From df88618efb32274e7b21493c48483d4761d2f9a3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20Ankarstr=C3=B6m?= <john@ankarstrom.se>
Date: Wed, 3 Aug 2022 16:55:03 +0200
Subject: Load uxtheme dynamically.

In case it is not supported. If I am not mistaken, SWI-Prolog supports
Windows 2000, so there is no reason why Episode Browser shouldn't.
---
 c/main.cpp | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

(limited to 'c/main.cpp')

diff --git a/c/main.cpp b/c/main.cpp
index 3ec6fee..d73a08a 100644
--- a/c/main.cpp
+++ b/c/main.cpp
@@ -2,7 +2,6 @@
 #include <stdexcept>
 #include <windows.h>
 #include <commctrl.h>
-#include <uxtheme.h>
 #include <SWI-Prolog.h>
 
 #include "debug.h"
@@ -14,7 +13,6 @@
 #include "pl.h"
 
 /* Looked-up constants. */
-int g_bThemes;
 int g_dpi = 96;
 
 /* Cursors. */
@@ -45,6 +43,10 @@ int g_bViewWatched = 1;
 int g_bViewTVOriginal = 1;
 char g_currentScreenwriter[64];
 
+/* Optional Windows functions. */
+BOOL (*IsThemeActive)();
+BOOL (*SetWindowTheme)(HWND, LPCWSTR, LPCWSTR);
+
 static LRESULT CALLBACK CBTProc(int, WPARAM, LPARAM);
 static LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
 static void HandleMainMenu(HWND, unsigned short);
@@ -165,15 +167,12 @@ static LRESULT CALLBACK CBTProc(const int nCode, const WPARAM wParam, const LPAR
 
 	g_hWnd = (HWND)wParam;
 
-	/* Look up constants. */
+	/* Look up DPI. */
 	if (auto lib = Library::Maybe(L"User32.dll");
 	    auto GetDpiForWindow = lib->GetProcAddress<UINT(HWND)>("GetDpiForWindow"))
 		g_dpi = GetDpiForWindow(g_hWnd);
 
-	if (auto lib = Library::Maybe(L"uxtheme.dll");
-	    lib->GetProcAddress<void>("SetWindowTheme"))
-		g_bThemes = 1;
-
+	/* Load fonts. */
 	if (auto lib = Library::Maybe(L"User32.dll");
 	    lib->GetProcAddress<void>("SystemParametersInfoW")) {
 		NONCLIENTMETRICS m;
@@ -189,6 +188,13 @@ static LRESULT CALLBACK CBTProc(const int nCode, const WPARAM wParam, const LPAR
 	lf.lfWeight = FW_BOLD;
 	g_hfBold = require(CreateFontIndirect(&lf));
 
+	/* Load theme functions, if available. */
+	if (HMODULE hModule = LoadLibrary(L"uxtheme.dll")) {
+		IsThemeActive = (BOOL(*)())(void*)GetProcAddress(hModule, "IsThemeActive");
+		SetWindowTheme = (BOOL(*)(HWND, LPCWSTR, LPCWSTR))(void*)
+			GetProcAddress(hModule, "SetWindowTheme");
+	}
+
 	/* Create child windows. */
 	g_dlv = new DataListView(g_hWnd);
 	g_elv = new EpisodeListView(g_hWnd);
@@ -558,7 +564,7 @@ INT_PTR CALLBACK AboutDlgProc(const HWND hWnd, const UINT uMsg, const WPARAM wPa
 /* Try to style application according to current Windows theme. */
 void UpdateTheme()
 {
-	if (!g_bThemes) return;
+	if (!IsThemeActive) return;
 	const BOOL bThemeActive = IsThemeActive();
 	g_dlv->UpdateTheme(bThemeActive);
 	g_elv->UpdateTheme(bThemeActive);
-- 
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