feat: Add preview pane for document preview

Explorer++/Explorer++/Config.h

@@ -113,6 +113,9 @@ struct Config
 	ValueWrapper<COLORREF> displayWindowTextColor = DisplayWindowDefaults::TEXT_COLOR;
 	ValueWrapper<LOGFONT> displayWindowFont = DisplayWindowDefaults::FONT;
 
+	// Preview pane - shows document previews on the right side
+	ValueWrapper<bool> showPreviewPane = true;
+
 	// These are settings that are shared between all tabs. It's not
 	// possible to adjust them on a per-tab basis.
 	GlobalFolderSettings globalFolderSettings;

Explorer++/Explorer++/DisplayWindow.cpp

@@ -8,8 +8,10 @@
 #include "Config.h"
 #include "DisplayWindow/DisplayWindow.h"
 #include "MainResource.h"
+#include "PreviewPane.h"
 #include "ShellBrowser/ShellBrowserImpl.h"
 #include "TabContainer.h"
+#include <glog/logging.h>
 #include "../Helper/FolderSize.h"
 #include "../Helper/Helper.h"
 #include "../Helper/ShellHelper.h"
@@ -390,3 +392,42 @@ void Explorerplusplus::UpdateDisplayWindowForMultipleFiles(const Tab &tab)
 
 	DisplayWindow_BufferText(m_displayWindow->GetHWND(), szTotalSize);
 }
+
+void Explorerplusplus::UpdatePreviewPane(const Tab &tab)
+{
+	OutputDebugString(L"[PreviewPane] UpdatePreviewPane called\n");
+
+	if (!m_config->showPreviewPane.get() || !m_previewPane)
+	{
+		OutputDebugString(L"[PreviewPane] Preview pane disabled or null\n");
+		return;
+	}
+
+	int nSelected = tab.GetShellBrowserImpl()->GetNumSelected();
+	wchar_t msg[256];
+	swprintf_s(msg, L"[PreviewPane] nSelected=%d\n", nSelected);
+	OutputDebugString(msg);
+
+	if (nSelected == 1)
+	{
+		int iSelected = ListView_GetNextItem(tab.GetShellBrowserImpl()->GetListView(), -1, LVNI_SELECTED);
+		swprintf_s(msg, L"[PreviewPane] iSelected=%d\n", iSelected);
+		OutputDebugString(msg);
+
+		if (iSelected != -1)
+		{
+			auto pidl = tab.GetShellBrowserImpl()->GetItemCompleteIdl(iSelected);
+			OutputDebugString(pidl.get() ? L"[PreviewPane] Got pidl, calling SetPreviewFile\n" 
+			                              : L"[PreviewPane] pidl is null\n");
+			m_previewPane->SetPreviewFile(pidl.get());
+		}
+		else
+		{
+			m_previewPane->ClearPreview();
+		}
+	}
+	else
+	{
+		m_previewPane->ClearPreview();
+	}
+}

Explorer++/Explorer++/Explorer++.cpp

@@ -10,6 +10,7 @@
 #include "Bookmarks/UI/BookmarksMainMenu.h"
 #include "Config.h"
 #include "DisplayWindow/DisplayWindow.h"
+#include "PreviewPane.h"
 #include "FrequentLocationsMenu.h"
 #include "HistoryMenu.h"
 #include "HolderWindow.h"
@@ -153,6 +154,8 @@ void Explorerplusplus::SetUpControlVisibilityConfigListeners()
 		m_config->showFolders.addObserver(std::bind(&Explorerplusplus::UpdateLayout, this)));
 	m_connections.push_back(
 		m_config->showDisplayWindow.addObserver(std::bind(&Explorerplusplus::UpdateLayout, this)));
+	m_connections.push_back(
+		m_config->showPreviewPane.addObserver(std::bind(&Explorerplusplus::UpdateLayout, this)));
 }
 
 void Explorerplusplus::Initialize(const WindowStorageData *storageData)
@@ -171,6 +174,7 @@ void Explorerplusplus::Initialize(const WindowStorageData *storageData)
 
 	CreateMainRebarAndChildren(storageData);
 	InitializeDisplayWindow();
+	InitializePreviewPane();
 	InitializeTabs();
 	CreateFolderControls();
 
@@ -206,6 +210,11 @@ void Explorerplusplus::InitializeDisplayWindow()
 	ApplyDisplayWindowPosition();
 }
 
