再学 GDI+[30]: TGPPen - 用画刷定义的画笔

本例效果图:

---

代码文件:

---

unit Unit1;



interface



uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, StdCtrls, ExtCtrls;



type

  TForm1 = class(TForm)

    RadioGroup1: TRadioGroup;

    procedure FormCreate(Sender: TObject);

    procedure FormPaint(Sender: TObject);

    procedure RadioGroup1Click(Sender: TObject);

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



uses GDIPOBJ,GDIPAPI;



procedure TForm1.FormCreate(Sender: TObject);

begin

  RadioGroup1.Caption := '制作画笔的画刷';

  RadioGroup1.Items.CommaText := '实心画刷,阴影画刷,纹理画刷,渐变画刷';

  RadioGroup1.ItemIndex := 0;

end;



procedure TForm1.FormPaint(Sender: TObject);

var

  g: TGPGraphics;

  p: TGPPen;

  img: TGPImage;

  b: TGPBrush;

begin

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

  img := TGPImage.Create('c:\temp\small.jpg'); {文件要存在}



  case RadioGroup1.ItemIndex of

    0: b := TGPSolidBrush.Create(aclRed);

    1: b := TGPHatchBrush.Create(HatchStyleSolidDiamond, aclYellow, aclCornflowerBlue);

    2: b := TGPTextureBrush.Create(img);

    3: b := TGPLinearGradientBrush.Create(

         MakePoint(0,0),

         MakePoint(ClientWidth - RadioGroup1.Width, ClientHeight),

         aclYellow,

         aclRed

       );

  end;



  p := TGPPen.Create(b, 24);



  g.DrawEllipse(p, 30, 30, ClientWidth-RadioGroup1.Width-60, ClientHeight-60);

  g.DrawLine(p, 0, 0, ClientWidth-RadioGroup1.Width, ClientHeight);



  img.Free;

  b.Free;

  p.Free;

  g.Free;

end;



procedure TForm1.RadioGroup1Click(Sender: TObject);

begin

  Repaint;

end;



end.


 
   

窗体文件:

---

object Form1: TForm1

  Left = 0

  Top = 0

  Caption = 'Form1'

  ClientHeight = 206

  ClientWidth = 339

  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 RadioGroup1: TRadioGroup

    Left = 248

    Top = 0

    Width = 91

    Height = 206

    Align = alRight

    Caption = 'RadioGroup1'

    TabOrder = 0

    OnClick = RadioGroup1Click

  end

end