From eb399d20c52d83f815176b85706ba7f6cc2ddba6 Mon Sep 17 00:00:00 2001
From: ArthurSonzogni <sonzogniarthur@gmail.com>
Date: Sat, 1 May 2021 18:13:56 +0200
Subject: [PATCH] Capture mouse for the slider component.

---
 CMakeLists.txt                                |  1 +
 examples/component/gallery.cpp                | 33 +++++++--
 include/ftxui/component/captured_mouse.hpp    | 14 ++++
 include/ftxui/component/component.hpp         |  6 +-
 include/ftxui/component/event.hpp             |  7 ++
 .../ftxui/component/screen_interactive.hpp    |  4 +
 include/ftxui/component/slider.hpp            | 11 ++-
 src/ftxui/component/button.cpp                |  4 +
 src/ftxui/component/checkbox.cpp              |  3 +
 src/ftxui/component/input.cpp                 |  3 +
 src/ftxui/component/menu.cpp                  |  5 ++
 src/ftxui/component/radiobox.cpp              |  5 ++
 src/ftxui/component/screen_interactive.cpp    | 20 +++++
 src/ftxui/component/slider.cpp                | 73 +++++++++++++------
 src/ftxui/component/toggle.cpp                |  3 +
 15 files changed, 157 insertions(+), 35 deletions(-)
 create mode 100644 include/ftxui/component/captured_mouse.hpp

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3b79204..c6182a0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -77,6 +77,7 @@ add_library(dom
 
 add_library(component
   include/ftxui/component/button.hpp
+  include/ftxui/component/captured_mouse.hpp
   include/ftxui/component/checkbox.hpp
   include/ftxui/component/component.hpp
   include/ftxui/component/container.hpp
diff --git a/examples/component/gallery.cpp b/examples/component/gallery.cpp
index 54f4d6c..9bd5c86 100644
--- a/examples/component/gallery.cpp
+++ b/examples/component/gallery.cpp
@@ -5,6 +5,7 @@
 #include "ftxui/component/menu.hpp"
 #include "ftxui/component/radiobox.hpp"
 #include "ftxui/component/screen_interactive.hpp"
+#include "ftxui/component/slider.hpp"
 #include "ftxui/component/toggle.hpp"
 
 using namespace ftxui;
@@ -20,6 +21,13 @@ class MyComponent : public Component {
   Input input;
   Button button;
 
+  int slider_value_1_ = 12;
+  int slider_value_2_ = 56;
+  int slider_value_3_ = 128;
+  ComponentPtr slider_1_ = Slider(L"R:", &slider_value_1_, 0, 256, 1);
+  ComponentPtr slider_2_ = Slider(L"G:", &slider_value_2_, 0, 256, 1);
+  ComponentPtr slider_3_ = Slider(L"B:", &slider_value_3_, 0, 256, 1);
+
  public:
   MyComponent() {
     Add(&container);
@@ -54,17 +62,25 @@ class MyComponent : public Component {
     input.placeholder = L"Input placeholder";
     container.Add(&input);
 
+    container.Add(slider_1_.get());
+    container.Add(slider_2_.get());
+    container.Add(slider_3_.get());
+
     button.label = L"Quit";
     button.on_click = [&] { on_quit(); };
     container.Add(&button);
   }
 
-  Element Render(std::wstring name, Component& component) {
+  Element Render(std::wstring name, Element element) {
     return hbox({
         text(name) | size(WIDTH, EQUAL, 8),
         separator(),
-        component.Render(),
-    });
+        element | xflex,
+    }) | xflex;
+  }
+
+  Element Render(std::wstring name, Component& component) {
+    return Render(name, component.Render());
   }
 
   Element Render() override {
@@ -78,11 +94,18 @@ class MyComponent : public Component {
             separator(),
             Render(L"radiobox", radiobox),
             separator(),
-            Render(L"input", input) | size(WIDTH, LESS_THAN, 30),
+            Render(L"input", input) | size(WIDTH, LESS_THAN, 50),
+            separator(),
+            Render(L"slider",  //
+                   vbox({
+                       slider_1_->Render(),
+                       slider_2_->Render(),
+                       slider_3_->Render(),
+                   })),
             separator(),
             Render(L"button", button),
         }) |
-        border;
+        xflex | size(WIDTH, GREATER_THAN, 40) | border;
   }
 
