diff --git a/.gitmodules b/.gitmodules
index 3cf1ef6..aaca960 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,3 +1,4 @@
 [submodule "deps/SFML"]
 	path = deps/SFML
 	url = https://github.com/SFML/SFML.git
+	branch = 2.6.1
\ No newline at end of file
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 40bcf90..378dbd5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -10,8 +10,10 @@ set(CONTAINER src/containers)
 
 set(SOURCES ${SOURCES} ${ROOT}/window.cpp)
 set(SOURCES ${SOURCES} ${ROOT}/font.cpp)
+set(SOURCES ${SOURCES} ${ROOT}/richText.cpp)
 set(SOURCES ${SOURCES} ${CONTAINER}/container.cpp)
 set(SOURCES ${SOURCES} ${CONTAINER}/label.cpp)
+set(SOURCES ${SOURCES} ${CONTAINER}/rtlabel.cpp)
 
 add_library(sftk SHARED ${SOURCES})
 target_link_libraries(sftk PUBLIC sfml-graphics sfml-audio sfml-network)
diff --git a/demo/SarasaUiSC-Bold.ttf b/demo/SarasaUiSC-Bold.ttf
new file mode 100644
index 0000000..3bb5a52
Binary files /dev/null and b/demo/SarasaUiSC-Bold.ttf differ
diff --git a/demo/SarasaUiSC-BoldItalic.ttf b/demo/SarasaUiSC-BoldItalic.ttf
new file mode 100644
index 0000000..9b736d4
Binary files /dev/null and b/demo/SarasaUiSC-BoldItalic.ttf differ
diff --git a/demo/SarasaUiSC-Italic.ttf b/demo/SarasaUiSC-Italic.ttf
new file mode 100644
index 0000000..ab7eb11
Binary files /dev/null and b/demo/SarasaUiSC-Italic.ttf differ
diff --git a/demo/demo1.cpp b/demo/demo1.cpp
index 21f14cb..98c4d23 100644
--- a/demo/demo1.cpp
+++ b/demo/demo1.cpp
@@ -1,13 +1,17 @@
-#include <iostream>
-
 #include <sftk.hpp>
 
 int main()
 {
     auto &window = sftk::Window::create(800, 600, L"demo1");
     window.setBackgroudColor(sf::Color::White);
-    auto &label = sftk::Label::create(L"hello SFTK.", sftk::Font("../demo/SarasaUiSC-Regular.ttf", "", 18));
+    auto &label = sftk::Label::create(
+        L"SFTK demo.\nBy Random World Studio.",
+        sftk::Font("../demo/SarasaUiSC-Regular.ttf", 18));
     label.setColor(sf::Color::Black);
-    label.setPosition(vec(100.f, 100.f));
+    window.registerEvent(
+        sftk::EventType::Resized,
+        std::function(
+            [&label](sf::Vector2f size)
+            { label.setPosition(size - label.getSize()); }));
     window.exec();
 }
diff --git a/include/containers/container.hpp b/include/containers/container.hpp
index 3aae428..74ed9e8 100644
--- a/include/containers/container.hpp
+++ b/include/containers/container.hpp
@@ -38,7 +38,7 @@ namespace sftk
         virtual bool isRoot() const;
         virtual bool hasInternalChange() const;
 
-        void update(sf::RenderWindow &window) const;
+        void update(sf::RenderWindow &window, sf::View parentView) const;
 
         template <class T>
         void registerEvent(EventType type, std::function<T> handler);
diff --git a/include/containers/label.hpp b/include/containers/label.hpp
index 3319f47..f7290c5 100644
--- a/include/containers/label.hpp
+++ b/include/containers/label.hpp
@@ -1,5 +1,5 @@
-#ifndef LABLE_HPP
-#define LABLE_HPP
+#ifndef LABEL_HPP
+#define LABEL_HPP
 
 #include <string>
 #include <vector>
@@ -38,6 +38,10 @@ namespace sftk
         Font font;
         sf::Color color;
 
