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