Added Tab. That just leaves Box...

group.go

@@ -58,8 +58,7 @@ func (g *Group) Handle() uintptr {
 	return uintptr(C.uiControlHandle(g.c))
 }
 
-// Show shows the Group. It uses the OS conception of "presenting"
-// the Group, whatever that may be on a given OS.
+// Show shows the Group.
 func (g *Group) Show() {
 	C.uiControlShow(g.c)
 }

tab.go

@@ -0,0 +1,122 @@
+// 12 december 2015
+
+package ui
+
+import (
+	"unsafe"
+)
+
+// #include "ui.h"
+import "C"
+
+// Tab is a Control that holds tabbed pages of Controls. Each tab
+// has a label. The user can click on the tabs themselves to switch
+// pages.
+type Tab struct {
+	c	*C.uiControl
+	t	*C.uiTab
+
+	children	[]Control
+}
+
+// NewTab creates a new Tab.
+func NewTab() *Tab {
+	t := new(Tab)
+
+	t.t = C.uiNewTab()
+	t.c = (*C.uiControl)(unsafe.Pointer(t.t))
+
+	return t
+}
+
+// Destroy destroys the Tab. If the Tab has pages,
+// Destroy calls Destroy on the pages's Controls as well.
+func (t *Tab) Destroy() {
+	for len(t.children) != 0 {
+		c := t.children[0]
+		t.Delete(0)
+		c.Destroy()
+	}
+	C.uiControlDestroy(t.c)
+}
+
+// LibuiControl returns the libui uiControl pointer that backs
+// the Tab. This is only used by package ui itself and should
+// not be called by programs.
+func (t *Tab) LibuiControl() uintptr {
+	return uintptr(unsafe.Pointer(t.c))
+}
+
+// Handle returns the OS-level handle associated with this Tab.
+// On Windows this is an HWND of a standard Windows API
+// WC_TABCONTROL class (as provided by Common Controls
+// version 6). The pages are not children of this window and there
+// currently is no way to directly access them.
+// On GTK+ this is a pointer to a GtkNotebook.
+// On OS X this is a pointer to a NSTabView.
+func (t *Tab) Handle() uintptr {
+	return uintptr(C.uiControlHandle(t.c))
+}
+
+// Show shows the Tab.
+func (t *Tab) Show() {
+	C.uiControlShow(t.c)
+}
+
+// Hide hides the Tab.
+func (t *Tab) Hide() {
+	C.uiControlHide(t.c)
+}
+
+// Enable enables the Tab.
+func (t *Tab) Enable() {
+	C.uiControlEnable(t.c)
+}
+
+// Disable disables the Tab.
+func (t *Tab) Disable() {
+	C.uiControlDisable(t.c)
+}
+
+// Append adds the given page to the end of the Tab.
+func (t *Tab) Append(name string, child Control) {
+	t.InsertAt(name, len(t.children), child)
+}
+
+// InsertAt adds the given page to the Tab such that it is the
+// nth page of the Tab (starting at 0).
+func (t *Tab) InsertAt(name string, n int, child Control) {
+	c := (*C.uiControl)(nil)
+	if child != nil {
+		c = touiControl(child.LibuiControl())
+	}
+	cname := C.CString(name)
+	// TODO why is this uintmax_t and not intmax_t
+	C.uiTabInsertAt(t.t, cname, C.uintmax_t(n), c)
+	freestr(cname)
+	t.children = append(t.children, child)
+}
+
+// Delete deletes the nth page of the Tab.
+func (t *Tab) Delete(n int) {
+	t.children = append(t.children[:n], t.children[n + 1:]...)
+	C.uiTabDelete(t.t, C.uintmax_t(n))
+}
+
+// NumPages returns the number of pages in the Tab.
+func (t *Tab) NumPages() int {
+	return len(t.children)
+}
+
+// Margined returns whether page n (starting at 0) of the Tab
+// has margins around its child.
+func (t *Tab) Margined(n int) bool {
+	return tobool(C.uiTabMargined(t.t, C.uintmax_t(n)))
+}
+
+// SetMargined controls whether page n (starting at 0) of the Tab
+// has margins around its child. The size of the margins are
+// determined by the OS and its best practices.
+func (t *Tab) SetMargined(n int, margined bool) {
+	C.uiTabSetMargined(t.t, C.uintmax_t(n), frombool(margined))
+}

zz_test.go

@@ -11,14 +11,12 @@ func TestIt(t *testing.T) {
 			Quit()
 			return true
 		})
-		s := NewGroup("Group")
-		w.SetChild(s)
+		t := NewTab()
+		w.SetChild(t)
 		w.SetMargined(true)
-		b := NewButton("Click Me")
-		b.OnClicked(func(*Button) {
-			s.SetMargined(!s.Margined())
-		})
-		s.SetChild(b)
+		t.Append("First Page", NewButton("Click Me"))
+		t.Append("Second Page", NewButton("Click Me Too"))
+		t.SetMargined(0, true)
 		w.Show()
 	})
 	if err != nil {