再学 GDI+[71]: 路径画刷(11) - RotateTransform、ScaleTransform 等变换

RotateTransform    {旋转}
ScaleTransform     {缩放}
TranslateTransform {平移}
SetTransform       {综合的矩阵变换}
ResetTransform     {取消变换}

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.

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