selection_style.cpp

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// Copyright 2024 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_shared
#include <utility>     // for move
 
#include "ftxui/dom/elements.hpp"  // for Element, Decorator, bgcolor, color
#include "ftxui/dom/node_decorator.hpp"  // for NodeDecorator
#include "ftxui/screen/cell.hpp"         // for Cell
#include "ftxui/screen/color.hpp"        // for Color
#include "ftxui/screen/screen.hpp"       // for Screen
 
namespace ftxui {
 
namespace {
 
class SelectionStyleReset : public NodeDecorator {
 public:
  explicit SelectionStyleReset(Element child)
      : NodeDecorator(std::move(child)) {}
 
  void Render(Screen& screen) final {
    auto old_style = screen.GetSelectionStyle();
    screen.SetSelectionStyle([](Cell&) {});
    NodeDecorator::Render(screen);
    screen.SetSelectionStyle(old_style);
  }
};
 
class SelectionStyle : public NodeDecorator {
 public:
  SelectionStyle(Element child, const std::function<void(Cell&)>& style)
      : NodeDecorator(std::move(child)), style_(style) {}
 
  void Render(Screen& screen) final {
    auto old_style = screen.GetSelectionStyle();
    auto new_style = [&, old_style](Cell& pixel) {
      old_style(pixel);
      style_(pixel);
    };
    screen.SetSelectionStyle(new_style);
    NodeDecorator::Render(screen);
    screen.SetSelectionStyle(old_style);
  }
 
  std::function<void(Cell&)> style_;
};
 
}  // namespace
 
/// @brief Reset the selection style of an element.
/// @param child The input element.
/// @return The output element with the selection style reset.
Element selectionStyleReset(Element child) {
  return std::make_shared<SelectionStyleReset>(std::move(child));
}
 
/// @brief Set the background color of an element when selected.
/// Note that the style is applied on top of the existing style.
Decorator selectionBackgroundColor(Color foreground) {
  return selectionStyle([foreground](Cell& pixel) {  //
    pixel.background_color = foreground;
  });
}
 
/// @brief Set the foreground color of an element when selected.
/// Note that the style is applied on top of the existing style.
Decorator selectionForegroundColor(Color foreground) {
  return selectionStyle([foreground](Cell& pixel) {  //
    pixel.foreground_color = foreground;
  });
}
 
/// @brief Set the color of an element when selected.
/// @param foreground The color to be applied.
/// Note that the style is applied on top of the existing style.
Decorator selectionColor(Color foreground) {
  return selectionForegroundColor(foreground);
}
 
/// @brief Set the style of an element when selected.
/// @param style The style to be applied.
/// Note that the style is applied on top of the existing style.
// NOLINTNEXTLINE
Decorator selectionStyle(std::function<void(Cell&)> style) {
  return [style](Element child) -> Element {
    return std::make_shared<SelectionStyle>(std::move(child), style);
  };
}
 
}  // namespace ftxui