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/common.h     | 12 ++++++++++++
 c/layout.cpp   |  7 +++----
 c/listview.cpp |  5 ++---
 c/main.cpp     | 22 ++++++++++++++--------
 4 files changed, 31 insertions(+), 15 deletions(-)

(limited to 'c')

diff --git a/c/common.h b/c/common.h
index f011565..9d322b3 100644
--- a/c/common.h
+++ b/c/common.h
@@ -120,4 +120,16 @@ inline BOOL SetWindowRect(const HWND hWnd, const RECT r)
 	return SetWindowRect(hWnd, r.left, r.top, r.right, r.bottom);
 }
 
+inline BOOL EBIsThemeActive()
+{
+	extern BOOL (*IsThemeActive)();
+	return IsThemeActive? IsThemeActive(): 0;
+}
+
+inline BOOL EBSetWindowTheme(HWND hWnd, LPCWSTR pszSubAppName, LPCWSTR pszSubIdList)
+{
+	extern BOOL (*SetWindowTheme)(HWND, LPCWSTR, LPCWSTR);
+	return SetWindowTheme? SetWindowTheme(hWnd, pszSubAppName, pszSubIdList): 0;
+}
+
 #endif
diff --git a/c/layout.cpp b/c/layout.cpp
index de1f1f7..4da7cd8 100644
--- a/c/layout.cpp
+++ b/c/layout.cpp
@@ -1,5 +1,4 @@
 #include <windows.h>
-#include <uxtheme.h>
 
 #include "common.h"
 #include "episodelistview.h"
@@ -23,7 +22,7 @@ void UpdateLayout(int w, int h)
 	SendMessage(g_hWnd, WM_SETREDRAW, FALSE, 0);
 
 	/* Resize list views. */
-	const long pad = IsThemeActive()? Dpi(6): 0; /* Add padding in modern themes. */
+	const long pad = EBIsThemeActive()? Dpi(6): 0; /* Add padding in modern themes. */
 	const long cyDlv = rrStatus.top-g_dlv->Height()-pad;
 	require(SetWindowRect(g_dlv->hWnd, pad, cyDlv, rc.right-pad, rrStatus.top-pad));
 	require(SetWindowRect(g_elv->hWnd, pad, pad, rc.right-pad, cyDlv-pad));
@@ -44,8 +43,8 @@ bool Dragger::InDragArea(const int x, const int y)
 	RECT rrDlv;
 	require(GetRelativeRect(g_dlv->hWnd, &rrDlv));
 
-	const int pad = IsThemeActive()? Dpi(6): 0;
-	const int extra = IsThemeActive()? 0: Dpi(2);
+	const int pad = EBIsThemeActive()? Dpi(6): 0;
+	const int extra = EBIsThemeActive()? 0: Dpi(2);
 	if (x < rrDlv.left || x > rrDlv.right) return false;
 	if (y < rrDlv.top-pad*2-extra*3 || y > rrDlv.top+extra) return false;
 	return true;
diff --git a/c/listview.cpp b/c/listview.cpp
index b10ae88..c2f5593 100644
--- a/c/listview.cpp
+++ b/c/listview.cpp
@@ -1,6 +1,5 @@
 #include <windows.h>
 #include <commctrl.h>
-#include <uxtheme.h>
 
 #include "common.h"
 #include "listview.h"
@@ -52,9 +51,9 @@ void ListView::UpdateTheme(const BOOL bThemeActive)
 {
 	const wchar_t* theme;
 	WORD action;
-	extern int g_bThemes;
+	extern BOOL (*SetWindowTheme)(HWND, LPCWSTR, LPCWSTR);
 
-	if (!g_bThemes) return;
+	if (!SetWindowTheme) return;
 	if (bThemeActive) {
 		theme = L"Explorer";
 		action = UIS_SET;
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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