Added Group on Windows.

redo/container_windows.go

@@ -15,6 +15,7 @@ type container struct {
 	containerbase
 	hwnd		C.HWND
 	nchildren		int
+	isGroup		bool
 }
 
 type sizing struct {
@@ -104,6 +105,11 @@ func fromdlgunitsY(du int, d *sizing) int {
 const (
 	marginDialogUnits = 7
 	paddingDialogUnits = 4
+
+	groupXMargin = 6
+	// TODO
+	groupYMarginTop = 11		// note this value /includes the groupbox label/
+	groupYMarginBottom = 7
 )
 
 func (c *container) beginResize() (d *sizing) {
@@ -123,6 +129,13 @@ func (c *container) beginResize() (d *sizing) {
 		d.xpadding = fromdlgunitsX(paddingDialogUnits, d)
 		d.ypadding = fromdlgunitsY(paddingDialogUnits, d)
 	}
+	if c.isGroup {
+		// note that these values apply regardless of whether or not spaced is set
+		// this is because Windows groupboxes have the client rect spanning the entire size of the control, not just the active work area
+		// the measurements Microsoft give us are for spaced margining; let's just use them
+		d.xmargin = fromdlgunitsX(groupXMargin, d)
+		d.ymargin = fromdlgunitsY(groupYMarginTop, d)
+	}
 
 	return d
 }

redo/group_windows.go

@@ -0,0 +1,82 @@
+// 15 august 2014
+
+package ui
+
+// #include "winapi_windows.h"
+import "C"
+
+type group struct {
+	_hwnd	C.HWND
+	_textlen	C.LONG
+
+	*container
+}
+
+func newGroup(text string, control Control) Group {
+	hwnd := C.newControl(buttonclass,
+		C.BS_GROUPBOX,
+		0)
+	g := &group{
+		_hwnd:		hwnd,
+		container:		newContainer(control),
+	}
+	g.SetText(text)
+	C.controlSetControlFont(g._hwnd)
+	g.container.setParent(g._hwnd)
+	g.container.isGroup = true
+	return g
+}
+
+func (g *group) Text() string {
+	return baseText(g)
+}
+
+func (g *group) SetText(text string) {
+	baseSetText(g, text)
+}
+
+func (g *group) hwnd() C.HWND {
+	return g._hwnd
+}
+
+func (g *group) textlen() C.LONG {
+	return g._textlen
+}
+
+func (g *group) settextlen(len C.LONG) {
+	g._textlen = len
+}
+
+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) {
+	width, height = g.child.preferredSize(d)
+	if width < int(g._textlen) {		// if the text is longer, try not to truncate
+		width = int(g._textlen)
+	}
+	// the two margin constants come from container_windows.go
+	return width, height + fromdlgunitsY(groupYMarginTop, d) + fromdlgunitsY(groupYMarginBottom, d)
+}
+
+func (g *group) commitResize(c *allocation, d *sizing) {
+	var r C.RECT
+
+	// pretend that the client area of the group box only includes the actual empty space
+	// container will handle the necessary adjustments properly
+	r.left = 0
+	r.top = 0
+	r.right = C.LONG(c.width)
+	r.bottom = C.LONG(c.height)
+	g.container.move(&r)
+	basecommitResize(g, c, d)
+}
+
+func (g *group) getAuxResizeInfo(d *sizing) {
+	basegetAuxResizeInfo(g, d)
+}