GUI::show_error() is now generalized for std::string and const char*

Fixed return type of std::string translate_utf8() with context
(incorrectly returned wxString, should return std::string).
Fixed double translation of BackgroundSlicingProcess::validate() in Plater.

src/slic3r/GUI/GUI.cpp

@@ -229,10 +229,15 @@ void show_error(wxWindow* parent, const wxString& message)
 	msg.ShowModal();
 }
 
+void show_error(wxWindow* parent, const char* message)
+{
+	show_error(parent, wxString::FromUTF8(message));
+}
+
 void show_error_id(int id, const std::string& message)
 {
 	auto *parent = id != 0 ? wxWindow::FindWindowById(id) : nullptr;
-	show_error(parent, from_u8(message));
+	show_error(parent, message);
 }
 
 void show_info(wxWindow* parent, const wxString& message, const wxString& title)

src/slic3r/GUI/GUI.hpp

@@ -39,6 +39,8 @@ extern void add_menus(wxMenuBar *menu, int event_preferences_changed, int event_
 void change_opt_value(DynamicPrintConfig& config, const t_config_option_key& opt_key, const boost::any& value, int opt_index = 0);
 
 void show_error(wxWindow* parent, const wxString& message);
+void show_error(wxWindow* parent, const char* message);
+inline void show_error(wxWindow* parent, const std::string& message) { show_error(parent, message.c_str()); }
 void show_error_id(int id, const std::string& message);   // For Perl
 void show_info(wxWindow* parent, const wxString& message, const wxString& title);
 void warning_catcher(wxWindow* parent, const wxString& message);

src/slic3r/GUI/GUI_App.cpp

@@ -244,7 +244,7 @@ bool GUI_App::on_init_inner()
     try {
         preset_bundle->load_presets(*app_config);
     } catch (const std::exception &ex) {
-        show_error(nullptr, from_u8(ex.what()));
+        show_error(nullptr, ex.what());
     }
 
     register_dpi_event();
@@ -1241,7 +1241,7 @@ void GUI_App::check_updates(const bool verbose)
 		}
 	}
 	catch (const std::exception & ex) {
-		show_error(nullptr, from_u8(ex.what()));
+		show_error(nullptr, ex.what());
 	}
 
 	

src/slic3r/GUI/I18N.hpp

@@ -67,10 +67,10 @@ namespace I18N {
 	inline wxString translate(const std::string &s, const char* ctx)  { return _wxGetTranslation_ctx(wxString(s.c_str(), wxConvUTF8), ctx); }
 	inline wxString translate(const std::wstring &s, const char* ctx) { return _wxGetTranslation_ctx(s.c_str(), ctx); }
 
-	inline wxString translate_utf8(const char *s, const char* ctx)         { return _wxGetTranslation_ctx(wxString(s, wxConvUTF8), ctx).ToUTF8().data(); }
+	inline std::string translate_utf8(const char *s, const char* ctx)         { return _wxGetTranslation_ctx(wxString(s, wxConvUTF8), ctx).ToUTF8().data(); }
-	inline wxString translate_utf8(const wchar_t *s, const char* ctx)      { return _wxGetTranslation_ctx(s, ctx).ToUTF8().data(); }
+	inline std::string translate_utf8(const wchar_t *s, const char* ctx)      { return _wxGetTranslation_ctx(s, ctx).ToUTF8().data(); }
-	inline wxString translate_utf8(const std::string &s, const char* ctx)  { return _wxGetTranslation_ctx(wxString(s.c_str(), wxConvUTF8), ctx).ToUTF8().data(); }
+	inline std::string translate_utf8(const std::string &s, const char* ctx)  { return _wxGetTranslation_ctx(wxString(s.c_str(), wxConvUTF8), ctx).ToUTF8().data(); }
-	inline wxString translate_utf8(const std::wstring &s, const char* ctx) { return _wxGetTranslation_ctx(s.c_str(), ctx).ToUTF8().data(); }
+	inline std::string translate_utf8(const std::wstring &s, const char* ctx) { return _wxGetTranslation_ctx(s.c_str(), ctx).ToUTF8().data(); }
 
 #undef _wxGetTranslation_ctx
 } // namespace I18N

src/slic3r/GUI/Plater.cpp

@@ -3074,10 +3074,10 @@ unsigned int Plater::priv::update_background_process(bool force_validation, bool
             auto *top_level_wnd = dynamic_cast<wxTopLevelWindow*>(p);
             if (! postpone_error_messages && top_level_wnd && top_level_wnd->IsActive()) {
                 // The error returned from the Print needs to be translated into the local language.
-                GUI::show_error(this->q, _(err));
+                GUI::show_error(this->q, err);
             } else {
                 // Show the error message once the main window gets activated.
-                this->delayed_error_message = _(err).ToUTF8();
+                this->delayed_error_message = err;
             }
             return_state |= UPDATE_BACKGROUND_PROCESS_INVALID;
         }

src/slic3r/GUI/PrintHostDialogs.cpp

@@ -275,7 +275,7 @@ void PrintHostQueueDialog::on_error(Event &evt)
 
     on_list_select();
 
-    GUI::show_error(nullptr, std::move(errormsg));
+    GUI::show_error(nullptr, errormsg);
 }
 
 void PrintHostQueueDialog::on_cancel(Event &evt)

src/slic3r/GUI/Tab.cpp

@@ -3032,7 +3032,7 @@ void Tab::save_preset(std::string name /*= ""*/)
         const Preset &preset = m_presets->get_selected_preset();
         auto default_name = preset.is_default ? "Untitled" :
 //                            preset.is_system ? (boost::format(_utf8(L("%1% - Copy"))) % preset.name).str() :
-                            preset.is_system ? (boost::format(_CTX_utf8(L_CONTEXT("%1% - Copy", "PresetName"), "PresetName").ToUTF8()) % preset.name).str() :
+                            preset.is_system ? (boost::format(_CTX_utf8(L_CONTEXT("%1% - Copy", "PresetName"), "PresetName")) % preset.name).str() :
                             preset.name;
 
         bool have_extention = boost::iends_with(default_name, ".ini");

src/slic3r/Utils/PresetUpdater.cpp

@@ -423,7 +423,7 @@ Updates PresetUpdater::priv::get_config_updates(const Semver &old_slic3r_version
 			// Any published config shall be always found in the latest config index.
 			auto message = (boost::format("Preset bundle `%1%` version not found in index: %2%") % idx.vendor() % vp.config_version.to_string()).str();
 			BOOST_LOG_TRIVIAL(error) << message;
-			GUI::show_error(nullptr, GUI::from_u8(message));
+			GUI::show_error(nullptr, message);
 			continue;
 		}