diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4a31b8a..78b1ffe 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -13,7 +13,9 @@ set(ROOT src/)
 set(CONTAINER src/containers)
 
 set(SOURCES ${SOURCES} ${ROOT}/window.cpp)
+set(SOURCES ${SOURCES} ${ROOT}/font.cpp)
 set(SOURCES ${SOURCES} ${CONTAINER}/container.cpp)
+set(SOURCES ${SOURCES} ${CONTAINER}/label.cpp)
 
 add_library(sftk SHARED ${SOURCES})
 target_link_libraries(sftk PUBLIC sfml-graphics sfml-audio sfml-network)
diff --git a/demo/demo1.cpp b/demo/demo1.cpp
index e1b37b7..60fdecc 100644
--- a/demo/demo1.cpp
+++ b/demo/demo1.cpp
@@ -5,15 +5,8 @@
 int main()
 {
     auto &window = sftk::Window::create(800, 600, L"demo1");
-    auto container = sftk::Container::create(vec(100.f, 100.f), vec(400.f, 400.f), window.getRoot());
-    container->setBackgroudColor(sf::Color::White);
-    container->registerEvent(
-        sftk::EventType::MouseDragged,
-        std::function(
-            [](sf::Vector2f start, sf::Vector2f now, sf::Mouse::Button button)
-            { std::cout << "(" << start.x << "," << start.y << ")"
-                        << "->(" << now.x << "," << now.y << ")"
-                        << "|" << button
-                        << std::endl; }));
+    auto &label = sftk::Label::create(L"hello SFTK.", sftk::Font("SarasaUiSC-Regular.ttf", "", 18));
+    label.setColor(sf::Color::White);
+    label.setPosition(vec(100.f, 100.f));
     window.exec();
 }
diff --git a/include/containers/container.hpp b/include/containers/container.hpp
index 218dd26..3aae428 100644
--- a/include/containers/container.hpp
+++ b/include/containers/container.hpp
@@ -2,6 +2,7 @@
 #define CONTAINER_HPP
 
 #include <vector>
+#include <map>
 #include <memory>
 #include <functional>
 
@@ -25,35 +26,38 @@ namespace sftk
 
         void setParent(pContainer parent);
         void setPosition(sf::Vector2f pos = sf::Vector2f(0, 0));
-        void setSize(sf::Vector2f pos);
-        void setBackgroudColor(sf::Color color);
+        void setSize(sf::Vector2f size);
 
+        pContainer asContainer() const;
         pContainer getParent() const;
         const sf::Vector2f &getPosition() const;
         const sf::Vector2f &getSize() const;
+        const sf::View &getView() const;
         sf::FloatRect getGlobalBouds() const;
 
         virtual bool isRoot() const;
         virtual bool hasInternalChange() const;
 
-        virtual void update() const;
+        void update(sf::RenderWindow &window) const;
 
-    public: // Event hadler register functions
         template <class T>
         void registerEvent(EventType type, std::function<T> handler);
 
     public: // Static and operators
-        static pContainer getRoot(Container *p = nullptr);
+        static pContainer getRoot(pContainer p = nullptr);
 
         friend bool sftk::operator==(pContainer &shp, Container *rawp);
 
     protected: // Must be overrided by child classes
         Container(pContainer parent = nullptr);
         Container(sf::Vector2f pos, sf::Vector2f size, pContainer parent = nullptr);
-        Container(sf::Vector2f pos, sf::Vector2f size, bool root);
+        // Only call by sftk::Window::Window()
+        Container(sf::Vector2f pos, sf::Vector2f size, bool root = false);
 
         virtual sf::RenderWindow &windowSFWindow();
 
+        virtual void draw(sf::RenderWindow &sfwindow) const;
+
         // The events bases on sfml's Event,
         // so the Window class must use this function to
         // pass event to the root container
@@ -61,23 +65,27 @@ namespace sftk
         // to process it as Event.
         void dispatchEvent(sf::Event &event);
 
-    private: // For this class to use
+    private:
+        uint64_t id;
+
         sf::RenderWindow &getSfWindow();
         // When this container did deal with the passed event
         // it returns true. On the oppsite case it returns false.
         bool dispatchEvent(Event &event);
 
         pContainer parent;
-        std::vector<pContainer> childs;
+        std::vector<pContainer> children;
         sf::Vector2f basepos;
         sf::Vector2f pos, size;
 
         sf::View view;
 
