Implemented workaround for the mouse wheel in Search Window and Undo/Redo lists on the Plater

Workaround is used because of ImGui::GetIO().MouseWheel returns zero always!

src/slic3r/GUI/GLCanvas3D.cpp

@@ -3458,6 +3458,15 @@ void GLCanvas3D::on_mouse_wheel(wxMouseEvent& evt)
         }
     }
 
+    // If the Search window or Undo/Redo list is opened, 
+    // update them according to the event
+    if (m_main_toolbar.is_item_pressed("search")    || 
+        m_undoredo_toolbar.is_item_pressed("undo")  || 
+        m_undoredo_toolbar.is_item_pressed("redo")) {
+        m_mouse_wheel = int((double)evt.GetWheelRotation() / (double)evt.GetWheelDelta());
+        return;
+    }
+
     // Inform gizmos about the event so they have the opportunity to react.
     if (m_gizmos.on_mouse_wheel(evt))
         return;
@@ -4465,7 +4474,7 @@ bool GLCanvas3D::_render_undo_redo_stack(const bool is_undo, float pos_x) const
 	em *= m_retina_helper->get_scale_factor();
 #endif
 
-    if (imgui->undo_redo_list(ImVec2(18 * em, 26 * em), is_undo, &string_getter, hovered, selected))
+    if (imgui->undo_redo_list(ImVec2(18 * em, 26 * em), is_undo, &string_getter, hovered, selected, m_mouse_wheel))
         m_imgui_undo_redo_hovered_pos = hovered;
     else
         m_imgui_undo_redo_hovered_pos = -1;
@@ -4519,7 +4528,7 @@ bool GLCanvas3D::_render_search_list(float pos_x) const
 
     imgui->search_list(ImVec2(45 * em, 30 * em), &search_string_getter, s, 
                        sidebar.get_searcher().view_params,
-                       selected, edited);
+                       selected, edited, m_mouse_wheel);
 
     search_line = s;
     delete [] s;

src/slic3r/GUI/GLCanvas3D.hpp

@@ -506,6 +506,7 @@ private:
 #endif // ENABLE_RENDER_STATISTICS
 
     mutable int m_imgui_undo_redo_hovered_pos{ -1 };
+    mutable int m_mouse_wheel {0};
     int m_selected_extruder;
 
     Labels m_labels;

src/slic3r/GUI/ImGuiWrapper.cpp

@@ -379,7 +379,40 @@ bool ImGuiWrapper::combo(const wxString& label, const std::vector<std::string>&
     return res;
 }
 
-bool ImGuiWrapper::undo_redo_list(const ImVec2& size, const bool is_undo, bool (*items_getter)(const bool , int , const char**), int& hovered, int& selected)
+// Scroll up for one item 
+static void scroll_up()
+{
+    ImGuiContext& g = *GImGui;
+    ImGuiWindow* window = g.CurrentWindow;
+
+    float item_size_y = window->DC.PrevLineSize.y + g.Style.ItemSpacing.y;
+    float win_top = window->Scroll.y;
+
+    ImGui::SetScrollY(win_top - item_size_y);
+}
+
+// Scroll down for one item 
+static void scroll_down()
+{
+    ImGuiContext& g = *GImGui;
+    ImGuiWindow* window = g.CurrentWindow;
+
+    float item_size_y = window->DC.PrevLineSize.y + g.Style.ItemSpacing.y;
+    float win_top = window->Scroll.y;
+
+    ImGui::SetScrollY(win_top + item_size_y);
+}
+
+static void process_mouse_wheel(int& mouse_wheel)
+{
+    if (mouse_wheel > 0)
+        scroll_up();
+    else if (mouse_wheel < 0)
+        scroll_down();
+    mouse_wheel = 0;
+}
+
+bool ImGuiWrapper::undo_redo_list(const ImVec2& size, const bool is_undo, bool (*items_getter)(const bool , int , const char**), int& hovered, int& selected, int& mouse_wheel)
 {
     bool is_hovered = false;
     ImGui::ListBoxHeader("", size);
@@ -401,6 +434,9 @@ bool ImGuiWrapper::undo_redo_list(const ImVec2& size, const bool is_undo, bool (
         i++;
     }
 
