// $Id: tek.c 11282 2010-10-28 16:26:09Z airwin $
//
//      PLplot tektronix device & emulators driver.
//
#include "plDevs.h"

#if defined ( PLD_xterm ) ||               /* xterm */              \
    defined ( PLD_tek4010 ) ||             /* TEK 4010 */           \
    defined ( PLD_tek4010f ) ||            /* ditto, file */        \
    defined ( PLD_tek4107 ) ||             /* TEK 4107 */           \
    defined ( PLD_tek4107f ) ||            /* ditto, file */        \
    defined ( PLD_mskermit ) ||            /* MS-kermit emulator */ \
    defined ( PLD_versaterm ) ||           /* Versaterm emulator */ \
    defined ( PLD_vlt ) ||                 /* VLT emulator */       \
    defined ( PLD_conex )                  // conex emulator 4010/4014/4105

#define NEED_PLDEBUG
#include "plplotP.h"
#include "drivers.h"
#include "plevent.h"

#include <ctype.h>

// Device info

PLDLLIMPEXP_DRIVER const char* plD_DEVICE_INFO_tek =
#if defined ( PLD_conex )
    "conex:Conex vt320/tek emulator:1:tek:24:conex\n"
#endif
#if defined ( PLD_mskermit )
    "mskermit:MS-Kermit emulator:1:tek:21:mskermit\n"
#endif
#if defined ( PLD_tek4107t )
    "tek4107t:Tektronix Terminal (4105/4107):1:tek:20:tek4107t\n"
#endif
#if defined ( PLD_tek4107f )
    "tek4107f:Tektronix File (4105/4107):0:tek:28:tek4107f\n"
#endif
#if defined ( PLD_tekt )
    "tekt:Tektronix Terminal (4010):1:tek:19:tekt\n"
#endif
#if defined ( PLD_tekf )
    "tekf:Tektronix File (4010):0:tek:27:tekf\n"
#endif
#if defined ( PLD_versaterm )
    "versaterm:Versaterm vt100/tek emulator:1:tek:22:versaterm\n"
#endif
#if defined ( PLD_vlt )
    "vlt:VLT vt100/tek emulator:1:tek:23:vlt\n"
#endif
#if defined ( PLD_xterm )
    "xterm:Xterm Window:1:tek:18:xterm\n"
#endif
;

// Prototype the driver entry points that will be used to initialize the
// dispatch table entries.

void plD_init_xterm( PLStream * );
void plD_init_tekt( PLStream * );
void plD_init_tekf( PLStream * );
void plD_init_tek4107t( PLStream * );
void plD_init_tek4107f( PLStream * );
void plD_init_mskermit( PLStream * );
void plD_init_versaterm( PLStream * );
void plD_init_vlt( PLStream * );
void plD_init_conex( PLStream * );

// External generic entry points

void plD_line_tek( PLStream *, short, short, short, short );
void plD_polyline_tek( PLStream *, short *, short *, PLINT );
void plD_eop_tek( PLStream * );
void plD_bop_tek( PLStream * );
void plD_tidy_tek( PLStream * );
void plD_state_tek( PLStream *, PLINT );
void plD_esc_tek( PLStream *, PLINT, void * );

// Static function prototypes

static void  WaitForPage( PLStream *pls );
static void  tek_init( PLStream *pls );
static void  tek_text( PLStream *pls );
static void  tek_graph( PLStream *pls );
static void  fill_polygon( PLStream *pls );
static void  GetCursor( PLStream *pls, PLGraphicsIn *ptr );
static void  encode_int( char *c, int i );
static void  encode_vector( char *c, int x, int y );
static void  decode_gin( char *c, PLGraphicsIn *gin );
static void  tek_vector( PLStream *pls, int x, int y );
static void  scolor( PLStream *pls, int icol, int r, int g, int b );
static void  setcmap( PLStream *pls );

static void  LookupEvent( PLStream *pls );
static void  InputEH( PLStream *pls );
static void  LocateEH( PLStream *pls );

// Stuff for handling tty cbreak mode

#ifdef HAVE_TERMIOS_H
#include <termios.h>
#include <unistd.h>
static struct termios         termios_cbreak, termios_reset;
static enum { RESET, CBREAK } ttystate = RESET;
static void tty_setup( void );
static int  tty_cbreak( void );
static int  tty_reset( void );
static void tty_atexit( void );
#else
static void tty_setup( void )
{
}
static int  tty_cbreak( void )
{
    return 0;
}
static int  tty_reset( void )
{
    return 0;
}
static void tty_atexit( void )
{
}
#endif

// Pixel settings

#define TEKX    1023
#define TEKY    779

// Graphics control characters.