+        // After setText() called, this vector will be filled.
+        std::vector<uint> wrongGlyphs;
+        // This vector records every characters' x offset.
+        std::vector<std::vector<float>> linesGlyphPrefixSum; 
         std::vector<float> linesWidths;
     };
 };
diff --git a/include/exceptions.hpp b/include/exceptions.hpp
index 8ccc141..63437e9 100644
--- a/include/exceptions.hpp
+++ b/include/exceptions.hpp
@@ -33,7 +33,7 @@ namespace sftk
          * {
          *     static char msg[] = "sftk::SomeClass 0x********_******** reported an exception.";
          *     SFTKException::formatAddress(msg, sizeof(msg));
-         *     return msg;
+         *     return const_cast<SomeClass *>(msg);
          * }
          * ```
          *
diff --git a/include/font.hpp b/include/font.hpp
index f2ad56f..0d5ce9b 100644
--- a/include/font.hpp
+++ b/include/font.hpp
@@ -13,10 +13,9 @@ namespace sftk
     {
     public:
         Font();
-        Font(std::string font, std::string fallback, int size);
+        Font(std::string font, int size);
 
         sf::Font font;
-        sf::Font fallback;
         int size;
 
     public:
@@ -35,6 +34,42 @@ namespace sftk
         };
     };
 
+    class FontFamily
+    {
+    public:
+        enum FontType
+        {
+            Regular,
+            Bold,
+            Italic,
+            BoldItalic,
+        };
+
+    private:
+        static std::string genFontFileName(FontType ftype, std::string name);
+
+    public:
+        FontFamily();
+        FontFamily(std::string name, uint baseSize, std::string findPath = "");
+
+        sf::Font &operator[](FontType ftype);
+
+        std::string name;
+        uint baseSize;
+        sf::Font regular;
+        sf::Font bold;
+        sf::Font italic;
+        sf::Font boldItalic;
+
+    public:
+        class UnexceptedFontType : public SFTKException<FontFamily>
+        {
+        public:
+            UnexceptedFontType(FontFamily *fntfml);
+            const char *what() const noexcept override;
+        };
+    };
+
 };
 
 #endif
diff --git a/include/gtypes.hpp b/include/gtypes.hpp
index 023e529..f9f80e5 100644
--- a/include/gtypes.hpp
+++ b/include/gtypes.hpp
@@ -16,7 +16,7 @@ constexpr sf::Vector3<T> vec(T x, T y, T z)
 }
 
 template <class T>
-constexpr sf::Rect<T> vec(T x, T y, T width, T height)
+constexpr sf::Rect<T> rec(T x, T y, T width, T height)
 {
     return sf::Rect(x, y, width, height);
 }
diff --git a/include/window.hpp b/include/window.hpp
index 042c8af..1d8bd67 100644
--- a/include/window.hpp
+++ b/include/window.hpp
@@ -11,10 +11,6 @@
 
 namespace sftk
 {
-    class Window;
-
-    typedef std::shared_ptr<Window> pWindow;
-
     /**
      * @brief Window type
      *
diff --git a/src/containers/container.cpp b/src/containers/container.cpp
index 5bd1cfa..1b5667e 100644
--- a/src/containers/container.cpp
+++ b/src/containers/container.cpp
@@ -5,6 +5,7 @@
 
 #include <iostream>
 #include <chrono>
+#include <cmath>
 
 using namespace sftk;
 
