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}


 
   

本例效果图:

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代码文件:

---

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.


 
   

窗体文件:

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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