From 22c815664a764f3b9cc10f162e9d6a63d1487b8a Mon Sep 17 00:00:00 2001
From: ravi688 <rp0412204@gmail.com>
Date: Tue, 7 Jan 2025 21:50:39 +0530
Subject: [PATCH] [SUTK] Bring tab associated with currently viewed
 NotebookPage into view 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 | 13 +++++++++++--
 sutk/source/NotebookView.cpp       | 15 +++++++++++++++
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/sutk/include/sutk/NotebookView.hpp b/sutk/include/sutk/NotebookView.hpp
index c87e7630..f28aa860 100644
--- a/sutk/include/sutk/NotebookView.hpp
+++ b/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; }
 
diff --git a/sutk/source/NotebookView.cpp b/sutk/source/NotebookView.cpp
index 7e4e08bd..af80786f 100644
--- a/sutk/source/NotebookView.cpp
+++ b/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