// 8 february 2014
package ui
import (
"fmt"
"syscall"
"unsafe"
)
var (
stdWndClass = toUTF16("gouiwnd")
)
var (
_defWindowProc = user32.NewProc("DefWindowProcW")
)
func defWindowProc(hwnd _HWND, uMsg uint32, wParam _WPARAM, lParam _LPARAM) _LRESULT {
r1, _, _ := _defWindowProc.Call(
uintptr(hwnd),
uintptr(uMsg),
uintptr(wParam),
uintptr(lParam))
return _LRESULT(r1)
}
// don't worry about error returns from GetWindowLongPtr()/SetWindowLongPtr()
// see comments of http://blogs.msdn.com/b/oldnewthing/archive/2014/02/03/10496248.aspx
func getWindowLongPtr(hwnd _HWND, what uintptr) uintptr {
r1, _, _ := _getWindowLongPtr.Call(
uintptr(hwnd),
what)
return r1
}
func setWindowLongPtr(hwnd _HWND, what uintptr, value uintptr) {
_setWindowLongPtr.Call(
uintptr(hwnd),
what,
value)
}
// we can store a pointer in extra space provided by Windows
// we'll store sysData there
// see http://blogs.msdn.com/b/oldnewthing/archive/2005/03/03/384285.aspx
func getSysData(hwnd _HWND) *sysData {
return (*sysData)(unsafe.Pointer(getWindowLongPtr(hwnd, negConst(_GWLP_USERDATA))))
}
func storeSysData(hwnd _HWND, uMsg uint32, wParam _WPARAM, lParam _LPARAM) _LRESULT {
// we can get the lpParam from CreateWindowEx() in WM_NCCREATE and WM_CREATE
// we can freely skip any messages that come prior
// see http://blogs.msdn.com/b/oldnewthing/archive/2005/04/22/410773.aspx and http://blogs.msdn.com/b/oldnewthing/archive/2014/02/03/10496248.aspx (note the date on the latter one!)
if uMsg == _WM_NCCREATE {
// the lpParam to CreateWindowEx() is the first uintptr of the CREATESTRUCT
// so rather than create that whole structure, we'll just grab the uintptr at the address pointed to by lParam
cs := (*uintptr)(unsafe.Pointer(lParam))
saddr := *cs
setWindowLongPtr(hwnd, negConst(_GWLP_USERDATA), saddr)
// also set s.hwnd here so it can be used by other window messages right away
s := (*sysData)(unsafe.Pointer(saddr))
s.hwnd = hwnd
}
// then regardless of what happens, defer to DefWindowProc() (if you trace the execution of the above links, this is what they do)
return defWindowProc(hwnd, uMsg, wParam, lParam)
}
var (
_getFocus = user32.NewProc("GetFocus")
_isChild = user32.NewProc("IsChild")
// _setFocus in area_windows.go
)
// this is needed to ensure focus is preserved when switching away from and back to our program
// from http://blogs.msdn.com/b/oldnewthing/archive/2014/05/21/10527168.aspx
func (s *sysData) handleFocus(wParam _WPARAM) {
// parameter splitting from Microsoft's windowsx.h
state := uint32(wParam.LOWORD()) // originally UINT
minimized := wParam.HIWORD() != 0
if minimized { // don't do anything on minimize
return
}
if state == _WA_INACTIVE { // focusing out
old, _, _ := _getFocus.Call()
if _HWND(old) != _HWND(_NULL) { // if there is one
r1, _, _ := _isChild.Call(
uintptr(s.hwnd),
old)
if r1 != 0 {
s.lastfocus = _HWND(old)
}
}
} else { // focusing in
if s.lastfocus != _HWND(_NULL) { // if we have one
// don't bother checking SetFocus()'s error; see http://stackoverflow.com/questions/24073695/winapi-can-setfocus-return-null-without-an-error-because-thats-what-im-see/24074912#24074912
