terminal.cpp

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#include <cstdlib>  // for getenv
#include <string>   // for string, allocator
 
#include "ftxui/screen/terminal.hpp"
 
#if defined(_WIN32)
#define WIN32_LEAN_AND_MEAN
 
#ifndef NOMINMAX
#define NOMINMAX
#endif
 
#include <Windows.h>
#else
#include <sys/ioctl.h>  // for winsize, ioctl, TIOCGWINSZ
#include <unistd.h>     // for STDOUT_FILENO
#endif
 
namespace ftxui {
 
#if defined(__EMSCRIPTEN__)
// This dimension was chosen arbitrarily to be able to display:
// https://arthursonzogni.com/FTXUI/examples
// This will have to be improved when someone has time to implement and need
// it.
static Dimensions fallback_size{140, 43};
Dimensions Terminal::Size() {
  return fallback_size;
}
 
#elif defined(_WIN32)
 
// The terminal size in VT100 was 80x24. It is still used nowadays by
// default in many terminal emulator. That's a good choice for a fallback
// value.
static Dimensions fallback_size{80, 24};
Dimensions Terminal::Size() {
  CONSOLE_SCREEN_BUFFER_INFO csbi;
 
  if (GetConsoleScreenBufferInfo(GetStdHandle(STD_OUTPUT_HANDLE), &csbi)) {
    return Dimensions{csbi.srWindow.Right - csbi.srWindow.Left + 1,
                      csbi.srWindow.Bottom - csbi.srWindow.Top + 1};
  }
 
  return fallback_size;
}
 
#else
// The terminal size in VT100 was 80x24. It is still used nowadays by
// default in many terminal emulator. That's a good choice for a fallback
// value.
static Dimensions fallback_size{80, 24};
Dimensions Terminal::Size() {
  winsize w{};
  const int status = ioctl(STDOUT_FILENO, TIOCGWINSZ, &w);
  // The ioctl return value result should be checked. Some operating systems
  // don't support TIOCGWINSZ.
  if (w.ws_col == 0 || w.ws_row == 0 || status < 0) {
    return fallback_size;
  }
  return Dimensions{w.ws_col, w.ws_row};
}
 
#endif
 
/// @brief Override terminal size in case auto-detection fails
/// @param fallbackSize Terminal dimensions to fallback to
void Terminal::SetFallbackSize(const Dimensions& fallbackSize) {
  fallback_size = fallbackSize;
}
 
namespace {
 
const char* Safe(const char* c) {
  return c ? c : "";
}
 
bool Contains(const std::string& s, const char* key) {
  return s.find(key) != std::string::npos;
}
 
static bool cached = false;
Terminal::Color cached_supported_color;
Terminal::Color ComputeColorSupport() {
#if defined(__EMSCRIPTEN__)
  return Terminal::Color::TrueColor;
#endif
 
  std::string COLORTERM = Safe(std::getenv("COLORTERM"));
  if (Contains(COLORTERM, "24bit") || Contains(COLORTERM, "truecolor"))
    return Terminal::Color::TrueColor;
 
  std::string TERM = Safe(std::getenv("TERM"));
  if (Contains(COLORTERM, "256") || Contains(TERM, "256"))
    return Terminal::Color::Palette256;
 
#if defined(FTXUI_MICROSOFT_TERMINAL_FALLBACK)
  // Microsoft terminals do not properly declare themselve supporting true
  // colors: https://github.com/microsoft/terminal/issues/1040
  // As a fallback, assume microsoft terminal are the ones not setting those
  // variables, and enable true colors.
  if (TERM == "" && COLORTERM == "")
    return Terminal::Color::TrueColor;
#endif
 
  return Terminal::Color::Palette16;
}
 
}  // namespace
 
Terminal::Color Terminal::ColorSupport() {
  if (!cached) {
    cached = true;
    cached_supported_color = ComputeColorSupport();
  }
  return cached_supported_color;
}
 
}  // 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.