BButton: Add flat property

* Add methods SetFlat()/IsFlat(). A flat button doesn't draw its frame,
  unless the mouse is hovering over it or it is otherwise activated.
* As a side effect this change also activates the hover glow that was
  already implemented in BControlLook, but not activated in BButton.

headers/os/interface/Button.h

@@ -39,6 +39,9 @@ public:
 	virtual	void				SetLabel(const char* string);
 			bool				IsDefault() const;
 
+			bool				IsFlat() const;
+			void				SetFlat(bool flat);
+
 	virtual	void				MessageReceived(BMessage* message);
 	virtual	void				WindowActivated(bool active);
 	virtual	void				MouseMoved(BPoint point, uint32 transit,
@@ -79,7 +82,6 @@ private:
 	virtual	void				_ReservedButton2();
 	virtual	void				_ReservedButton3();
 
-private:
 			BButton&			operator=(const BButton &);
 
 			BSize				_ValidatePreferredSize();
@@ -87,9 +89,15 @@ private:
 			BRect				_DrawDefault(BRect bounds, bool enabled);
 			void 				_DrawFocusLine(float x, float y, float width, 
 									bool bVisible);
+
+	inline	bool				_Flag(uint32 flag) const;
+	inline	bool				_SetFlag(uint32 flag, bool set);
 			 
+private:
 			BSize				fPreferredSize;
+			uint32				fFlags;
 			bool				fDrawAsDefault;
+			bool				fFlat;
 
 			uint32				_reserved[2];
 };

headers/os/interface/ControlLook.h

@@ -82,6 +82,7 @@ public:
 		B_DEFAULT_BUTTON		= 1 << 5,
 		B_IGNORE_OUTLINE		= 1 << 6,
 		B_PARTIALLY_ACTIVATED	= 1 << 7, // like B_ACTIVATED, but for tri-state
+		B_FLAT					= 1 << 8, // flat look (e.g. button background)
 
 		B_BLEND_FRAME		= 1 << 16
 	};

src/kits/interface/Button.cpp

@@ -26,6 +26,13 @@
 #include <binary_compatibility/Interface.h>
 
 
+enum {
+	FLAG_DEFAULT 	= 0x01,
+	FLAG_FLAT		= 0x02,
+	FLAG_INSIDE		= 0x04,
+};
+
+
 static const float kLabelMargin = 3;
 
 
@@ -34,7 +41,7 @@ BButton::BButton(BRect frame, const char* name, const char* label,
 	: BControl(frame, name, label, message, resizingMode,
 			flags | B_WILL_DRAW | B_FULL_UPDATE_ON_RESIZE),
 	fPreferredSize(-1, -1),
-	fDrawAsDefault(false)
+	fFlags(0)
 {
 	// Resize to minimum height if needed
 	font_height fh;
@@ -50,7 +57,7 @@ BButton::BButton(const char* name, const char* label, BMessage* message,
 	: BControl(name, label, message,
 			flags | B_WILL_DRAW | B_FULL_UPDATE_ON_RESIZE),
 	fPreferredSize(-1, -1),
-	fDrawAsDefault(false)
+	fFlags(0)
 {
 }
 
@@ -59,7 +66,7 @@ BButton::BButton(const char* label, BMessage* message)
 	: BControl(NULL, label, message,
 			B_WILL_DRAW | B_NAVIGABLE | B_FULL_UPDATE_ON_RESIZE),
 	fPreferredSize(-1, -1),
-	fDrawAsDefault(false)
+	fFlags(0)
 {
 }
 
@@ -71,10 +78,12 @@ BButton::~BButton()
 
 BButton::BButton(BMessage* archive)
 	: BControl(archive),
-	fPreferredSize(-1, -1)
+	fPreferredSize(-1, -1),
+	fFlags(0)
 {
-	if (archive->FindBool("_default", &fDrawAsDefault) != B_OK)
+	bool isDefault = false;
-		fDrawAsDefault = false;
+	if (archive->FindBool("_default", &isDefault) == B_OK && isDefault)
+		_SetFlag(FLAG_DEFAULT, true);
 	// NOTE: Default button state will be synchronized with the window
 	// in AttachedToWindow().
 }
@@ -112,8 +121,13 @@ BButton::Draw(BRect updateRect)
 	rgb_color background = LowColor();
 	rgb_color base = background;
 	uint32 flags = be_control_look->Flags(this);
-	if (IsDefault())
+	if (_Flag(FLAG_DEFAULT))
 		flags |= BControlLook::B_DEFAULT_BUTTON;
+	if (_Flag(FLAG_FLAT) && !IsTracking())
+		flags |= BControlLook::B_FLAT;
+	if (_Flag(FLAG_INSIDE))
+		flags |= BControlLook::B_HOVER;
+
 	be_control_look->DrawButtonFrame(this, rect, updateRect,
 		base, background, flags);
 	be_control_look->DrawButtonBackground(this, rect, updateRect,
@@ -207,12 +221,10 @@ BButton::MakeDefault(bool flag)
 		oldDefault = window->DefaultButton();
 
 	if (flag) {
-		if (fDrawAsDefault && oldDefault == this)
+		if (_Flag(FLAG_DEFAULT) && oldDefault == this)
 			return;
 