-        sf::Color backgroudColor;
-
         static const int64_t maxClickTime = 300;
 
+        static thread_local uint64_t containerCounter;
+        static thread_local std::map<uint64_t, pContainer> globalContainers;
+        static thread_local pContainer root;
+
     private: // Called on construction
         static void rootTest(Container *self);
         inline static int64_t currentTime();
@@ -125,6 +133,13 @@ namespace sftk
             HandlerNotMatched(Container *container);
             const char *what() const noexcept override;
         };
+
+        class ConstructorCalledIllegally : public SFTKException<Container>
+        {
+        public:
+            ConstructorCalledIllegally(Container *container);
+            const char *what() const noexcept override;
+        };
     };
 
 };
diff --git a/include/containers/label.hpp b/include/containers/label.hpp
new file mode 100644
index 0000000..3319f47
--- /dev/null
+++ b/include/containers/label.hpp
@@ -0,0 +1,45 @@
+#ifndef LABLE_HPP
+#define LABLE_HPP
+
+#include <string>
+#include <vector>
+
+#include <font.hpp>
+#include <containers/container.hpp>
+
+namespace sftk
+{
+    class Label : public Container
+    {
+    public:
+        static Label &create(pContainer parent = nullptr);
+        static Label &create(sf::Vector2f pos, pContainer parent = nullptr);
+        static Label &create(std::wstring text, pContainer parent = nullptr);
+        static Label &create(Font font, pContainer parent = nullptr);
+        static Label &create(std::wstring text, Font font, pContainer parent = nullptr);
+
+        void setText(std::wstring text);
+        void setFont(Font font);
+        void setColor(sf::Color color);
+        void setSize(sf::Vector2f size) = delete;
+
+        const std::wstring &getText() const;
+        const Font &getFont() const;
+        sf::Color getColor() const;
+
+    protected:
+        Label(pContainer parent = nullptr);
+        Label(sf::Vector2f pos, pContainer parent = nullptr);
+
+        void draw(sf::RenderWindow &sfwindow) const;
+
+    private:
+        std::wstring text;
+        Font font;
+        sf::Color color;
+
+        std::vector<float> linesWidths;
+    };
+};
+
+#endif
diff --git a/include/exceptions.hpp b/include/exceptions.hpp
index 0b11618..8ccc141 100644
--- a/include/exceptions.hpp
+++ b/include/exceptions.hpp
@@ -40,17 +40,23 @@ namespace sftk
          * @param msg exception message
          * @param len message length
          */
-        void formatAddress(char *msg, int len) const
+        void formatAddress(char *msg, int len) const noexcept
         {
-            std::stringstream ss;
-            ss << std::hex << std::setw(16) << std::setfill('0') << reinterpret_cast<uintptr_t>(sftkObj);
-            auto it = ss.str().begin();
-            for (int i = 0; i < len; i++)
+            auto ptr = reinterpret_cast<uintptr_t>(sftkObj);
+            while (--len >= 0)
             {
-                if (msg[i] == '*')
+                if (msg[len] == '*')
                 {
-                    msg[i] = *it;
-                    ++it;
+                    auto bit = ptr-- & 0xf;
+                    if (bit < 10)
+                    {
+                        bit += '0';
+                    }
+                    else
+                    {
+                        bit -= 10 - 'a';
+                    }
+                    msg[len] = bit;
                 }
             }
         }
diff --git a/include/font.hpp b/include/font.hpp
new file mode 100644
index 0000000..f2ad56f
--- /dev/null
+++ b/include/font.hpp
@@ -0,0 +1,40 @@
+#ifndef FONT_HPP
+#define FONT_HPP
+
+#include <string>
+
+#include <SFML/Graphics.hpp>
+
+#include <exceptions.hpp>
+
+namespace sftk
+{
+    class Font
+    {
+    public:
+        Font();
+        Font(std::string font, std::string fallback, int size);
+
+        sf::Font font;
+        sf::Font fallback;
+        int size;
+
+    public:
+        class MainFontIsEmpty : public SFTKException<Font>
+        {
+        public:
+            MainFontIsEmpty(Font *font);
+            const char *what() const noexcept override;
+        };
+
+        class FailedToLoadFont : public SFTKException<Font>
+        {
+        public:
+            FailedToLoadFont(Font *font);
+            const char *what() const noexcept override;
+        };
+    };
+
+};
+
+#endif
diff --git a/include/sftk.hpp b/include/sftk.hpp
index 9ec0109..36f49a2 100644
--- a/include/sftk.hpp
+++ b/include/sftk.hpp
@@ -4,7 +4,7 @@
 #include <gtypes.hpp>
 
