Delphi图象截取编程示例(7)

(七)抓取窗体或控件图片窗体
创建一个新的Form2，保存为Capture2.pas。设置属性BorderIcons的四个属性为false.
BorderStyle设为bsNone,FormStyle设为fsStayOnTop.
两个公共变量:fRect:TRect,fBmp:TBitmap;

unit Capture2;

interface

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

type
  TForm2 = class(TForm)
    PRocedure FormCreate(Sender: TObject);
    procedure FormActivate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
    procedure FormPaint(Sender: TObject);
    procedure FormMouseUp(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
  private
    { Private declarations }
  public
    fRect:TRect;
    fBmp:TBitmap;
  end;

var
  Form2: TForm2;

implementation

{$R *.dfm}

//创建一个新的自定义光标CURSOR_1,放在Capture2.res资源
//文件中.是32*32的白色矩形边框，用来指示抓图的范围.
procedure TForm2.FormCreate(Sender: TObject);
var aDC:HDC;
const crHand = -18;
begin
  Screen.Cursors[crHand]:=LoadCursor(hInstance,'CURSOR_1');
  Cursor:=crHand;
  fBmp:= TBitmap.Create ;
  fBmp.Width := Screen.Width ;
  fBmp.Height:= Screen.Height ;
  aDC := GetDC(0);
  BitBlt(fBmp.Canvas.Handle,0,0,Screen.Width,Screen.Height,aDC,0,0,srcCopy);
  ReleaseDC(0,aDC);
  SetBounds(0,0,Screen.Width,Screen.Height);
end;

procedure TForm2.FormActivate(Sender: TObject);
const crHand=-18;
begin
  Screen.Cursors[crHand]:=LoadCursor(hInstance,pChar('CURSOR_1'));
  Cursor:=crHand;
end;

procedure TForm2.FormDestroy(Sender: TObject);
begin
  fBmp.Free;
  Screen.Cursor := crDefault;
end;

procedure TForm2.FormPaint(Sender: TObject);
begin
  Canvas.Draw(0,0,fBmp);
end;

procedure TForm2.FormMouseUp(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  ModalResult:=mrOK;
end;

end.