Title bar background color and text color follow windows settings whe…

…n not customized (WinMerge#2505) (2)

-  Use accent color as titlebar color only if "Show accent color in title bars and window borders" is set to "On" in the Windows Settings > Personalization > Colors page.

-  For Windows XP support, I would like to avoid using DwmGetColorizationColor(). I would like to get accent color from registry.

-  WinMerge originally used COLOR_ACTIVECAPTION and COLOR_INACTIVECAPTION, but I don't want to use them as titlebar color because they are documented as unsupported in Windows 10 and later.

-  Move accent color related handling from CMDITabBar to CTitleBarHelper.

Src/Common/AccentColor.cpp

@@ -0,0 +1,39 @@
+// Copyright (c) 2024 Takashi Sawanaka
+// SPDX-License-Identifier: BSL-1.0
+/**
+ * @file  AccentColor.cpp
+ *
+ * @brief Implementation of the CAccentColor class
+ */
+
+#include "StdAfx.h"
+#include "AccentColor.h"
+#include "RegKey.h"
+
+CAccentColor::CAccentColor()
+	: m_accentColor(CLR_NONE)
+	, m_accentColorInactive(CLR_NONE)
+	, m_colorPrevalence(false)
+{
+	Reload();
+}
+
+CAccentColor& CAccentColor::Get()
+{
+	static CAccentColor s_accentColor;
+	return s_accentColor;
+}
+
+void CAccentColor::Reload()
+{
+	CRegKeyEx reg;
+	if (ERROR_SUCCESS != reg.Open(HKEY_CURRENT_USER, _T("SOFTWARE\\Microsoft\\Windows\\DWM")))
+		return;
+	m_accentColor = reg.ReadDword(_T("AccentColor"), CLR_NONE);
+	if (m_accentColor != CLR_NONE)
+		m_accentColor &= 0xffffff;
+	m_accentColorInactive = reg.ReadDword(_T("AccentColorInactive"), CLR_NONE);
+	if (m_accentColorInactive != CLR_NONE)
+		m_accentColorInactive &= 0xffffff;
+	m_colorPrevalence = reg.ReadDword(_T("ColorPrevalence"), false);
+}

Src/Common/AccentColor.h

@@ -0,0 +1,22 @@
+// Copyright (c) 2024 Takashi Sawanaka
+// SPDX-License-Identifier: BSL-1.0
+/**
+ * @file  AccentColor.h
+ *
+ * @brief Declaration file for CAccentColor class
+ */
+
+class CAccentColor
+{
+public:
+	CAccentColor();
+	COLORREF GetAccentColor() const { return m_accentColor; };
+	COLORREF GetAccentColorInactive() const { return m_accentColorInactive; }
+	bool GetColorPrevalence() const { return m_colorPrevalence; }
+	void Reload();
+	static CAccentColor& Get();
+private:
+	COLORREF m_accentColor;
+	COLORREF m_accentColorInactive;
+	bool m_colorPrevalence;
+};

Src/Common/MDITabBar.cpp

@@ -9,9 +9,6 @@
 #include "IMDITab.h"
 #include "cecolor.h"
 #include "RoundedRectWithShadow.h"
-#include <dwmapi.h>
-#include <RegKey.h>
-#pragma comment(lib, "dwmapi.lib")
 
 #ifdef _DEBUG
 #define new DEBUG_NEW
@@ -72,15 +69,6 @@ BOOL CMyTabCtrl::Create(CMDIFrameWnd* pMainFrame, CWnd* pParent)
 	m_pMainFrame = pMainFrame;
 	m_tooltips.Create(m_pMainFrame, TTS_NOPREFIX);
 	m_tooltips.AddTool(this, _T(""));
-	CRegKeyEx reg;
-	constexpr tchar_t* AccentColorInactive = _T("AccentColorInactive");
-	constexpr tchar_t* RegDir = _T("SOFTWARE\\Microsoft\\Windows\\DWM");
-	if (ERROR_SUCCESS == reg.Open(HKEY_CURRENT_USER, RegDir))
-	{
-		const auto clr = reg.ReadDword(AccentColorInactive, 0);
-		if (clr)
-			m_dwInactiveTitleColor = RGB(GetRValue(clr), GetGValue(clr), GetBValue(clr));
-	}
 	return TRUE;
 }
 
@@ -98,67 +86,27 @@ BOOL CMyTabCtrl::PreTranslateMessage(MSG* pMsg)
 	return __super::PreTranslateMessage(pMsg);
 }
 
