再学 GDI+[77]: 区域(6) - GetRegionScans - 获取区域中的所有矩形

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;



type

  TForm1 = class(TForm)

    procedure FormPaint(Sender: TObject);

    procedure FormClick(Sender: TObject);

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



uses GDIPOBJ, GDIPAPI;



procedure TForm1.FormPaint(Sender: TObject);

var

  g: TGPGraphics;

  b: TGPSolidBrush;

  path: TGPGraphicsPath;

  rgn: TGPRegion;

  Matrix: TGPMatrix;

  RectCount: Integer;

  rts: array of TGPRect;

  i: Integer;

begin

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

  b := TGPSolidBrush.Create(MakeColor(50, 0, 0, 255));



  path := TGPGraphicsPath.Create;

  path.AddEllipse(MakeRect(20, 10, ClientWidth-40, ClientHeight-20));

  rgn := TGPRegion.Create(path);



  Matrix := TGPMatrix.Create; {它在本例中只是个摆设, 因为参选需要}



  RectCount := rgn.GetRegionScansCount(Matrix);

  SetLength(rts, RectCount);

  rgn.GetRegionScans(Matrix, PGPRect(rts), RectCount);



  Randomize;

  for i := 0 to RectCount - 1 do

  begin

    b.SetColor(ColorRefToARGB(Random($FFFFFF)));

    g.FillRectangle(b, rts[i]);

  end;



  Matrix.Free;

  rgn.Free;

  path.Free;

  b.Free;

  g.Free;

end;



procedure TForm1.FormClick(Sender: TObject);

begin

  Repaint;

end;



end.


 
   

窗体文件:

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object Form1: TForm1

  Left = 0

  Top = 0

  Caption = 'Form1'

  ClientHeight = 217

  ClientWidth = 219

  Color = clBtnFace

  Font.Charset = DEFAULT_CHARSET

  Font.Color = clWindowText

  Font.Height = -11

  Font.Name = 'Tahoma'

  Font.Style = []

  OldCreateOrder = False

  Position = poDesktopCenter

  OnClick = FormClick

  OnPaint = FormPaint

  PixelsPerInch = 96

  TextHeight = 13

end