矩陣變換(Matrix)功能很強大, 這裡只是旋轉了一下.
本例效果圖:
代碼文件:unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, ComCtrls;
type
TForm1 = class(TForm)
TrackBar1: TTrackBar;
procedure FormPaint(Sender: TObject);
procedure FormCreate(Sender: TObject);
procedure TrackBar1Change(Sender: TObject);
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
uses GDIPOBJ, GDIPAPI;
procedure TForm1.FormCreate(Sender: TObject);
begin
TrackBar1.Min := -45;
TrackBar1.Max := 45;
DoubleBuffered := True;
end;
procedure TForm1.FormPaint(Sender: TObject);
var
g: TGPGraphics;
b: TGPBrush;
rgn: TGPRegion;
Matrix: TGPMatrix;
begin
g := TGPGraphics.Create(Canvas.Handle);
b := TGPHatchBrush.Create(HatchStyleMin, aclSilver, aclChocolate);
rgn := TGPRegion.Create(MakeRect(40, 40, ClientWidth-80, ClientHeight-100));
Matrix := TGPMatrix.Create;
Matrix.Rotate(TrackBar1.Position);
rgn.Transform(Matrix);
g.FillRegion(b, rgn);
Matrix.Free;
rgn.Free;
b.Free;
g.Free;
end;
procedure TForm1.TrackBar1Change(Sender: TObject);
begin
Repaint;
end;
end.
窗體文件:object Form1: TForm1
Left = 0
Top = 0
Caption = 'Form1'
ClientHeight = 174
ClientWidth = 197
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 TrackBar1: TTrackBar
Left = 0
Top = 151
Width = 193
Height = 23
ShowSelRange = False
TabOrder = 0
OnChange = TrackBar1Change
end
end