 #include <window.hpp>
-
 #include <containers/container.hpp>
+#include <containers/label.hpp>
 
 #endif
diff --git a/include/window.hpp b/include/window.hpp
index c012fd8..042c8af 100644
--- a/include/window.hpp
+++ b/include/window.hpp
@@ -28,6 +28,9 @@ namespace sftk
         void exec();
 
         void setSize(sf::Vector2u size);
+        void setBackgroudColor(sf::Color color);
+
+        const sf::Color &getBackgroundColor() const;
 
         bool isRoot() const;
 
@@ -45,6 +48,7 @@ namespace sftk
 
     private:
         std::unique_ptr<std::vector<sf::Vector2f>> v2f_dumpst;
+        sf::Color backgroud;
 
     public:
         class WindowMultipleConstructed : public SFTKException<Window>
diff --git a/src/containers/container.cpp b/src/containers/container.cpp
index db4149d..5bd1cfa 100644
--- a/src/containers/container.cpp
+++ b/src/containers/container.cpp
@@ -8,11 +8,14 @@
 
 using namespace sftk;
 
-pContainer Container::getRoot(Container *p)
+thread_local uint64_t Container::containerCounter = 0;
+thread_local std::map<uint64_t, pContainer> Container::globalContainers;
+thread_local pContainer Container::root = nullptr;
+
+pContainer Container::getRoot(pContainer p)
 {
-    static thread_local pContainer root;
     if (p)
-        root.reset(p);
+        root = p;
     return root;
 }
 
@@ -22,8 +25,13 @@ void Container::rootTest(Container *self)
         throw RootContainerNotPresent(self);
 }
 
-Container::Container(pContainer parent) : parent(nullptr)
+Container::Container(pContainer parent)
+    : parent(nullptr),
+      pos(vec(0.f, 0.f)),
+      size(vec(0.f, 0.f)),
+      view(vec(0.f, 0.f, 0.f, 0.f))
 {
+    id = containerCounter++;
     if (!parent.get())
     {
         Container::rootTest(this);
@@ -33,7 +41,9 @@ Container::Container(pContainer parent) : parent(nullptr)
     {
         this->parent = parent;
     }
-    this->parent->childs.push_back(pContainer(this));
+    pContainer pthis(this);
+    globalContainers[id] = pthis;
+    this->parent->children.push_back(pthis);
     for (auto &p : lastMousePressPos)
         p = vec(-1.f, -1.f);
 }
@@ -42,10 +52,9 @@ Container::Container(sf::Vector2f pos, sf::Vector2f size, pContainer parent)
     : parent(nullptr),
       pos(pos),
       size(size),
-      view(vec(0.f, 0.f, size.x, size.y)),
-      basepos(parent->basepos + parent->pos),
-      backgroudColor(sf::Color::Black)
+      view(vec(0.f, 0.f, size.x, size.y))
 {
+    id = containerCounter++;
     if (!parent.get())
     {
         Container::rootTest(this);
@@ -55,7 +64,10 @@ Container::Container(sf::Vector2f pos, sf::Vector2f size, pContainer parent)
     {
         this->parent = parent;
     }
-    this->parent->childs.push_back(pContainer(this));
+    basepos = this->parent->basepos + this->parent->pos;
+    pContainer pthis(this);
+    globalContainers[id] = pthis;
+    this->parent->children.push_back(pthis);
     auto rootsize = getRoot()->getSize();
     view.setViewport(vec(
         (parent->basepos.x + pos.x) / rootsize.x, (parent->basepos.y + pos.y) / rootsize.y,
@@ -69,9 +81,14 @@ Container::Container(sf::Vector2f pos, sf::Vector2f size, bool root)
       pos(pos),
       size(size),
       view(vec(0.f, 0.f, size.x, size.y)),
-      basepos(vec(0.f, 0.f)),
-      backgroudColor(sf::Color::Black)
+      basepos(vec(0.f, 0.f))
 {
+    if (!root)
+    {
+        throw new ConstructorCalledIllegally(this);
+    }
+    id = containerCounter++;
+    globalContainers[id] = pContainer(this);
     view.setViewport(vec(0.f, 0.f, 1.f, 1.f));
     for (auto &p : lastMousePressPos)
         p = vec(-1.f, -1.f);
@@ -79,20 +96,20 @@ Container::Container(sf::Vector2f pos, sf::Vector2f size, bool root)
 