@@ -29,7 +30,7 @@ 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))
+      view(rec(0.f, 0.f, 0.f, 0.f))
 {
     id = containerCounter++;
     if (!parent.get())
@@ -52,7 +53,7 @@ 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))
+      view(rec(0.f, 0.f, size.x, size.y))
 {
     id = containerCounter++;
     if (!parent.get())
@@ -69,7 +70,7 @@ Container::Container(sf::Vector2f pos, sf::Vector2f size, pContainer parent)
     globalContainers[id] = pthis;
     this->parent->children.push_back(pthis);
     auto rootsize = getRoot()->getSize();
-    view.setViewport(vec(
+    view.setViewport(rec(
         (parent->basepos.x + pos.x) / rootsize.x, (parent->basepos.y + pos.y) / rootsize.y,
         size.x / rootsize.x, size.y / rootsize.y));
     for (auto &p : lastMousePressPos)
@@ -80,7 +81,7 @@ Container::Container(sf::Vector2f pos, sf::Vector2f size, bool root)
     : parent(nullptr),
       pos(pos),
       size(size),
-      view(vec(0.f, 0.f, size.x, size.y)),
+      view(rec(0.f, 0.f, size.x, size.y)),
       basepos(vec(0.f, 0.f))
 {
     if (!root)
@@ -89,7 +90,7 @@ Container::Container(sf::Vector2f pos, sf::Vector2f size, bool root)
     }
     id = containerCounter++;
     globalContainers[id] = pContainer(this);
-    view.setViewport(vec(0.f, 0.f, 1.f, 1.f));
+    view.setViewport(rec(0.f, 0.f, 1.f, 1.f));
     for (auto &p : lastMousePressPos)
         p = vec(-1.f, -1.f);
 }
@@ -116,7 +117,7 @@ void Container::setPosition(sf::Vector2f pos)
 {
     this->pos = pos;
     auto rootsize = getRoot()->getSize();
-    view.setViewport(vec(
+    view.setViewport(rec(
         (basepos.x + pos.x) / rootsize.x, (basepos.x + pos.y) / rootsize.y,
         size.x / rootsize.x, size.y / rootsize.y));
     for (auto c : children)
@@ -129,7 +130,7 @@ void Container::setSize(sf::Vector2f size)
 {
     this->size = size;
     auto rootsize = getRoot()->getSize();
-    view.setViewport(vec(
+    view.setViewport(rec(
         (basepos.x + pos.x) / rootsize.x, (basepos.y + pos.y) / rootsize.y,
         size.x / rootsize.x, size.y / rootsize.y));
     view.setSize(size);
@@ -162,7 +163,7 @@ const sf::View &Container::getView() const
 
 sf::FloatRect Container::getGlobalBouds() const
 {
-    return vec(basepos.x + pos.x, basepos.y + pos.y, size.x, size.y);
+    return rec(basepos.x + pos.x, basepos.y + pos.y, size.x, size.y);
 }
 
 bool Container::isRoot() const
@@ -175,13 +176,26 @@ bool Container::hasInternalChange() const
     return false;
 }
 
-void Container::update(sf::RenderWindow &window) const
+static sf::FloatRect calViewportOverlap(sf::FloatRect vpa, sf::FloatRect vpb)
 {
+    auto left = std::max(vpa.left, vpb.left);
+    auto right = std::min(vpa.left + vpa.width, vpb.left + vpb.width);
+    auto top = std::max(vpa.top, vpb.top);
+    auto bottom = std::min(vpa.top + vpa.height, vpb.top + vpb.height);
+    return sf::FloatRect(left, top, right - left, bottom - top);
+}
+
+void Container::update(sf::RenderWindow &window, sf::View parentView) const
+{
+    auto view = this->view;
+    auto sz = getSize();
+    sf::View currView(rec(0.f, 0.f, sz.x, sz.y));
+    currView.setViewport(calViewportOverlap(view.getViewport(), parentView.getViewport()));
     window.setView(view);
     draw(window);
     for (auto c : children)
     {
-        c->update(window);
+        c->update(window, currView);
     }
 }
 
@@ -361,6 +375,7 @@ bool Container::dispatchEvent(Event &event)
         }
         break;
     case EventType::Resized:
+        broadcast = true;
         rsz = event.data.resized;
         if (resized)
         {
diff --git a/src/containers/label.cpp b/src/containers/label.cpp
index 9b31aeb..74d75d9 100644
--- a/src/containers/label.cpp
+++ b/src/containers/label.cpp
@@ -44,10 +44,13 @@ Label &Label::create(std::wstring text, Font font, pContainer parent)
 
