upaintrgn.pas

DelphiWin32核心API参考光盘内容.是学习书籍中的源码,便于学习.

unit UPaintRGN;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls;

type
  TForm1 = class(TForm)
    procedure FormPaint(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.FormPaint(Sender: TObject);
var
  PointsArray: Array[0..5] of TPoint;       // points defining a region
  RegionHandle: HRgn;                       // the handle of the region
begin
  {define the region}
  PointsArray[0].X := 50;
  PointsArray[0].y := 50;
  PointsArray[1].x := 100;
  PointsArray[1].y := 50;
  PointsArray[2].x := 125;
  PointsArray[2].y := 75;
  PointsArray[3].x := 100;
  PointsArray[3].y := 100;
  PointsArray[4].x := 50;
  PointsArray[4].y := 100;
  PointsArray[5].x := 25;
  PointsArray[5].y := 75;

  {create the region}
  RegionHandle := CreatePolygonRgn(PointsArray, 6, ALTERNATE);

  {paint the region using the canvas's brush}
  Canvas.Brush.Color := clGreen;
  Canvas.Brush.Style := bsBDiagonal;
  PaintRgn(Canvas.Handle, RegionHandle);
end;

end.