再學GDI+[71]: 路徑畫刷(11)

RotateTransform、ScaleTransform 等變換

RotateTransform　　{旋轉}
ScaleTransform　　 {縮放}
TranslateTransform {平移}
SetTransform　　　 {綜合的矩陣變換}
ResetTransform　　 {取消變換}本例效果圖:

代碼文件:unit Unit1;
interface
uses
　Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
　Dialogs, ComCtrls, StdCtrls, ExtCtrls;
type
　TForm1 = class(TForm)
　　TrackBar1: TTrackBar;
　　TrackBar2: TTrackBar;
　　procedure FormCreate(Sender: TObject);
　　procedure FormPaint(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 := -50;
　TrackBar1.Max := 50;
　TrackBar1.Position := 0;
　TrackBar2.Min := 1;
　TrackBar2.Max := 10;
　TrackBar2.Position := 10;
end;
procedure TForm1.FormPaint(Sender: TObject);
const
　colors: array[0..3] of TGPColor = (aclRed, aclYellow, aclGreen, aclBlue);
var
　g: TGPGraphics;
　p: TGPPen;
　path: TGPGraphicsPath;
　pb: TGPPathGradientBrush;
　num: Integer;
begin
　g := TGPGraphics.Create(Canvas.Handle);
　p := TGPPen.Create(aclRed);
　path := TGPGraphicsPath.Create;
　path.AddRectangle(MakeRect(50, 20, 120, 100));
　pb := TGPPathGradientBrush.Create(path);
　num := Length(colors);
　pb.SetSurroundColors(@colors, num);
　//pb.ResetTransform;
　pb.RotateTransform(TrackBar1.Position);
　pb.ScaleTransform(TrackBar2.Position / 10, TrackBar2.Position / 10);
　g.FillPath(pb, path);
　g.DrawPath(p, path);
　pb.Free;
　path.Free;
　p.Free;
　g.Free;
end;
procedure TForm1.TrackBar1Change(Sender: TObject);
begin
　Repaint;
end;
procedure TForm1.TrackBar2Change(Sender: TObject);
begin
　Repaint;
end;
end.

窗體文件:object Form1: TForm1
　Left = 0
　Top = 0
　Caption = 'Form1'
　ClientHeight = 165
　ClientWidth = 222
　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 = 13
　　Top = 136
　　Width = 100
　　Height = 23
　　ShowSelRange = False
　　TabOrder = 0
　　OnChange = TrackBar1Change
　end
　object TrackBar2: TTrackBar
　　Left = 110
　　Top = 134
　　Width = 100
　　Height = 23
　　ShowSelRange = False
　　TabOrder = 1
　　OnChange = TrackBar2Change
　end
end