delphi如何在桌面上或其它窗口上画图?
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs;
type
TForm1 = 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 FormKeyDown(Sender: TObject; var Key: Word;
Shift: TShiftState);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
procedure TForm1.FormCreate(Sender: TObject);
begin
Brush.Style :=bsClear;//这里的实现方法用Delphi是最简单的了
Tag:=0; //使用Form的Tag属性作标志位
end;
procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
begin
Tag:=1; //置位
Canvas.MoveTo(X,Y); //将Pen的位置移到当前
Canvas.Pen.Width := 8;
Canvas.Pen.Color :=clred;
end;
procedure TForm1.FormMouseMove(Sender: TObject; Shift: TShiftState; X,
Y: Integer);
begin
if Tag=1 then
begin
Canvas.LineTo(x,y);//画线
end;
end;
procedure TForm1.FormMouseUp(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
begin
Tag:=0; //标志位
end;
procedure TForm1.FormKeyDown(Sender: TObject; var Key: Word;
Shift: TShiftState);
begin
if key=27 then
begin
form1.WindowState:=wsMinimized;
end;
end;
end.
这段代码是从网上找到的,它只能画在自己的窗体上,我想实现在桌面或其它窗口上涂鸦,请问怎么办?
最好能给出代码!