screen.cpp

Go to the documentation of this file.

#include <stdint.h>  // for uint16_t
#include <iostream>  // for operator<<, stringstream, basic_ostream, flush, cout, ostream
#include <map>      // for _Rb_tree_const_iterator, map, operator!=, operator==
#include <memory>   // for allocator, allocator_traits<>::value_type
#include <sstream>  // IWYU pragma: keep
#include <utility>  // for pair
 
#include "ftxui/screen/screen.hpp"
#include "ftxui/screen/string.hpp"    // for string_width
#include "ftxui/screen/terminal.hpp"  // for Dimensions, Size
 
#if defined(_WIN32)
#define WIN32_LEAN_AND_MEAN
#ifndef NOMINMAX
#define NOMINMAX
#endif
#include <Windows.h>
#endif
 
namespace ftxui {
 
namespace {
static const char BOLD_SET[] = "\x1B[1m";
static const char BOLD_RESET[] = "\x1B[22m";  // Can't use 21 here.
 
static const char DIM_SET[] = "\x1B[2m";
static const char DIM_RESET[] = "\x1B[22m";
 
static const char UNDERLINED_SET[] = "\x1B[4m";
static const char UNDERLINED_RESET[] = "\x1B[24m";
 
static const char BLINK_SET[] = "\x1B[5m";
static const char BLINK_RESET[] = "\x1B[25m";
 
static const char INVERTED_SET[] = "\x1B[7m";
static const char INVERTED_RESET[] = "\x1B[27m";
 
static const char MOVE_LEFT[] = "\r";
static const char MOVE_UP[] = "\x1B[1A";
static const char CLEAR_LINE[] = "\x1B[2K";
 
Pixel dev_null_pixel;
 
#if defined(_WIN32)
void WindowsEmulateVT100Terminal() {
  static bool done = false;
  if (done)
    return;
  done = true;
 
  // Enable VT processing on stdout and stdin
  auto stdout_handle = GetStdHandle(STD_OUTPUT_HANDLE);
 
  DWORD out_mode = 0;
  GetConsoleMode(stdout_handle, &out_mode);
 
  // https://docs.microsoft.com/en-us/windows/console/setconsolemode
  const int enable_virtual_terminal_processing = 0x0004;
  const int disable_newline_auto_return = 0x0008;
  out_mode |= enable_virtual_terminal_processing;
  out_mode |= disable_newline_auto_return;
 
  SetConsoleMode(stdout_handle, out_mode);
}
#endif
 
void UpdatePixelStyle(std::stringstream& ss,
                      Pixel& previous,
                      const Pixel& next) {
  if (next.bold != previous.bold)
    ss << (next.bold ? BOLD_SET : BOLD_RESET);
 
  if (next.dim != previous.dim)
    ss << (next.dim ? DIM_SET : DIM_RESET);
 
  if (next.underlined != previous.underlined)
    ss << (next.underlined ? UNDERLINED_SET : UNDERLINED_RESET);
 
  if (next.blink != previous.blink)
    ss << (next.blink ? BLINK_SET : BLINK_RESET);
 
  if (next.inverted != previous.inverted)
    ss << (next.inverted ? INVERTED_SET : INVERTED_RESET);
 
  if (next.foreground_color != previous.foreground_color ||
      next.background_color != previous.background_color) {
    ss << "\x1B[" + next.foreground_color.Print(false) + "m";
    ss << "\x1B[" + next.background_color.Print(true) + "m";
  }
 
  previous = next;
}
 
struct TileEncoding {
  unsigned int left : 2;
  unsigned int top : 2;
  unsigned int right : 2;
  unsigned int down : 2;
  unsigned int round : 1;
 
  bool operator<(const TileEncoding& other) const {
    union Converter {
      TileEncoding input;
      uint16_t output = 0;
    };
    Converter a, b;
    a.input = *this;
    b.input = other;
    return a.output < b.output;
  }
};
 
// clang-format off
const std::map<std::string, TileEncoding> tile_encoding = {
    {"─", {1, 0, 1, 0, 0}},
    {"━", {2, 0, 2, 0, 0}},
 
    {"│", {0, 1, 0, 1, 0}},
    {"┃", {0, 2, 0, 2, 0}},
 
    {"┌", {0, 0, 1, 1, 0}},
    {"┍", {0, 0, 2, 1, 0}},
    {"┎", {0, 0, 1, 2, 0}},
    {"┏", {0, 0, 2, 2, 0}},
 
