Capture mouse for the slider component.

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 &&

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;
 

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;
 

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;

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;

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);
   }
 

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

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;