+void Explorerplusplus::InitializePreviewPane()
+{
+	m_previewPane = PreviewPane::Create(m_hContainer, m_config);
+}
+
 void Explorerplusplus::CreateFolderControls()
 {
 	UINT holderStyle = WS_CHILD | WS_CLIPSIBLINGS | WS_CLIPCHILDREN;

Explorer++/Explorer++/Explorer++.h

@@ -63,6 +63,7 @@ class TabBacking;
 class TabContainer;
 class TaskbarThumbnails;
 class ThemeWindowTracker;
+class PreviewPane;
 class WindowSubclass;
 
 namespace Applications
@@ -350,6 +351,8 @@ class Explorerplusplus : public BrowserWindow, public CoreInterface, public Plug
 
 	/* Miscellaneous. */
 	void InitializeDisplayWindow();
+	void InitializePreviewPane();
+	void UpdatePreviewPane(const Tab &tab);
 
 	static void FolderSizeCallbackStub(int nFolders, int nFiles, PULARGE_INTEGER lTotalFolderSize,
 		LPVOID pData);
@@ -386,6 +389,10 @@ class Explorerplusplus : public BrowserWindow, public CoreInterface, public Plug
 	int m_displayWindowWidth = LayoutDefaults::DEFAULT_DISPLAY_WINDOW_WIDTH;
 	int m_displayWindowHeight = LayoutDefaults::DEFAULT_DISPLAY_WINDOW_HEIGHT;
 
+	// Preview pane
+	PreviewPane *m_previewPane = nullptr;
+	int m_previewPaneWidth = LayoutDefaults::DEFAULT_PREVIEW_PANE_WIDTH;
+
 	wil::com_ptr_nothrow<IImageList> m_mainMenuSystemImageList;
 	std::vector<wil::unique_hbitmap> m_mainMenuImages;
 	MainMenuPreShowSignal m_mainMenuPreShowSignal;

Explorer++/Explorer++/Explorer++.vcxproj

@@ -1404,6 +1404,7 @@
     <ClCompile Include="DialogStorageHelper.cpp" />
     <ClCompile Include="DisplayColoursDialog.cpp" />
     <ClCompile Include="DisplayWindow.cpp" />
+    <ClCompile Include="PreviewPane.cpp" />
     <ClCompile Include="DrivesToolbar.cpp" />
     <ClCompile Include="Plugins\Event.cpp" />
     <ClCompile Include="EventSwitcher.cpp" />
@@ -1773,6 +1774,7 @@
     <ClInclude Include="DialogConstants.h" />
     <ClInclude Include="DisplayColoursDialog.h" />
     <ClInclude Include="DisplayWindow\DisplayWindow.h" />
+    <ClInclude Include="PreviewPane.h" />
     <ClInclude Include="DrivesToolbar.h" />
     <ClInclude Include="Plugins\Event.h" />
     <ClInclude Include="Explorer++.h" />

Explorer++/Explorer++/HandleWindowState.cpp

@@ -19,6 +19,7 @@
 void Explorerplusplus::UpdateWindowStates(const Tab &tab)
 {
 	UpdateDisplayWindow(tab);
+	UpdatePreviewPane(tab);
 }
 
 /*
@@ -89,6 +90,7 @@ void Explorerplusplus::SetProgramMenuItemStates(HMENU hProgramMenu)
 	MenuHelper::CheckItem(hProgramMenu, IDM_VIEW_STATUSBAR, m_config->showStatusBar.get());
 	MenuHelper::CheckItem(hProgramMenu, IDM_VIEW_FOLDERS, m_config->showFolders.get());
 	MenuHelper::CheckItem(hProgramMenu, IDM_VIEW_DISPLAYWINDOW, m_config->showDisplayWindow.get());
+	MenuHelper::CheckItem(hProgramMenu, IDM_VIEW_PREVIEWPANE, m_config->showPreviewPane.get());
 	MenuHelper::CheckItem(hProgramMenu, IDM_VIEW_TOOLBARS_ADDRESS_BAR,
 		m_config->showAddressBar.get());
 	MenuHelper::CheckItem(hProgramMenu, IDM_VIEW_TOOLBARS_MAIN_TOOLBAR,

Explorer++/Explorer++/LayoutDefaults.h

@@ -10,6 +10,7 @@ namespace LayoutDefaults
 inline constexpr UINT DEFAULT_TREEVIEW_WIDTH = 208;
 inline constexpr UINT DEFAULT_DISPLAY_WINDOW_WIDTH = 300;
 inline constexpr UINT DEFAULT_DISPLAY_WINDOW_HEIGHT = 90;
+inline constexpr UINT DEFAULT_PREVIEW_PANE_WIDTH = 350;
 
