diff --git a/Makefile b/Makefile
index ee24373..16f3965 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
 proto = userinput.proto hostinput.proto transportinstruction.proto
-source = parse.cpp parserstate.cpp parser.cpp terminal.cpp termemu.cpp parseraction.cpp terminalfunctions.cpp swrite.cpp terminalframebuffer.cpp terminaldispatcher.cpp terminaluserinput.cpp terminaldisplay.cpp network.cpp ntester.cpp ocb.cpp base64.cpp encrypt.cpp decrypt.cpp crypto.cpp networktransport.cpp transportfragment.cpp user.cpp userinput.pb.cc completeterminal.cpp stm-server.cpp stm.cpp transportinstruction.pb.cc transportsender.cpp stmclient.cpp terminaloverlay.cpp hostinput.pb.cc
+source = parse.cpp parserstate.cpp parser.cpp terminal.cpp termemu.cpp parseraction.cpp terminalfunctions.cpp swrite.cpp terminalframebuffer.cpp terminaldispatcher.cpp terminaluserinput.cpp terminaldisplay.cpp network.cpp ntester.cpp ocb.cpp base64.cpp encrypt.cpp decrypt.cpp crypto.cpp networktransport.cpp transportfragment.cpp user.cpp userinput.pb.cc completeterminal.cpp stm-server.cpp stm.cpp transportinstruction.pb.cc transportsender.cpp stmclient.cpp terminaloverlay.cpp hostinput.pb.cc screencap.cpp
 objects = parserstate.o parser.o terminal.o parseraction.o terminalfunctions.o swrite.o terminalframebuffer.o terminaldispatcher.o terminaluserinput.o terminaldisplay.o network.o ocb.o base64.o crypto.o networktransport.o transportfragment.o user.o userinput.pb.o completeterminal.o transportinstruction.pb.o transportsender.o stmclient.o terminaloverlay.o hostinput.pb.o
-executables = parse termemu ntester encrypt decrypt stm-server stm
+executables = parse termemu ntester encrypt decrypt stm-server stm screencap
 
 CXX = g++
 CXXFLAGS = -g -O2 --std=c++0x -pedantic -Werror -Wall -Wextra -Weffc++ -fno-default-inline -pipe -D_FILE_OFFSET_BITS=64 -D_XOPEN_SOURCE=500 -D_GNU_SOURCE -D_BSD_SOURCE
@@ -16,6 +16,9 @@ parse: parse.o $(objects)
 termemu: termemu.o $(objects)
 	$(CXX) $(CXXFLAGS) -o $@ termemu.o $(objects) $(LIBS)
 
+screencap: screencap.o $(objects)
+	$(CXX) $(CXXFLAGS) -o $@ screencap.o $(objects) $(LIBS)
+
 ntester: ntester.o $(objects)
 	$(CXX) $(CXXFLAGS) -o $@ ntester.o $(objects) $(LIBS)
 
