Started the Windows implementation of Area.

area_windows.go

@@ -0,0 +1,74 @@
+// 24 march 2014
+
+package ui
+
+import (
+	"fmt"
+	"syscall"
+	"unsafe"
+	"sync"
+)
+
+const (
+	areastyle = 0 | controlstyle
+	areaxstyle = 0 | controlxstyle
+)
+
+const (
+	areaWndClassFormat = "gouiarea%X"
+)
+
+var (
+	areaWndClassNum uintptr
+	areaWndClassNumLock sync.Mutex
+)
+
+func areaWndProc(s *sysData) func(hwnd _HWND, uMsg uint32, wParam _WPARAM, lParam _LPARAM) _LRESULT {
+	return func(hwnd _HWND, uMsg uint32, wParam _WPARAM, lParam _LPARAM) _LRESULT {
+		switch uMsg {
+		default:
+			r1, _, _ := defWindowProc.Call(
+				uintptr(hwnd),
+				uintptr(uMsg),
+				uintptr(wParam),
+				uintptr(lParam))
+			return _LRESULT(r1)
+		}
+		panic(fmt.Sprintf("areaWndProc message %d did not return: internal bug in ui library", uMsg))
+	}
+}
+
+func registerAreaWndClass(s *sysData) (newClassName string, err error) {
+	const (
+		// from winuser.h
+		_CS_DBLCLKS = 0x0008
+	)
+
+	areaWndClassNumLock.Lock()
+	newClassName = fmt.Sprintf(areaWndClassFormat, areaWndClassNum)
+	areaWndClassNum++
+	areaWndClassNumLock.Unlock()
+
+	wc := &_WNDCLASS{
+		style:			_CS_DBLCLKS,		// needed to be able to register double-clicks
+		lpszClassName:	uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(newClassName))),
+		lpfnWndProc:		syscall.NewCallback(areaWndProc(s)),
+		hInstance:		hInstance,
+		hIcon:			icon,
+		hCursor:			cursor,
+		hbrBackground:	_HBRUSH(_COLOR_BTNFACE + 1),
+	}
+
+	ret := make(chan uiret)
+	defer close(ret)
+	uitask <- &uimsg{
+		call:		_registerClass,
+		p:		[]uintptr{uintptr(unsafe.Pointer(wc))},
+		ret:		ret,
+	}
+	r := <-ret
+	if r.ret == 0 {		// failure
+		return "", r.err
+	}
+	return newClassName, nil
+}

sysdata_windows.go

@@ -21,6 +21,7 @@ type sysData struct {
 
 type classData struct {
 	name			string
+	register			func(s *sysData) (newClassName string, err error)
 	style				uint32
 	xstyle			uint32
 	mkid				bool
@@ -40,6 +41,7 @@ const controlxstyle = 0
 
 var classTypes = [nctypes]*classData{
 	c_window:		&classData{
+		register:			registerStdWndClass,
 		style:			_WS_OVERLAPPEDWINDOW,
 		xstyle:			0,
 	},
@@ -103,6 +105,11 @@ var classTypes = [nctypes]*classData{
 		style:			_PBS_SMOOTH | controlstyle,
 		xstyle:			0 | controlxstyle,
 	},
+	c_area:			&classData{
+		register:			registerAreaWndClass,
+		style:			areastyle,
+		xstyle:			areaxstyle,
+	},
 }
 
 func (s *sysData) addChild(child *sysData) _HMENU {
@@ -132,10 +139,11 @@ func (s *sysData) make(initText string, window *sysData) (err error) {
 	if window != nil {		// this is a child control
 		cid = window.addChild(s)
 		pwin = uintptr(window.hwnd)
-	} else {				// need a new class
-		n, err := registerStdWndClass(s)
+	}
+	if classname == "" {		// need a new window class
+		n, err := ct.register(s)
 		if err != nil {
-			return fmt.Errorf("error creating window class for new window: %v", err)
+			return fmt.Errorf("error creating window class for new window/control (type %d): %v", s.ctype, err)
 		}
 		classname = n
 	}
@@ -613,3 +621,7 @@ func (s *sysData) len() int {
 	}
 	return int(r.ret)
 }
+
+func (s *sysData) setAreaSize(width int, height int) {
+	// TODO
+}