Adjusted sizing data to act as the base container type; this is needed for proper resizing on both GTK+ and Mac OS X.

redo/sizing.go

@@ -33,16 +33,31 @@ type controlSizing interface {
 	getAuxResizeInfo(*sizing)
 }
 
-func (w *window) doresize(width, height int) {
-	if w.child == nil {		// no children; nothing to do
+// on Windows, this is only embedded by window, as all other containers cannot have their own children
+// on GTK+ and Mac OS X, one is embedded by window and all containers; the containers call container.continueResize()
+type container struct {
+	child			Control
+	spaced		bool
+	beginResize	func() (d *sizing)
+}
+
+func (c *container) resize(width, height int) {
+	if c.child == nil {		// no children; nothing to do
 		return
 	}
-	d := w.beginResize()
-	allocations := w.child.allocate(0, 0, width, height, d)
-	w.translateAllocationCoords(allocations, width, height)
+	d := c.beginResize()
+	c.continueResize(width, height, d)
+}
+
+func (c *container) continueResize(width, height int, d *sizing) {
+	if c.child == nil {		// no children; nothing to do
+		return
+	}
+	allocations := c.child.allocate(0, 0, width, height, d)
+	c.translateAllocationCoords(allocations, width, height)
 	// move in reverse so as to approximate right->left order so neighbors make sense
 	for i := len(allocations) - 1; i >= 0; i-- {
 		allocations[i].this.commitResize(allocations[i], d)
 	}
-	w.endResize(d)
+	c.endResize(d)
 }

redo/sizing_windows.go

@@ -21,6 +21,7 @@ const (
 	paddingDialogUnits = 4
 )
 
+// only windows are containers, so only windows get beginResize()
 func (w *window) beginResize() (d *sizing) {
 	d = new(sizing)
 
@@ -43,11 +44,11 @@ func (w *window) beginResize() (d *sizing) {
 	return d
 }
 
-func (w *window) endResize(d *sizing) {
+func (c *container) endResize(d *sizing) {
 	// redraw
 }
 
-func (w *window) translateAllocationCoords(allocations []*allocation, winwidth, winheight int) {
+func (c *container) translateAllocationCoords(allocations []*allocation, winwidth, winheight int) {
 	// no translation needed on windows
 }
 

redo/window_windows.go

@@ -12,14 +12,12 @@ import (
 import "C"
 
 type window struct {
+	*container
+
 	hwnd		C.HWND
 	shownbefore	bool
 
-	child			Control
-
 	closing		*event
-
-	spaced		bool
 }
 
 const windowclassname = ""
@@ -42,8 +40,10 @@ type controlParent interface {
 func newWindow(title string, width int, height int, control Control) *window {
 	w := &window{
 		// hwnd set in WM_CREATE handler
-		closing:	newEvent(),
+		closing:		newEvent(),
+		container:		new(container),
 	}
+	w.container.beginResize = w.beginResize
 	hwnd := C.newWindow(toUTF16(title), C.int(width), C.int(height), unsafe.Pointer(w))
 	if hwnd != w.hwnd {
 		panic(fmt.Errorf("inconsistency: hwnd returned by CreateWindowEx() (%p) and hwnd stored in window (%p) differ", hwnd, w.hwnd))
@@ -97,7 +97,7 @@ func storeWindowHWND(data unsafe.Pointer, hwnd C.HWND) {
 //export windowResize
 func windowResize(data unsafe.Pointer, r *C.RECT) {
 	w := (*window)(data)
-	w.doresize(int(r.right - r.left), int(r.bottom - r.top))
+	w.resize(int(r.right - r.left), int(r.bottom - r.top))
 }
 
 //export windowClosing