+    if (is_hovered)
+        process_mouse_wheel(mouse_wheel);
+
     ImGui::ListBoxFooter();
     return is_hovered;
 }
@@ -563,30 +599,6 @@ static void scroll_y(int hover_id)
         ImGui::SetScrollY(win_top - item_size_y);
 }
 
-// Scroll up for one item 
-static void scroll_up()
-{
-    ImGuiContext& g = *GImGui;
-    ImGuiWindow* window = g.CurrentWindow;
-
-    float item_size_y = window->DC.PrevLineSize.y + g.Style.ItemSpacing.y;
-    float win_top = window->Scroll.y;
-
-    ImGui::SetScrollY(win_top - item_size_y);
-}
-
-// Scroll down for one item 
-static void scroll_down()
-{
-    ImGuiContext& g = *GImGui;
-    ImGuiWindow* window = g.CurrentWindow;
-
-    float item_size_y = window->DC.PrevLineSize.y + g.Style.ItemSpacing.y;
-    float win_top = window->Scroll.y;
-
-    ImGui::SetScrollY(win_top + item_size_y);
-}
-
 // Use this function instead of ImGui::IsKeyPressed.
 // ImGui::IsKeyPressed is related for *GImGui.IO.KeysDownDuration[user_key_index]
 // And after first key pressing IsKeyPressed() return "true" always even if key wasn't pressed
@@ -602,7 +614,7 @@ static void process_key_down(ImGuiKey imgui_key, std::function<void()> f)
 }
 
 void ImGuiWrapper::search_list(const ImVec2& size_, bool (*items_getter)(int, const char** label, const char** tooltip), char* search_str,
-                               Search::OptionViewParameters& view_params, int& selected, bool& edited)
+                               Search::OptionViewParameters& view_params, int& selected, bool& edited, int& mouse_wheel)
 {
     // ImGui::ListBoxHeader("", size);
     {   
@@ -678,6 +690,10 @@ void ImGuiWrapper::search_list(const ImVec2& size_, bool (*items_getter)(int, co
 
     scroll_y(mouse_hovered);
 
+    // Process mouse wheel
+    if (mouse_hovered > 0)
+        process_mouse_wheel(mouse_wheel);
+
     // process Up/DownArrows and Enter
     process_key_down(ImGuiKey_UpArrow, [&hovered_id, mouse_hovered]() {
         if (mouse_hovered > 0)

src/slic3r/GUI/ImGuiWrapper.hpp

@@ -77,9 +77,9 @@ public:
     bool slider_float(const std::string& label, float* v, float v_min, float v_max, const char* format = "%.3f", float power = 1.0f);
     bool slider_float(const wxString& label, float* v, float v_min, float v_max, const char* format = "%.3f", float power = 1.0f);
     bool combo(const wxString& label, const std::vector<std::string>& options, int& selection);   // Use -1 to not mark any option as selected
-    bool undo_redo_list(const ImVec2& size, const bool is_undo, bool (*items_getter)(const bool, int, const char**), int& hovered, int& selected);
+    bool undo_redo_list(const ImVec2& size, const bool is_undo, bool (*items_getter)(const bool, int, const char**), int& hovered, int& selected, int& mouse_wheel);
     void search_list(const ImVec2& size, bool (*items_getter)(int, const char** label, const char** tooltip), char* search_str,
-                     Search::OptionViewParameters& view_params, int& selected, bool& edited);
+                     Search::OptionViewParameters& view_params, int& selected, bool& edited, int& mouse_wheel);
 
     void disabled_begin(bool disabled);
     void disabled_end();