Improve ImGui loop managment

extensions/ImGui/ImGuiPresenter.cpp

@@ -236,8 +236,10 @@ void ImGuiPresenter::cleanup()
 
     ImGui::DestroyContext();
 
-    if(!_renderLoops.empty()) {
+    if (!_renderLoops.empty())
-        for(auto item : _renderLoops) {
+    {
+        for (auto item : _renderLoops)
+        {
             delete item.second.tracker;
         }
         _renderLoops.clear();
@@ -288,6 +290,9 @@ float ImGuiPresenter::enableDPIScale(float userScale)
 #if (AX_TARGET_PLATFORM != AX_PLATFORM_ANDROID)
     // Gets scale
     glfwGetMonitorContentScale(glfwGetPrimaryMonitor(), &xscale, nullptr);
+#else
+    // refer to: https://developer.android.com/training/multiscreen/screendensities?hl=en-us
+    xscale = Device::getDPI() / 160.0f;
 #endif
 
     auto zoomFactor = userScale * xscale;
@@ -414,11 +419,14 @@ void ImGuiPresenter::update()
     usedCCRef.clear();
     // drawing commands
 
-    for (auto iter = _renderLoops.begin(); iter != _renderLoops.end(); ) {
+    for (auto iter = _renderLoops.begin(); iter != _renderLoops.end();)
+    {
         auto& imLoop = iter->second;
-        if(imLoop.removing) {
+        if (imLoop.removing)
-            delete imLoop.tracker;
+        {
+            auto tracker = imLoop.tracker;
             iter         = _renderLoops.erase(iter);
+            delete tracker;
             continue;
         }
         imLoop.func();  // invoke ImGui loop func
@@ -430,25 +438,28 @@ void ImGuiPresenter::update()
 
 bool ImGuiPresenter::addRenderLoop(std::string_view id, std::function<void()> func, Scene* target)
 {
-    // TODO: check whether exist
+
+    auto tracker = target ? static_cast<ImGuiEventTracker*>(utils::newInstance<ImGuiSceneEventTracker>(
+                                &ImGuiSceneEventTracker::initWithScene, target))
+                          : static_cast<ImGuiEventTracker*>(utils::newInstance<ImGuiGlobalEventTracker>());
+
     auto fourccId = fourccValue(id);
-    if (_renderLoops.find(fourccId) != _renderLoops.end())
+    auto iter     = _renderLoops.find(fourccId);
-    {
+    if (iter == _renderLoops.end())
-        return false;
-    }
-
-    ImGuiEventTracker* tracker;
-    if (target)
-        tracker = utils::newInstance<ImGuiSceneEventTracker>(&ImGuiSceneEventTracker::initWithScene, target);
-    else
-        tracker = utils::newInstance<ImGuiGlobalEventTracker>();
-
-    if (tracker)
     {
         _renderLoops.emplace(fourccId, ImGuiLoop{tracker, std::move(func)});
         return true;
     }
-    return false;
+
+    // allow reuse imLoop, update func, tracker, removing status
+    auto& imLoop   = iter->second;
+    imLoop.func    = std::move(func);
+    imLoop.tracker = tracker;
+
+    if (imLoop.removing)
+        imLoop.removing = false;
+
+    return true;
 }
 
 void ImGuiPresenter::removeRenderLoop(std::string_view id)

extensions/ImGui/ImGuiPresenter.h

@@ -3,7 +3,7 @@
 #include <stdint.h>
 #include <tuple>
 
-#include "cocos2d.h"
+#include "axmol.h"
 #include "ExtensionMacros.h"
 
 #include "imgui/imgui.h"
@@ -36,14 +36,17 @@ public:
     static void destroyInstance();
     static void setOnInit(const std::function<void(ImGuiPresenter*)>& callBack);
 
+    /// deprecated use enableDPIScale instead
+    float scaleAllByDPI(float userScale = 1.0f) { return enableDPIScale(userScale); }
+
     /// <summary>
     /// Scale ImGui with majorMoniter DPI scaling
     /// </summary>
     /// <param name="userScale">Usually is 1.0</param>
     /// <param name="fontFile">The full path of .ttc/.ttf file</param>
     /// <returns>The final contentZoomFactor = userScale * dpiScale</returns>
-    float scaleAllByDPI(float userScale = 1.0f) { return enableDPIScale(userScale); }
     float enableDPIScale(float userScale = 1.0f);
+
     float getContentZoomFactor() const { return _contentZoomFactor; }
 
     void setViewResolution(float width, float height);