unitabout.pas

在delphi下基于MapX5.0的GIS程序

unit UnitAbout;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  ExtCtrls, StdCtrls, Buttons;

type
  TFrmAbout = class(TForm)
    Bevel1: TBevel;
    Image1: TImage;
    Bevel2: TBevel;
    Label1: TLabel;
    Label3: TLabel;
    Label4: TLabel;
    BitBtn1: TBitBtn;
    TimerInfo: TTimer;
    procedure TimerInfoTimer(Sender: TObject);
    procedure FormCloseQuery(Sender: TObject; var CanClose: Boolean);
    procedure FormShow(Sender: TObject);
  private
    procedure WMNCPaint(var Msg: TWMNCPaint); message WM_NCPAINT;
    { Private declarations }
  public
    { Public declarations }
  end;

const
  WS_EX_LAYERED = $80000;
  AC_SRC_OVER = $0;
  AC_SRC_ALPHA = $1;
  AC_SRC_NO_PREMULT_ALPHA = $1;
  AC_SRC_NO_ALPHA = $2;
  AC_DST_NO_PREMULT_ALPHA = $10;
  AC_DST_NO_ALPHA = $20;
  LWA_COLORKEY = $1;
  LWA_ALPHA = $2;
  ULW_COLORKEY = $1;
  ULW_ALPHA = $2;
  ULW_OPAQUE = $4;

var
  FrmAbout: TFrmAbout;
  OnShowing: Boolean;

implementation

{$R *.DFM}

function SetLayeredWindowAttributes(hwnd:HWND; crKey:Longint; bAlpha:byte; dwFlags:longint ):longint; stdcall; external user32;

procedure TFrmAbout.WMNCPaint(var Msg: TWMNCPaint);
var
  dc : hDc;
  Pen : hPen;
  OldPen : hPen;
  OldBrush : hBrush;
begin
  inherited;
  dc := GetWindowDC(Handle);
  msg.Result := 1;
  Pen := CreatePen(PS_SOLID, 2, RGB(255, 0, 0));
  OldPen := SelectObject(dc, Pen);
  OldBrush := SelectObject(dc, GetStockObject(NULL_BRUSH));
  if OnShowing and TimerInfo.Enabled then Windows.Rectangle(dc, 0, 0, Width, Height+5);
  if Not TimerInfo.Enabled then Windows.Rectangle(dc, 0, 0, Width, Height);
  if Not OnShowing and TimerInfo.Enabled then Windows.Rectangle(dc, 0, 0, Width, Height-5);
  SelectObject(dc, OldBrush);
  SelectObject(dc, OldPen);
  DeleteObject(Pen);
  ReleaseDC(Handle, Canvas.Handle);
end;

procedure TFrmAbout.TimerInfoTimer(Sender: TObject);
begin
  if OnShowing then
  begin
    Height := Height + 5;
    if Height > 155 then TimerInfo.Enabled := False;
  end
  else
  begin
    Height := Height - 5;
    if Height < 30 then
    begin
      TimerInfo.Enabled := False;
      Close;
    end;
  end;
end;

procedure TFrmAbout.FormCloseQuery(Sender: TObject; var CanClose: Boolean);
begin
  if Height > 30 then
  begin
    CanClose := False;
    OnShowing := False;
    TimerInfo.Enabled := True;
  end;

end;

procedure TFrmAbout.FormShow(Sender: TObject);
begin
  TimerInfo.Enabled := True;
  OnShowing := True;
end;

end.