NSIS：实现程序窗口逐渐透明的渐入渐出效果

/*
<a href="http://www.flighty.cn" target="_blank">www.flighty.cn</a>
*/
!AddPluginDir .\
;--------------------------------
!define MUI2  ;定义UI版本(MUI,MUI2)
!define iTransparentPercent 90   ;定义透明度
Var DIALOG
var iTransparent
var bTransparent
Name "Transparent Example"
SetCompressor /SOLID lzma
InstallDir $ExeDir
OutFile transparent_nsis.exe
!ifdef MUI2
!include MUI2.nsh
Var TIMERID
!else
!include MUI.nsh
;定义INI文件
!define INI $PLUGINSDIR\transparent.ini
!endif
!include LogicLib.nsh
!ifndef GWL_EXSTYLE
!define GWL_EXSTYLE -20
!endif
!ifndef WS_EX_LAYERED
!define WS_EX_LAYERED 0x80000
!endif
!ifndef LWA_ALPHA
!define LWA_ALPHA 2
!endif
!define MUI_CUSTOMFUNCTION_ABORT UserAbort
!ifdef MUI2
Page custom nsDialogsPage
!else
page custom InstallOptionsPage
!endif
!define MUI_PAGE_CUSTOMFUNCTION_SHOW welcome_PageShow
; 欢迎页面
!insertmacro MUI_PAGE_WELCOME
!insertmacro MUI_PAGE_DIRECTORY
 !insertmacro MUI_PAGE_INSTFILES
 !insertmacro MUI_PAGE_FINISH
;--------------------------------
 !insertmacro MUI_LANGUAGE "SimpChinese"
Section -Nil
SectionEnd
Function welcome_PageShow
!ifdef MUI2
  Pop $0
   nsDialogs::KillTimer /NOUNLOAD $TIMERID
!endif
  GetDlgItem $0 $hwndparent 3
  ShowWindow $0 0
  ${if} $bTransparent == 0
    ${For} $R0 0 $iTransparent
      system::call 'user32::SetLayeredWindowAttributes(i $HWNDPARENT, i 0, i R0, i ${LWA_ALPHA}) .iR1'
      sleep 1
    ${Next}
  ${endif}
  StrCpy $bTransparent 1
FunctionEnd
Function Exit
  ${ForEach} $R0 $iTransparent 0 - 1
    system::call 'user32::SetLayeredWindowAttributes(i $HWNDPARENT, i 0, i R0, i ${LWA_ALPHA}) .iR1'
    sleep 1
  ${Next}
FunctionEnd
Function UserAbort
  Messagebox MB_YESNO|MB_ICONQUESTION "Are Sure you want to cancel?" IDYES +2
  Abort
  call Exit
FunctionEnd
Function .onInstSuccess
  Messagebox MB_OK|MB_ICONINFORMATION "Install Success!"
  call Exit
FunctionEnd
Function SetWindowAttrib
  ${if} $bTransparent == 0
    system::call 'user32::GetWindowLong(i $HWNDPARENT, i ${GWL_EXSTYLE}) .iR0'
    ;messagebox mb_ok $R0
    IntOp $R0 $R0 + ${WS_EX_LAYERED}
    system::call 'user32::SetWindowLong(i $HWNDPARENT, i ${GWL_EXSTYLE}, i R0) .iR1'
    system::call 'user32::SetLayeredWindowAttributes(i $HWNDPARENT, i 0, i 0, i ${LWA_ALPHA}) .iR2'
  Pop $R2
  Pop $R1
  Pop $R0
  ${endif}
FunctionEnd
!ifndef MUI2
Function InstallOptionsPage
  Call SetWindowAttrib
  InstallOptions::initDialog /NOUNLOAD ${INI}
    Pop $DIALOG
;如果你想做的更逼真一些，请把它仿成欢迎页面(你的初始页面)一样的
  InstallOptions::Show
FunctionEnd
!endif
!ifdef MUI2
Function OnTimer
  Pop $0 ;Free Timer id
  GetDlgItem $1 $HWNDPARENT 1
  SendMessage $1 ${BM_CLICK} 0  1
FunctionEnd
Function nsDialogsPage
  Call SetWindowAttrib
  nsDialogs::Create /NOUNLOAD 1018
  Pop $DIALOG
;如果你想做的更逼真一些，请把它仿成欢迎页面(你的初始页面)一样的
  GetFunctionAddress $0 OnTimer
  nsDialogs::CreateTimer /NOUNLOAD $0 10
  Pop $TIMERID
  nsDialogs::Show
FunctionEnd
!endif
Function .OnInit
  InitPluginsDir
!ifndef MUI2
  File /oname=${INI} "transparent.ini"
!endif
  IntOp $iTransparent ${iTransparentPercent} * 255
  IntOp $iTransparent $iTransparent / 100
  StrCpy $bTransparent 0
FunctionEnd