   std::function<void()> on_quit = [] {};
diff --git a/include/ftxui/component/captured_mouse.hpp b/include/ftxui/component/captured_mouse.hpp
new file mode 100644
index 0000000..b76ac10
--- /dev/null
+++ b/include/ftxui/component/captured_mouse.hpp
@@ -0,0 +1,14 @@
+#ifndef FTXUI_CAPTURED_MOUSE_HPP
+#define FTXUI_CAPTURED_MOUSE_HPP
+
+#include <memory>
+
+namespace ftxui {
+class CapturedMouseInterface {
+ public:
+  virtual ~CapturedMouseInterface() {}
+};
+using CapturedMouse = std::unique_ptr<CapturedMouseInterface>;
+}  // namespace ftxui
+
+#endif /* end of include guard: FTXUI_CAPTURED_MOUSE_HPP */
diff --git a/include/ftxui/component/component.hpp b/include/ftxui/component/component.hpp
index fcaf3f9..5a42216 100644
--- a/include/ftxui/component/component.hpp
+++ b/include/ftxui/component/component.hpp
@@ -52,13 +52,13 @@ class Component {
   // Configure all the ancestors to give focus to this component.
   void TakeFocus();
 
+ protected:
+  std::vector<Component*> children_;
+
  private:
   Component* parent_ = nullptr;
   void Detach();
   void Attach(Component* parent);
-
- protected:
-  std::vector<Component*> children_;
 };
 
 using ComponentPtr = std::unique_ptr<Component>;
diff --git a/include/ftxui/component/event.hpp b/include/ftxui/component/event.hpp
index bb87c6a..6295c91 100644
--- a/include/ftxui/component/event.hpp
+++ b/include/ftxui/component/event.hpp
@@ -10,6 +10,8 @@
 
 namespace ftxui {
 
+class ScreenInteractive;
+
 /// @brief Represent an event. It can be key press event, a terminal resize, or
 /// more ...
 ///
@@ -65,6 +67,9 @@ struct Event {
 
   const std::string& input() const { return input_; }
 
+  ScreenInteractive* screen() { return screen_; }
+  void SetScreen(ScreenInteractive* screen) { screen_ = screen; }
+
   bool operator==(const Event& other) const { return input_ == other.input_; }
 
   //--- State section ----------------------------------------------------------
@@ -88,6 +93,8 @@ struct Event {
     struct Cursor cursor_;
   };
   std::string input_;
+
+  ScreenInteractive* screen_;
 };
 
 
diff --git a/include/ftxui/component/screen_interactive.hpp b/include/ftxui/component/screen_interactive.hpp
index 8f5903a..c61132c 100644
--- a/include/ftxui/component/screen_interactive.hpp
+++ b/include/ftxui/component/screen_interactive.hpp
@@ -9,6 +9,7 @@
 #include <mutex>
 #include <queue>
 
+#include "ftxui/component/captured_mouse.hpp"
 #include "ftxui/component/event.hpp"
 #include "ftxui/screen/screen.hpp"
 
@@ -27,6 +28,7 @@ class ScreenInteractive : public Screen {
   std::function<void()> ExitLoopClosure();
 
   void PostEvent(Event event);
+  CapturedMouse CaptureMouse();
 
  private:
   void Draw(Component* component);
@@ -55,6 +57,8 @@ class ScreenInteractive : public Screen {
 
   int cursor_x_ = 0;
   int cursor_y_ = 0;
+
+  bool mouse_captured = false;
 };
 
 }  // namespace ftxui
diff --git a/include/ftxui/component/slider.hpp b/include/ftxui/component/slider.hpp
index 35a139d..f9bff71 100644
--- a/include/ftxui/component/slider.hpp
+++ b/include/ftxui/component/slider.hpp
@@ -11,11 +11,14 @@ namespace ftxui {
 // float max = 100.f,
 // float increment = (max - min) * 0.05f);
 
+template<class T> // T = {int, float}
 ComponentPtr Slider(std::wstring label,
-                    int* value,
-                    int min,
-                    int max,
-                    int increment);
+                    T* value,
+                    T min,
+                    T max,
+                    T increment);
+
+
 }  // namespace ftxui
 
 #endif /* end of include guard: FTXUI_COMPONENT_SLIDER_HPP */
diff --git a/src/ftxui/component/button.cpp b/src/ftxui/component/button.cpp
index 4da42dd..3ea1b77 100644
--- a/src/ftxui/component/button.cpp
+++ b/src/ftxui/component/button.cpp
@@ -1,4 +1,5 @@
 #include "ftxui/component/button.hpp"
+#include "ftxui/component/screen_interactive.hpp"
 
 #include <functional>
 
@@ -11,6 +12,9 @@ Element Button::Render() {
 
 bool Button::OnEvent(Event event) {
   if (event.is_mouse() && box_.Contain(event.mouse().x, event.mouse().y)) {
+    if (!event.screen()->CaptureMouse())
+      return false;
+
     TakeFocus();
 
     if (event.mouse().button == Mouse::Left &&
diff --git a/src/ftxui/component/checkbox.cpp b/src/ftxui/component/checkbox.cpp
index 5fe251a..8c04a08 100644
--- a/src/ftxui/component/checkbox.cpp
+++ b/src/ftxui/component/checkbox.cpp
@@ -1,4 +1,5 @@
 #include "ftxui/component/checkbox.hpp"
+#include "ftxui/component/screen_interactive.hpp"
 
