[libwin32darkmode] TGDarkMode.cpp: Use GetProcAddress() for some Vista+ functions.

These functions were added in Windows Vista:
- BeginBufferedPaint()
- BufferedPaintSetAlpha()
- EndBufferedPaint()

Need to use GetProcAddress() [in DarkMode.cpp]. Otherwise, the program
won't run on Windows XP.

See #487: Installer fails on Windows XP

(cherry picked from commit 134bdf5)

Author: GerbilSoft

src/libwin32darkmode/DarkMode.cpp

@@ -42,6 +42,12 @@ fnSetWindowCompositionAttribute _SetWindowCompositionAttribute = nullptr;
 fnShouldSystemUseDarkMode _ShouldSystemUseDarkMode = nullptr;
 fnSetPreferredAppMode _SetPreferredAppMode = nullptr;
 
+// UxTheme functions used by TGDarkMode.cpp, added in Windows Vista.
+fnBeginBufferedPaint _BeginBufferedPaint;
+fnBufferedPaintSetAlpha _BufferedPaintSetAlpha;
+fnEndBufferedPaint _EndBufferedPaint;
+
+
 bool g_darkModeSupported = false;
 bool g_darkModeEnabled = false;
 static DWORD g_buildNumber = 0;
@@ -199,12 +205,21 @@ int InitDarkModePFNs(void)
 	_SetWindowCompositionAttribute = reinterpret_cast<fnSetWindowCompositionAttribute>(
 		GetProcAddress(GetModuleHandle(_T("user32.dll")), "SetWindowCompositionAttribute"));
 
+	// UxTheme functions used by TGDarkMode.cpp, added in Windows Vista.
+	_BeginBufferedPaint = reinterpret_cast<fnBeginBufferedPaint>(
+		GetProcAddress(hUxtheme, "BeginBufferedPaint"));
+	_BufferedPaintSetAlpha = reinterpret_cast<fnBufferedPaintSetAlpha>(
+		GetProcAddress(hUxtheme, "BufferedPaintSetAlpha"));
+	_EndBufferedPaint = reinterpret_cast<fnEndBufferedPaint>(
+		GetProcAddress(hUxtheme, "EndBufferedPaint"));
+
 	if (_OpenNcThemeData &&
 	    // 1809 17763
 	    _ShouldAppsUseDarkMode && _AllowDarkModeForWindow &&
 	    (_AllowDarkModeForApp || _SetPreferredAppMode) &&
 	    //_FlushMenuThemes &&
-	    _RefreshImmersiveColorPolicyState && _IsDarkModeAllowedForWindow)
+	    _RefreshImmersiveColorPolicyState && _IsDarkModeAllowedForWindow &&
+	    _BeginBufferedPaint && _BufferedPaintSetAlpha && _EndBufferedPaint)
 	{
 		// Dark mode is supported.
 
@@ -232,6 +247,10 @@ int InitDarkModePFNs(void)
 	_SetWindowCompositionAttribute = nullptr;
 	_ShouldSystemUseDarkMode = nullptr;
 	_SetPreferredAppMode = nullptr;
+	// UxTheme functions used by TGDarkMode.cpp.
+	_BeginBufferedPaint = nullptr;
+	_BufferedPaintSetAlpha = nullptr;
+	_EndBufferedPaint = nullptr;
 	FreeLibrary(hUxtheme);
 	return 7;
 }

src/libwin32darkmode/DarkMode.hpp

@@ -98,6 +98,16 @@ extern fnSetWindowCompositionAttribute _SetWindowCompositionAttribute;
 extern fnShouldSystemUseDarkMode _ShouldSystemUseDarkMode;
 extern fnSetPreferredAppMode _SetPreferredAppMode;
 
+// UxTheme functions used by TGDarkMode.cpp, added in Windows Vista.
+// TODO: Verify definition against Windows SDK.
+typedef HPAINTBUFFER (WINAPI *fnBeginBufferedPaint)(HDC hdcTarget, const RECT *prcTarget, BP_BUFFERFORMAT dwFormat, _In_ BP_PAINTPARAMS *pPaintParams, _Out_ HDC *phdc);
+typedef HRESULT (WINAPI *fnBufferedPaintSetAlpha)(HPAINTBUFFER hBufferedPaint, _In_ const RECT *prc, BYTE alpha);
+typedef HRESULT (WINAPI *fnEndBufferedPaint)(HPAINTBUFFER hBufferedPaintm, BOOL fUpdateTarget);
+
+extern fnBeginBufferedPaint _BeginBufferedPaint;
+extern fnBufferedPaintSetAlpha _BufferedPaintSetAlpha;
+extern fnEndBufferedPaint _EndBufferedPaint;
+
 extern bool g_darkModeSupported;
 extern bool g_darkModeEnabled;
 

src/libwin32darkmode/TGDarkMode.cpp

@@ -259,13 +259,13 @@ static void PaintControl(HWND hWnd, HDC hdc, RECT* prc, bool bDrawBorder)
 	if (bDrawBorder)
 		InflateRect(prc, 1, 1);
 