#define RING_BELL       "\007"          // ^G = 7
#define CLEAR_VIEW      "\033\f"        // clear the view = ESC FF

#define ALPHA_MODE      "\037"          // Enter Alpha  mode:  US
#define VECTOR_MODE     "\035"          // Enter Vector mode:  GS
#define GIN_MODE        "\033\032"      // Enter GIN    mode:  ESC SUB
#define BYPASS_MODE     "\033\030"      // Enter Bypass mode:  ESC CAN
#define XTERM_VTMODE    "\033\003"      // End xterm-Tek mode: ESC ETX
#define CANCEL          "\033KC"        // Cancel

// Static vars

enum { tek4010, tek4105, tek4107, xterm, mskermit, vlt, versaterm };

// One of these holds the tek driver state information

typedef struct
{
    PLINT        xold, yold;     // Coordinates of last point plotted
    int          exit_eventloop; // Break out of event loop
    int          locate_mode;    // Set while in locate (pick) mode
    int          curcolor;       // Current color index
    PLGraphicsIn gin;            // Graphics input structure
} TekDev;

// color for MS-DOS Kermit v2.31 (and up) tektronix emulator
//	0 = normal, 1 = bright
//	foreground color (30-37) = 30 + colors
//		where colors are   1=red, 2=green, 4=blue
//
#ifdef PLD_mskermit
static char *kermit_color[15] = {
    "0;30", "0;37",
    "0;32", "0;36","0;31",  "0;35",
    "1;34", "1;33","1;31",  "1;37",
    "1;35", "1;32","1;36",  "0;34",
    "0;33"
};
#endif

static void tek_dispatch_init_helper( PLDispatchTable *pdt,
                                      char *menustr, char *devnam,
                                      int type, int seq, plD_init_fp init )
{
#ifndef ENABLE_DYNDRIVERS
    pdt->pl_MenuStr = menustr;
    pdt->pl_DevName = devnam;
#endif
    pdt->pl_type     = type;
    pdt->pl_seq      = seq;
    pdt->pl_init     = init;
    pdt->pl_line     = (plD_line_fp) plD_line_tek;
    pdt->pl_polyline = (plD_polyline_fp) plD_polyline_tek;
    pdt->pl_eop      = (plD_eop_fp) plD_eop_tek;
    pdt->pl_bop      = (plD_bop_fp) plD_bop_tek;
    pdt->pl_tidy     = (plD_tidy_fp) plD_tidy_tek;
    pdt->pl_state    = (plD_state_fp) plD_state_tek;
    pdt->pl_esc      = (plD_esc_fp) plD_esc_tek;
}

void plD_dispatch_init_xterm( PLDispatchTable *pdt )
{
    tek_dispatch_init_helper( pdt,
        "Xterm Window", "xterm",
        plDevType_Interactive, 18,
        (plD_init_fp) plD_init_xterm );
}

void plD_dispatch_init_tekt( PLDispatchTable *pdt )
{
    tek_dispatch_init_helper( pdt,
        "Tektronix Terminal (4010)", "tekt",
        plDevType_Interactive, 19,
        (plD_init_fp) plD_init_tekt );
}

void plD_dispatch_init_tek4107t( PLDispatchTable *pdt )
{
    tek_dispatch_init_helper( pdt,
        "Tektronix Terminal (4105/4107)", "tek4107t",
        plDevType_Interactive, 20,
        (plD_init_fp) plD_init_tek4107t );
}

void plD_dispatch_init_mskermit( PLDispatchTable *pdt )
{
    tek_dispatch_init_helper( pdt,
        "MS-Kermit emulator", "mskermit",
        plDevType_Interactive, 21,
        (plD_init_fp) plD_init_mskermit );
}

