TabWidget: Add support for tab page image, fixes #74

declarative/tabpage.go

@@ -28,6 +28,7 @@ type TabPage struct {
 	DataBinder       DataBinder
 	Layout           Layout
 	Children         []Widget
+	Image            *walk.Bitmap
 	Title            Property
 	Content          Widget
 }
@@ -39,6 +40,10 @@ func (tp TabPage) Create(builder *Builder) error {
 	}
 
 	return builder.InitWidget(tp, w, func() error {
+		if err := w.SetImage(tp.Image); err != nil {
+			return err
+		}
+
 		if tp.Content != nil && len(tp.Children) == 0 {
 			if err := tp.Content.Create(builder); err != nil {
 				return err

tabpage.go

@@ -4,10 +4,6 @@
 
 package walk
 
-import (
-	"syscall"
-)
-
 import (
 	"github.com/lxn/win"
 )
@@ -24,6 +20,7 @@ func init() {
 
 type TabPage struct {
 	ContainerBase
+	image                 *Bitmap
 	title                 string
 	tabWidget             *TabWidget
 	titleChangedPublisher EventPublisher
@@ -75,6 +72,20 @@ func (tp *TabPage) Font() *Font {
 	return defaultFont
 }
 
+func (tp *TabPage) Image() *Bitmap {
+	return tp.image
+}
+
+func (tp *TabPage) SetImage(value *Bitmap) error {
+	tp.image = value
+
+	if tp.tabWidget == nil {
+		return nil
+	}
+
+	return tp.tabWidget.onPageChanged(tp)
+}
+
 func (tp *TabPage) Title() string {
 	return tp.title
 }
@@ -90,15 +101,3 @@ func (tp *TabPage) SetTitle(value string) error {
 
 	return tp.tabWidget.onPageChanged(tp)
 }
-
-func (tp *TabPage) tcItem() *win.TCITEM {
-	text := syscall.StringToUTF16(tp.Title())
-
-	item := &win.TCITEM{
-		Mask:       win.TCIF_TEXT,
-		PszText:    &text[0],
-		CchTextMax: int32(len(text)),
-	}
-
-	return item
-}

tabwidget.go

@@ -23,6 +23,7 @@ func init() {
 type TabWidget struct {
 	WidgetBase
 	hWndTab                      win.HWND
+	imageList                    *ImageList
 	pages                        *TabPageList
 	currentIndex                 int
 	currentIndexChangedPublisher EventPublisher
@@ -71,6 +72,15 @@ func NewTabWidget(parent Container) (*TabWidget, error) {
 	return tw, nil
 }
 
+func (tw *TabWidget) Dispose() {
+	tw.WidgetBase.Dispose()
+
+	if tw.imageList != nil {
+		tw.imageList.Dispose()
+		tw.imageList = nil
+	}
+}
+
 func (tw *TabWidget) LayoutFlags() LayoutFlags {
 	if tw.pages.Len() == 0 {
 		return ShrinkableHorz | ShrinkableVert | GrowableHorz | GrowableVert | GreedyHorz | GreedyVert
@@ -293,7 +303,7 @@ func (tw *TabWidget) WndProc(hwnd win.HWND, msg uint32, wParam, lParam uintptr)
 
 func (tw *TabWidget) onPageChanged(page *TabPage) (err error) {
 	index := tw.pages.Index(page)
-	item := page.tcItem()
+	item := tw.tcitemFromPage(page)
 
 	if 0 == win.SendMessage(tw.hWndTab, win.TCM_SETITEM, uintptr(index), uintptr(unsafe.Pointer(item))) {
 		return newError("SendMessage(TCM_SETITEM) failed")
@@ -307,7 +317,7 @@ func (tw *TabWidget) onInsertingPage(index int, page *TabPage) (err error) {
 }
 
 func (tw *TabWidget) onInsertedPage(index int, page *TabPage) (err error) {
-	item := page.tcItem()
+	item := tw.tcitemFromPage(page)
 
 	if idx := int(win.SendMessage(tw.hWndTab, win.TCM_INSERTITEM, uintptr(index), uintptr(unsafe.Pointer(item)))); idx == -1 {
 		return newError("SendMessage(TCM_INSERTITEM) failed")
@@ -420,3 +430,37 @@ func (tw *TabWidget) onClearedPages(pages []*TabPage) (err error) {
 	tw.currentIndex = -1
 	return nil
 }
+
+func (tw *TabWidget) tcitemFromPage(page *TabPage) *win.TCITEM {
+	imageIndex, _ := tw.imageIndex(page.image)
+	text := syscall.StringToUTF16(page.title)
+
+	item := &win.TCITEM{
+		Mask:       win.TCIF_IMAGE | win.TCIF_TEXT,
+		IImage:     imageIndex,
+		PszText:    &text[0],
+		CchTextMax: int32(len(text)),
+	}
+
+	return item
+}
+
+func (tw *TabWidget) imageIndex(image *Bitmap) (index int32, err error) {
+	index = -1
+	if image != nil {
+		if tw.imageList == nil {
+			if tw.imageList, err = NewImageList(Size{16, 16}, 0); err != nil {
+				return
+			}
+
+			win.SendMessage(tw.hWndTab, win.TCM_SETIMAGELIST, 0, uintptr(tw.imageList.hIml))
+		}
+
+		// FIXME: Protect against duplicate insertion
+		if index, err = tw.imageList.AddMasked(image); err != nil {
+			return
+		}
+	}
+
+	return
+}

walk.go

@@ -39,3 +39,32 @@ func tr(source string, context ...string) string {
 
 	return translation(source, context...)
 }
+
+type Disposable interface {
+	Dispose()
+}
+
+type Disposables struct {
+	items []Disposable
+	done  bool
+}
+
+func (d *Disposables) Add(item Disposable) {
+	d.items = append(d.items, item)
+}
+
+func (d *Disposables) Spare() {
+	d.done = true
+}
+
+func (d *Disposables) Treat() {
+	if d.done {
+		return
+	}
+
+	for _, item := range d.items {
+		item.Dispose()
+	}
+
+	d.done = true
+}