-	HPAINTBUFFER hBufferedPaint = BeginBufferedPaint(hdc, prc, BPBF_TOPDOWNDIB, nullptr, &hdcPaint);
+	HPAINTBUFFER hBufferedPaint = _BeginBufferedPaint(hdc, prc, BPBF_TOPDOWNDIB, nullptr, &hdcPaint);
 	if (hdcPaint && hBufferedPaint) {
 		RECT rc;
 		GetWindowRect(hWnd, &rc);
 
 		PatBlt(hdcPaint, 0, 0, RECTWIDTH(rc), RECTHEIGHT(rc), BLACKNESS);
-		BufferedPaintSetAlpha(hBufferedPaint, &rc, 0x00);
+		_BufferedPaintSetAlpha(hBufferedPaint, &rc, 0x00);
 
 		///
 		/// first blit white so list ctrls don't look ugly:
@@ -285,8 +285,8 @@ static void PaintControl(HWND hWnd, HDC hdc, RECT* prc, bool bDrawBorder)
 		// don't make a possible border opaque, only the inner part of the control
 		InflateRect(prc, -2, -2);
 		// Make every pixel opaque
-		BufferedPaintSetAlpha(hBufferedPaint, prc, 255);
-		EndBufferedPaint(hBufferedPaint, TRUE);
+		_BufferedPaintSetAlpha(hBufferedPaint, prc, 255);
+		_EndBufferedPaint(hBufferedPaint, TRUE);
 	}
 }
 
@@ -408,7 +408,7 @@ LRESULT WINAPI TGDarkMode_ButtonSubclassProc(
 					rcExclusion.bottom -= 2;
 
 					HDC hdcPaint = nullptr;
-					HPAINTBUFFER hBufferedPaint = BeginBufferedPaint(hdc, &rcClient, BPBF_TOPDOWNDIB, &params, &hdcPaint);
+					HPAINTBUFFER hBufferedPaint = _BeginBufferedPaint(hdc, &rcClient, BPBF_TOPDOWNDIB, &params, &hdcPaint);
 					if (hdcPaint) {
 						// now we again retrieve the font, but this time we select it into
 						// the buffered DC:
@@ -419,7 +419,7 @@ LRESULT WINAPI TGDarkMode_ButtonSubclassProc(
 						::SetBkColor(hdcPaint, g_darkBkColor);
 						::ExtTextOut(hdcPaint, 0, 0, ETO_OPAQUE, &rcClient, nullptr, 0, nullptr);
 
-						BufferedPaintSetAlpha(hBufferedPaint, &ps.rcPaint, 0x00);
+						_BufferedPaintSetAlpha(hBufferedPaint, &ps.rcPaint, 0x00);
 
 						DTTOPTS DttOpts = { sizeof(DTTOPTS) };
 						DttOpts.dwFlags = DTT_COMPOSITED | DTT_GLOWSIZE;
@@ -471,7 +471,7 @@ LRESULT WINAPI TGDarkMode_ButtonSubclassProc(
 							hFontOld = nullptr;
 						}
 
-						EndBufferedPaint(hBufferedPaint, TRUE);
+						_EndBufferedPaint(hBufferedPaint, TRUE);
 					}
 					CloseThemeData(hTheme);
 				}
@@ -484,12 +484,12 @@ LRESULT WINAPI TGDarkMode_ButtonSubclassProc(
 					HDC hdcPaint = nullptr;
 					BP_PAINTPARAMS params = { sizeof(BP_PAINTPARAMS) };
 					params.dwFlags = BPPF_ERASE;
-					HPAINTBUFFER hBufferedPaint = BeginBufferedPaint(hdc, &rcClient, BPBF_TOPDOWNDIB, &params, &hdcPaint);
+					HPAINTBUFFER hBufferedPaint = _BeginBufferedPaint(hdc, &rcClient, BPBF_TOPDOWNDIB, &params, &hdcPaint);
 					if (hdcPaint && hBufferedPaint) {
 						::SetBkColor(hdcPaint, g_darkBkColor);
 						::ExtTextOut(hdcPaint, 0, 0, ETO_OPAQUE, &rcClient, nullptr, 0, nullptr);
 
-						BufferedPaintSetAlpha(hBufferedPaint, &ps.rcPaint, 0x00);
+						_BufferedPaintSetAlpha(hBufferedPaint, &ps.rcPaint, 0x00);
 
 						LRESULT dwCheckState = SendMessage(hWnd, BM_GETCHECK, 0, 0);
 						POINT pt;
@@ -639,7 +639,7 @@ LRESULT WINAPI TGDarkMode_ButtonSubclassProc(
 							hFontOld = nullptr;
 						}
 
-						EndBufferedPaint(hBufferedPaint, TRUE);
+						_EndBufferedPaint(hBufferedPaint, TRUE);
 					}
 					CloseThemeData(hTheme);
 				}