    {"┐", {1, 0, 0, 1, 0}},
    {"┑", {2, 0, 0, 1, 0}},
    {"┒", {1, 0, 0, 2, 0}},
    {"┓", {2, 0, 0, 2, 0}},
 
    {"└", {0, 1, 1, 0, 0}},
    {"┕", {0, 1, 2, 0, 0}},
    {"┖", {0, 2, 1, 0, 0}},
    {"┗", {0, 2, 2, 0, 0}},
 
    {"┘", {1, 1, 0, 0, 0}},
    {"┙", {2, 1, 0, 0, 0}},
    {"┚", {1, 2, 0, 0, 0}},
    {"┛", {2, 2, 0, 0, 0}},
 
    {"├", {0, 1, 1, 1, 0}},
    {"┝", {0, 1, 2, 1, 0}},
    {"┞", {0, 2, 1, 1, 0}},
    {"┟", {0, 1, 1, 2, 0}},
    {"┠", {0, 2, 1, 2, 0}},
    {"┡", {0, 2, 2, 1, 0}},
    {"┢", {0, 1, 2, 2, 0}},
    {"┣", {0, 2, 2, 2, 0}},
 
    {"┤", {1, 1, 0, 1, 0}},
    {"┥", {2, 1, 0, 1, 0}},
    {"┦", {1, 2, 0, 1, 0}},
    {"┧", {1, 1, 0, 2, 0}},
    {"┨", {1, 2, 0, 2, 0}},
    {"┩", {2, 2, 0, 1, 0}},
    {"┪", {2, 1, 0, 2, 0}},
    {"┫", {2, 2, 0, 2, 0}},
 
    {"┬", {1, 0, 1, 1, 0}},
    {"┭", {2, 0, 1, 1, 0}},
    {"┮", {1, 0, 2, 1, 0}},
    {"┯", {2, 0, 2, 1, 0}},
    {"┰", {1, 0, 1, 2, 0}},
    {"┱", {2, 0, 1, 2, 0}},
    {"┲", {1, 0, 2, 2, 0}},
    {"┳", {2, 0, 2, 2, 0}},
 
    {"┴", {1, 1, 1, 0, 0}},
    {"┵", {2, 1, 1, 0, 0}},
    {"┶", {1, 1, 2, 0, 0}},
    {"┷", {2, 1, 2, 0, 0}},
    {"┸", {1, 2, 1, 0, 0}},
    {"┹", {2, 2, 1, 0, 0}},
    {"┺", {1, 2, 2, 0, 0}},
    {"┻", {2, 2, 2, 0, 0}},
 
    {"┼", {1, 1, 1, 1, 0}},
    {"┽", {2, 1, 1, 1, 0}},
    {"┾", {1, 1, 2, 1, 0}},
    {"┿", {2, 1, 2, 1, 0}},
    {"╀", {1, 2, 1, 1, 0}},
    {"╁", {1, 1, 1, 2, 0}},
    {"╂", {1, 2, 1, 2, 0}},
    {"╃", {2, 2, 1, 1, 0}},
    {"╄", {1, 2, 2, 1, 0}},
    {"╅", {2, 1, 1, 2, 0}},
    {"╆", {1, 1, 2, 2, 0}},
    {"╇", {2, 2, 2, 1, 0}},
    {"╈", {2, 1, 2, 2, 0}},
    {"╉", {2, 2, 1, 2, 0}},
    {"╊", {1, 2, 2, 2, 0}},
    {"╋", {2, 2, 2, 2, 0}},
 