 pContainer Container::create(pContainer parent)
 {
-    return pContainer(new Container(parent));
+    return (new Container(parent))->asContainer();
 }
 
 pContainer Container::create(sf::Vector2f pos, sf::Vector2f size, pContainer parent)
 {
-    return pContainer(new Container(pos, size, parent));
+    return (new Container(pos, size, parent))->asContainer();
 }
 
 void Container::setParent(pContainer parent)
 {
-    auto it = std::find(this->parent->childs.begin(), this->parent->childs.end(), this);
-    this->parent->childs.erase(it);
+    auto it = std::find(this->parent->children.begin(), this->parent->children.end(), this);
+    this->parent->children.erase(it);
     this->parent = parent;
-    this->parent->childs.push_back(pContainer(this));
+    this->parent->children.push_back(pContainer(this));
 }
 
 void Container::setPosition(sf::Vector2f pos)
@@ -100,8 +117,12 @@ void Container::setPosition(sf::Vector2f pos)
     this->pos = pos;
     auto rootsize = getRoot()->getSize();
     view.setViewport(vec(
-        (parent->pos.x + pos.x) / rootsize.x, (parent->pos.y + pos.y) / rootsize.y,
+        (basepos.x + pos.x) / rootsize.x, (basepos.x + pos.y) / rootsize.y,
         size.x / rootsize.x, size.y / rootsize.y));
+    for (auto c : children)
+    {
+        c->basepos = basepos + pos;
+    }
 }
 
 void Container::setSize(sf::Vector2f size)
@@ -111,11 +132,12 @@ void Container::setSize(sf::Vector2f size)
     view.setViewport(vec(
         (basepos.x + pos.x) / rootsize.x, (basepos.y + pos.y) / rootsize.y,
         size.x / rootsize.x, size.y / rootsize.y));
+    view.setSize(size);
 }
 
-void Container::setBackgroudColor(sf::Color color)
+pContainer Container::asContainer() const
 {
-    backgroudColor = color;
+    return globalContainers[id];
 }
 
 pContainer Container::getParent() const
@@ -133,6 +155,11 @@ const sf::Vector2f &Container::getSize() const
     return size;
 }
 
+const sf::View &Container::getView() const
+{
+    return view;
+}
+
 sf::FloatRect Container::getGlobalBouds() const
 {
     return vec(basepos.x + pos.x, basepos.y + pos.y, size.x, size.y);
@@ -148,27 +175,18 @@ bool Container::hasInternalChange() const
     return false;
 }
 
-void Container::update() const
+void Container::update(sf::RenderWindow &window) const
 {
-    auto &window = getRoot()->windowSFWindow();
-    if (isRoot())
+    window.setView(view);
+    draw(window);
+    for (auto c : children)
     {
-        window.clear(backgroudColor);
-    }
-    else
-    {
-        window.setView(view);
-        sf::RectangleShape bg(vec(size.x, size.y));
-        bg.setPosition(vec(0.f, 0.f));
-        bg.setFillColor(backgroudColor);
-        window.draw(bg);
-    }
-    for (auto c : childs)
-    {
-        c->update();
+        c->update(window);
     }
 }
 
