FTXUI/src/ftxui/dom/border.cpp

#include <algorithm>  // for max
#include <iterator>   // for begin, end
#include <memory>     // for make_shared, __shared_ptr_access
#include <utility>    // for move
#include <vector>     // for vector, __alloc_traits<>::value_type

#include "ftxui/dom/elements.hpp"  // for unpack, Element, Decorator, Elements, border, borderWith, window
#include "ftxui/dom/node.hpp"         // for Node
#include "ftxui/dom/requirement.hpp"  // for Requirement
#include "ftxui/screen/box.hpp"       // for Box
#include "ftxui/screen/screen.hpp"    // for Pixel, Screen

namespace ftxui {

static wchar_t simple_border_charset[] = L"╭╮╰╯─│┬┴┤├";

// For reference, here is the charset for normal border:
// L"┌┐└┘─│┬┴┤├";
// TODO(arthursonzogni): Consider adding options to choose the kind of borders
// to use.

class Border : public Node {
 public:
  Border(Elements children)
      : Node(std::move(children)),
        charset(std::begin(simple_border_charset),
                std::end(simple_border_charset)) {}
  Border(Elements children, Pixel pixel)
      : Node(std::move(children)), charset_pixel(10, pixel) {}

  std::vector<Pixel> charset_pixel;
  std::vector<wchar_t> charset;

  void ComputeRequirement() override {
    Node::ComputeRequirement();
    requirement_ = children_[0]->requirement();
    requirement_.min_x += 2;
    requirement_.min_y += 2;
    if (children_.size() == 2) {
      requirement_.min_x =
          std::max(requirement_.min_x, children_[1]->requirement().min_x + 2);
    }
    requirement_.selected_box.x_min++;
    requirement_.selected_box.x_max++;
    requirement_.selected_box.y_min++;
    requirement_.selected_box.y_max++;
  }

  void SetBox(Box box) override {
    Node::SetBox(box);
    if (children_.size() == 2) {
      Box title_box;
      title_box.x_min = box.x_min + 1;
      title_box.x_max = box.x_max - 1;
      title_box.y_min = box.y_min;
      title_box.y_max = box.y_min;
      children_[1]->SetBox(title_box);
    }
    box.x_min++;
    box.x_max--;
    box.y_min++;
    box.y_max--;
    children_[0]->SetBox(box);
  }

  void Render(Screen& screen) override {
    // Draw content.
    children_[0]->Render(screen);

    // Draw the border.
    if (box_.x_min >= box_.x_max || box_.y_min >= box_.y_max)
      return;

    if (!charset.empty())
      RenderPixel(screen);
    else
      RenderChar(screen);
  }

  void RenderPixel(Screen& screen) {
    screen.at(box_.x_min, box_.y_min) = charset[0];
    screen.at(box_.x_max, box_.y_min) = charset[1];
    screen.at(box_.x_min, box_.y_max) = charset[2];
    screen.at(box_.x_max, box_.y_max) = charset[3];
    for (float x = box_.x_min + 1; x < box_.x_max; ++x) {
      screen.at(x, box_.y_min) = charset[4];
      screen.at(x, box_.y_max) = charset[4];
    }
    for (float y = box_.y_min + 1; y < box_.y_max; ++y) {
      screen.at(box_.x_min, y) = charset[5];
      screen.at(box_.x_max, y) = charset[5];
    }

    // Draw title.
    if (children_.size() == 2)
      children_[1]->Render(screen);
  }

  void RenderChar(Screen& screen) {
    screen.PixelAt(box_.x_min, box_.y_min) = charset_pixel[0];
    screen.PixelAt(box_.x_max, box_.y_min) = charset_pixel[1];
    screen.PixelAt(box_.x_min, box_.y_max) = charset_pixel[2];
    screen.PixelAt(box_.x_max, box_.y_max) = charset_pixel[3];
    for (float x = box_.x_min + 1; x < box_.x_max; ++x) {
      screen.PixelAt(x, box_.y_min) = charset_pixel[4];
      screen.PixelAt(x, box_.y_max) = charset_pixel[4];
    }
    for (float y = box_.y_min + 1; y < box_.y_max; ++y) {
      screen.PixelAt(box_.x_min, y) = charset_pixel[5];
      screen.PixelAt(box_.x_max, y) = charset_pixel[5];
    }
  }
};
/// @brief Draw a border around the element.
/// @ingroup dom
///
/// Add a border around an element
///
/// ### Example
///
/// ```cpp
/// // Use 'border' as a function...
/// Element document = border(text(L"The element"));
///
/// // ...Or as a 'pipe'.
/// Element document = text(L"The element") | border;
/// ```
///
/// ### Output
///
/// ```bash
/// ┌───────────┐
/// │The element│
/// └───────────┘
/// ```
Element border(Element child) {
  return std::make_shared<Border>(unpack(std::move(child)));
}

/// @brief Draw window with a title and a border around the element.
/// @param title The title of the window.
/// @param content The element to be wrapped.
/// @ingroup dom
/// @see border
///
/// ### Example
///
/// ```cpp
/// Element document = window(text(L"Title"),
///                           text(L"content")
///                    );
/// ```
///
/// ### Output
///
/// ```bash
/// ┌Title──┐
/// │content│
/// └───────┘
/// ```
Element window(Element title, Element content) {
  return std::make_shared<Border>(unpack(std::move(content), std::move(title)));
}

/// @brief Same as border but with a constant Pixel around the element.
/// @ingroup dom
/// @see border
Decorator borderWith(Pixel pixel) {
  return [pixel](Element child) {
    return std::make_shared<Border>(unpack(std::move(child)), pixel);
  };
}

}  // namespace ftxui

// 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.