    {"═", {3, 0, 3, 0, 0}},
    {"║", {0, 3, 0, 3, 0}},
 
    {"╒", {0, 0, 3, 1, 0}},
    {"╓", {0, 0, 1, 3, 0}},
    {"╔", {0, 0, 3, 3, 0}},
 
    {"╕", {3, 0, 0, 1, 0}},
    {"╖", {1, 0, 0, 3, 0}},
    {"╗", {3, 0, 0, 3, 0}},
 
    {"╘", {0, 1, 3, 0, 0}},
    {"╙", {0, 3, 1, 0, 0}},
    {"╚", {0, 3, 3, 0, 0}},
 
    {"╛", {3, 1, 0, 0, 0}},
    {"╜", {1, 3, 0, 0, 0}},
    {"╝", {3, 3, 0, 0, 0}},
 
    {"╞", {0, 1, 3, 1, 0}},
    {"╟", {0, 3, 1, 3, 0}},
    {"╠", {0, 3, 3, 3, 0}},
 
    {"╡", {3, 1, 0, 1, 0}},
    {"╢", {1, 3, 0, 3, 0}},
    {"╣", {3, 3, 0, 3, 0}},
 
    {"╤", {3, 0, 3, 1, 0}},
    {"╥", {1, 0, 1, 3, 0}},
    {"╦", {3, 0, 3, 3, 0}},
 
    {"╧", {3, 1, 3, 0, 0}},
    {"╨", {1, 3, 1, 0, 0}},
    {"╩", {3, 3, 3, 0, 0}},
 
    {"╪", {3, 1, 3, 1, 0}},
    {"╫", {1, 3, 1, 3, 0}},
    {"╬", {3, 3, 3, 3, 0}},
 
    {"╭", {0, 0, 1, 1, 1}},
    {"╮", {1, 0, 0, 1, 1}},
    {"╯", {1, 1, 0, 0, 1}},
    {"╰", {0, 1, 1, 0, 1}},
 
    {"╴", {1, 0, 0, 0, 0}},
    {"╵", {0, 1, 0, 0, 0}},
    {"╶", {0, 0, 1, 0, 0}},
    {"╷", {0, 0, 0, 1, 0}},
 
    {"╸", {2, 0, 0, 0, 0}},
    {"╹", {0, 2, 0, 0, 0}},
    {"╺", {0, 0, 2, 0, 0}},
    {"╻", {0, 0, 0, 2, 0}},
 
    {"╼", {1, 0, 2, 0, 0}},
    {"╽", {0, 1, 0, 2, 0}},
    {"╾", {2, 0, 1, 0, 0}},
    {"╿", {0, 2, 0, 1, 0}},
};
// clang-format on
 
template <class A, class B>
const std::map<B, A> InvertMap(const std::map<A, B> input) {
  std::map<B, A> output;
  for (const auto& it : input)
    output[it.second] = it.first;
  return output;
}
 
const std::map<TileEncoding, std::string> tile_encoding_inverse =
    InvertMap(tile_encoding);
 
void UpgradeLeftRight(std::string& left, std::string& right) {
  const auto it_left = tile_encoding.find(left);
  if (it_left == tile_encoding.end())
    return;
  const auto it_right = tile_encoding.find(right);
  if (it_right == tile_encoding.end())
    return;
 
  if (it_left->second.right == 0 && it_right->second.left != 0) {
    TileEncoding encoding_left = it_left->second;
    encoding_left.right = it_right->second.left;
    const auto it_left_upgrade = tile_encoding_inverse.find(encoding_left);
    if (it_left_upgrade != tile_encoding_inverse.end())
      left = it_left_upgrade->second;
  }
 
  if (it_right->second.left == 0 && it_left->second.right != 0) {
    TileEncoding encoding_right = it_right->second;
    encoding_right.left = it_left->second.right;
    const auto it_right_upgrade = tile_encoding_inverse.find(encoding_right);
    if (it_right_upgrade != tile_encoding_inverse.end())
      right = it_right_upgrade->second;
  }
}
 
void UpgradeTopDown(std::string& top, std::string& down) {
  const auto it_top = tile_encoding.find(top);
  if (it_top == tile_encoding.end())
    return;
  const auto it_down = tile_encoding.find(down);
  if (it_down == tile_encoding.end())
    return;
 
  if (it_top->second.down == 0 && it_down->second.top != 0) {
    TileEncoding encoding_top = it_top->second;
    encoding_top.down = it_down->second.top;
    const auto it_top_down = tile_encoding_inverse.find(encoding_top);
    if (it_top_down != tile_encoding_inverse.end())
      top = it_top_down->second;
  }
 
  if (it_down->second.top == 0 && it_top->second.down != 0) {
    TileEncoding encoding_down = it_down->second;
    encoding_down.top = it_top->second.down;
    const auto it_down_top = tile_encoding_inverse.find(encoding_down);
    if (it_down_top != tile_encoding_inverse.end())
      down = it_down_top->second;
  }
}
 
}  // namespace
 
/// A fixed dimension.
/// @see Fit
/// @see Full
Dimensions Dimension::Fixed(int v) {
  return {v, v};
}
 
/// Use the terminal dimensions.
/// @see Fixed
/// @see Fit
Dimensions Dimension::Full() {
  return Terminal::Size();
}
 
// static
/// Create a screen with the given dimension along the x-axis and y-axis.
Screen Screen::Create(Dimensions width, Dimensions height) {
  return Screen(width.dimx, height.dimy);
}
 
