再学 GDI+[47]: 路径 CloseFigure

本例效果图:

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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.

窗体文件:

---

object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 179
  ClientWidth = 243
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  Position = poDesktopCenter
  OnCreate = FormCreate
  OnPaint = FormPaint
  PixelsPerInch = 96
  TextHeight = 13
  object CheckBox1: TCheckBox
    Left = 44
    Top = 145
    Width = 97
    Height = 17
    Caption = 'CheckBox1'
    TabOrder = 0
    OnClick = CheckBox1Click
  end
  object CheckBox2: TCheckBox
    Left = 132
    Top = 145
    Width = 97
    Height = 17
    Caption = 'CheckBox2'
    TabOrder = 1
    OnClick = CheckBox2Click
  end
end