Delphi图象截取编程示例(8)

(七)抓取图标（ICON）的窗体

创建一个新的Form3，保存为Capture3.pas。设置属性BorderIcons的四个属性为false.

BorderStyle设为bsNone,FormStyle设为fsStayOnTop.

一个私有变量：fDragging:Boolean; 两个公共变量:fRect:TRect,fBmp:TBitmap;

unit Capture3;

interface

uses

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

Dialogs;

type

TForm3 = class(TForm)

PRocedure FormCreate(Sender: TObject);

procedure FormMouseDown(Sender: TObject; Button: TMouseButton;

Shift: TShiftState; X, Y: Integer);

procedure FormMouseMove(Sender: TObject; Shift: TShiftState;

X, Y: Integer);

procedure FormMouseUp(Sender: TObject; Button: TMouseButton;

Shift: TShiftState; X, Y: Integer);

procedure FormActivate(Sender: TObject);

procedure FormDestroy(Sender: TObject);

procedure FormPaint(Sender: TObject);

private

fDragging:Boolean;

public

fRect:TRect;

fBmp:TBitmap;

end;

var

Form3: TForm3;

implementation

{$R *.dfm}

//创建一个新的自定义光标CURSOR_2,放在Capture3.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 TForm3.FormCreate(Sender: TObject);

var aDC:HDC ;

const crBox = -19;

begin

Screen.Cursors[crBox]:=LoadCursor(hInstance,'CURSOR_2');

Cursor := crBox;

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 TForm3.FormMouseDown(Sender: TObject; Button: TMouseButton;

Shift: TShiftState; X, Y: Integer);

begin

if mbLeft = Button then begin

fDragging := true;

SetRect(fRect,X,Y,X+32,Y+32);

Canvas.DrawFocusRect(fRect);

end;

end;

procedure TForm3.FormMouseMove(Sender: TObject; Shift: TShiftState;

X, Y: Integer);

begin

if fDragging then begin

Canvas.DrawFocusRect(fRect);

fRect.Left := X ;

fRect.Top := Y ;

fRect.Right:= X+32;

fRect.Bottom:=Y+32;

Canvas.DrawFocusRect(fRect);

end;

end;

procedure TForm3.FormMouseUp(Sender: TObject; Button: TMouseButton;

Shift: TShiftState; X, Y: Integer);

begin

ModalResult:=mrOK;

end;

procedure TForm3.FormActivate(Sender: TObject);

const crHand=-18;

begin

Screen.Cursors[crHand]:=LoadCursor(hInstance,pChar('CURSOR_1'));

Cursor:=crHand;

end;

procedure TForm3.FormDestroy(Sender: TObject);

begin

fBmp.Free;

Screen.Cursor := crDefault;

end;

procedure TForm3.FormPaint(Sender: TObject);

begin

Canvas.Draw(0,0,fBmp);

end;

end.