Add webassembly support

src/ftxui/component/screen_interactive.cpp

@@ -38,6 +38,11 @@ namespace ftxui {
 
 namespace {
 
+void Flush() {
+  // Emscripten doesn't implement flush. We interpret zero as flush.
+  std::cout << std::flush << (char)0;
+}
+
 constexpr int timeout_milliseconds = 20;
 constexpr int timeout_microseconds = timeout_milliseconds * 1000;
 #if defined(_WIN32)
@@ -90,8 +95,25 @@ void EventListener(std::atomic<bool>* quit,
   }
 }
 
-#else
+#elif defined(__EMSCRIPTEN__)
+#include <emscripten.h>
 
+// Read char from the terminal.
+void EventListener(std::atomic<bool>* quit, Sender<Event> out) {
+  (void)timeout_microseconds;
+  auto parser = TerminalInputParser(std::move(out));
+
+  char c;
+  while (!*quit) {
+    while(read(STDIN_FILENO, &c, 1), c)
+      parser.Add(c);
+
+    emscripten_sleep(1);
+    parser.Timeout(1);
+  }
+}
+
+#else
 #include <sys/time.h>
 
 int CheckStdinReady(int usec_timeout) {
@@ -260,12 +282,13 @@ void ScreenInteractive::Loop(Component* component) {
   // Hide the cursor and show it at exit.
   std::cout << HIDE_CURSOR;
   std::cout << DISABLE_LINE_WRAP;
-  std::cout << std::flush;
+  Flush();
   on_exit_functions.push([&] {
     std::cout << reset_cursor_position;
     std::cout << SHOW_CURSOR;
     std::cout << ENABLE_LINE_WRAP;
     std::cout << std::endl;
+    Flush();
   });
 
   auto event_listener =
@@ -276,7 +299,8 @@ void ScreenInteractive::Loop(Component* component) {
     if (!event_receiver_->HasPending()) {
       std::cout << reset_cursor_position << ResetPosition();
       Draw(component);
-      std::cout << ToString() << set_cursor_position << std::flush;
+      std::cout << ToString() << set_cursor_position;
+      Flush();
       Clear();
     }
     Event event;

src/ftxui/dom/text_test.cpp

@@ -42,7 +42,7 @@ TEST(TextTest, ScreenBigger2) {
   Screen screen(6, 2);
   Render(screen, element);
 
-  EXPECT_EQ("test  \n      ", screen.ToString());
+  EXPECT_EQ("test  \r\n      ", screen.ToString());
 }
 
 // See https://github.com/ArthurSonzogni/FTXUI/issues/2#issuecomment-504871456
@@ -51,8 +51,8 @@ TEST(TextTest, CJK) {
   Screen screen(6, 3);
   Render(screen, element);
   EXPECT_EQ(
-      "┌────┐\n"
-      "│测试│\n"
+      "┌────┐\r\n"
+      "│测试│\r\n"
       "└────┘",
       screen.ToString());
 }
@@ -63,8 +63,8 @@ TEST(TextTest, CJK_2) {
   Screen screen(5, 3);
   Render(screen, element);
   EXPECT_EQ(
-      "┌───┐\n"
-      "│测试\n"
+      "┌───┐\r\n"
+      "│测试\r\n"
       "└───┘",
       screen.ToString());
 }
@@ -75,8 +75,8 @@ TEST(TextTest, CJK_3) {
   Screen screen(4, 3);
   Render(screen, element);
   EXPECT_EQ(
-      "┌──┐\n"
-      "│测│\n"
+      "┌──┐\r\n"
+      "│测│\r\n"
       "└──┘",
       screen.ToString());
 }

src/ftxui/dom/vbox_test.cpp

@@ -6,6 +6,7 @@ using namespace ftxui;
 using namespace ftxui;
 
 std::string rotate(std::string str) {
+  str.erase(std::remove(str.begin(), str.end(), '\r'), str.end());
   str.erase(std::remove(str.begin(), str.end(), '\n'), str.end());
   return str;
 }

src/ftxui/screen/screen.cpp

@@ -2,6 +2,7 @@
 
 #include <algorithm>
 #include <sstream>
+#include <iostream>
 
 #include "ftxui/dom/node.hpp"
 #include "ftxui/screen/string.hpp"
@@ -149,6 +150,7 @@ Screen::Screen(int dimx, int dimy)
 }
 
 /// 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::wstringstream ss;
 
@@ -158,7 +160,7 @@ std::string Screen::ToString() {
   for (int y = 0; y < dimy_; ++y) {
     if (y != 0) {
       UpdatePixelStyle(ss, previous_pixel, final_pixel);
-      ss << '\n';
+      ss << L"\r\n";
     }
     for (int x = 0; x < dimx_;) {
       auto& pixel = pixels_[y][x];
@@ -181,6 +183,10 @@ std::string Screen::ToString() {
   return to_string(ss.str());
 }
 
+void Screen::Print() {
+  std::cout << ToString() << std::flush << (char)0;
+}
+
 /// @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.
@@ -254,6 +260,7 @@ void Screen::ApplyShader() {
     }
   }
 }
+
 // clang-format on
 
 }  // namespace ftxui

src/ftxui/screen/terminal.cpp

@@ -19,7 +19,7 @@ namespace ftxui {
 
 Terminal::Dimensions Terminal::Size() {
 #if defined(__EMSCRIPTEN__)
-  return Dimensions{80, 43};
+  return Dimensions{140, 43};
 #elif defined(_WIN32)
   CONSOLE_SCREEN_BUFFER_INFO csbi;
   int columns, rows;
@@ -48,6 +48,10 @@ bool Contains(const std::string& s, const char* key) {
 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;