Added Group and implemented it on GTK+.

redo/basicctrls.go

@@ -102,3 +102,19 @@ func NewLabel(text string) Label {
 func NewStandaloneLabel(text string) Label {
 	return newStandaloneLabel(text)
 }
+
+// Group is a Control that holds a single Control; if that Control also contains other Controls, then the Controls will appear visually grouped together.
+// The appearance of a Group varies from system to system; for the most part a Group consists of a thin frame.
+// All Groups have a text label indicating what the Group is for.
+type Group interface {
+	Control
+
+	// Text and SetText get and set the Group's label text.
+	Text() string
+	SetText(text string)
+}
+
+// NewGroup creates a new Group with the given text label and child Control.
+func NewGroup(text string, control Control) Group {
+	return newGroup(text, control)
+}

redo/group_unix.go

@@ -0,0 +1,86 @@
+// +build !windows,!darwin
+
+// 15 august 2014
+
+package ui
+
+import (
+	"unsafe"
+)
+
+// #include "gtk_unix.h"
+import "C"
+
+type group struct {
+	_widget		*C.GtkWidget
+	gcontainer	*C.GtkContainer
+	frame		*C.GtkFrame
+
+	*container
+}
+
+func newGroup(text string, control Control) Group {
+	ctext := togstr(text)
+	defer freegstr(ctext)
+	widget := C.gtk_frame_new(ctext)
+	g := &group{
+		_widget:		widget,
+		gcontainer:	(*C.GtkContainer)(unsafe.Pointer(widget)),
+		frame:		(*C.GtkFrame)(unsafe.Pointer(widget)),
+	}
+
+	// with GTK+, groupboxes by default have frames and slightly x-offset regular text
+	// they should have no frame and fully left-justified, bold text
+	var yalign C.gfloat
+
+	// preserve default y-alignment
+	C.gtk_frame_get_label_align(g.frame, nil, &yalign)
+	C.gtk_frame_set_label_align(g.frame, 0, yalign)
+	C.gtk_frame_set_shadow_type(g.frame, C.GTK_SHADOW_NONE)
+	label := (*C.GtkLabel)(unsafe.Pointer(C.gtk_frame_get_label_widget(g.frame)))
+	// TODO confirm this boldness level against Glade
+	bold := C.pango_attr_weight_new(C.PANGO_WEIGHT_BOLD)
+	boldlist := C.pango_attr_list_new()
+	C.pango_attr_list_insert(boldlist, bold)
+	C.gtk_label_set_attributes(label, boldlist)
+	// TODO free either bold or boldlist?
+
+	g.container = newContainer(control)
+	g.container.setParent(&controlParent{g.gcontainer})
+
+	return g
+}
+
+func (g *group) Text() string {
+	return fromgstr(C.gtk_frame_get_label(g.frame))
+}
+
+func (g *group) SetText(text string) {
+	ctext := togstr(text)
+	defer freegstr(ctext)
+	C.gtk_frame_set_label(g.frame, ctext)
+}
+
+func (g *group) widget() *C.GtkWidget {
+	return g._widget
+}
+
+func (g *group) setParent(p *controlParent) {
+	basesetParent(g, p)
+}
+
+func (g *group) allocate(x int, y int, width int, height int, d *sizing) []*allocation {
+	return baseallocate(g, x, y, width, height, d)
+}
+
+func (g *group) preferredSize(d *sizing) (width, height int) {
+	return basepreferredSize(g, d)
+}
+
+func (g *group) commitResize(a *allocation, d *sizing) {
+	basecommitResize(g, a, d)
+}
+
+func (g *group) getAuxResizeInfo(d *sizing) {
+	basegetAuxResizeInfo(g, d)
+}

redo/zz_test.go

@@ -32,6 +32,7 @@ var ddata = []dtype{
 type testwin struct {
 	t		Tab
 	w		Window
+	group	Group
 	grid		Grid
 	nt		Tab
 	a		Area
@@ -69,6 +70,8 @@ func (tw *testwin) make(done chan struct{}) {
 		done <- struct{}{}
 		return true
 	})
+	tw.group = NewGroup("Group", NewVerticalStack(NewCheckbox("Checkbox in Group")))
+	tw.t.Append("Group", tw.group)
 	tw.grid = NewGrid(3,
 		NewLabel("0,0"), NewTextField(), NewLabel("0,2"),
 		NewButton("1,0"), NewButton("1,1"), NewButton("1,2"),