* Implemented Min/Max/PreferredSize().

* Reworked the internal layout. _ValidateLayoutData() computes and caches the
  layout related data and all other methods just use those values. Now, in
  layout-aware mode the class should properly work not only when using the
  layout items. And when using layout items, the class does actually do
  internal layout; it was basically good luck that it worked in the tests,
  before. Vertical resizing is supported, too. 
* We do a few mean tricks to get the probably mostly preferred layout behavior:
  By default our own explicit max width and that of the menu bar layout item is
  set to unlimited and the horizontal menu bar alignment to left aligned. This
  allows to horizontally resize a BMenuField beyond its preferred size,
  although both label and menu bar have a limited max width. The user can, of
  course, override those explicit sizes/alignments to get a different behavior,
  if desired.
* Fixed invalidation in SetDivider(). When having the focus, the left and top
  border of the blue frame were not invalidated.
* The label is no longer drawn at vertical position font ascent + descent
  + leading + 2 (not sure how this calculation was supposed to work), but
  vertically centers the label around the ascent. With big fonts the label is
  shown a bit too far to the bottom. Not sure how to fix this in a generic way.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@21466 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/os/interface/MenuField.h

@@ -28,7 +28,7 @@ class BMenuField : public BView {
 								BMessage* message,
 								uint32 flags = B_WILL_DRAW | B_NAVIGABLE); 
 							BMenuField(const char* label,
-								BMenu* menu, BMessage* message); 
+								BMenu* menu, BMessage* message = NULL); 
 							BMenuField(BMessage* data);
 	virtual					~BMenuField();
 
@@ -77,20 +77,31 @@ class BMenuField : public BView {
 	virtual void			ResizeToPreferred();
 	virtual void			GetPreferredSize(float* width, float* height);
 
-				BLayoutItem* CreateLabelLayoutItem();
-				BLayoutItem* CreateMenuBarLayoutItem();
+	virtual	BSize			MinSize();
+	virtual	BSize			MaxSize();
+	virtual	BSize			PreferredSize();
+
+	virtual	void			InvalidateLayout(bool descendants = false);
+
+			BLayoutItem*	CreateLabelLayoutItem();
+			BLayoutItem*	CreateMenuBarLayoutItem();
 
 	
 	/*----- Private or reserved -----------------------------------------*/
 	virtual status_t		Perform(perform_code d, void* arg);
 
+protected:
+	virtual	void			DoLayout();
+
  private:
 			class LabelLayoutItem;
 			class MenuBarLayoutItem;
+ 			struct LayoutData;
 
 			friend class _BMCMenuBar_;
 			friend class LabelLayoutItem;
 			friend class MenuBarLayoutItem;
+			friend class LayoutData;
 
 	virtual	void			_ReservedMenuField1();
 	virtual	void			_ReservedMenuField2();
@@ -108,22 +119,22 @@ class BMenuField : public BView {
 			void			_InitMenuBar(BMenu* menu,
 								BRect frame, bool fixedSize);
 
+			void			_ValidateLayoutData();
+
 			char*			fLabel;
 			BMenu*			fMenu;
 			BMenuBar*		fMenuBar;
 			alignment		fAlign;
 			float			fDivider;
-			float			fStringWidth;
 			bool			fEnabled;
 			bool			fSelected;
 			bool			fTransition;
 			bool			fFixedSizeMB;
 			thread_id		fMenuTaskID;
 
-			BLayoutItem*	fLabelLayoutItem;
-			BLayoutItem*	fMenuBarLayoutItem;
+			LayoutData*		fLayoutData;
 
-			uint32			_reserved[1];
+			uint32			_reserved[3];
 };
 
 #endif // _MENU_FIELD_H