再学 GDI+[63]: 路径画刷(3) - SetFocusScales、GetFocusScales

本例效果图:

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代码文件:

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unit Unit1;



interface



uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, StdCtrls, CheckLst, ExtCtrls, TeCanvas, ComCtrls;



type

  TForm1 = class(TForm)

    TrackBar1: TTrackBar;

    TrackBar2: TTrackBar;

    procedure FormCreate(Sender: TObject);

    procedure FormDestroy(Sender: TObject);

    procedure FormPaint(Sender: TObject);

    procedure TrackBar1Change(Sender: TObject);

    procedure TrackBar2Change(Sender: TObject);

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



uses GDIPOBJ, GDIPAPI;



var

  rect: TGPRect;

  pb: TGPPathGradientBrush;



procedure TForm1.FormCreate(Sender: TObject);

var

  path: TGPGraphicsPath;

  ColorSurround: TGPColor;

  num: Integer;

begin

  rect := MakeRect(10, 10, ClientWidth-40, ClientHeight-40);

  path := TGPGraphicsPath.Create;

  path.AddEllipse(rect);



  pb := TGPPathGradientBrush.Create(path);

  pb.SetCenterColor(aclLime);



  ColorSurround := aclBlack;

  num := 1;

  pb.SetSurroundColors(@ColorSurround, num);



  path.Free;



  DoubleBuffered := True;



  TrackBar1.Max := 100;

  TrackBar2.Max := 100;

end;



procedure TForm1.FormDestroy(Sender: TObject);

begin

  pb.Free;

end;



procedure TForm1.FormPaint(Sender: TObject);

var

  g: TGPGraphics;

  p: TGPPen;

  x,y: Single;

begin

  g := TGPGraphics.Create(Canvas.Handle);

  p := TGPPen.Create(aclRed);



  g.FillEllipse(pb, rect);



  pb.SetCenterPoint(MakePoint(rect.X + rect.Width div 2, rect.Y + rect.Height div 2));



  {SetFocusScales}

  pb.SetFocusScales(TrackBar1.Position / 100, TrackBar2.Position / 100);



  {GetFocusScales}

  pb.GetFocusScales(x, y);

  Text := Format('%f,%f',[x,y]);



  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 = 164

  ClientWidth = 208

  Color = clBtnFace

  Font.Charset = DEFAULT_CHARSET

  Font.Color = clWindowText

  Font.Height = -11

  Font.Name = 'Tahoma'

  Font.Style = []

  OldCreateOrder = False

  Position = poDesktopCenter

  OnCreate = FormCreate

  OnDestroy = FormDestroy

  OnPaint = FormPaint

  PixelsPerInch = 96

  TextHeight = 13

  object TrackBar1: TTrackBar

    Left = 0

    Top = 143

    Width = 200

    Height = 23

    ShowSelRange = False

    TabOrder = 0

    OnChange = TrackBar1Change

  end

  object TrackBar2: TTrackBar

    Left = 185

    Top = 0

    Width = 23

    Height = 156

    Orientation = trVertical

    ShowSelRange = False

    TabOrder = 1

    OnChange = TrackBar2Change

  end

end