-		if (!fDrawAsDefault) {
+		if (_SetFlag(FLAG_DEFAULT, true)) {
-			fDrawAsDefault = true;
-
 			if ((Flags() & B_SUPPORTS_LAYOUT) != 0)
 				InvalidateLayout();
 			else {
@@ -224,11 +236,9 @@ BButton::MakeDefault(bool flag)
 		if (window && oldDefault != this)
 			window->SetDefaultButton(this);
 	} else {
-		if (!fDrawAsDefault)
+		if (!_SetFlag(FLAG_DEFAULT, false))
 			return;
 
-		fDrawAsDefault = false;
-
 		if ((Flags() & B_SUPPORTS_LAYOUT) != 0)
 			InvalidateLayout();
 		else {
@@ -252,7 +262,22 @@ BButton::SetLabel(const char *string)
 bool
 BButton::IsDefault() const
 {
-	return fDrawAsDefault;
+	return _Flag(FLAG_DEFAULT);
+}
+
+
+bool
+BButton::IsFlat() const
+{
+	return _Flag(FLAG_FLAT);
+}
+
+
+void
+BButton::SetFlat(bool flat)
+{
+	if (_SetFlag(FLAG_FLAT, flat))
+		Invalidate();
 }
 
 
@@ -273,11 +298,13 @@ BButton::WindowActivated(bool active)
 void
 BButton::MouseMoved(BPoint point, uint32 transit, const BMessage *message)
 {
+	bool inside = Bounds().Contains(point);
+	if (_SetFlag(FLAG_INSIDE, inside))
+		Invalidate();
+
 	if (!IsTracking())
 		return;
 
-	bool inside = Bounds().Contains(point);
-
 	if ((Value() == B_CONTROL_ON) != inside)
 		SetValue(inside ? B_CONTROL_ON : B_CONTROL_OFF);
 }
@@ -291,6 +318,8 @@ BButton::MouseUp(BPoint point)
 
 	if (Bounds().Contains(point))
 		Invoke();
+	else if (_Flag(FLAG_FLAT))
+		Invalidate();
 
 	SetTracking(false);
 }
@@ -516,7 +545,7 @@ BButton::_ValidatePreferredSize()
 		float left, top, right, bottom;
 		be_control_look->GetInsets(BControlLook::B_BUTTON_FRAME,
 			BControlLook::B_BUTTON_BACKGROUND,
-			fDrawAsDefault ? BControlLook::B_DEFAULT_BUTTON : 0,
+			IsDefault() ? BControlLook::B_DEFAULT_BUTTON : 0,
 			left, top, right, bottom);
 
 		// width
@@ -608,6 +637,28 @@ BButton::_DrawFocusLine(float x, float y, float width, bool visible)
 }
 
 
+inline bool
+BButton::_Flag(uint32 flag) const
+{
+	return (fFlags & flag) != 0;
+}
+
+
+inline bool
+BButton::_SetFlag(uint32 flag, bool set)
+{
+	if (((fFlags & flag) != 0) == set)
+		return false;
+
+	if (set)
+		fFlags |= flag;
+	else
+		fFlags &= ~flag;
+
+	return true;
+}
+
+
 extern "C" void
 B_IF_GCC_2(InvalidateLayout__7BButtonb, _ZN7BButton16InvalidateLayoutEb)(
 	BView* view, bool descendants)

src/kits/interface/ControlLook.cpp

@@ -2046,6 +2046,20 @@ BControlLook::_DrawButtonFrame(BView* view, BRect& rect,
 	BRegion clipping(updateRect);
 	view->ConstrainClippingRegion(&clipping);
 
+	// If the button is flat and neither activated nor otherwise highlighted
+	// (mouse hovering or focussed), draw it flat.
+	if ((flags & B_FLAT) != 0
+		&& (flags & (B_ACTIVATED | B_PARTIALLY_ACTIVATED)) == 0
+		&& ((flags & (B_HOVER | B_FOCUSED)) == 0
+			|| (flags & B_DISABLED) != 0)) {
+		_DrawFrame(view, rect, background, background, background,
+			background, borders);
+		_DrawFrame(view, rect, background, background, background,
+			background, borders);
+		view->PopState();
+		return;
+	}
+
 	// outer edge colors
 	rgb_color edgeLightColor;
 	rgb_color edgeShadowColor;
@@ -2317,6 +2331,19 @@ BControlLook::_DrawButtonBackground(BView* view, BRect& rect,
 	BRegion clipping(updateRect);
 	view->ConstrainClippingRegion(&clipping);
 
+	// If the button is flat and neither activated nor otherwise highlighted
+	// (mouse hovering or focussed), draw it flat.
+	if ((flags & B_FLAT) != 0
+		&& (flags & (B_ACTIVATED | B_PARTIALLY_ACTIVATED)) == 0
+		&& ((flags & (B_HOVER | B_FOCUSED)) == 0
+			|| (flags & B_DISABLED) != 0)) {
+		_DrawFrame(view, rect, base, base, base, base, borders);
+		view->SetHighColor(base);
+		view->FillRect(rect);
+		view->PopState();
+		return;
+	}
+
 	// inner bevel colors
 	rgb_color bevelLightColor  = _BevelLightColor(base, flags);
 	rgb_color bevelShadowColor = _BevelShadowColor(base, flags);