Changed Areas on WIndows so that they all use the same window class, rather than having one per Area.

area_windows.go

@@ -6,7 +6,6 @@ import (
 	"fmt"
 	"syscall"
 	"unsafe"
-	"sync"
 	"image"
 )
 
@@ -16,12 +15,7 @@ const (
 )
 
 const (
-	areaWndClassFormat = "gouiarea%X"
-)
-
-var (
-	areaWndClassNum uintptr
-	areaWndClassNumLock sync.Mutex
+	areaWndClass = "gouiarea"
 )
 
 func getScrollPos(hwnd _HWND) (xpos int32, ypos int32) {
@@ -604,8 +598,7 @@ var (
 	_setFocus = user32.NewProc("SetFocus")
 )
 
-func areaWndProc(unused *sysData) func(hwnd _HWND, uMsg uint32, wParam _WPARAM, lParam _LPARAM) _LRESULT {
-	return func(hwnd _HWND, uMsg uint32, wParam _WPARAM, lParam _LPARAM) _LRESULT {
+func areaWndProc(hwnd _HWND, uMsg uint32, wParam _WPARAM, lParam _LPARAM) _LRESULT {
 	s := getSysData(hwnd)
 	if s == nil {		// not yet saved
 		return storeSysData(hwnd, uMsg, wParam, lParam)
@@ -711,36 +704,22 @@ func areaWndProc(unused *sysData) func(hwnd _HWND, uMsg uint32, wParam _WPARAM,
 	}
 	panic(fmt.Sprintf("areaWndProc message %d did not return: internal bug in ui library", uMsg))
 }
-}
-
-func registerAreaWndClass(s *sysData) (newClassName string, err error) {
-	areaWndClassNumLock.Lock()
-	newClassName = fmt.Sprintf(areaWndClassFormat, areaWndClassNum)
-	areaWndClassNum++
-	areaWndClassNumLock.Unlock()
 
+func registerAreaWndClass() (err error) {
 	wc := &_WNDCLASS{
 		style:			_CS_HREDRAW | _CS_VREDRAW,		// no CS_DBLCLKS because do that manually
-		lpszClassName:	uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(newClassName))),
-		lpfnWndProc:		syscall.NewCallback(areaWndProc(s)),
+		lpszClassName:	uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(areaWndClass))),
+		lpfnWndProc:		syscall.NewCallback(areaWndProc),
 		hInstance:		hInstance,
 		hIcon:			icon,
 		hCursor:			cursor,
 		hbrBackground:	_HBRUSH(_NULL),		// no brush; we handle WM_ERASEBKGND
 	}
-
-	ret := make(chan uiret)
-	defer close(ret)
-	uitask <- &uimsg{
-		call:		_registerClass,
-		p:		[]uintptr{uintptr(unsafe.Pointer(wc))},
-		ret:		ret,
+	r1, _, err := _registerClass.Call(uintptr(unsafe.Pointer(wc)))
+	if r1 == 0 {		// failure
+		return err
 	}
-	r := <-ret
-	if r.ret == 0 {		// failure
-		return "", r.err
-	}
-	return newClassName, nil
+	return nil
 }
 
 type _BITMAPINFO struct {

init_windows.go

@@ -69,6 +69,10 @@ func doWindowsInit() (err error) {
 	if err != nil {
 		return fmt.Errorf("error registering standard window class (for Window): %v", err)
 	}
+	err = registerAreaWndClass()
+	if err != nil {
+		return fmt.Errorf("error registering Area window class: %v", err)
+	}
 	err = getStandardWindowFonts()
 	if err != nil {
 		return fmt.Errorf("error getting standard window fonts: %v", err)

sysdata_windows.go

@@ -113,7 +113,7 @@ var classTypes = [nctypes]*classData{
 		doNotLoadFont:	true,
 	},
 	c_area:			&classData{
-		register:			registerAreaWndClass,
+		name:			areaWndClass,
 		style:			areastyle,
 		xstyle:			areaxstyle,
 		storeSysData:		true,