 #include <functional>
 
@@ -26,6 +27,8 @@ bool CheckBox::OnEvent(Event event) {
 }
 
 bool CheckBox::OnMouseEvent(Event event) {
+  if (!event.screen()->CaptureMouse())
+    return false;
   if (!box_.Contain(event.mouse().x, event.mouse().y))
     return false;
 
diff --git a/src/ftxui/component/input.cpp b/src/ftxui/component/input.cpp
index 9ca7bcd..d39ec1b 100644
--- a/src/ftxui/component/input.cpp
+++ b/src/ftxui/component/input.cpp
@@ -1,4 +1,5 @@
 #include "ftxui/component/input.hpp"
+#include "ftxui/component/screen_interactive.hpp"
 
 #include <algorithm>
 
@@ -102,6 +103,8 @@ bool Input::OnEvent(Event event) {
 }
 
 bool Input::OnMouseEvent(Event event) {
+  if (!event.screen()->CaptureMouse())
+    return false;
   if (!input_box_.Contain(event.mouse().x, event.mouse().y))
     return false;
 
diff --git a/src/ftxui/component/menu.cpp b/src/ftxui/component/menu.cpp
index 4eccfed..44f5f36 100644
--- a/src/ftxui/component/menu.cpp
+++ b/src/ftxui/component/menu.cpp
@@ -1,4 +1,5 @@
 #include "ftxui/component/menu.hpp"
+#include "ftxui/component/screen_interactive.hpp"
 
 #include <algorithm>
 #include <iostream>
@@ -27,6 +28,8 @@ Element Menu::Render() {
 }
 
 bool Menu::OnEvent(Event event) {
+  if (!event.screen()->CaptureMouse())
+    return false;
   if (event.is_mouse())
     return OnMouseEvent(event);
 
@@ -60,6 +63,8 @@ bool Menu::OnEvent(Event event) {
 }
 
 bool Menu::OnMouseEvent(Event event) {
+  if (!event.screen()->CaptureMouse())
+    return false;
   for (int i = 0; i < boxes_.size(); ++i) {
     if (!boxes_[i].Contain(event.mouse().x, event.mouse().y))
       continue;
diff --git a/src/ftxui/component/radiobox.cpp b/src/ftxui/component/radiobox.cpp
index d3ab38f..7c50655 100644
--- a/src/ftxui/component/radiobox.cpp
+++ b/src/ftxui/component/radiobox.cpp
@@ -1,4 +1,5 @@
 #include "ftxui/component/radiobox.hpp"
+#include "ftxui/component/screen_interactive.hpp"
 
 #include <algorithm>
 #include <functional>
@@ -23,6 +24,8 @@ Element RadioBox::Render() {
 }
 
 bool RadioBox::OnEvent(Event event) {
+  if (!event.screen()->CaptureMouse())
+    return false;
   if (event.is_mouse())
     return OnMouseEvent(event);
 
@@ -55,6 +58,8 @@ bool RadioBox::OnEvent(Event event) {
 }
 
 bool RadioBox::OnMouseEvent(Event event) {
+  if (!event.screen()->CaptureMouse())
+    return false;
   for (int i = 0; i < boxes_.size(); ++i) {
     if (!boxes_[i].Contain(event.mouse().x, event.mouse().y))
       continue;
diff --git a/src/ftxui/component/screen_interactive.cpp b/src/ftxui/component/screen_interactive.cpp
index 385271a..95cc26c 100644
--- a/src/ftxui/component/screen_interactive.cpp
+++ b/src/ftxui/component/screen_interactive.cpp
@@ -9,6 +9,7 @@
 #include <stack>
 #include <thread>
 
+#include "ftxui/component/captured_mouse.hpp"
 #include "ftxui/component/component.hpp"
 #include "ftxui/component/terminal_input_parser.hpp"
 #include "ftxui/screen/string.hpp"
@@ -216,6 +217,16 @@ void OnResize(int /* signal */) {
   on_resize();
 }
 
+class CapturedMouseImpl : public CapturedMouseInterface {
+ public:
+  CapturedMouseImpl(std::function<void(void)> callback)
+      : callback_(callback) {}
+  ~CapturedMouseImpl() override { callback_(); }
+
+ private:
+  std::function<void(void)> callback_;
+};
+
 }  // namespace
 
 ScreenInteractive::ScreenInteractive(int dimx,
@@ -256,6 +267,14 @@ void ScreenInteractive::PostEvent(Event event) {
     event_sender_->Send(event);
 }
 