-COLORREF CMyTabCtrl::GetDwmTitlebarColors()
-{
-	if (!m_bActive)
-	{
-		if (m_dwInactiveTitleColor)
-			return m_dwInactiveTitleColor;
-		return GetSysColor(COLOR_INACTIVECAPTION);
-	}
-	DWORD czclr = 0;
-	BOOL opaqueBlend = FALSE;
-	HRESULT hr = DwmGetColorizationColor(&czclr, &opaqueBlend);
-	if (SUCCEEDED(hr))
-	{
-		return RGB(static_cast<BYTE>(czclr >> 16), static_cast<BYTE>(czclr >> 8), static_cast<BYTE>(czclr));
-	}
-	return GetSysColor(COLOR_ACTIVECAPTION);
-}
-
-COLORREF CMyTabCtrl::GetDwmTitleTextColors()
+void CMyTabCtrl::SetActive(bool bActive)
 {
-	if (!m_bActive)
-	{
-		COLORREF clr = m_dwInactiveTitleColor ? m_dwInactiveTitleColor : GetSysColor(COLOR_INACTIVECAPTION);
-		if (GetRValue(clr) < 128 && GetGValue(clr) < 128 && GetBValue(clr) < 128)
-			return RGB(245, 245, 245);
-		return RGB(10, 10, 10);
-	}
-	DWORD czclr = 0;
-	BOOL opaqueBlend = FALSE;
-	HRESULT hr = DwmGetColorizationColor(&czclr, &opaqueBlend);
-	if (SUCCEEDED(hr))
-	{
-		const BYTE r = static_cast<BYTE>(czclr >> 16);
-		const BYTE g = static_cast<BYTE>(czclr >> 8);
-		const BYTE b = static_cast<BYTE>(czclr);
-		if (r < 128 && g < 128 && b < 128)
-			return RGB(255, 255, 255);
-		return RGB(0, 0, 0);
-	}
-	return GetSysColor(COLOR_CAPTIONTEXT);
+	CTitleBarHelper::ReloadAccentColor();
+	m_bActive = bActive;
 }
 
 static inline COLORREF getTextColor()
 {
 	return GetSysColor(COLOR_WINDOWTEXT);
 }
 
-COLORREF CMyTabCtrl::GetBackColor()
+COLORREF CMyTabCtrl::GetBackColor() const
 {
 	const COLORREF clr = GetSysColor(COLOR_3DFACE);
 	if (!m_bOnTitleBar)
 		return clr;
-	if (!m_bCustomSystemColor)
-		return GetDwmTitlebarColors();
-	const COLORREF bgclr = m_bActive ?
-		RGB(GetRValue(clr), std::clamp(GetGValue(clr) + 8, 0, 255), std::clamp(GetBValue(clr) + 8, 0, 255))
-		: clr;
-	return bgclr;
+	return CTitleBarHelper::GetBackColor(m_bActive);
 }
 
 static inline bool IsHighContrastEnabled()
+
 {
 	HIGHCONTRAST hc = { sizeof(HIGHCONTRAST) };
 	SystemParametersInfo(SPI_GETHIGHCONTRAST, sizeof(hc), &hc, 0);
@@ -179,8 +127,8 @@ void CMyTabCtrl::OnPaint()
 	const int nCount = GetItemCount();
 	if (nCount == 0)
 	{
-		const COLORREF winTitleTextColor = (m_bOnTitleBar && !m_bCustomSystemColor) ?
-			GetDwmTitleTextColors() : GetSysColor(COLOR_WINDOWTEXT);
+		const COLORREF winTitleTextColor = m_bOnTitleBar ?
+			CTitleBarHelper::GetTextColor(m_bActive) : getTextColor();
 		dc.SetTextColor(winTitleTextColor);
 		TCHAR szBuf[256];
 		AfxGetMainWnd()->GetWindowText(szBuf, sizeof(szBuf) / sizeof(szBuf[0]));
@@ -445,8 +393,8 @@ void CMyTabCtrl::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct)
 	}
 	else
 	{
-		const COLORREF txtclr = (m_bOnTitleBar && !m_bCustomSystemColor) ?
-			GetDwmTitleTextColors() : GetSysColor(COLOR_BTNTEXT);
+		const COLORREF txtclr = m_bOnTitleBar ?
+			CTitleBarHelper::GetTextColor(m_bActive) : GetSysColor(COLOR_BTNTEXT);
 		SetTextColor(lpDraw->hDC, txtclr);
 	}
 	CSize iconsize(determineIconSize(), determineIconSize());

