From fbba1e712440d2abf9180eae732a8cb8d6f114ba Mon Sep 17 00:00:00 2001
From: "Michael Z. Kadaner" <MKadaner@users.noreply.github.com>
Date: Sat, 12 Aug 2023 21:34:24 -0700
Subject: [PATCH] Work in progress.

---
 far/vmenu.cpp | 116 +++++++++++++++++++++++++++++---------------------
 far/vmenu.hpp |   2 +
 2 files changed, 69 insertions(+), 49 deletions(-)

diff --git a/far/vmenu.cpp b/far/vmenu.cpp
index 861ff72c17..b937d5a004 100644
--- a/far/vmenu.cpp
+++ b/far/vmenu.cpp
@@ -2088,7 +2088,7 @@ void VMenu::DrawTitles() const
 
 void VMenu::ShowMenu()
 {
-	const auto ServiceAreaSize = GetServiceAreaSize();
+	const auto ServiceAreaSize{ GetServiceAreaSize() };
 	MaxLineWidth = ServiceAreaSize > static_cast<size_t>(m_Where.width())? 0 : m_Where.width() - ServiceAreaSize;
 
 	if (m_Where.right <= m_Where.left || m_Where.bottom <= m_Where.top)
@@ -2116,50 +2116,22 @@ void VMenu::ShowMenu()
 		AssignHighlights(CheckFlags(VMENU_REVERSEHIGHLIGHT));
 
 	const auto ClientRect{ GetClientRect() };
+	const auto VisualTopPos{ AdjustTopPos(ClientRect.height()) };
 
-	int VisualSelectPos = GetVisualPos(SelectPos);
-	int VisualTopPos = GetVisualPos(TopPos);
-
-	// коррекция Top`а
-	// 2023-07-09 MZK: What is it? Should it be ClientRect.height() instead of m_Where.height()?
-	if (VisualTopPos+GetShowItemCount() >= m_Where.height() - 1 && VisualSelectPos == GetShowItemCount()-1)
-	{
-		VisualTopPos--;
-
-		if (VisualTopPos<0)
-			VisualTopPos=0;
-	}
-
-	VisualTopPos = std::min(VisualTopPos, GetShowItemCount() - (ClientRect.height() - 4));
-
-	if (VisualSelectPos > VisualTopPos + (ClientRect.height() - 1))
-	{
-		VisualTopPos = VisualSelectPos - (ClientRect.height() - 1);
-	}
-
-	if (VisualSelectPos < VisualTopPos)
-	{
-		TopPos=SelectPos;
-		VisualTopPos=VisualSelectPos;
-	}
-	else
-	{
-		TopPos=VisualPosToReal(VisualTopPos);
-	}
-
-	if (VisualTopPos<0)
-		VisualTopPos=0;
+	if (ClientRect.width() <= 0)
+		return;
 
-	if (TopPos<0)
-		TopPos=0;
+	string LineBuffer(ClientRect.width(), L' ');
 
 	for (int Y = ClientRect.top, I = TopPos; Y <= ClientRect.bottom; ++Y, ++I)
 	{
 		if (I >= static_cast<int>(Items.size()))
 		{
+			LineBuffer.replace(LineBuffer.cbegin(), LineBuffer.cend(), ClientRect.width(), L' ');
+
 			SetColor(Colors[VMenuColorText]);
 			GotoXY(ClientRect.left, Y);
-			Text(string(ClientRect.width(), L' '));
+			Text(string(LineBuffer));
 			continue;
 		}
 
@@ -2183,27 +2155,22 @@ void VMenu::ShowMenu()
 			continue;
 		}
 
+		LineBuffer.at(0) = GetItemCheckMark(Items[I]);
+		LineBuffer.replace(LineBuffer.cbegin() + 1, LineBuffer.cend(), ClientRect.width(), L' ');
+
+		const auto ItemIndent{ Items[I].Indent() };
+		const auto ItemHanging{ Items[I].Hanging() };
+
+
 		const auto ColorIndices{ GetItemColors(Items[I]) };
 
 		GotoXY(m_Where.left + (m_BoxType == NO_BOX? 0 : 1), Y);
 
 		SetColor(Colors[ColorIndices.Normal]);
 
