth = 224

  Color = clBtnFace

  Font.Charset = DEFAULT_CHARSET

  Font.Color = clWindowText

  Font.Height = -11

  Font.Name = 'Tahoma'

  Font.Style = []

  OldCreateOrder = False

  Position = poDesktopCenter

  OnCreate = FormCreate

  OnDestroy = FormDestroy

  OnPaint = FormPaint

  PixelsPerInch = 96

  TextHeight = 13

  object Button1: TButton

    Left = 13

    Top = 114

    Width = 94

    Height = 25

    Caption = 'Button1'

    TabOrder = 0

    OnClick = Button1Click

  end

  object Button2: TButton

    Left = 117

    Top = 114

    Width = 94

    Height = 25

    Caption = 'Button2'

    TabOrder = 1

    OnClick = Button2Click

  end

end