imp: use navigation buttons to switch layers

src/imp/imp.cpp

@@ -1167,6 +1167,11 @@ void ImpBase::create_context_menu(Gtk::Menu *parent, const std::set<SelectableRe
 
 bool ImpBase::handle_click(GdkEventButton *button_event)
 {
+    if (button_event->button > 3) {
+        handle_extra_button(button_event);
+        return false;
+    }
+
     if (button_event->button != 2)
         set_search_mode(false);
 

src/imp/imp.hpp

@@ -113,6 +113,9 @@ class ImpBase {
     bool handle_key_press(GdkEventKey *key_event);
     void handle_cursor_move(const Coordi &pos);
     bool handle_click(GdkEventButton *button_event);
+    virtual void handle_extra_button(const GdkEventButton *button_event)
+    {
+    }
     bool handle_click_release(GdkEventButton *button_event);
     bool handle_context_menu(GdkEventButton *button_event);
     void tool_process(ToolResponse &resp);

src/imp/imp_layer.cpp

@@ -66,6 +66,26 @@ void ImpLayer::construct_layer_box(bool pack)
     }
 }
 
+void ImpLayer::handle_extra_button(const GdkEventButton *button_event)
+{
+    if (!preferences.mouse.switch_layers)
+        return;
+
+    switch (button_event->button) {
+    case 6:
+    case 8:
+        trigger_action(ActionID::LAYER_DOWN);
+        break;
+
+    case 7:
+    case 9:
+        trigger_action(ActionID::LAYER_UP);
+        break;
+
+    default:;
+    }
+}
+
 void ImpLayer::load_default_layers()
 {
     layer_box->load_from_json(

src/imp/imp_layer.hpp

@@ -27,6 +27,8 @@ class ImpLayer : public ImpBase {
         return &preferences.canvas_layer;
     }
 
+    void handle_extra_button(const GdkEventButton *button_event) override;
+
     ~ImpLayer()
     {
     }

src/pool-prj-mgr/preferences/preferences_window_misc.cpp

@@ -254,6 +254,17 @@ MiscPreferencesEditor::MiscPreferencesEditor(Preferences &prefs) : preferences(p
             gr->add_row(*r);
         }
     }
+    {
+        auto gr = Gtk::manage(new PreferencesGroup("Mouse"));
+        box->pack_start(*gr, false, false, 0);
+        gr->show();
+        {
+            auto r = Gtk::manage(new PreferencesRowBool("Switch layers with navigation buttons",
+                                                        "Use back/forward buttons on mouse to move one layer down/up",
+                                                        preferences, preferences.mouse.switch_layers));
+            gr->add_row(*r);
+        }
+    }
     {
         auto gr = Gtk::manage(new PreferencesGroup("Action Bar"));
         box->pack_start(*gr, false, false, 0);

src/preferences/preferences.cpp

@@ -386,6 +386,18 @@ void ActionBarPreferences::load_from_json(const json &j)
     show_in_tool = j.value("show_in_tool", true);
 }
 
+json MousePreferences::serialize() const
+{
+    json j;
+    j["switch_layers"] = switch_layers;
+    return j;
+}
+
+void MousePreferences::load_from_json(const json &j)
+{
+    switch_layers = j.value("switch_layers", true);
+}
+
 json Preferences::serialize() const
 {
     json j;
@@ -399,6 +411,7 @@ json Preferences::serialize() const
     j["capture_output"] = capture_output;
     j["partinfo"] = partinfo.serialize();
     j["action_bar"] = action_bar.serialize();
+    j["mouse"] = mouse.serialize();
     j["show_pull_request_tools"] = show_pull_request_tools;
     return j;
 }
@@ -428,6 +441,8 @@ void Preferences::load_from_json(const json &j)
         in_tool_key_sequences.load_from_json(j.at("in_tool_key_sequences"));
     if (j.count("action_bar"))
         action_bar.load_from_json(j.at("action_bar"));
+    if (j.count("mouse"))
+        mouse.load_from_json(j.at("mouse"));
     key_sequences.append_from_json(json_from_resource("/org/horizon-eda/horizon/imp/keys_default.json"));
     in_tool_key_sequences.append_from_json(
             json_from_resource("/org/horizon-eda/horizon/imp/in_tool_keys_default.json"));

src/preferences/preferences.hpp

@@ -96,6 +96,14 @@ class ActionBarPreferences {
     json serialize() const;
 };
 
+class MousePreferences {
+public:
+    bool switch_layers = true;
+
+    void load_from_json(const json &j);
+    json serialize() const;
+};
+
 class Preferences {
 public:
     Preferences();
@@ -117,6 +125,7 @@ class Preferences {
     PartInfoPreferences partinfo;
     ActionBarPreferences action_bar;
     InToolKeySequencesPreferences in_tool_key_sequences;
+    MousePreferences mouse;
 
     bool show_pull_request_tools = false;