src/ftxui/dom/selection.cpp

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// Copyright 2024 Arthur Sonzogni. All rights reserved.
// 本源代码的使用受 MIT 许可协议的约束，该协议可在 LICENSE 文件中找到。
 
#include "ftxui/dom/selection.hpp"  // for Selection
#include <algorithm>                // for max, min
#include <string>                   // for string
#include <tuple>                    // for ignore
 
#include "ftxui/dom/node_decorator.hpp"  // for NodeDecorator
 
namespace ftxui {
 
namespace {
class Unselectable : public NodeDecorator {
 public:
  using NodeDecorator::NodeDecorator;
 
  void Select(Selection& ignored) override {
    std::ignore = ignored;
    // 覆盖 select 方法，使其不执行任何操作。
  }
};
}  // namespace
 
/// @brief 创建一个空选择。
Selection::Selection() = default;
 
/// @brief 创建一个选择。
/// @param start_x 选择起始的x坐标。
/// @param start_y 选择起始的y坐标。
/// @param end_x 选择结束的x坐标。
/// @param end_y 选择结束的y坐标。
Selection::Selection(int start_x, int start_y, int end_x, int end_y)
    : start_x_(start_x),
      start_y_(start_y),
      end_x_(end_x),
      end_y_(end_y),
      box_{
          std::min(start_x, end_x),
          std::max(start_x, end_x),
          std::min(start_y, end_y),
          std::max(start_y, end_y),
      },
      empty_(false) {}
 
Selection::Selection(int start_x,
                     int start_y,
                     int end_x,
                     int end_y,
                     Selection* parent)
    : start_x_(start_x),
      start_y_(start_y),
      end_x_(end_x),
      end_y_(end_y),
      box_{
          std::min(start_x, end_x),
          std::max(start_x, end_x),
          std::min(start_y, end_y),
          std::max(start_y, end_y),
      },
      parent_(parent),
      empty_(false) {}
 
/// @brief 获取选择框。
/// @return 选择框。
const Box& Selection::GetBox() const {
  return box_;
}
 
/// @brief 将选择饱和到框内。
/// 这由 `hbox` 调用，以将选择传播到其子级。
/// @param box 用于饱和选择的框。
/// @return 饱和后的选择。
Selection Selection::SaturateHorizontal(Box box) {
  int start_x = start_x_;
  int start_y = start_y_;
  int end_x = end_x_;
  int end_y = end_y_;
 
  const bool start_outside = !box.Contain(start_x, start_y);
  const bool end_outside = !box.Contain(end_x, end_y);
  const bool properly_ordered =
      start_y < end_y || (start_y == end_y && start_x <= end_x);
  if (properly_ordered) {
    if (start_outside) {
      start_x = box.x_min;
      start_y = box.y_min;
    }
    if (end_outside) {
      end_x = box.x_max;
      end_y = box.y_max;
    }
  } else {
    if (start_outside) {
      start_x = box.x_max;
      start_y = box.y_max;
    }
    if (end_outside) {
      end_x = box.x_min;
      end_y = box.y_min;
    }
  }
  return {
      start_x, start_y, end_x, end_y, parent_,
  };
}
 
/// @brief 将选择饱和到框内。
/// 这由 `vbox` 调用，以将选择传播到其子级。
/// @param box 用于饱和选择的框。
/// @return 饱和后的选择。
Selection Selection::SaturateVertical(Box box) {
  int start_x = start_x_;
  int start_y = start_y_;
  int end_x = end_x_;
  int end_y = end_y_;
 
  const bool start_outside = !box.Contain(start_x, start_y);
  const bool end_outside = !box.Contain(end_x, end_y);
  const bool properly_ordered =
      start_y < end_y || (start_y == end_y && start_x <= end_x);
 
  if (properly_ordered) {
    if (start_outside) {
      start_x = box.x_min;
      start_y = box.y_min;
    }
    if (end_outside) {
      end_x = box.x_max;
      end_y = box.y_max;
    }
  } else {
    if (start_outside) {
      start_x = box.x_max;
      start_y = box.y_max;
    }
    if (end_outside) {
      end_x = box.x_min;
      end_y = box.y_min;
    }
  }
  return {start_x, start_y, end_x, end_y, parent_};
}
 
void Selection::AddPart(const std::string& part, int y, int left, int right) {
  if (parent_ != this) {
    parent_->AddPart(part, y, left, right);
    return;
  }
  [&] {
    if (parts_.str().empty()) {
      parts_ << part;
      return;
    }
 
    if (y_ != y) {
      parts_ << '\n' << part;
      return;
    }
 
    if (x_ == left + 1) {
      parts_ << part;
      return;
    }
 
    parts_ << part;
  }();
  y_ = y;
  x_ = right;
}
 
}  // namespace ftxui