 RECT GetDefaultMainWindowBounds();
 

Explorer++/Explorer++/MainWndSwitch.cpp

@@ -96,7 +96,7 @@ LRESULT Explorerplusplus::WindowProcedure(HWND hwnd, UINT msg, WPARAM wParam, LP
 		{
 			Tab &selectedTab = GetActivePane()->GetTabContainer()->GetSelectedTab();
 
-			UpdateDisplayWindow(selectedTab);
+			UpdateWindowStates(selectedTab);
 			m_mainToolbar->UpdateToolbarButtonStates();
 
 			KillTimer(m_hContainer, LISTVIEW_ITEM_CHANGED_TIMER_ID);
@@ -431,6 +431,10 @@ LRESULT Explorerplusplus::HandleMenuOrToolbarButtonOrAccelerator(HWND hwnd, UINT
 		m_commandController.ExecuteCommand(id);
 		break;
 
+	case IDM_VIEW_PREVIEWPANE:
+		m_config->showPreviewPane = !m_config->showPreviewPane.get();
+		break;
+
 	case IDM_DISPLAYWINDOW_VERTICAL:
 		m_config->displayWindowVertical = !m_config->displayWindowVertical;
 		ApplyDisplayWindowPosition();

Explorer++/Explorer++/MsgHandler.cpp

@@ -11,6 +11,7 @@
 #include "DarkModeManager.h"
 #include "DisplayWindow/DisplayWindow.h"
 #include "HolderWindow.h"
+#include "PreviewPane.h"
 #include "MainRebarStorage.h"
 #include "MainRebarView.h"
 #include "MainResource.h"
@@ -337,6 +338,11 @@ void Explorerplusplus::UpdateLayout()
 		}
 	}
 
+	if (m_config->showPreviewPane.get() && m_previewPane)
+	{
+		indentRight += m_previewPaneWidth;
+	}
+
 	if (m_config->showFolders.get())
 	{
 		indentLeft = m_treeViewWidth;
@@ -429,7 +435,12 @@ void Explorerplusplus::UpdateLayout()
 
 	if (m_config->displayWindowVertical)
 	{
-		SetWindowPos(m_displayWindow->GetHWND(), nullptr, mainWindowWidth - indentRight,
+		int displayWindowLeft = mainWindowWidth - indentRight;
+		if (m_config->showPreviewPane.get())
+		{
+			displayWindowLeft += m_previewPaneWidth;
+		}
+		SetWindowPos(m_displayWindow->GetHWND(), nullptr, displayWindowLeft,
 			indentRebar, m_displayWindowWidth, mainWindowHeight - indentRebar - indentBottom,
 			displayWindowShowFlags);
 	}
@@ -439,6 +450,23 @@ void Explorerplusplus::UpdateLayout()
 			mainWindowWidth, m_displayWindowHeight, displayWindowShowFlags);
 	}
 
+	/* <---- Preview pane ----> */
+
+	if (m_previewPane)
+	{
+		UINT previewPaneShowFlags =
+			(m_config->showPreviewPane.get() ? SWP_SHOWWINDOW : SWP_HIDEWINDOW) | SWP_NOZORDER;
+
+		int previewPaneLeft = mainWindowWidth - m_previewPaneWidth;
+		if (m_config->showDisplayWindow.get() && m_config->displayWindowVertical)
+		{
+			previewPaneLeft -= m_displayWindowWidth;
+		}
+
+		SetWindowPos(m_previewPane->GetHWND(), nullptr, previewPaneLeft, indentRebar,
+			m_previewPaneWidth, mainWindowHeight - indentRebar - indentBottom, previewPaneShowFlags);
+	}
+
 	/* <---- ALL listview windows ----> */
 
 	for (auto &tab : GetActivePane()->GetTabContainer()->GetAllTabs() | boost::adaptors::map_values)
@@ -688,7 +716,7 @@ void Explorerplusplus::CopyColumnInfoToClipboard()
 void Explorerplusplus::OnDirectoryContentsChanged(const ShellBrowser *shellBrowser)
 {
 	const auto *tab = shellBrowser->GetTab();
-	UpdateDisplayWindow(*tab);
+	UpdateWindowStates(*tab);
 }
 
 void Explorerplusplus::CreateNewWindow(const std::vector<TabStorageData> &tabs)