Fix bloating of history with live preview

src/slic3r/GUI/Gizmos/GLGizmoSimplify.hpp

@@ -7,6 +7,9 @@
 #include "GLGizmoPainterBase.hpp" // for render wireframe
 #include "admesh/stl.h" // indexed_triangle_set
 #include <thread>
+#include <mutex>
+#include <condition_variable>
+#include <chrono>
 #include <optional>
 #include <atomic>
 
@@ -47,6 +50,7 @@ private:
     void set_its(indexed_triangle_set &its);
     void create_gui_cfg();
     void request_rerender();
+
     // move to global functions
     static ModelVolume *get_volume(const Selection &selection, Model &model);
     static const ModelVolume *get_volume(const GLVolume::CompositeID &cid, const Model &model);
@@ -62,10 +66,14 @@ private:
     size_t m_obj_index;
 
     std::optional<indexed_triangle_set> m_original_its;
-    bool m_show_wireframe;
+    bool m_show_wireframe; 
 
     volatile bool m_need_reload; // after simplify, glReload must be on main thread
+
     std::thread m_worker;
+    // wait before process
+    std::mutex m_state_mutex;
+    std::condition_variable m_dealy_process_cv;
 
     enum class State {
         settings,
@@ -87,8 +95,14 @@ private:
 
         void fix_count_by_ratio(size_t triangle_count)
         {
-            wanted_count = static_cast<uint32_t>(
-                std::round(triangle_count * (100.f-decimate_ratio) / 100.f));
+            if (decimate_ratio <= 0.f) { 
+                wanted_count = static_cast<uint32_t>(triangle_count);
+                return;
+            } else if (decimate_ratio >= 1.f) {
+                wanted_count = 0;
+                return;
+            }
+            wanted_count = static_cast<uint32_t>(std::round(triangle_count * (100.f-decimate_ratio) / 100.f));
         }
     } m_configuration;
 
@@ -106,6 +120,10 @@ private:
 
         // trunc model name when longer
         size_t max_char_in_name = 30;
+
+        // to prevent freezing when move in gui
+        // delay before process in [ms]
+        std::chrono::duration<long int, std::milli> prcess_delay = std::chrono::milliseconds(250);
     };
     std::optional<GuiCfg> m_gui_cfg;
 
@@ -122,6 +140,16 @@ private:
     void free_gpu();
     GLuint m_wireframe_VBO_id, m_wireframe_IBO_id;
     size_t m_wireframe_IBO_size;
+
+    // cancel exception
+    class SimplifyCanceledException: public std::exception
+    {
+    public:
+        const char *what() const throw()
+        {
+            return L("Model simplification has been canceled");
+        }
+    };
 };
 
 } // namespace GUI