Src/Common/MDITabBar.h

@@ -24,7 +24,6 @@ class CMyTabCtrl : public CTabCtrl
 		, m_nTooltipTabItemIndex(-1)
 		, m_bOnTitleBar(false)
 		, m_bActive(false)
-		, m_dwInactiveTitleColor(0)
 	{}
 
 protected:
@@ -34,13 +33,11 @@ class CMyTabCtrl : public CTabCtrl
 	bool m_bCloseButtonDown;
 	bool m_bOnTitleBar;
 	bool m_bActive;
-	bool m_bCustomSystemColor;
 	CRect m_rcCurrentCloseButtom;
 	int   m_nDraggingTabItemIndex;
 	int   m_nTooltipTabItemIndex;	/**< Index of the tab displaying tooltip */
 	CMDIFrameWnd *m_pMainFrame;
 	CToolTipCtrl m_tooltips;		/**< Tooltip for the tab */
-	COLORREF m_dwInactiveTitleColor;
 
 public:
 	BOOL Create(CMDIFrameWnd* pMainFrame, CWnd* pParent);
@@ -49,10 +46,8 @@ class CMyTabCtrl : public CTabCtrl
 	void UpdateTabs();
 	void SetOnTitleBar(bool onTitleBar) { m_bOnTitleBar = onTitleBar; }
 	bool GetActive() const { return m_bActive; }
-	void SetActive(bool bActive) { m_bActive = bActive; }
-	COLORREF GetBackColor();
-	bool GetCustomSystemColor() const { return m_bCustomSystemColor; }
-	void SetCustomSystemColor(bool bCustom) { m_bCustomSystemColor = bCustom; }
+	void SetActive(bool bActive);
+	COLORREF GetBackColor() const;
 
 // Overrides
 	// ClassWizard generated virtual function overrides
@@ -86,8 +81,8 @@ class CMyTabCtrl : public CTabCtrl
 	void SwapTabs(int nIndexA, int nIndexB);
 	int GetMaxTitleLength() const;
 	void UpdateToolTips(int index);
-	COLORREF GetDwmTitleTextColors();
-	COLORREF GetDwmTitlebarColors();
+	COLORREF GetDwmTitleTextColor() const;
+	COLORREF GetDwmTitlebarColor() const;
 };
 
 /**
@@ -111,7 +106,6 @@ class CMDITabBar : public CControlBar
 	virtual ~CMDITabBar() {}
 	BOOL Update(bool bOnTitleBar, bool bMaxmized);
 	void UpdateActive(bool bActive);
-	void UpdateCustomSystemColor(bool bCustom) { m_tabCtrl.SetCustomSystemColor(bCustom); };
 	BOOL Create(CMDIFrameWnd* pParentWnd);
 	void UpdateTabs() { m_tabCtrl.UpdateTabs(); }
 	bool GetAutoMaxWidth() const { return m_tabCtrl.GetAutoMaxWidth(); }

Src/MainFrm.cpp

@@ -71,6 +71,10 @@
 #include "DirWatcher.h"
 #include "Win_VersionHelper.h"
 
+#if !defined(SM_CXPADDEDBORDER)
+#define SM_CXPADDEDBORDER       92
+#endif
+
 using std::vector;
 using boost::begin;
 using boost::end;
@@ -416,7 +420,6 @@ int CMainFrame::OnCreate(LPCREATESTRUCT lpCreateStruct)
 		m_bTabsOnTitleBar = GetOptionsMgr()->GetBool(OPT_TABBAR_ON_TITLEBAR);
 
 	m_wndTabBar.Update(m_bTabsOnTitleBar.value_or(false), false);
-	m_wndTabBar.UpdateCustomSystemColor(GetOptionsMgr()->GetBool(OPT_SYSCOLOR_HOOK_ENABLED));
 
 	if (m_bTabsOnTitleBar.value_or(false) && !m_wndTabBar.Create(this))
 	{
@@ -1235,11 +1238,9 @@ void CMainFrame::OnOptions()
 		for (auto pImgMergeFrame : GetAllImgMergeFrames())
 			pImgMergeFrame->RefreshOptions();
 
-		const bool optSysColorHookEnabled = GetOptionsMgr()->GetBool(OPT_SYSCOLOR_HOOK_ENABLED);
-		if (sysColorHookEnabled != optSysColorHookEnabled ||
-			sysColorsSerialized != GetOptionsMgr()->GetString(OPT_SYSCOLOR_HOOK_COLORS))
+		if (sysColorHookEnabled != GetOptionsMgr()->GetBool(OPT_SYSCOLOR_HOOK_ENABLED) ||
+		    sysColorsSerialized != GetOptionsMgr()->GetString(OPT_SYSCOLOR_HOOK_COLORS))
 		{
-			m_wndTabBar.UpdateCustomSystemColor(optSysColorHookEnabled);
 			theApp.ReloadCustomSysColors();
 			AfxGetMainWnd()->SendMessage(WM_SYSCOLORCHANGE);
 			RedrawWindow(nullptr, nullptr, RDW_INVALIDATE | RDW_UPDATENOW | RDW_ERASE | RDW_ALLCHILDREN);

