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maybe.cpp
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// Copyright 2021 Arthur Sonzogni. All rights reserved.
// Use of this source code is governed by the MIT license that can be found in
// the LICENSE file.
#include <functional> // for function
#include <memory> // for make_unique, __shared_ptr_access, __shared_ptr_access<>::element_type, shared_ptr
#include <utility> // for move
#include "ftxui/component/component.hpp" // for ComponentDecorator, Maybe, Make
#include "ftxui/component/component_base.hpp" // for Component, ComponentBase
#include "ftxui/component/event.hpp" // for Event
#include "ftxui/dom/elements.hpp" // for Element
#include "ftxui/dom/node.hpp" // for Node
namespace ftxui {
/// @brief Decorate a component |child|. It is shown only when |show| returns
/// true.
/// @param child the compoenent to decorate.
/// @param show a function returning whether |child| should shown.
/// @ingroup component
Component Maybe(Component child, std::function<bool()> show) {
class Impl : public ComponentBase {
public:
explicit Impl(std::function<bool()> show) : show_(std::move(show)) {}
private:
Element OnRender() override {
return show_() ? ComponentBase::OnRender() : std::make_unique<Node>();
}
bool Focusable() const override {
return show_() && ComponentBase::Focusable();
}
bool OnEvent(Event event) override {
return show_() && ComponentBase::OnEvent(event);
}
std::function<bool()> show_;
};
auto maybe = Make<Impl>(std::move(show));
maybe->Add(std::move(child));
return maybe;
}
/// @brief Decorate a component. It is shown only when the |show| function
/// returns true.
/// @param show a function returning whether the decorated component should
/// be shown.
/// @ingroup component
///
/// ### Example
///
/// ```cpp
/// auto component = Renderer([]{ return text("Hello World!"); });
/// auto maybe_component = component | Maybe([&]{ return counter == 42; });
/// ```
ComponentDecorator Maybe(std::function<bool()> show) {
return [show = std::move(show)](Component child) mutable {
return Maybe(std::move(child), std::move(show));
};
}
/// @brief Decorate a component |child|. It is shown only when |show| is true.
/// @param child the compoennt to decorate.
/// @param show a boolean. |child| is shown when |show| is true.
/// @ingroup component
///
/// ### Example
///
/// ```cpp
/// auto component = Renderer([]{ return text("Hello World!"); });
/// auto maybe_component = Maybe(component, &show);
/// ```
Component Maybe(Component child, const bool* show) {
return Maybe(std::move(child), [show] { return *show; });
}
/// @brief Decorate a component. It is shown only when |show| is true.
/// @param show a boolean. |child| is shown when |show| is true.
/// @ingroup component
///
/// ### Example
///
/// ```cpp
/// auto component = Renderer([]{ return text("Hello World!"); });
/// auto maybe_component = component | Maybe(&show);
/// ```
ComponentDecorator Maybe(const bool* show) {
return [show](Component child) { return Maybe(std::move(child), show); };
}
} // namespace ftxui
ftxui::ComponentBase
It implement rendering itself as ftxui::Element. It implement keyboard navigation by responding to ft...
Definition component_base.hpp:30
ftxui::ComponentBase::Focusable
virtual bool Focusable() const
Return true when the component contains focusable elements. The non focusable Components will be skip...
Definition component.cpp:196
ftxui::ComponentBase::OnRender
virtual Element OnRender()
Draw the component. Build a ftxui::Element to be drawn on the ftxi::Screen representing this ftxui::C...
Definition component.cpp:147
ftxui::ComponentBase::OnEvent
virtual bool OnEvent(Event)
Called in response to an event.
Definition component.cpp:161
component.hpp
component_base.hpp
elements.hpp
event.hpp
ftxui
Definition animation.hpp:10
ftxui::Maybe
Component Maybe(Component, const bool *show)
Decorate a component |child|. It is shown only when |show| is true.
Definition maybe.cpp:74
ftxui::Make
std::shared_ptr< T > Make(Args &&... args)
Definition component.hpp:26
ftxui::Element
std::shared_ptr< Node > Element
Definition elements.hpp:22
ftxui::ComponentDecorator
std::function< Component(Component)> ComponentDecorator
Definition component.hpp:31
ftxui::Component
std::shared_ptr< ComponentBase > Component
Definition component_base.hpp:24
node.hpp
ftxui::Event
Represent an event. It can be key press event, a terminal resize, or more ...
Definition event.hpp:27