再学 GDI+[27]: TGPPen - 画笔样式 - SetDashStyle

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, ExtCtrls;



type

  TForm1 = class(TForm)

    ComboBox1: TComboBox;

    procedure FormCreate(Sender: TObject);

    procedure FormPaint(Sender: TObject);

    procedure ComboBox1Change(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 5 do

    ComboBox1.Items.Add(GetEnumName(TypeInfo(TDashStyle), i));

  ComboBox1.ItemIndex := 0;

end;



procedure TForm1.FormPaint(Sender: TObject);

var

  g: TGPGraphics;

  p: TGPPen;

begin

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

  g.Clear($FFFFFFFF);

  p := TGPPen.Create(aclLimeGreen, 10);



  p.SetDashStyle(TDashStyle(ComboBox1.ItemIndex));

  g.DrawLine(p, 0, 0, ClientWidth, ClientHeight);



  p.Free;

  g.Free;

end;



procedure TForm1.ComboBox1Change(Sender: TObject);

begin

  Repaint;

end;



end.


 
   

窗体文件:

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object Form1: TForm1

  Left = 0

  Top = 0

  Caption = 'Form1'

  ClientHeight = 167

  ClientWidth = 242

  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 ComboBox1: TComboBox

    Left = 89

    Top = 8

    Width = 145

    Height = 21

    ItemHeight = 13

    TabOrder = 0

    Text = 'ComboBox1'

    OnChange = ComboBox1Change

  end

end


 
   

画笔样式枚举的定义:

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DashStyle = (

  DashStyleSolid,      {指定实线}

  DashStyleDash,       {指定由划线段组成的直线}

  DashStyleDot,        {指定由点构成的直线}

  DashStyleDashDot,    {指定由重复的划线点图案构成的直线}

  DashStyleDashDotDot, {指定由重复的划线点点图案构成的直线}

  DashStyleCustom      {指定用户定义的自定义划线段样式}

);

TDashStyle = DashStyle;