+CapturedMouse ScreenInteractive::CaptureMouse() {
+  if (mouse_captured)
+    return nullptr;
+  mouse_captured = true;
+  return std::make_unique<CapturedMouseImpl>(
+      [this] { mouse_captured = false; });
+}
+
 void ScreenInteractive::Loop(Component* component) {
   // Install a SIGINT handler and restore the old handler on exit.
   auto old_sigint_handler = std::signal(SIGINT, OnExit);
@@ -387,6 +406,7 @@ void ScreenInteractive::Loop(Component* component) {
       event.mouse().y -= cursor_y_;
     }
 
+    event.SetScreen(this);
     component->OnEvent(event);
   }
 
diff --git a/src/ftxui/component/slider.cpp b/src/ftxui/component/slider.cpp
index 894f9ee..8ddb4fb 100644
--- a/src/ftxui/component/slider.cpp
+++ b/src/ftxui/component/slider.cpp
@@ -1,9 +1,13 @@
 #include "ftxui/component/slider.hpp"
+#include "ftxui/component/captured_mouse.hpp"
+#include "ftxui/component/screen_interactive.hpp"
 
 namespace ftxui {
-class SliderInt : public Component {
+
+template<class T>
+class SliderImpl : public Component {
  public:
-  SliderInt(std::wstring label, int* value, int min, int max, int increment)
+  SliderImpl(std::wstring label, T* value, T min, T max, T increment)
       : label_(label),
         value_(value),
         min_(min),
@@ -45,36 +49,59 @@ class SliderInt : public Component {
   }
 
   bool OnMouseEvent(Event event) {
-    if (!box_.Contain(event.mouse().x, event.mouse().y))
-      return false;
-    TakeFocus();
-    if (!gauge_box_.Contain(event.mouse().x, event.mouse().y))
-      return false;
-    if (event.mouse().button == Mouse::Left &&
-        event.mouse().motion == Mouse::Pressed) {
-      *value_ = min_ + (event.mouse().x - gauge_box_.x_min) * (max_ - min_) /
-                          (gauge_box_.x_max - gauge_box_.x_min);
+    if (captured_mouse_ && event.mouse().motion == Mouse::Released) {
+      captured_mouse_ = nullptr;
+      return true;
     }
-    return true;
+
+    if (box_.Contain(event.mouse().x, event.mouse().y) &&
+        event.screen()->CaptureMouse()) {
+      TakeFocus();
+    }
+
+    if (event.mouse().button == Mouse::Left &&
+        event.mouse().motion == Mouse::Pressed &&
+        gauge_box_.Contain(event.mouse().x, event.mouse().y) &&
+        !captured_mouse_) {
+      captured_mouse_ = event.screen()->CaptureMouse();
+    }
+
+    if (captured_mouse_) {
+      *value_ = min_ + (event.mouse().x - gauge_box_.x_min) * (max_ - min_) /
+                           (gauge_box_.x_max - gauge_box_.x_min);
+      *value_ = std::max(min_, std::min(max_, *value_));
+      return true;
+    }
+    return false;
   }
 
  private:
   std::wstring label_;
-  int* value_;
-  int min_;
-  int max_;
-  int increment_ = 1;
+  T* value_;
+  T min_;
+  T max_;
+  T increment_ = 1;
   Box box_;
   Box gauge_box_;
+  CapturedMouse captured_mouse_;
 };
 
-ComponentPtr Slider(std::wstring label,
-                    int* value,
-                    int min,
-                    int max,
-                    int increment) {
-  return std::make_unique<SliderInt>(std::move(label), value, min, max,
-                                     increment);
+template <class T>
+ComponentPtr Slider(std::wstring label, T* value, T min, T max, T increment) {
+  return std::make_unique<SliderImpl<T>>(std::move(label), value, min, max,
+                                         increment);
 }
 
+template ComponentPtr Slider(std::wstring label,
+                             int* value,
+                             int min,
+                             int max,
+                             int increment);
+
+template ComponentPtr Slider(std::wstring label,
+                             float* value,
+                             float min,
+                             float max,
+                             float increment);
+
 }  // namespace ftxui
diff --git a/src/ftxui/component/toggle.cpp b/src/ftxui/component/toggle.cpp
index 5c8b32e..8936096 100644
--- a/src/ftxui/component/toggle.cpp
+++ b/src/ftxui/component/toggle.cpp
@@ -1,4 +1,5 @@
 #include "ftxui/component/toggle.hpp"
+#include "ftxui/component/screen_interactive.hpp"
 
 #include <algorithm>
 
@@ -59,6 +60,8 @@ bool Toggle::OnEvent(Event event) {
 }
 
 bool Toggle::OnMouseEvent(Event event) {
+  if (!event.screen()->CaptureMouse())
+    return false;
   for (int i = 0; i < boxes_.size(); ++i) {
     if (!boxes_[i].Contain(event.mouse().x, event.mouse().y))
       continue;