diff --git a/screencap.cpp b/screencap.cpp
new file mode 100644
index 0000000..35ee886
--- /dev/null
+++ b/screencap.cpp
@@ -0,0 +1,280 @@
+#include <pty.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <errno.h>
+#include <poll.h>
+#include <string.h>
+#include <locale.h>
+#include <langinfo.h>
+#include <wchar.h>
+#include <assert.h>
+#include <wctype.h>
+#include <iostream>
+#include <typeinfo>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/signalfd.h>
+#include <termios.h>
+#include <sys/types.h>
+#include <pwd.h>
+#include <sys/time.h>
+
+#include "parser.hpp"
+#include "completeterminal.hpp"
+#include "swrite.hpp"
+
+const size_t buf_size = 16384;
+
+void emulate_terminal( int fd );
+
+int main( void )
+{
+  int master;
+  struct termios saved_termios, raw_termios, child_termios;
+
+  if ( NULL == setlocale( LC_ALL, "" ) ) {
+    perror( "setlocale" );
+    exit( 1 );
+  }
+
+  if ( strcmp( nl_langinfo( CODESET ), "UTF-8" ) != 0 ) {
+    fprintf( stderr, "stm requires a UTF-8 locale.\n" );
+    exit( 1 );
+  }
+
+  if ( tcgetattr( STDIN_FILENO, &saved_termios ) < 0 ) {
+    perror( "tcgetattr" );
+    exit( 1 );
+  }
+
+  child_termios = saved_termios;
+
+  if ( !(child_termios.c_iflag & IUTF8) ) {
+    fprintf( stderr, "Warning: Locale is UTF-8 but termios IUTF8 flag not set. Setting IUTF8 flag.\n" );
+    child_termios.c_iflag |= IUTF8;
+  }
+
+  pid_t child = forkpty( &master, NULL, &child_termios, NULL );
+
+  if ( child == -1 ) {
+    perror( "forkpty" );
+    exit( 1 );
+  }
+
+  if ( child == 0 ) {
+    /* child */
+    if ( setenv( "TERM", "xterm", true ) < 0 ) {
+      perror( "setenv" );
+      exit( 1 );
+    }
+
+    /* ask ncurses to send UTF-8 instead of ISO 2022 for line-drawing chars */
+    if ( setenv( "NCURSES_NO_UTF8_ACS", "1", true ) < 0 ) {
+      perror( "setenv" );
+      exit( 1 );
+    }
+
+    /* get shell name */
+    struct passwd *pw = getpwuid( geteuid() );
+    if ( pw == NULL ) {
+      perror( "getpwuid" );
+      exit( 1 );
+    }
+
+    char *my_argv[ 2 ];
+    my_argv[ 0 ] = strdup( pw->pw_shell );
+    assert( my_argv[ 0 ] );
+    my_argv[ 1 ] = NULL;
+
+    if ( execve( pw->pw_shell, my_argv, environ ) < 0 ) {
+      perror( "execve" );
+      exit( 1 );
+    }
+    exit( 0 );
+  } else {
+    /* parent */
+    raw_termios = saved_termios;
+
+    cfmakeraw( &raw_termios );
+
+    if ( tcsetattr( STDIN_FILENO, TCSANOW, &raw_termios ) < 0 ) {
+      perror( "tcsetattr" );
+      exit( 1 );
+    }
+
+    emulate_terminal( master );
+
+    if ( tcsetattr( STDIN_FILENO, TCSANOW, &saved_termios ) < 0 ) {
+      perror( "tcsetattr" );
+      exit( 1 );
+    }
+  }
+
+  printf( "[stm is exiting.]\n" );
+
+  return 0;
+}
+
+/* Print a frame */
+void tick( Terminal::Framebuffer &state, const Terminal::Framebuffer &new_frame )
+{
+  static bool initialized = false;
+
+  if ( !(state == new_frame) ) {
+    Terminal::Display::debug_print( new_frame );
+  }
+
+  std::string update = Terminal::Display::new_frame( initialized, state, new_frame );
+  swrite( STDOUT_FILENO, update.c_str() );
+
+  state = new_frame;
+
+  initialized = true;
+}
+
+/* This is the main loop.
+
+   1. New bytes from the user get applied to the terminal emulator
+      as "UserByte" actions.
+
+   2. New bytes from the host get sent to the Parser, and then
+      those actions are applied to the terminal.
+
+   3. Resize events (from a SIGWINCH signal) get turned into
+      "Resize" actions and applied to the terminal.
+
+   At every event from poll(), we run the tick() function to
+   possibly print a new frame (if we haven't printed one in the
+   last 1/50 second). The new frames are "differential" -- they
+   assume the previous frame was sent to the real terminal.
+*/
+
+void emulate_terminal( int fd )
+{
+  /* establish WINCH fd and start listening for signal */
+  sigset_t signal_mask;
+  assert( sigemptyset( &signal_mask ) == 0 );
+  assert( sigaddset( &signal_mask, SIGWINCH ) == 0 );
+
+  /* stop "ignoring" WINCH signal */
+  assert( sigprocmask( SIG_BLOCK, &signal_mask, NULL ) == 0 );
+
+  int winch_fd = signalfd( -1, &signal_mask, 0 );
+  if ( winch_fd < 0 ) {
+    perror( "signalfd" );
+    return;
+  }
+
+  /* get current window size */
+  struct winsize window_size;
+  if ( ioctl( STDIN_FILENO, TIOCGWINSZ, &window_size ) < 0 ) {
+    perror( "ioctl TIOCGWINSZ" );
+    return;
+  }
+
+  /* tell child process */
+  if ( ioctl( fd, TIOCSWINSZ, &window_size ) < 0 ) {
+    perror( "ioctl TIOCSWINSZ" );
+    return;
+  }
+
+  /* open parser and terminal */
+  Terminal::Complete complete( window_size.ws_col, window_size.ws_row );
+  Terminal::Framebuffer state( window_size.ws_col, window_size.ws_row );
+
+  struct pollfd pollfds[ 3 ];
+
+  pollfds[ 0 ].fd = STDIN_FILENO;
+  pollfds[ 0 ].events = POLLIN;
+
+  pollfds[ 1 ].fd = fd;
+  pollfds[ 1 ].events = POLLIN;
+
+  pollfds[ 2 ].fd = winch_fd;
+  pollfds[ 2 ].events = POLLIN;
+
+  swrite( STDOUT_FILENO, Terminal::Emulator::open().c_str() );
+
+  while ( 1 ) {
+    int active_fds = poll( pollfds, 3, -1 );
+    if ( active_fds < 0 ) {
+      perror( "poll" );
+      break;
+    }
+
+    if ( pollfds[ 0 ].revents & POLLIN ) {
+      /* input from user */
+      char buf[ buf_size ];
+
+      /* fill buffer if possible */
+      ssize_t bytes_read = read( pollfds[ 0 ].fd, buf, buf_size );
+      if ( bytes_read == 0 ) { /* EOF */
+	return;
+      } else if ( bytes_read < 0 ) {
+	perror( "read" );
+	return;
+      }
+      
+      std::string terminal_to_host;
+      
+      for ( int i = 0; i < bytes_read; i++ ) {
+	Parser::UserByte ub( buf[ i ] );
+	terminal_to_host += complete.act( &ub );
+      }
+      
+      if ( swrite( fd, terminal_to_host.c_str(), terminal_to_host.length() ) < 0 ) {
+	break;
+      }
+    } else if ( pollfds[ 1 ].revents & POLLIN ) {
+      /* input from host */
+      char buf[ buf_size ];
+
+      /* fill buffer if possible */
+      ssize_t bytes_read = read( pollfds[ 1 ].fd, buf, buf_size );
+      if ( bytes_read == 0 ) { /* EOF */
+	return;
+      } else if ( bytes_read < 0 ) {
+	perror( "read" );
+	return;
+      }
+      
+      std::string terminal_to_host = complete.act( std::string( buf, bytes_read ) );
+      if ( swrite( fd, terminal_to_host.c_str(), terminal_to_host.length() ) < 0 ) {
+	break;
+      }
+    } else if ( pollfds[ 2 ].revents & POLLIN ) {
+      /* resize */
+      struct signalfd_siginfo info;
+      assert( read( winch_fd, &info, sizeof( info ) ) == sizeof( info ) );
+      assert( info.ssi_signo == SIGWINCH );
+
+      /* get new size */
+      if ( ioctl( STDIN_FILENO, TIOCGWINSZ, &window_size ) < 0 ) {
+	perror( "ioctl TIOCGWINSZ" );
+	return;
+      }
+
+      /* tell emulator */
+      Parser::Resize r( window_size.ws_col, window_size.ws_row );
+      complete.act( &r );
+
+      /* tell child process */
+      if ( ioctl( fd, TIOCSWINSZ, &window_size ) < 0 ) {
+	perror( "ioctl TIOCSWINSZ" );
+	return;
+      }
+    } else if ( (pollfds[ 0 ].revents | pollfds[ 1 ].revents)
+		& (POLLERR | POLLHUP | POLLNVAL) ) {
+      break;
+    }
+
+    tick( state, complete.get_fb() );
+  }
+
+  std::string update = Terminal::Display::new_frame( true, state, complete.get_fb() );
+  swrite( STDOUT_FILENO, update.c_str() );
+
+  swrite( STDOUT_FILENO, Terminal::Emulator::close().c_str() );
+}
diff --git a/terminaldisplay.cpp b/terminaldisplay.cpp
index 18abe0c..c3fa344 100644
--- a/terminaldisplay.cpp
+++ b/terminaldisplay.cpp
@@ -1,4 +1,6 @@
 #include <assert.h>
+#include <sys/time.h>
+#include <wchar.h>
 
