再学GDI+[78]: 区域(7)

本例效果图:

代码文件:unit Unit1;
interface
uses
　Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
　Dialogs, StdCtrls, ComCtrls;
type
　TForm1 = class(TForm)
　　TrackBar1: TTrackBar;
　　TrackBar2: TTrackBar;
　　procedure FormPaint(Sender: TObject);
　　procedure FormCreate(Sender: TObject);
　　procedure TrackBar1Change(Sender: TObject);
　　procedure TrackBar2Change(Sender: TObject);
　end;
var
　Form1: TForm1;
implementation
{$R *.dfm}
uses GDIPOBJ, GDIPAPI;
procedure TForm1.FormCreate(Sender: TObject);
begin
　TrackBar1.Min := -ClientWidth div 2;
　TrackBar1.Max := ClientWidth div 2;
　TrackBar2.Min := -ClientHeight div 2;
　TrackBar2.Max := ClientHeight div 2;
　DoubleBuffered := True;
end;
procedure TForm1.FormPaint(Sender: TObject);
var
　g: TGPGraphics;
　b: TGPBrush;
　rgn: TGPRegion;
begin
　g := TGPGraphics.Create(Canvas.Handle);
　b := TGPHatchBrush.Create(HatchStyleShingle, aclSilver, aclDarkCyan);
　rgn := TGPRegion.Create(MakeRect(40, 40, ClientWidth-100, ClientHeight-100));
　rgn.Translate(TrackBar1.Position, TrackBar2.Position);
　g.FillRegion(b, rgn);
　rgn.Free;
　b.Free;
　g.Free;
end;
procedure TForm1.TrackBar1Change(Sender: TObject);
begin
　Repaint;
end;
procedure TForm1.TrackBar2Change(Sender: TObject);
begin
　Repaint;
end;
end.