 void Label::setText(std::wstring text)
 {
+    sf::Font font = this->font.font;
+    uint font_size = this->font.size;
     this->text = text;
     linesWidths.clear();
     float currentLineWidth = 0;
     float maxWidth = 0;
+    uint index = 0;
     for (auto ch : text)
     {
         if (ch == L'\n')
@@ -57,7 +60,9 @@ void Label::setText(std::wstring text)
                 maxWidth = currentLineWidth;
             currentLineWidth = 0;
         }
-        auto glyph = font.font.getGlyph(ch, font.size, false);
+        if (!font.hasGlyph(ch))
+            wrongGlyphs.push_back(index);
+        auto glyph = font.getGlyph(ch, font_size, false);
         currentLineWidth += glyph.advance;
     }
     if (currentLineWidth != 0)
@@ -66,7 +71,7 @@ void Label::setText(std::wstring text)
         if (currentLineWidth > maxWidth)
             maxWidth = currentLineWidth;
     }
-    auto lineSpacing = font.font.getLineSpacing(font.size);
+    auto lineSpacing = font.getLineSpacing(font_size);
     Container::setSize(vec(maxWidth, linesWidths.size() * lineSpacing));
 }
 
diff --git a/src/font.cpp b/src/font.cpp
index b7358e5..532f2f4 100644
--- a/src/font.cpp
+++ b/src/font.cpp
@@ -1,19 +1,19 @@
 #include <font.hpp>
 
+#include <filesystem>
+namespace fs = std::filesystem;
+
 using namespace sftk;
 
 Font::Font() {}
 
-Font::Font(std::string font, std::string fallback, int size)
+Font::Font(std::string font, 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)
@@ -35,3 +35,75 @@ const char *Font::FailedToLoadFont::what() const noexcept
     SFTKException::formatAddress(msg, sizeof(msg));
     return const_cast<const char *>(msg);
 }
+
+FontFamily::FontFamily() {}
+
+FontFamily::FontFamily(std::string name, uint baseSize, std::string findPath)
+    : name(name), baseSize(baseSize)
+{
+    fs::path path(findPath);
+    for (auto &entry : fs::recursive_directory_iterator(path))
+    {
+        if (fs::is_regular_file(entry))
+        {
+            auto fname = entry.path().filename().generic_string();
+            if (!fname.find(genFontFileName(FontType::Regular, name)))
+                regular.loadFromFile(entry.path());
+            else if (!fname.find(genFontFileName(FontType::Bold, name)))
+                bold.loadFromFile(entry.path());
+            else if (!fname.find(genFontFileName(FontType::Italic, name)))
+                italic.loadFromFile(entry.path());
+            else if (!fname.find(genFontFileName(FontType::BoldItalic, name)))
+                boldItalic.loadFromFile(entry.path());
+        }
+    }
+}
+
+sf::Font &FontFamily::operator[](FontType ftype)
+{
+    switch (ftype)
+    {
+    case FontType::Regular:
+        return regular;
+    case FontType::Bold:
+        return bold;
+    case FontType::Italic:
+        return italic;
+    case FontType::BoldItalic:
+        return boldItalic;
+    default:
+        throw new UnexceptedFontType(this);
+    }
+}
+
+std::string FontFamily::genFontFileName(FontType ftype, std::string name)
+{
+    name += '-';
+    switch (ftype)
+    {
+    case FontType::Regular:
+        name += "Regular";
+        break;
+    case FontType::Bold:
+        name += "Bold";
+        break;
+    case FontType::Italic:
+        name += "Italic";
+        break;
+    case FontType::BoldItalic:
+        name += "BoldItalic";
+        break;
+    }
+    return name;
+}
+
+FontFamily::UnexceptedFontType::UnexceptedFontType(FontFamily *fntfml)
+    : SFTKException(fntfml) {}
+
+const char *FontFamily::UnexceptedFontType::what() const noexcept
+{
+    static char msg[] = "sftk::FontFamily 0x********_********:"
+                        " Using wrong index calling sftk::FontFamily::operator[](FontType).";
+    SFTKException::formatAddress(msg, sizeof(msg));
+    return const_cast<const char *>(msg);
+}
diff --git a/src/window.cpp b/src/window.cpp
index 5ea665d..6446e05 100644
--- a/src/window.cpp
+++ b/src/window.cpp
@@ -48,7 +48,7 @@ void Window::exec()
         if (event_occured || hasInternalChange())
         {
             sfwindow.clear(backgroud);
-            update(sfwindow);
+            update(sfwindow, getView());
             sfwindow.display();
         }
     }