Src/Merge.vcxproj

@@ -913,6 +913,7 @@
       <PrecompiledHeaderFile>pch.h</PrecompiledHeaderFile>
       <PrecompiledHeaderOutputFile>$(IntDir)$(TargetName)2.pch</PrecompiledHeaderOutputFile>
     </ClCompile>
+    <ClCompile Include="Common\AccentColor.cpp" />
     <ClCompile Include="Common\cio.cpp">
       <PrecompiledHeaderFile>pch.h</PrecompiledHeaderFile>
       <PrecompiledHeaderOutputFile>$(IntDir)$(TargetName)2.pch</PrecompiledHeaderOutputFile>
@@ -1456,6 +1457,7 @@
     <ClInclude Include="BasicFlatStatusBar.h" />
     <ClInclude Include="ClipboardHistory.h" />
     <ClInclude Include="ColorSchemes.h" />
+    <ClInclude Include="Common\AccentColor.h" />
     <ClInclude Include="Common\SysColorHook.h" />
     <ClInclude Include="MouseHook.h" />
     <ClInclude Include="MenuBar.h" />

Src/Merge.vcxproj.filters

@@ -750,6 +750,9 @@
     <ClCompile Include="ColorSchemes.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="Common\AccentColor.cpp">
+      <Filter>MFCGui\Common\Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="charsets.h">
@@ -1436,6 +1439,9 @@
     <ClInclude Include="ColorSchemes.h">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="Common\AccentColor.h">
+      <Filter>MFCGui\Common\Header Files</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <None Include="res\binarydiff.ico">

Src/TitleBarHelper.cpp

@@ -8,6 +8,7 @@
 
 #include "StdAfx.h"
 #include "TitleBarHelper.h"
+#include "AccentColor.h"
 
 #if !defined(SM_CXPADDEDBORDER)
 #define SM_CXPADDEDBORDER       92
@@ -288,3 +289,48 @@ COLORREF CTitleBarHelper::GetIntermediateColor(COLORREF a, COLORREF b, float rat
 	const uint8_t B = static_cast<int8_t>((GetBValue(a) - GetBValue(b)) * ratio) + GetBValue(b);
 	return RGB(R, G, B);
 }
+
+COLORREF CTitleBarHelper::GetBackColor(bool bActive)
+{
+	if (!CAccentColor::Get().GetColorPrevalence())
+	{
+		const COLORREF clr = GetSysColor(COLOR_3DFACE);
+		const COLORREF bgclr = bActive ?
+			RGB(GetRValue(clr), std::clamp(GetGValue(clr) + 8, 0, 255), std::clamp(GetBValue(clr) + 8, 0, 255))
+			: clr;
+		return bgclr;
+	}
+	const COLORREF czclr = (!bActive) ?
+		CAccentColor::Get().GetAccentColorInactive() :
+		CAccentColor::Get().GetAccentColor();
+	return czclr != CLR_NONE ? czclr : GetSysColor(COLOR_3DFACE);
+}
+
+COLORREF CTitleBarHelper::GetTextColor(bool bActive)
+{
+	if (!CAccentColor::Get().GetColorPrevalence())
+		return GetSysColor(COLOR_BTNTEXT);
+	if (!bActive)
+	{
+		COLORREF clr = GetSysColor(COLOR_3DFACE);
+		if (GetRValue(clr) < 128 && GetGValue(clr) < 128 && GetBValue(clr) < 128)
+			return RGB(245, 245, 245);
+		return RGB(10, 10, 10);
+	}
+	const COLORREF czclr = CAccentColor::Get().GetAccentColor();
+	if (czclr != CLR_NONE)
+	{
+		const BYTE r = static_cast<BYTE>(czclr >> 16);
+		const BYTE g = static_cast<BYTE>(czclr >> 8);
+		const BYTE b = static_cast<BYTE>(czclr);
+		if (r < 128 && g < 128 && b < 128)
+			return RGB(255, 255, 255);
+		return RGB(0, 0, 0);
+	}
+	return GetSysColor(COLOR_BTNTEXT);
+}
+
+void CTitleBarHelper::ReloadAccentColor()
+{
+	CAccentColor::Get().Reload();
+}

Src/TitleBarHelper.h

@@ -23,6 +23,9 @@ class CTitleBarHelper {
 	void SetMaximized(bool maximized) { m_maximized = maximized; }
 	bool GetMaximized() const { return m_maximized; }
 	void SetSize(int cx, int cy);
+	static COLORREF GetBackColor(bool bActive);
+	static COLORREF GetTextColor(bool bActive);
+	static void ReloadAccentColor();
 	LRESULT OnNcHitTest(CPoint pt);
 	void OnNcMouseMove(UINT nHitTest, CPoint point);
 	void OnNcMouseLeave();