* Changed the signature of UpdateText() to return a "const char*" (char*

really makes no sense if the pointer belongs to the derived class and
  only confuses). Note this change does not affect binary compatibility.
* Introduced a new MaxUpdateTextWidth() virtual method which is really
  necessary to handle the update text correctly in the layout.
* Introduced a new UpdateTextChanged() method which can be called to
  notify the control of a changed update text. Internally, SetValue()
  also uses it.
* Handle the width or height of the UpdateText() correctly in the layout.
  For horizontal layout, the width was forgotten to be included in
  GetPreferredSize(), for vertical layout, it was completely broken before.
* Handle invalidation correctly when the UpdateText() changes.
* Remove the arbitrary insets for labels from the border the control. This
  makes it easier to align the control's labels with other controls.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26447 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/os/interface/Slider.h

@@ -91,7 +91,8 @@ class BSlider : public BControl {
 		virtual void		DrawThumb();
 		virtual void		DrawFocusMark();
 		virtual	void		DrawText();
-		virtual char*		UpdateText() const;			
+		virtual const char*	UpdateText() const;
+				void		UpdateTextChanged();
 
 		virtual BRect		BarFrame() const;
 		virtual BRect		HashMarksFrame() const;
@@ -145,6 +146,8 @@ class BSlider : public BControl {
 
 		virtual void		SetLimits(int32 minimum, int32 maximum);
 
+		virtual	float		MaxUpdateTextWidth();
+
 		virtual	void		InvalidateLayout(bool descendants = false);
 
 		virtual	BSize		MinSize();
@@ -164,7 +167,6 @@ class BSlider : public BControl {
 
 				BSize		_ValidateMinSize();
 
-		virtual	void		_ReservedSlider5();
 		virtual	void		_ReservedSlider6();
 		virtual	void		_ReservedSlider7();
 		virtual	void		_ReservedSlider8();
@@ -187,7 +189,7 @@ class BSlider : public BControl {
 
 		char*				fMinLimitLabel;
 		char*				fMaxLimitLabel;
-		char*				fUpdateText;
+		const char*			fUpdateText;
 
 		int32 				fMinValue;
 		int32 				fMaxValue;
@@ -211,10 +213,12 @@ class BSlider : public BControl {
 
 		BSize				fMinSize;
 
+		float				fMaxUpdateTextWidth;
+
 #if USE_OFF_SCREEN_VIEW
-		uint32				_reserved[5];
+		uint32				_reserved[4];
 #else
-		uint32				_reserved[7];
+		uint32				_reserved[6];
 #endif
 };