鼠标拖动虚影效果

PS:

1.form2是主窗体，form1是子窗体，我当时安装的是XE8，新建第一个窗体就是叫form2。

2.事件处理用到了控件（ApplicationEvents1）。

3.源代码下载地址：“https://download.csdn.net/download/zhujianqiangqq/7551317”。

unit Unit2;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, unit1, Vcl.StdCtrls, Vcl.ExtCtrls,
  Vcl.AppEvnts;

type
  TForm2 = class(TForm)
    ApplicationEvents1: TApplicationEvents;
    Label1: TLabel;
    procedure MYHideMessage(var Msg: tagMSG; var Handled: Boolean);
  private
    { Private declarations }

  public
    { Public declarations }

  end;

var
  Form2: TForm2;
implementation

{$R *.dfm}

procedure TForm2.MYHideMessage(var Msg: tagMSG; var Handled: Boolean);
var
  pt:TPoint;
  bit: TBitmap;
begin
  case Msg.message of
    WM_LBUTTONDOWN:  //鼠标左键按下显示虚窗体
    begin
      //复制一个主窗体的图片
      bit := TBitmap.Create;
      bit.Width := Width;
      bit.Height := Height;
      BitBlt(bit.Canvas.Handle, 0, 0, Width, Height, GetWindowDC(Handle), 0, 0, SRCCOPY);
      //虚窗体加载图片
      Form1.Image1.Picture.Assign(bit);
      //我这里为了方便大家看代码没有用TRY，大家写时注意了
      bit.Free;
      //设置虚窗体的大小
      Form1.Height:=Form2.Height;
      Form1.Width:=Form2.Width;
      Form1.Image1.Align:=alClient;
      Form1.BorderStyle:=bsNone;
      //显示虚窗体
      Form1.Show;
      //设置透明度
      Form1.AlphaBlend:=True;
      Form1.AlphaBlendValue:=100;
    end;
    WM_MOUSEMOVE: //鼠标移动虚窗体根着移动
    begin
      //取出鼠标的位置
      GetCursorPos(pt);
      Caption:='X坐标： '+inttostr(pt.X)+'   Y坐标：  '+inttostr(pt.Y);
      //设置虚窗体的位置
      Form1.Top:=pt.Y;
      Form1.Left:=pt.X;
    end;
    WM_LBUTTONUP: //鼠标左键跳起虚窗体隐藏
    begin
      Form1.Hide;
    end;
  end;
end;

end.