void plD_dispatch_init_versaterm( PLDispatchTable *pdt )
{
    tek_dispatch_init_helper( pdt,
        "Versaterm vt100/tek emulator", "versaterm",
        plDevType_Interactive, 22,
        (plD_init_fp) plD_init_versaterm );
}

void plD_dispatch_init_vlt( PLDispatchTable *pdt )
{
    tek_dispatch_init_helper( pdt,
        "VLT vt100/tek emulator", "vlt",
        plDevType_Interactive, 23,
        (plD_init_fp) plD_init_vlt );
}

void plD_dispatch_init_conex( PLDispatchTable *pdt )
{
    tek_dispatch_init_helper( pdt,
        "Conex vt320/tek emulator", "conex",
        plDevType_Interactive, 24,
        (plD_init_fp) plD_init_conex );
}

void plD_dispatch_init_tekf( PLDispatchTable *pdt )
{
    tek_dispatch_init_helper( pdt,
        "Tektronix File (4010)", "tekf",
        plDevType_FileOriented, 27,
        (plD_init_fp) plD_init_tekf );
}

void plD_dispatch_init_tek4107f( PLDispatchTable *pdt )
{
    tek_dispatch_init_helper( pdt,
        "Tektronix File (4105/4107)", "tek4107f",
        plDevType_FileOriented, 28,
        (plD_init_fp) plD_init_tek4107f );
}

//--------------------------------------------------------------------------
// plD_init_xterm()	xterm
// plD_init_tekt()	Tek 4010 terminal
// plD_init_tekf()	Tek 4010 file
// plD_init_tek4107t()	Tek 4105/4107 terminal
// plD_init_tek4107f()	Tek 4105/4107 file
// plD_init_mskermit()	MS-Kermit emulator (DOS)
// plD_init_vlt()	VLT emulator (Amiga)
// plD_init_versaterm()	VersaTerm emulator (Mac)
// plD_init_conex()	Conex vt320/Tek 4105 emulator (DOS)
//
// These just set attributes for the particular tektronix device, then call
// tek_init().  The following attributes can be set:
//
// pls->termin		if a terminal device
// pls->color		if color (1), if only fixed colors (2)
// pls->dev_fill0	if can handle solid area fill
// pls->dev_fill1	if can handle pattern area fill
//--------------------------------------------------------------------------

void
plD_init_xterm( PLStream *pls )
{
    pls->dev_minor = xterm;
    pls->termin    = 1;
    tek_init( pls );
}

void
plD_init_tekt( PLStream *pls )
{
    pls->termin = 1;
    plD_init_tekf( pls );
}

void
plD_init_tekf( PLStream *pls )
{
    pls->dev_minor = tek4010;
    tek_init( pls );
}

void
plD_init_tek4107t( PLStream *pls )
{
    pls->termin = 1;
    plD_init_tek4107f( pls );
}

void
plD_init_tek4107f( PLStream *pls )
{
    pls->dev_minor = tek4107;
    pls->color     = 1;
    pls->dev_fill0 = 1;
    tek_init( pls );
}

void
plD_init_mskermit( PLStream *pls )
{
    pls->dev_minor = mskermit;
    pls->termin    = 1;
    pls->color     = 1;
    pls->dev_fill0 = 1;
    tek_init( pls );
}

void
plD_init_vlt( PLStream *pls )
{
    pls->dev_minor = vlt;
    pls->termin    = 1;
    pls->color     = 1;
    pls->dev_fill0 = 1;
    tek_init( pls );
}

void
plD_init_versaterm( PLStream *pls )
{
    pls->dev_minor = versaterm;
    pls->termin    = 1;
    pls->color     = 1;
    pls->dev_fill0 = 1;
    tek_init( pls );
}

void
plD_init_conex( PLStream *pls )
{
    pls->dev_minor = xterm;             // responds to xterm escape codes
    pls->termin    = 1;
    pls->color     = 2;                 // only fixed colours
    tek_init( pls );
}

//--------------------------------------------------------------------------
// tek_init()
//
// Generic tektronix device initialization.
//--------------------------------------------------------------------------

static void
tek_init( PLStream *pls )
{
    TekDev *dev;
    int    xmin = 0;
    int    xmax = TEKX;
    int    ymin = 0;
    int    ymax = TEKY;

