From 280a456ae1da8fa648be1e9f68140f045b306e32 Mon Sep 17 00:00:00 2001
From: Carl Hetherington <cth@carlh.net>
Date: Thu, 2 Jun 2022 12:20:41 +0200
Subject: [PATCH] Ask fontconfig to scan the system for fonts requested by text
 subtitle files (#2264).

---
 src/lib/font_config.cc              | 28 ++++++++++++++++++++++++++++
 src/lib/font_config.h               |  1 +
 src/lib/string_text_file_content.cc | 18 +++++++++++-------
 3 files changed, 40 insertions(+), 7 deletions(-)

diff --git a/src/lib/font_config.cc b/src/lib/font_config.cc
index c7361bc04..5c9eebb3f 100644
--- a/src/lib/font_config.cc
+++ b/src/lib/font_config.cc
@@ -22,6 +22,7 @@
 #include "dcpomatic_assert.h"
 #include "font_config.h"
 #include <fontconfig/fontconfig.h>
+#include <boost/filesystem.hpp>
 #include <boost/optional.hpp>
 
 
@@ -85,6 +86,33 @@ FontConfig::make_font_available(boost::filesystem::path font_file)
 }
 
 
+optional<boost::filesystem::path>
+FontConfig::system_font_with_name(string name)
+{
+	optional<boost::filesystem::path> path;
+
+	auto pattern = FcNameParse(reinterpret_cast<FcChar8 const*>(name.c_str()));
+	auto object_set = FcObjectSetBuild(FC_FILE, nullptr);
+	auto font_set = FcFontList(_config, pattern, object_set);
+	if (font_set) {
+		for (int i = 0; i < font_set->nfont; ++i) {
+			auto font = font_set->fonts[i];
+			FcChar8* file;
+			if (FcPatternGetString(font, FC_FILE, 0, &file) == FcResultMatch) {
+				path = boost::filesystem::path(reinterpret_cast<char*>(file));
+				break;
+			}
+		}
+		FcFontSetDestroy(font_set);
+	}
+
+	FcObjectSetDestroy(object_set);
+	FcPatternDestroy(pattern);
+
+	return path;
+}
+
+
 FontConfig *
 FontConfig::instance()
 {
diff --git a/src/lib/font_config.h b/src/lib/font_config.h
index 7527d9127..6dadbae8a 100644
--- a/src/lib/font_config.h
+++ b/src/lib/font_config.h
@@ -32,6 +32,7 @@ public:
 	static FontConfig* instance();
 
 	std::string make_font_available(boost::filesystem::path font_file);
+	boost::optional<boost::filesystem::path> system_font_with_name(std::string name);
 
 private:
 	FontConfig();
diff --git a/src/lib/string_text_file_content.cc b/src/lib/string_text_file_content.cc
index 3750b0a50..eea9362bb 100644
--- a/src/lib/string_text_file_content.cc
+++ b/src/lib/string_text_file_content.cc
@@ -19,13 +19,15 @@
 */
 
 
-#include "string_text_file_content.h"
-#include "util.h"
-#include "string_text_file.h"
 #include "film.h"
 #include "font.h"
+#include "font_config.h"
+#include "string_text_file.h"
+#include "string_text_file_content.h"
 #include "text_content.h"
+#include "util.h"
 #include <dcp/raw_convert.h>
+#include <fontconfig/fontconfig.h>
 #include <libxml++/libxml++.h>
 #include <iostream>
 
@@ -76,10 +78,12 @@ StringTextFileContent::examine (shared_ptr<const Film> film, shared_ptr<Job> job
 	}
 
 	for (auto name: names) {
-		/* Make a font for each family name that somebody might later
-		 * ask about.
-		 */
-		only_text()->add_font(make_shared<Font>(name));
+		auto path = FontConfig::instance()->system_font_with_name(name);
+		if (path) {
+			only_text()->add_font(make_shared<Font>(name, *path));
+		} else {
+			only_text()->add_font(make_shared<Font>(name));
+		}
 	}
 
 	boost::mutex::scoped_lock lm (_mutex);
-- 
2.30.2