Perform additional checks for gtk scaling factor

2 files changed, 20 insertions, 2 deletions

diff --git a/Telegram/SourceFiles/platform/linux/linux_gtk_integration.cpp b/Telegram/SourceFiles/platform/linux/linux_gtk_integration.cpp
index cef2133667..59fcd12d9a 100644
--- a/Telegram/SourceFiles/platform/linux/linux_gtk_integration.cpp
+++ b/Telegram/SourceFiles/platform/linux/linux_gtk_integration.cpp
@@ -328,6 +328,7 @@ void GtkIntegration::load() {
 
 	if (GtkLoaded) {
 		LOAD_GTK_SYMBOL(lib_gtk, "gdk_display_get_default", gdk_display_get_default);
+		LOAD_GTK_SYMBOL(lib_gtk, "gdk_display_get_monitor", gdk_display_get_monitor);
 		LOAD_GTK_SYMBOL(lib_gtk, "gdk_display_get_primary_monitor", gdk_display_get_primary_monitor);
 		LOAD_GTK_SYMBOL(lib_gtk, "gdk_monitor_get_scale_factor", gdk_monitor_get_scale_factor);
 
@@ -440,13 +441,29 @@ std::optional<QString> GtkIntegration::getStringSetting(
 std::optional<int> GtkIntegration::scaleFactor() const {
 	if (!loaded()
 		|| (gdk_display_get_default == nullptr)
+		|| (gdk_display_get_monitor == nullptr)
 		|| (gdk_display_get_primary_monitor == nullptr)
 		|| (gdk_monitor_get_scale_factor == nullptr)) {
 		return std::nullopt;
 	}
 
-	return gdk_monitor_get_scale_factor(
-		gdk_display_get_primary_monitor(gdk_display_get_default()));
+	const auto display = gdk_display_get_default();
+	if (!display) {
+		return std::nullopt;
+	}
+
+	const auto monitor = [&] {
+		if (const auto primary = gdk_display_get_primary_monitor(display)) {
+			return primary;
+		}
+		return gdk_display_get_monitor(display, 0);
+	}();
+
+	if (!monitor) {
+		return std::nullopt;
+	}
+
+	return gdk_monitor_get_scale_factor(monitor);
 }
 
 bool GtkIntegration::fileDialogSupported() const {
diff --git a/Telegram/SourceFiles/platform/linux/linux_gtk_integration_p.h b/Telegram/SourceFiles/platform/linux/linux_gtk_integration_p.h
index c12faa846b..b0b60e6bcf 100644
--- a/Telegram/SourceFiles/platform/linux/linux_gtk_integration_p.h
+++ b/Telegram/SourceFiles/platform/linux/linux_gtk_integration_p.h
@@ -149,6 +149,7 @@ inline bool g_type_cit_helper(Object *instance, GType iface_type) {
 inline gint (*gtk_dialog_run)(GtkDialog *dialog) = nullptr;
 inline GdkAtom (*gdk_atom_intern)(const gchar *atom_name, gboolean only_if_exists) = nullptr;
 inline GdkDisplay* (*gdk_display_get_default)(void) = nullptr;
+inline GdkMonitor* (*gdk_display_get_monitor)(GdkDisplay *display, int monitor_num) = nullptr;
 inline GdkMonitor* (*gdk_display_get_primary_monitor)(GdkDisplay *display) = nullptr;
 inline int (*gdk_monitor_get_scale_factor)(GdkMonitor *monitor) = nullptr;
 inline GdkPixbuf* (*gdk_pixbuf_new_from_file_at_size)(const gchar *filename, int width, int height, GError **error) = nullptr;