refactoring: reduce duplicated code for default drawing of WidgetGroup

src/dlangui/dialogs/filedlg.d

@@ -473,7 +473,7 @@ class FilePathPanelItem : HorizontalLayout {
 }
 
 /// Panel with buttons - path segments - for fast navigation to subdirs.
-class FilePathPanelButtons : WidgetGroup {
+class FilePathPanelButtons : WidgetGroupDefaultDrawing {
     protected string _path;
 	Listener!OnPathSelectionHandler onPathSelectionListener;
 	protected bool onPathSelected(string path) {
@@ -583,22 +583,6 @@ class FilePathPanelButtons : WidgetGroup {
 
     }
 
-    /// Draw widget at its position to buffer
-    override void onDraw(DrawBuf buf) {
-        if (visibility != Visibility.Visible)
-            return;
-        super.onDraw(buf);
-        Rect rc = _pos;
-        applyMargins(rc);
-        applyPadding(rc);
-		auto saver = ClipRectSaver(buf, rc);
-		for (int i = 0; i < _children.count; i++) {
-			Widget item = _children.get(i);
-			if (item.visibility != Visibility.Visible)
-				continue;
-			item.onDraw(buf);
-		}
-    }
 
 }
 

src/dlangui/widgets/layouts.d

@@ -472,7 +472,7 @@ class ResizerWidget : Widget {
 
 
 /// Arranges items either vertically or horizontally
-class LinearLayout : WidgetGroup {
+class LinearLayout : WidgetGroupDefaultDrawing {
     protected Orientation _orientation = Orientation.Vertical;
     /// returns linear layout orientation (Vertical, Horizontal)
     @property Orientation orientation() { return _orientation; }
@@ -519,22 +519,6 @@ class LinearLayout : WidgetGroup {
         applyPadding(rc);
         _layoutItems.layout(rc);
     }
-    /// Draw widget at its position to buffer
-    override void onDraw(DrawBuf buf) {
-        if (visibility != Visibility.Visible)
-            return;
-        super.onDraw(buf);
-        Rect rc = _pos;
-        applyMargins(rc);
-        applyPadding(rc);
-		auto saver = ClipRectSaver(buf, rc);
-		for (int i = 0; i < _children.count; i++) {
-			Widget item = _children.get(i);
-			if (item.visibility != Visibility.Visible)
-				continue;
-			item.onDraw(buf);
-		}
-    }
 
 }
 
@@ -565,7 +549,7 @@ class HorizontalLayout : LinearLayout {
 }
 
 /// place all children into same place (usually, only one child should be visible at a time)
-class FrameLayout : WidgetGroup {
+class FrameLayout : WidgetGroupDefaultDrawing {
     /// empty parameter list constructor - for usage by factory
     this() {
         this(null);
@@ -617,23 +601,6 @@ class FrameLayout : WidgetGroup {
         }
     }
 
-    /// Draw widget at its position to buffer
-    override void onDraw(DrawBuf buf) {
-        if (visibility != Visibility.Visible)
-            return;
-        super.onDraw(buf);
-        Rect rc = _pos;
-        applyMargins(rc);
-        applyPadding(rc);
-        auto saver = ClipRectSaver(buf, rc);
-		for (int i = 0; i < _children.count; i++) {
-			Widget item = _children.get(i);
-			if (item.visibility != Visibility.Visible)
-				continue;
-			item.onDraw(buf);
-		}
-    }
-
     /// make one of children (with specified ID) visible, for the rest, set visibility to otherChildrenVisibility
     bool showChild(string ID, Visibility otherChildrenVisibility = Visibility.Invisible, bool updateFocus = false) {
         bool found = false;
@@ -655,7 +622,7 @@ class FrameLayout : WidgetGroup {
 }
 
 /// layout children as table with rows and columns
-class TableLayout : WidgetGroup {
+class TableLayout : WidgetGroupDefaultDrawing {
 
 	this(string ID = null) {
 		super(ID);
@@ -845,21 +812,4 @@ class TableLayout : WidgetGroup {
 		_cells.layout(rc);
 	}
 	
