再学 GDI+[31]: TGPPen - 设置端点连接方式 - SetLineJoin

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)

    ListBox1: TListBox;

    procedure FormCreate(Sender: TObject);

    procedure FormPaint(Sender: TObject);

    procedure ListBox1Click(Sender: TObject);

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



uses GDIPOBJ, GDIPAPI, TypInfo;



procedure TForm1.FormCreate(Sender: TObject);

var

  i: Integer;

begin

  for i := 0 to 3 do

    ListBox1.Items.Add(GetEnumName(TypeInfo(TLineJoin),i));

  ListBox1.ItemIndex := 0;

end;



procedure TForm1.FormPaint(Sender: TObject);

const

  PtArr: array[0..2] of TGPPoint = ((X:50;Y:150), (X:240;Y:30), (X:240;Y:150));

var

  g: TGPGraphics;

  p: TGPPen;

begin

  g := TGPGraphics.Create(Canvas.Handle);

  p := TGPPen.Create(aclBlueViolet, 28);

  p.SetLineJoin(TLineJoin(ListBox1.ItemIndex));



  g.DrawPolygon(p, PGPPoint(@PtArr), Length(PtArr));



  p.Free;

  g.Free;

end;



procedure TForm1.ListBox1Click(Sender: TObject);

begin

  Repaint;

end;



end.


 
   

窗体文件:

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object Form1: TForm1

  Left = 0

  Top = 0

  Caption = 'Form1'

  ClientHeight = 177

  ClientWidth = 382

  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 ListBox1: TListBox

    Left = 277

    Top = 0

    Width = 105

    Height = 177

    Align = alRight

    ItemHeight = 13

    TabOrder = 0

    OnClick = ListBox1Click

    ExplicitHeight = 173

  end

end


 
   

端点连接方式枚举:

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LineJoin = (

  LineJoinMiter,

  LineJoinBevel,

  LineJoinRound,

  LineJoinMiterClipped

);

TLineJoin = LineJoin;