Added sizing of windows and the main window control. It presently deadlocks; I'll need to redo my mutexes...

button.go

@@ -49,6 +49,13 @@ func (b *Button) apply(window *sysData) error {
 	// TODO size to parent size
 }
 
+func (b *Button) setRect(x int, y int, width int, height int) error {
+	b.lock.Lock()
+	defer b.lock.Unlock()
+
+	return b.sysData.setRect(x, y, width, height)
+}
+
 func (b *Button) setParent(c Control) {
 	b.parent = c
 }

control.go

@@ -9,5 +9,6 @@ import (
 // A Control represents an UI control. Note that Control contains unexported members; this has the consequence that you can't build custom controls that interface directly with the system-specific code (fo rinstance, to import an unsupported control), or at least not without some hackery. If you want to make your own controls, embed Area and provide its necessities.
 type Control interface {
 	apply(window *sysData) error
+	setRect(x int, y int, width int, height int) error
 	setParent(c Control)
 }

stdwndclass_windows.go

@@ -42,7 +42,20 @@ func stdWndProc(s *sysData) func(hwnd _HWND, uMsg uint32, wParam _WPARAM, lParam
 			_ = mm
 			return 0
 		case _WM_SIZE:
-			// TODO
+			if s.resize != nil {
+				var r _RECT
+
+				r1, _, err := _getClientRect.Call(
+					uintptr(hwnd),
+					uintptr(unsafe.Pointer(&r)))
+				if r1 == 0 {
+					panic("GetClientRect failed: " + err.Error())
+				}
+				err = s.resize(int(r.Left), int(r.Top), int(r.Right), int(r.Bottom))
+				if err != nil {
+					panic("child resize failed: " + err.Error())
+				}
+			}
 			return 0
 		case _WM_CLOSE:
 			if s.event != nil {

sysdata.go

@@ -9,6 +9,7 @@ import (
 type cSysData struct {
 	ctype	int
 	event	chan struct{}
+	resize	func(x int, y int, width int, height int) error
 }
 func (c *cSysData) make(initText string, initWidth int, initHeight int, window *sysData) error {
 	panic(runtime.GOOS + " sysData does not define make()")
@@ -22,6 +23,9 @@ func (c *cSysData) hide() error {
 func (c *cSysData) setText(text string) error {
 	panic(runtime.GOOS + " sysData does not define setText()")
 }
+func (c *cSysData) setRect(x int, y int, width int, height int) error {
+	panic(runtime.GOOS + " sysData does not define setRect()")
+}
 
 const (
 	c_window = iota

sysdata_windows.go

@@ -174,3 +174,25 @@ func (s *sysData) setText(text string) error {
 	}
 	return nil
 }
+
+func (s *sysData) setRect(x int, y int, width int, height int) error {
+	ret := make(chan uiret)
+	defer close(ret)
+	uitask <- &uimsg{
+		call:		_moveWindow,
+		p:		[]uintptr{
+			uintptr(s.hwnd),
+			uintptr(x),
+			uintptr(y),
+			uintptr(width),
+			uintptr(height),
+			uintptr(_TRUE),
+		},
+		ret:		ret,
+	}
+	r := <-ret
+	if r.ret == 0 {		// failure
+		return r.err
+	}
+	return nil
+}

window.go

@@ -77,6 +77,7 @@ func (w *Window) Open(control Control) (err error) {
 		return err
 	}
 	if control != nil {
+		w.sysData.resize = control.setRect
 		err = control.apply(w.sysData)
 		if err != nil {
 			return err
@@ -101,6 +102,9 @@ func (w *Window) Hide() (err error) {
 func (w *Window) apply(window *sysData) error {
 	panic("Window.apply() should never be called")
 }
+func (w *Window) setRect(x int, y int, width int, height int) error {
+	panic("Window.setRect() should never be called")
+}
 func (w *Window) setParent(c Control) {
 	panic("Window.setParent() should never be called")
 }

windows_windows.go

@@ -169,6 +169,7 @@ var (
 	_destroyWindow = user32.NewProc("DestroyWindow")
 	_getClientRect = user32.NewProc("GetClientRect")
 	_enumChildWindows = user32.NewProc("EnumChildWindows")
+	_moveWindow = user32.NewProc("MoveWindow")
 	_setWindowPos = user32.NewProc("SetWindowPos")
 	_setWindowText = user32.NewProc("SetWindowTextW")
 	_showWindow = user32.NewProc("ShowWindow")
@@ -203,33 +204,6 @@ func EnumChildWindows(hWndParent HWND, lpEnumFunc WNDENUMPROC, lParam LPARAM) (e
 		uintptr(lParam))
 	return nil
 }
-
-// TODO return the rect itself?
-func GetClientRect(hWnd HWND) (lpRect *RECT, err error) {
-	lpRect = new(RECT)
-	r1, _, err := getClientRect.Call(
-		uintptr(hWnd),
-		uintptr(unsafe.Pointer(lpRect)))
-	if r1 == 0 {		// failure
-		return nil, err
-	}
-	return lpRect, nil
-}
-
-func SetWindowPos(hWnd HWND, hWndInsertAfter HWND, X int, Y int, cx int, cy int, uFlags uint32) (err error) {
-	r1, _, err := setWindowPos.Call(
-		uintptr(hWnd),
-		uintptr(hWndInsertAfter),
-		uintptr(X),
-		uintptr(Y),
-		uintptr(cx),
-		uintptr(cy),
-		uintptr(uFlags))
-	if r1 == 0 {		// failure
-		return err
-	}
-	return nil
-}
 */
 
 // WM_SETICON and WM_GETICON values.