[SUTK] Bring tab associated with currently viewed NotebookPage into v…

…iew of TabBar's ScrollContainer

 - Affected test: NOTEBOOK
 - Changes can be noticed by adding many new tabs and the newly created tab should come into view (i.e. shouldn't be hiding on the either side).

sutk/include/sutk/NotebookView.hpp

@@ -136,7 +136,16 @@ namespace SUTK
 		Tab* getSelectedTab() noexcept { return m_selectedTab; }
 	};
 
-	typedef MaskedScrollableContainer<TabBar> ScrollableTabBar;
+	class SUTK_API ScrollableTabBar : public MaskedScrollableContainer<TabBar>
+	{
+		using MaskedScrollableContainer::MaskedScrollableContainer;
+	public:
+		// Brings (instantaneously) TabView associated with the Tab under the area of ScrollContainer of this ScrollableTabBar.
+		// If the Tab is hiding on the right side of the ScrollContainer, then the Tab is brought into view on the Right side
+		// If the Tab is hiding on the left side of the ScrollContainer, then the Tab is brought into view on the Left side
+		// No action is taken if the Tab is already into view.
+		void scrollToTab(Tab* tab) noexcept;
+	};
 
 	class TabRemoveAnimation;
 	class TabInsertAnimation;
@@ -231,7 +240,7 @@ namespace SUTK
 		~NotebookView() noexcept;
 		void checkForTabSwap() noexcept;
 
-		TabBar* getTabBar() noexcept { return m_tabBar; }
+		ScrollableTabBar* getTabBar() noexcept { return m_tabBar; }
 
 		OnPageSelectEvent& getOnPageSelectEvent() noexcept { return m_onPageSelectEvent; }
 

sutk/source/NotebookView.cpp

@@ -594,6 +594,19 @@ namespace SUTK
 		}
 	}
 
+	void ScrollableTabBar::scrollToTab(Tab* tab) noexcept
+	{
+		ScrollContainer* scrollCont = getScrollContainer();
+		// Get rectangle of TabView in the local space of ScrollContainer
+		auto rect = tab->getTabView()->getRectRelativeTo(scrollCont);
+		// If the TabView is hiding on the right side of the ScrollContainer then scroll to left
+		if(f32 distance = rect.getRight() - scrollCont->getSize().width; distance > 0)
+			scrollCont->addScrollDelta(Vec2Df::left() * distance);
+		// else If the TabView is hiding on the left side of the ScrollContainer then scroll to right
+		else if(f32 distance = rect.getLeft() - scrollCont->getPosition().x; distance < 0)
+			scrollCont->addScrollDelta(Vec2Df::left() * distance);
+	}
+
 	Tab* NotebookView::createTab(const std::string_view labelStr, NotebookPage* page, Tab* afterTab) noexcept
 	{
 		// Create TabView
@@ -656,6 +669,8 @@ namespace SUTK
 	void NotebookView::viewPage(NotebookPage* page) noexcept
 	{
 		m_tabBar->selectTab(page->getTab());
+		// The tab associated with this page must be in the view
+		m_tabBar->scrollToTab(page->getTab());
 	}
 
 	static NotebookPage* GetAdjacentPage(NotebookPage* page) noexcept