(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.
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