_setFocus.Call(uintptr(s.lastfocus))
}
}
}
func stdWndProc(hwnd _HWND, uMsg uint32, wParam _WPARAM, lParam _LPARAM) _LRESULT {
s := getSysData(hwnd)
if s == nil { // not yet saved
return storeSysData(hwnd, uMsg, wParam, lParam)
}
switch uMsg {
case msgPost:
data := (*interface{})(unsafe.Pointer(lParam))
s.post(*data)
return 0
case _WM_COMMAND:
id := _HMENU(wParam.LOWORD())
s.childrenLock.Lock()
ss := s.children[id]
s.childrenLock.Unlock()
switch ss.ctype {
case c_button:
if wParam.HIWORD() == _BN_CLICKED {
ss.event()
}
case c_checkbox:
// we opt into doing this ourselves because http://blogs.msdn.com/b/oldnewthing/archive/2014/05/22/10527522.aspx
if wParam.HIWORD() == _BN_CLICKED {
state, _, _ := _sendMessage.Call(
uintptr(ss.hwnd),
uintptr(_BM_GETCHECK),
uintptr(0),
uintptr(0))
if state == _BST_CHECKED {
state = _BST_UNCHECKED
} else if state == _BST_UNCHECKED {
state = _BST_CHECKED
}
_sendMessage.Call(
uintptr(ss.hwnd),
uintptr(_BM_SETCHECK),
state, // already uintptr
uintptr(0))
}
}
return 0
case _WM_ACTIVATE:
s.handleFocus(wParam)
return 0
case _WM_GETMINMAXINFO:
mm := lParam.MINMAXINFO()
// ... minimum size
_ = mm
return 0
case _WM_SIZE:
if s.allocate != nil {
var r _RECT
r1, _, err := _getClientRect.Call(
uintptr(hwnd),
uintptr(unsafe.Pointer(&r)))
if r1 == 0 {
panic("GetClientRect failed: " + err.Error())
}
// top-left corner of a client rect is always (0,0) so no need for left/top
s.resizeWindow(int(r.right), int(r.bottom))
// TODO use the Defer movement functions here?
// TODO redraw window and all children here?
}
return 0
case _WM_CLOSE:
if s.close() {
// TODO destroy
s.hide()
}
return 0
default:
return defWindowProc(hwnd, uMsg, wParam, lParam)
}
panic(fmt.Sprintf("stdWndProc message %d did not return: internal bug in ui library", uMsg))
}
type _WNDCLASS struct {
style uint32
lpfnWndProc uintptr
cbClsExtra int32 // originally int
cbWndExtra int32 // originally int
hInstance _HANDLE
hIcon _HANDLE
hCursor _HANDLE
hbrBackground _HBRUSH
lpszMenuName *uint16
lpszClassName uintptr
}
var (
icon, cursor _HANDLE
)
var (
_registerClass = user32.NewProc("RegisterClassW")
)
func registerStdWndClass() (err error) {
wc := &_WNDCLASS{
lpszClassName: utf16ToArg(stdWndClass),
lpfnWndProc: syscall.NewCallback(stdWndProc),
hInstance: hInstance,
hIcon: icon,
hCursor: cursor,
hbrBackground: _HBRUSH(_COLOR_BTNFACE + 1),
}
r1, _, err := _registerClass.Call(uintptr(unsafe.Pointer(wc)))
if r1 == 0 { // failure
return err
}
return nil
}
// no need to use/recreate MAKEINTRESOURCE() here as the Windows constant generator already took care of that because Microsoft's headers do already
func initWndClassInfo() (err error) {
r1, _, err := user32.NewProc("LoadIconW").Call(
uintptr(_NULL),
uintptr(_IDI_APPLICATION))
if r1 == 0 { // failure
return fmt.Errorf("error getting window icon: %v", err)
}
icon = _HANDLE(r1)
r1, _, err = user32.NewProc("LoadCursorW").Call(
uintptr(_NULL),
uintptr(_IDC_ARROW))
if r1 == 0 { // failure
return fmt.Errorf("error getting window cursor: %v", err)
}
cursor = _HANDLE(r1)
return nil
}