Edit控件多行文本垂直居中

主要功能是创建一个带有垂直居中文本的 GUI，其中的两个编辑框 Edit 控件用来展示字符串。代码通过修改编辑框内容的显示矩形区域，实现了多行文本在编辑框中垂直居中的效果。

#NoEnv
String := "你好`n世界"
Gui, Font, S20
Gui, Add, Edit, -VScroll -E0x200 hwndHEdit1 w200 r3 Center, %String%
Gui, Add, Edit, -VScroll -E0x200 hwndHEdit2 w200 r3 Center, %String%
Gui, Show, , Gui
Edit_VCENTER(HEdit2)
Return

GuiClose:
ExitApp

Edit_VCENTER(HEDIT) { ; The Edit control must have the ES_MULTILINE style (0x0004 \ +Multi)!
  ; EM_GETRECT := 0x00B2 <- msdn.microsoft.com/en-us/library/bb761596(v=vs.85).aspx
  ; EM_SETRECT := 0x00B3 <- msdn.microsoft.com/en-us/library/bb761657(v=vs.85).aspx
  VarSetCapacity(RC, 16, 0)
  DllCall("User32.dll\GetClientRect", "Ptr", HEDIT, "Ptr", &RC)
  CLHeight := NumGet(RC, 12, "Int")
  SendMessage, 0x0031, 0, 0, , ahk_id %HEDIT% ; WM_GETFONT
  HFONT := ErrorLevel
  HDC := DllCall("GetDC", "Ptr", HEDIT, "UPtr")
  DllCall("SelectObject", "Ptr", HDC, "Ptr", HFONT)
  VarSetCapacity(RC, 16, 0)
  DTH := DllCall("DrawText", "Ptr", HDC, "Str", "W", "Int", 1, "Ptr", &RC, "UInt", 0x2400)
  DllCall("ReleaseDC", "Ptr", HEDIT, "Ptr", HDC)
  SendMessage, 0x00BA, 0, 0, , ahk_id %HEDIT% ; EM_GETLINECOUNT
  TXHeight := DTH * ErrorLevel
  If (TXHeight > CLHeight)
    Return False
  VarSetCapacity(RC, 16, 0)
  SendMessage, 0x00B2, 0, &RC, , ahk_id %HEDIT%
  DY := (CLHeight - TXHeight) // 2
  NumPut(DY, RC, 4, "Int")
  NumPut(TXHeight + DY, RC, 12, "Int")
  SendMessage, 0x00B3, 0, &RC, , ahk_id %HEDIT%
}