// static
/// Create a screen with the given dimension.
Screen Screen::Create(Dimensions dimension) {
  return Screen(dimension.dimx, dimension.dimy);
}
 
Screen::Screen(int dimx, int dimy)
    : stencil{0, dimx - 1, 0, dimy - 1},
      dimx_(dimx),
      dimy_(dimy),
      pixels_(dimy, std::vector<Pixel>(dimx)) {
#if defined(_WIN32)
  // The placement of this call is a bit weird, however we can assume that
  // anybody who instantiates a Screen object eventually wants to output
  // something to the console.
  // As we require UTF8 for all input/output operations we will just switch to
  // UTF8 encoding here
  SetConsoleOutputCP(CP_UTF8);
  SetConsoleCP(CP_UTF8);
  WindowsEmulateVT100Terminal();
#endif
}
 
/// Produce a std::string that can be used to print the Screen on the terminal.
/// Don't forget to flush stdout. Alternatively, you can use Screen::Print();
std::string Screen::ToString() {
  std::stringstream ss;
 
  Pixel previous_pixel;
  Pixel final_pixel;
 
  for (int y = 0; y < dimy_; ++y) {
    if (y != 0) {
      UpdatePixelStyle(ss, previous_pixel, final_pixel);
      ss << "\r\n";
    }
    bool previous_fullwidth = false;
    for (const auto& pixel : pixels_[y]) {
      if (!previous_fullwidth) {
        UpdatePixelStyle(ss, previous_pixel, pixel);
        ss << pixel.character;
      }
      previous_fullwidth = (string_width(pixel.character) == 2);
    }
  }
 
  UpdatePixelStyle(ss, previous_pixel, final_pixel);
 
  return ss.str();
}
 
void Screen::Print() {
  std::cout << ToString() << '\0' << std::flush;
}
 
/// @brief Access a character a given position.
/// @param x The character position along the x-axis.
/// @param y The character position along the y-axis.
std::string& Screen::at(int x, int y) {
  return PixelAt(x, y).character;
}
 
/// @brief Access a Pixel at a given position.
/// @param x The pixel position along the x-axis.
/// @param y The pixel position along the y-axis.
Pixel& Screen::PixelAt(int x, int y) {
  return stencil.Contain(x, y) ? pixels_[y][x] : dev_null_pixel;
}
 
/// @brief Return a string to be printed in order to reset the cursor position
///        to the beginning of the screen.
///
/// ```cpp
/// std::string reset_position;
/// while(true) {
///   auto document = render();
///   auto screen = Screen::Create(Dimension::Full(), Dimension::Fit(document));
///   Render(screen, document);
///   std::cout << reset_position << screen.ToString() << std::flush;
///   reset_position = screen.ResetPosition();
///
///   using namespace std::chrono_literals;
///   std::this_thread::sleep_for(0.01s);
/// }
/// ```
///
/// @return The string to print in order to reset the cursor position to the
///         beginning.
std::string Screen::ResetPosition(bool clear) {
  std::stringstream ss;
  if (clear) {
    ss << MOVE_LEFT << CLEAR_LINE;
    for (int y = 1; y < dimy_; ++y) {
      ss << MOVE_UP << CLEAR_LINE;
    }
  } else {
    ss << MOVE_LEFT;
    for (int y = 1; y < dimy_; ++y) {
      ss << MOVE_UP;
    }
  }
  return ss.str();
}
 
/// @brief Clear all the pixel from the screen.
void Screen::Clear() {
  pixels_ = std::vector<std::vector<Pixel>>(dimy_,
                                            std::vector<Pixel>(dimx_, Pixel()));
  cursor_.x = dimx_ - 1;
  cursor_.y = dimy_ - 1;
}
 
// clang-format off
void Screen::ApplyShader() {
  // Merge box characters togethers.
  for (int y = 1; y < dimy_; ++y) {
    for (int x = 1; x < dimx_; ++x) {
      // Box drawing character uses exactly 3 byte.
      std::string& cur = pixels_[y][x].character;
      if (cur.size() != 3u)
        continue;
 
      // Left vs current.
      std::string& left = pixels_[y][x-1].character;
      if (left.size() == 3u)
        UpgradeLeftRight(left, cur);
 
      // Top vs current.
      std::string& top = pixels_[y-1][x].character;
      if (top.size() == 3u)
        UpgradeTopDown(top, cur);
    }
  }
}
 
// clang-format on
 
}  // 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.