+void Container::draw(sf::RenderWindow &sfwindow) const {}
+
 template <>
 void Container::registerEvent(EventType type, std::function<void()> handler)
 {
@@ -507,7 +525,7 @@ bool Container::dispatchEvent(Event &event)
 
     bool child_handled;
     bool handler_handled = false;
-    for (auto container : childs)
+    for (auto container : children)
     {
         if ((child_handled = container->dispatchEvent(event)) && !broadcast)
         {
@@ -548,7 +566,7 @@ const char *Container::RootContainerNotPresent::what() const noexcept
 {
     static char msg[] = "sftk::Container 0x********_********: Root container not present.";
     SFTKException::formatAddress(msg, sizeof(msg));
-    return msg;
+    return const_cast<const char *>(msg);
 }
 
 Container::NotAWindowObj::NotAWindowObj(Container *container)
@@ -558,7 +576,7 @@ const char *Container::NotAWindowObj::what() const noexcept
 {
     static char msg[] = "sftk::Container 0x********_********: Not a sftk::Window.";
     SFTKException::formatAddress(msg, sizeof(msg));
-    return msg;
+    return const_cast<const char *>(msg);
 }
 
 Container::HandlerNotMatched::HandlerNotMatched(Container *container)
@@ -566,7 +584,19 @@ Container::HandlerNotMatched::HandlerNotMatched(Container *container)
 
 const char *Container::HandlerNotMatched::what() const noexcept
 {
-    static char msg[] = "sftk::Container 0x********_********: When calling Container::registerEvent(), passed a closure with wrong arguments.";
+    static char msg[] = "sftk::Container 0x********_********:"
+                        " When calling Container::registerEvent(), passed a closure with wrong arguments.";
     SFTKException::formatAddress(msg, sizeof(msg));
-    return msg;
+    return const_cast<const char *>(msg);
+}
+
+Container::ConstructorCalledIllegally::ConstructorCalledIllegally(Container *container)
+    : SFTKException(container) {}
+
+const char *Container::ConstructorCalledIllegally::what() const noexcept
+{
+    static char msg[] = "sftk::Container 0x********_********:"
+                        " This constructor can only be called by sftk::Window::Window().";
+    SFTKException::formatAddress(msg, sizeof(msg));
+    return const_cast<const char *>(msg);
 }
diff --git a/src/containers/label.cpp b/src/containers/label.cpp
new file mode 100644
index 0000000..9b31aeb
--- /dev/null
+++ b/src/containers/label.cpp
@@ -0,0 +1,108 @@
+#include <containers/label.hpp>
+
+#include <iostream>
+#include <gtypes.hpp>
+
+using namespace sftk;
+
+Label::Label(pContainer parent) : Container(parent) {}
+
+Label::Label(sf::Vector2f pos, pContainer parent)
+    : Container(pos, vec(0.f, 0.f), parent) {}
+
+Label &Label::create(pContainer parent)
+{
+    return *new Label(parent);
+}
+
+Label &Label::create(sf::Vector2f pos, pContainer parent)
+{
+    return *new Label(pos, parent);
+}
+
+Label &Label::create(std::wstring text, pContainer parent)
+{
+    auto *label = new Label(parent);
+    label->setText(text);
+    return *label;
+}
+
+Label &Label::create(Font font, pContainer parent)
+{
+    auto *label = new Label(parent);
+    label->setFont(font);
+    return *label;
+}
+
+Label &Label::create(std::wstring text, Font font, pContainer parent)
+{
+    auto *label = new Label(parent);
+    label->setFont(font);
+    label->setText(text);
+    return *label;
+}
+
+void Label::setText(std::wstring text)
+{
+    this->text = text;
+    linesWidths.clear();
+    float currentLineWidth = 0;
+    float maxWidth = 0;
+    for (auto ch : text)
+    {
+        if (ch == L'\n')
+        {
+            linesWidths.push_back(currentLineWidth);
+            if (currentLineWidth > maxWidth)
+                maxWidth = currentLineWidth;
+            currentLineWidth = 0;
+        }
+        auto glyph = font.font.getGlyph(ch, font.size, false);
+        currentLineWidth += glyph.advance;
+    }
+    if (currentLineWidth != 0)
+    {
+        linesWidths.push_back(currentLineWidth);
+        if (currentLineWidth > maxWidth)
+            maxWidth = currentLineWidth;
+    }
+    auto lineSpacing = font.font.getLineSpacing(font.size);
+    Container::setSize(vec(maxWidth, linesWidths.size() * lineSpacing));
+}
+
+void Label::setFont(Font font)
+{
+    this->font = font;
+}
+
+void Label::setColor(sf::Color color)
+{
+    this->color = color;
+}
+
+const std::wstring &Label::getText() const
+{
+    return text;
+}
+
+const Font &Label::getFont() const
+{
+    return font;
+}
+
+sf::Color Label::getColor() const
+{
+    return color;
+}
+
+void Label::draw(sf::RenderWindow &sfwindow) const
+{
+    sf::Text textObj;
+    auto sz = getSize();
+    textObj.setPosition(vec(-sz.x / 2, -sz.y / 2));
+    textObj.setString(text);
+    textObj.setFont(font.font);
+    textObj.setCharacterSize(font.size);
+    textObj.setFillColor(color);
+    sfwindow.draw(textObj);
+}
diff --git a/src/font.cpp b/src/font.cpp
new file mode 100644
index 0000000..b7358e5
--- /dev/null
+++ b/src/font.cpp
@@ -0,0 +1,37 @@
+#include <font.hpp>
+
+using namespace sftk;
+
+Font::Font() {}
+
+Font::Font(std::string font, std::string fallback, int size)
+    : size(size)
+{
+    if (font.empty())
+        throw new MainFontIsEmpty(this);
+    if (!this->font.loadFromFile(font))
+        throw new FailedToLoadFont(this);
+    if (!fallback.empty())
+        if (!this->fallback.loadFromFile(fallback))
+            throw new FailedToLoadFont(this);
+}
+
+Font::MainFontIsEmpty::MainFontIsEmpty(Font *font)
+    : SFTKException(font) {}
+
+const char *Font::MainFontIsEmpty::what() const noexcept
+{
+    static char msg[] = "sftk::Font 0x********_********: The main font must be set.";
+    SFTKException::formatAddress(msg, sizeof(msg));
+    return const_cast<const char *>(msg);
+}
+
+Font::FailedToLoadFont::FailedToLoadFont(Font *font)
+    : SFTKException(font) {}
+
+const char *Font::FailedToLoadFont::what() const noexcept
+{
+    static char msg[] = "sftk::Font 0x********_********: Failed to load font file.";
+    SFTKException::formatAddress(msg, sizeof(msg));
+    return const_cast<const char *>(msg);
+}
diff --git a/src/window.cpp b/src/window.cpp
index 690e51b..5ea665d 100644
--- a/src/window.cpp
+++ b/src/window.cpp
@@ -2,6 +2,7 @@
 