-		wchar_t CheckMark = L' ';
-
-		if (Items[I].Flags & LIF_CHECKED)
-		{
-			if (!(Items[I].Flags & 0x0000FFFF))
-				CheckMark = 0x221A;
-			else
-				CheckMark = static_cast<wchar_t>(Items[I].Flags & 0x0000FFFF);
-		}
-
-		const auto ItemIndent{ Items[I].Indent() };
-		const auto ItemHanging{ Items[I].Hanging() };
 
 		string strMenuLine{ CheckMark };
-		strMenuLine.push_back(L' '); // left scroller (<<) placeholder
+		// LineBuffer.at(1) = L' '; // left scroller («) placeholder
 		const auto LineWidthPlusLeftMargin{ strMenuLine.size() + MaxLineWidth };
 		strMenuLine.append(ItemIndent, L' ');
 		const auto PrefixSize = strMenuLine.size();
@@ -2320,6 +2287,46 @@ rectangle VMenu::GetClientRect() const noexcept
 	return { m_Where.left + 1, m_Where.top + 1, m_Where.right - 1, m_Where.bottom - 1 };
 }
 
+int VMenu::AdjustTopPos(const int ClientHeight)
+{
+	int VisualSelectPos = GetVisualPos(SelectPos);
+	int VisualTopPos = GetVisualPos(TopPos);
+
+	// 2023-07-09 MZK: What is it? Should it be ClientRect.height() instead of m_Where.height()?
+	if (VisualTopPos + GetShowItemCount() >= m_Where.height() - 1 && VisualSelectPos == GetShowItemCount() - 1)
+	{
+		VisualTopPos--;
+
+		if (VisualTopPos < 0)
+			VisualTopPos = 0;
+	}
+
+	VisualTopPos = std::min(VisualTopPos, GetShowItemCount() - (ClientHeight - 4));
+
+	if (VisualSelectPos > VisualTopPos + (ClientHeight - 1))
+	{
+		VisualTopPos = VisualSelectPos - (ClientHeight - 1);
+	}
+
+	if (VisualSelectPos < VisualTopPos)
+	{
+		TopPos = SelectPos;
+		VisualTopPos = VisualSelectPos;
+	}
+	else
+	{
+		TopPos = VisualPosToReal(VisualTopPos);
+	}
+
+	if (VisualTopPos < 0)
+		VisualTopPos = 0;
+
+	if (TopPos < 0)
+		TopPos = 0;
+
+	return VisualTopPos;
+}
+
 void VMenu::ConnectSeparator(size_t CurItem, string& separator) const
 {
 	if (CheckFlags(VMENU_NOMERGEBORDER) || separator.size() <= 3)
@@ -2366,6 +2373,17 @@ void VMenu::ApplySeparatorName(size_t CurItem, string& separator) const
 	separator.at(NamePos + NameWidth) = L' ';
 }
 
+wchar_t VMenu::GetItemCheckMark(const MenuItemEx& CurItem) const noexcept
+{
+	if (!(CurItem.Flags & LIF_CHECKED))
+		return L' ';
+
+	if (!(CurItem.Flags & 0x0000FFFF))
+		return 0x221A;
+
+	return static_cast<wchar_t>(CurItem.Flags & 0x0000FFFF);
+}
+
 VMenu::ItemColorIndicies VMenu::GetItemColors(const MenuItemEx& CurItem) const
 {
 	const auto Selected{ !!(CurItem.Flags & LIF_SELECTED) };
diff --git a/far/vmenu.hpp b/far/vmenu.hpp
index c0daa81df6..a6dcdbc2ea 100644
--- a/far/vmenu.hpp
+++ b/far/vmenu.hpp
@@ -309,8 +309,10 @@ class VMenu final: public Modal
 
 	void ShowMenu();
 	rectangle GetClientRect() const noexcept;
+	int AdjustTopPos(int ClientHeight);
 	void ConnectSeparator(size_t CurItem, string& separator) const;
 	void ApplySeparatorName(size_t CurItem, string& separator) const;
+	wchar_t GetItemCheckMark(const MenuItemEx& CurItem) const noexcept;
 	ItemColorIndicies GetItemColors(const MenuItemEx& CurItem) const;
 	void DrawTitles() const;
 	int GetItemPosition(int Position) const;