Wrote windows/resize.c, which is the code that runs every so often to do a resize (instead of doing them immediately).

redo/ui.idl

@@ -43,7 +43,8 @@ interface Control {
 	field Internal *void;		// for use by ui only
 	func Destroy(void);
 	func Handle(void) uintptr_t;
-	func SetParent(c *Container);
+	func Parent(void) *Control;
+	func SetParent(c *Control);
 	func PreferredSize(d *Sizing, width *intmax_t, height *intmax_t);
 	func Resize(x intmax_t, y intmax_t, width intmax_t, height intmax_t, d *Sizing);
 	func QueueResize(void);

redo/windows/resize.c

@@ -1,2 +1,60 @@
 // 14 may 2015
 #include "uipriv_windows.h"
+
+static struct ptrArray *resizes;
+
+void initResizes(void)
+{
+	resizes = newPtrArray();
+}
+
+void uninitResizes(void)
+{
+	while (resizes->len != 0)
+		ptrArrayDelete(resizes, 0);
+	ptrArrayDestroy(resizes);
+}
+
+void queueResize(uiControl *c)
+{
+	// TODO make this more robust
+	ptrArrayAppend(resizes, c);
+}
+
+void doResizes(void)
+{
+	uiControl *c, *parent;
+	intmax_t x, y, width, height;
+	uiSizing d;
+	uiSizngSys sys;
+
+	while (resizes->len != 0) {
+		c = ptrArrayIndex(resizes, uiControl *, 0);
+		ptrArrayDelete(resizes, 0);
+		parent = uiControlParent(c);
+		if (parent == NULL)		// not in a parent; can't resize
+			continue;			// this is for uiBox, etc.
+		d.sys = &sys;
+		uiControlComputeChildSizeArea(parent, &x, &y, &width, &height, &d);
+		uiControlResize(c, x, y, width, height, &d);
+		hwnd = (HWND) uiControlHandle(c);
+		// we used SWP_NOREDRAW; we need to queue a redraw ourselves
+		// TODO use RedrawWindow() to bypass WS_CLIPCHILDREN complications
+		if (InvalidateRect(hwnd, NULL, TRUE) == 0)
+			logLastError("error redrawing controls after a resize in doResizes()");
+	}
+}
+
+#define swpflags (SWP_NOACTIVATE | SWP_NOOWNERZORDER | SWP_NOREDRAW)
+
+void moveWindow(HWND hwnd, intmax_t x, intmax_t y, intmax_t width, intmax_t height)
+{
+	if (SetWindowPos(hwnd, NULL, x, y, width, height, swpflags | SWP_NOZORDER) == 0)
+		logLastError("error moving window in moveWindow()");
+}
+
+void moveAndReorderWindow(HWND hwnd, HWND insertAfter, intmax_t x, intmax_t y, intmax_t width, intmax_t height)
+{
+	if (SetWindowPos(hwnd, insertAfter, x, y, width, height, swpflags) == 0)
+		logLastError("error moving and reordering window in moveAndReorderWindow()");
+}