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Delphi图象截取编程示例(6)

 2006-02-04 13:52:23 来源:WEB开发网   
核心提示: (六)区域抓图窗体创建一个新的Form1,保存为Capture1.pas,Delphi图象截取编程示例(6),设置属性BorderIcons的四个属性为false.BorderStyle设为bsNone,Cursor设为crCross,FormStyle设为fsStayOnTop.添加一个私有变量:fDragging
 

(六)区域抓图窗体
创建一个新的Form1,保存为Capture1.pas。设置属性BorderIcons的四个属性为false.
BorderStyle设为bsNone,Cursor设为crCross,FormStyle设为fsStayOnTop.
添加一个私有变量:fDragging:Boolean;两个公共变量:fRect:TRect,fBmp:TBitmap;
Form1的作用:在区域抓图时创建,抓图后消失.

unit Capture1;

interface

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

type
  TForm1 = class(TForm)
   PRocedure FormCreate(Sender: TObject);
   procedure FormDestroy(Sender: TObject);
   procedure FormPaint(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);
  private
   fDragging:Boolean;
  public
   fRect:TRect;
   fBmp:TBitmap;
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
var aDC:HDC;  //设备描述表的句柄
begin
  fBmp := TBitmap.Create ;
  fBmp.Width := Screen.Width ;
  fBmp.Height:= Screen.Height;
  aDC := GetDC(0); //获取一个窗口的设备描述表的句柄,0参数返回屏幕窗口设备描述表的句柄
  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 TForm1.FormDestroy(Sender: TObject);
begin
  fBmp.Free ;
end;

procedure TForm1.FormPaint(Sender: TObject);
begin
  Canvas.Draw(0,0,fBmp);  //将图形绘制到 Canvas
end;

//如果按下鼠标左键,用SetRect设置矩形fRect,使其只是一个点。
//用 DrawFocusRect 把这个矩形画出来
procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  if Button=mbLeft then begin
   fDragging:=true;
   SetRect(fRect,x,y,x,y);
   Canvas.DrawFocusRect(fRect);
  end;
end;

//鼠标移动时, 判断是否在画图中(按下鼠标左键),DrawFocusRect重新设置矩形
//使右下角为当前鼠标位置,在调用DrawFocusRect画出矩形

procedure TForm1.FormMouseMove(Sender: TObject; Shift: TShiftState; X,
  Y: Integer);
begin
  if fDragging then begin
   Canvas.DrawFocusRect(fRect);
   fRect.Right := X ;
   fRect.Bottom:= Y ;
   Canvas.DrawFocusRect(fRect);
  end;
end;

//判断是否在画图中(按下鼠标左键),鼠标弹起时,
//DrawFocusRect重新设置矩形  .关闭窗体

procedure TForm1.FormMouseUp(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  if fDragging then begin
   Canvas.DrawFocusRect(fRect);
   fDragging:=false;
  end;
  ModalResult:=mrOK;  //关闭窗体
end;

end.

Tags:Delphi 图象 截取

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