 #include "terminaldisplay.hpp"
 
@@ -252,3 +254,33 @@ void FrameState::append_silent_move( int y, int x )
   cursor_x = x;
   cursor_y = y;
 }
+
+void Display::debug_print( const Framebuffer &fb )
+{
+  struct timeval tv;
+  gettimeofday( &tv, NULL );
+
+  double the_time = tv.tv_sec * 1000 + double(tv.tv_usec) / 1000.0;
+
+  fprintf( stderr, "%f ", the_time );
+  
+  for ( int y = 0; y < fb.ds.get_height(); y++ ) {
+    for ( int x = 0; x < fb.ds.get_width(); x++ ) {
+      const Cell *cell = fb.get_cell( y, x );
+      
+      if ( cell->contents.empty() ) {
+	fprintf( stderr, "_" );
+      } else {
+	wchar_t first = cell->contents.front();
+	if ( (first > 254) || (first < 0x20) ) {
+	  fprintf( stderr, "&" );
+	} else {
+	  fprintf( stderr, "%c", (char)first );
+	}
+      }
+    }
+  }
+
+  fprintf( stderr, "\n" );
+  fflush( stderr );
+}
diff --git a/terminaldisplay.hpp b/terminaldisplay.hpp
index c7949dd..c777f24 100644
--- a/terminaldisplay.hpp
+++ b/terminaldisplay.hpp
@@ -35,6 +35,7 @@ namespace Terminal {
 
   public:
     static std::string new_frame( bool initialized, const Framebuffer &last, const Framebuffer &f );
+    static void debug_print( const Framebuffer &fb );
   };
 }