 #include <sstream>
 #include <iomanip>
+#include <iostream>
 
 #include <gtypes.hpp>
 #include <containers/container.hpp>
@@ -16,11 +17,12 @@ Window &Window::create(int width, int height, std::wstring name)
 Window::Window(int width, int height, std::wstring name)
     : Container(vec(0.f, 0.f), vec((float)width, (float)height), true),
       sfwindow(sf::VideoMode(width, height), name),
-      running(new bool(true))
+      running(new bool(true)),
+      backgroud(sf::Color::Black)
 {
     if (Container::getRoot().get())
         throw WindowMultipleConstructed(this);
-    Container::getRoot(this);
+    Container::getRoot(this->asContainer());
 }
 
 void Window::exec()
@@ -45,7 +47,8 @@ void Window::exec()
         }
         if (event_occured || hasInternalChange())
         {
-            update();
+            sfwindow.clear(backgroud);
+            update(sfwindow);
             sfwindow.display();
         }
     }
@@ -57,6 +60,16 @@ void Window::setSize(sf::Vector2u size)
     Container::setSize(vec((float)size.x, (float)size.y));
 }
 
+void Window::setBackgroudColor(sf::Color color)
+{
+    backgroud = color;
+}
+
+const sf::Color &Window::getBackgroundColor() const
+{
+    return backgroud;
+}
+
 bool Window::isRoot() const
 {
     return true;
@@ -82,5 +95,5 @@ const char *Window::WindowMultipleConstructed::what() const noexcept
 {
     static char msg[] = "sftk::Window 0x********_********: Multiply constructed in one thread.";
     SFTKException::formatAddress(msg, sizeof(msg));
-    return msg;
+    return const_cast<const char *>(msg);
 }