completing refactoring, something does not work on resize

data/layout.xml

@@ -1,7 +1,4 @@
 <?xml version="1.0"?>
-<layout id="button">
-  
-</layout>
 <layout id="main">
   <node dir="col" wrap="0" width="100%" height="100%" pad="5">
     <!-- toolbar -->

engine/app.cpp

@@ -5,7 +5,7 @@ App App::I; // singleton
 
 void App::create()
 {
-    width = 500;
+    width = 800;
     height = 500;
 }
 
@@ -75,7 +75,7 @@ void App::init()
 #endif
     
     layout.load("data/layout.xml");
-    //layout.update(width, height);
+    layout["main"].update(width, height);
 
     sampler.create();
     ShaderManager::create(kShader::Texture, shader_v, shader_f);
@@ -109,11 +109,16 @@ void App::init()
 
 void App::update(float dt)
 {
+    constexpr auto main_id = const_hash("main");
+
     glClearColor(.1f, .1f, .1f, 1.f);
     glViewport(0, 0, (GLsizei)width, (GLsizei)height);
     glClear(GL_COLOR_BUFFER_BIT);
 
-    layout.reload();
+    if (layout.reload())
+    {
+        layout[main_id].update(width, height);
+    }
 
     glActiveTexture(GL_TEXTURE0);
     tex.bind();
@@ -122,17 +127,16 @@ void App::update(float dt)
     ShaderManager::u_int(kShaderUniform::Tex, 0);
 
     glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
-    glEnable(GL_SCISSOR_TEST);
-//     for (auto& n : layout)
-//     {
-// 
-//         if (n.m_widget)
-//         {
-//             auto box = n.m_widget->clip;
-//             glScissor(box.x, height - box.y - box.w, box.z, box.w);
-//             n.m_widget->draw();
-//         }
-//     }
+    //glEnable(GL_SCISSOR_TEST);
+    for (auto& n : layout[main_id])
+    {
+        if (n.m_widget)
+        {
+            auto box = n.m_widget->clip;
+            glScissor(box.x, height - box.y - box.w, box.z, box.w);
+            n.m_widget->draw();
+        }
+    }
     glDisable(GL_SCISSOR_TEST); 
     tex.unbind();
     sampler.unbind();
@@ -140,9 +144,8 @@ void App::update(float dt)
 
 void App::resize(float w, float h)
 {
-    width = w;
-    height = h;
-//    layout.update(width, height);
+    constexpr auto main_id = const_hash("main");
+    layout[main_id].update(w, h);
 }
 
 void App::mouse_down(int button, float x, float y)

engine/layout.cpp

@@ -9,7 +9,7 @@ void Node::update(float width, float height)
     YGNodeStyleSetWidth(y_node, width);
     YGNodeStyleSetHeight(y_node, height);
     YGNodeCalculateLayout(y_node, YGUndefined, YGUndefined, YGDirectionLTR);
-    glm::mat4 proj = glm::ortho(0.f, m_size.x, m_size.y, 0.f, -1.f, 1.f);
+    glm::mat4 proj = glm::ortho(0.f, width, height, 0.f, -1.f, 1.f);
     update_internal({ 0, 0 }, proj);
 }
 
@@ -218,7 +218,7 @@ bool LayoutManager::load(const char* path)
     m_file_info = tmp_info;
     m_path = path;
 
-    m_layouts.clear();
+    auto old = std::move(m_layouts);
 
     tinyxml2::XMLDocument xml;
     auto ret = xml.LoadFile(path);
@@ -235,11 +235,18 @@ bool LayoutManager::load(const char* path)
             return false;
         }
         uint16_t id = const_hash(id_str);
-        auto p = m_layouts.try_emplace(id);
+        auto& p = m_layouts.try_emplace(id);
         if (p.second)
         {
             auto& node = p.first->second;
-            node.load_internal(current);
+            // try to copy the old size values
+            if (old.count(id))
+            {
+                const auto& old_node = old[id];
+                YGNodeCopyStyle(node.y_node, old_node.y_node);
+            }
+            if (!current->NoChildren())
+                node.load_internal(current->FirstChildElement());
         }
         else
         {
@@ -247,14 +254,13 @@ bool LayoutManager::load(const char* path)
         }
         current = current->NextSiblingElement("layout");
     }
+
+    return true;
 }
 
-void LayoutManager::reload()
+bool LayoutManager::reload()
 {
-//     float w = YGNodeLayoutGetWidth(y_node);
-//     float h = YGNodeLayoutGetHeight(y_node);
-//     // avoid conflict when assigning the same string from c_str
-//     std::string path_copy = m_path; 
-//     load(path_copy.c_str());
-//     update(w, h);
+     // avoid conflict when assigning the same string from c_str
+     std::string path_copy = m_path;
+     return load(path_copy.c_str());
 }

engine/layout.h

@@ -182,6 +182,8 @@ public:
 
 class Node
 {
+    friend class LayoutManager;
+
     const Node* parent{ nullptr };
     YGNodeRef y_node{ nullptr };
 
@@ -293,5 +295,7 @@ class LayoutManager
     struct stat m_file_info { 0 };
 public:
     bool load(const char* path);
-    void reload();
+    bool reload();
+    Node& operator[](uint16_t id) { return m_layouts[id]; }
+    Node& operator[](const char* ids) { return m_layouts[const_hash(ids)]; }
 };