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再学GDI+[79]: 区域(8) - Transform - 区域的 Matrix 变换

时间:2012-05-23 | 栏目:Delphi教程 | 点击:

矩阵变换(Matrix)功能很强大, 这里只是旋转了一下.

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;
  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.

窗体文件: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

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