-	/// Draw widget at its position to buffer
-	override void onDraw(DrawBuf buf) {
-		if (visibility != Visibility.Visible)
-			return;
-		super.onDraw(buf);
-		Rect rc = _pos;
-		applyMargins(rc);
-		applyPadding(rc);
-		auto saver = ClipRectSaver(buf, rc);
-		for (int i = 0; i < _children.count; i++) {
-			Widget item = _children.get(i);
-			if (item.visibility != Visibility.Visible)
-				continue;
-			item.onDraw(buf);
-		}
-	}
-	
 }

src/dlangui/widgets/menu.d

@@ -206,7 +206,7 @@ class MenuItem {
 }
 
 /// widget to draw menu item
-class MenuItemWidget : WidgetGroup {
+class MenuItemWidget : WidgetGroupDefaultDrawing {
 	protected bool _mainMenu;
     protected MenuItem _item;
 	protected ImageWidget _icon;
@@ -298,24 +298,6 @@ class MenuItemWidget : WidgetGroup {
 			resetState(State.Checked);
 	}
 
-	/// Draw widget at its position to buffer
-	override void onDraw(DrawBuf buf) {
-		if (visibility != Visibility.Visible)
-			return;
-		super.onDraw(buf);
-		Rect rc = _pos;
-		applyMargins(rc);
-		applyPadding(rc);
-		updateState();
-		auto saver = ClipRectSaver(buf, rc, alpha);
-		for (int i = 0; i < _children.count; i++) {
-			Widget item = _children.get(i);
-			if (item.visibility != Visibility.Visible)
-				continue;
-			item.onDraw(buf);
-		}
-	}
-
 	this(MenuItem item, bool mainMenu) {
         id="menuitem";
 		_mainMenu = mainMenu;

src/dlangui/widgets/scroll.d

@@ -300,9 +300,9 @@ class ScrollWidgetBase :  WidgetGroup, OnScrollHandler {
     If size of content widget exceeds available space, allows to scroll it.
  */
 class ScrollWidget :  ScrollWidgetBase {
-    protected WidgetGroup _contentWidget;
+    protected Widget _contentWidget;
-    @property WidgetGroup contentWidget() { return _contentWidget; }
+    @property Widget contentWidget() { return _contentWidget; }
-    @property ScrollWidget contentWidget(WidgetGroup newContent) { 
+    @property ScrollWidget contentWidget(Widget newContent) { 
         if (_contentWidget) {
             removeChild(childIndex(_contentWidget));
             destroy(_contentWidget);

src/dlangui/widgets/tabs.d

@@ -167,7 +167,7 @@ class TabItemList {
 }
 
 /// tab header - tab labels, with optional More button
-class TabControl : WidgetGroup {
+class TabControl : WidgetGroupDefaultDrawing {
     protected TabItemList _items;
     protected ImageButton _moreButton;
     protected bool _enableCloseButton;
@@ -338,24 +338,6 @@ class TabControl : WidgetGroup {
         }
         //Log.d("tabControl.layout exit");
     }
-    /// Draw widget at its position to buffer
-    override void onDraw(DrawBuf buf) {
-        //Log.d("tabControl.onDraw enter");
-        if (visibility != Visibility.Visible)
-            return;
-        super.onDraw(buf);
-        Rect rc = _pos;
-        applyMargins(rc);
-        applyPadding(rc);
-        auto saver = ClipRectSaver(buf, rc);
-		for (int i = 0; i < _children.count; i++) {
-			Widget item = _children.get(i);
-			if (item.visibility != Visibility.Visible)
-				continue;
-			item.onDraw(buf);
-		}
-        //Log.d("tabControl.onDraw exit");
-    }
 
     protected string _selectedTabId;
 

src/dlangui/widgets/widget.d

@@ -1336,6 +1336,34 @@ class WidgetGroup : Widget {
 
 }
 
+/** WidgetGroup with default drawing of children (just draw all children) */
+class WidgetGroupDefaultDrawing : WidgetGroup {
+    /// empty parameter list constructor - for usage by factory
+    this() {
+        this(null);
+    }
+    /// create with ID parameter
+	this(string ID) {
+		super(ID);
+	}
+    /// Draw widget at its position to buffer
+    override void onDraw(DrawBuf buf) {
+        if (visibility != Visibility.Visible)
+            return;
+        super.onDraw(buf);
+        Rect rc = _pos;
+        applyMargins(rc);
+        applyPadding(rc);
+		auto saver = ClipRectSaver(buf, rc);
+		for (int i = 0; i < _children.count; i++) {
+			Widget item = _children.get(i);
+			if (item.visibility != Visibility.Visible)
+				continue;
+			item.onDraw(buf);
+		}
+    }
+}
+
 immutable long ONE_SECOND = 10000000L;
 
 /// Helper to handle animation progress