disable multithread on iOS

src/canvas.cpp

@@ -1176,6 +1176,10 @@ void Canvas::clear_context()
 
 void Canvas::import_equirectangular(std::string file_path)
 {
+#if __IOS__
+    import_equirectangular_thread(file_path);
+    return;
+#endif
     std::thread t(&Canvas::import_equirectangular_thread, this, file_path);
     t.detach();
 }
@@ -1249,6 +1253,12 @@ void Canvas::export_equirectangular(std::string file_path, std::function<void()>
 {
     if (App::I.check_license())
     {
+#if __IOS__
+        export_equirectangular_thread(file_path);
+        if (on_complete)
+            on_complete();
+        return;
+#endif
         std::thread t([=] {
             export_equirectangular_thread(file_path);
             if (on_complete)
@@ -1553,6 +1563,12 @@ void Canvas::export_layers(std::string file_name, std::function<void()> on_compl
 {
     if (App::I.check_license())
     {
+#if __IOS__
+        export_layers_thread(file_name);
+        if (on_complete)
+            on_complete();
+        return;
+#endif
         std::thread t([=] {
             export_layers_thread(file_name);
             if (on_complete)
@@ -1808,6 +1824,12 @@ void Canvas::project_save(std::function<void(bool)> on_complete)
 {
     if (App::I.check_license())
     {
+#if __IOS__
+        bool ret = project_save_thread(App::I.doc_path);
+        if (on_complete)
+            on_complete(ret);
+        return;
+#endif
         std::thread t([=] {
             bool ret = project_save_thread(App::I.doc_path);
             if (on_complete)
@@ -1822,6 +1844,12 @@ void Canvas::project_save(std::string file_path, std::function<void(bool)> on_co
     LOG("saving %s", file_path.c_str());
     if (App::I.check_license())
     {
+#if __IOS__
+        bool ret = project_save_thread(file_path);
+        if (on_complete)
+            on_complete(ret);
+        return;
+#endif
         std::thread t([=] {
             bool ret = project_save_thread(file_path);
             if (on_complete)
@@ -2018,6 +2046,12 @@ bool Canvas::project_save_thread(std::string file_path)
 
 void Canvas::project_open(std::string file_path, std::function<void(bool)> on_complete)
 {
+#if __IOS__
+    bool ret = project_open_thread(file_path);
+    if (on_complete)
+        on_complete(ret);
+    return;
+#endif
     std::thread t([=] {
         bool result = project_open_thread(file_path);
         if (on_complete)

src/node_stroke_preview.cpp

@@ -477,6 +477,10 @@ void NodeStrokePreview::draw_stroke()
 {
     if (m_size.x == 0 || m_size.y == 0)
         return;
+#if __IOS__
+    draw_stroke_immediate();
+    return;
+#endif
     s_queue.mutex.lock();
     if (!s_running)
     {