Add focusable Renderer. (#173)

examples/component/renderer.cpp

@@ -0,0 +1,49 @@
+#include <memory>  // for shared_ptr, allocator, __shared_ptr_access
+
+#include "ftxui/component/captured_mouse.hpp"  // for ftxui
+#include "ftxui/component/component.hpp"       // for Renderer, Button, Vertical
+#include "ftxui/component/component_base.hpp"  // for ComponentBase
+#include "ftxui/component/screen_interactive.hpp"  // for ScreenInteractive
+#include "ftxui/dom/elements.hpp"  // for operator|, Element, text, bold, border, center, color
+#include "ftxui/screen/color.hpp"  // for Color, Color::Red
+
+int main(int argc, const char* argv[]) {
+  using namespace ftxui;
+  auto screen = ScreenInteractive::FitComponent();
+
+  // A Renderer() is a component using a lambda function as a parameter to
+  // render itself.
+
+  // 1. Example of focusable renderer:
+  auto renderer_focusable = Renderer([](bool focused) {
+    if (focused)
+      return text(L"FOCUSABLE RENDERER()") | center | bold | border;
+    else
+      return text(L" Focusable renderer() ") | center | border;
+  });
+
+  // 2. Examples of a non focusable renderer.
+  auto renderer_non_focusable = Renderer([&] {
+    return text(L"~~~~~ Non Focusable renderer() ~~~~~");  //
+  });
+
+  // 3. Renderer can wrap other components to redefine their Render() function.
+  auto button = Button(L"Wrapped quit button", screen.ExitLoopClosure());
+  auto renderer_wrap = Renderer(button, [&] {
+    if (button->Focused())
+      return button->Render() | bold | color(Color::Red);
+    else
+      return button->Render();
+  });
+
+  // Let's renderer everyone:
+  screen.Loop(Container::Vertical({
+      renderer_focusable,
+      renderer_non_focusable,
+      renderer_wrap,
+  }));
+}
+
+// Copyright 2020 Arthur Sonzogni. All rights reserved.
+// Use of this source code is governed by the MIT license that can be found in
+// the LICENSE file.