再学 GDI+[80]: 区域(9) GetHRGN 转为 GDI 的区域句柄

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, StdCtrls, ComCtrls;

type
  TForm1 = class(TForm)
    procedure FormPaint(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

uses GDIPOBJ, GDIPAPI;

procedure TForm1.FormPaint(Sender: TObject);
var
  g: TGPGraphics;
  b: TGPBrush;
  rgn: TGPRegion;
  RegionHandle: HRGN;
begin
  g := TGPGraphics.Create(Canvas.Handle);
  b := TGPHatchBrush.Create(HatchStyleDiagonalCross, aclSilver, aclLemonChiffon);
  rgn := TGPRegion.Create(MakeRect(40.0, 40, ClientWidth-80, ClientHeight-80));
  g.FillRegion(b, rgn);

  RegionHandle := rgn.GetHRGN(g);

  Canvas.Brush.Color := clRed;
  FrameRgn(Canvas.Handle, RegionHandle, Canvas.Brush.Handle, 2, 2);

  DeleteObject(RegionHandle);
  rgn.Free;
  b.Free;
  g.Free;
end;

end.

窗体文件:

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object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 162
  ClientWidth = 197
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  Position = poDesktopCenter
  OnPaint = FormPaint
  PixelsPerInch = 96
  TextHeight = 13
end