    PLFLT  pxlx = 4.771;
    PLFLT  pxly = 4.653;

    pls->graphx = TEXT_MODE;

// Allocate and initialize device-specific data

    pls->dev = calloc( 1, (size_t) sizeof ( TekDev ) );
    if ( pls->dev == NULL )
        plexit( "tek_init: Out of memory." );

    dev = (TekDev *) pls->dev;

    dev->curcolor = 1;
    dev->xold     = PL_UNDEFINED;
    dev->yold     = PL_UNDEFINED;

    plP_setpxl( pxlx, pxly );
    plP_setphy( xmin, xmax, ymin, ymax );

// Terminal/file initialization

    if ( pls->termin )
    {
        pls->OutFile = stdout;
        tty_setup();
    }
    else
    {
        plFamInit( pls );
        plOpenFile( pls );
    }

    switch ( pls->dev_minor )
    {
#ifdef PLD_tek4107
    case tek4107:
        pls->graphx = GRAPHICS_MODE;
        fprintf( pls->OutFile, "\033%%!0" );      // set tek mode
        fprintf( pls->OutFile, "\033KN1" );       // clear the view
        fprintf( pls->OutFile, "\033LZ" );        // clear dialog buffer
        fprintf( pls->OutFile, "\033ML1" );       // set default color
        break;
#endif  // PLD_tek4107

// A sneaky hack: VLT sometimes has leftover panel information, causing
// garbage at the beginning of a sequence of color fills.  Since
// there is no clear panel command, instead I set the fill color to the
// same as background and issue an end panel command.
//
#ifdef PLD_vlt
    case vlt: {
        char fillcol[4];
        tek_graph( pls );
        encode_int( fillcol, 0 );
        fprintf( pls->OutFile, "\033MP%s\033LE", fillcol );
        break;
    }
#endif  // PLD_vlt

    default:
        tek_graph( pls );
    }

// Initialize palette

    if ( pls->color & 0x01 )
    {
        printf( "\033TM111" );  // Switch to RGB colors
        setcmap( pls );
    }

// Finish initialization

    fprintf( pls->OutFile, VECTOR_MODE );    // Enter vector mode
    if ( pls->termin )
        fprintf( pls->OutFile, CLEAR_VIEW ); // erase and home

    fflush( pls->OutFile );
}

//--------------------------------------------------------------------------
// plD_line_tek()
//
// Draw a line from (x1,y1) to (x2,y2).
//--------------------------------------------------------------------------

void
plD_line_tek( PLStream *pls, short x1, short y1, short x2, short y2 )
{
    TekDev *dev = (TekDev *) pls->dev;

    tek_graph( pls );

// If not continuation of previous line, begin a new one

    if ( x1 != dev->xold || y1 != dev->yold )
    {
        pls->bytecnt += fprintf( pls->OutFile, VECTOR_MODE );
        tek_vector( pls, x1, y1 );
    }

// Now send following point to complete line draw

    tek_vector( pls, x2, y2 );

    dev->xold = x2;
    dev->yold = y2;
}

//--------------------------------------------------------------------------
// plD_polyline_tek()
//
// Draw a polyline in the current color.
//--------------------------------------------------------------------------

void
plD_polyline_tek( PLStream *pls, short *xa, short *ya, PLINT npts )
{
    PLINT  i;
    TekDev *dev = (TekDev *) pls->dev;
    short  x    = xa[0], y = ya[0];

    tek_graph( pls );

// If not continuation of previous line, begin a new one

    if ( x != dev->xold || y != dev->yold )
    {
        pls->bytecnt += fprintf( pls->OutFile, VECTOR_MODE );
        tek_vector( pls, x, y );
    }

// Now send following points to complete polyline draw

    for ( i = 1; i < npts; i++ )
        tek_vector( pls, xa[i], ya[i] );

    dev->xold = xa[npts - 1];
    dev->yold = ya[npts - 1];
}

//--------------------------------------------------------------------------
// plD_eop_tek()
//
// End of page.  User must hit a <CR> to continue (terminal output).
//--------------------------------------------------------------------------

void
plD_eop_tek( PLStream *pls )
{
    tek_graph( pls );

    if ( pls->termin )
    {
        if ( !pls->nopause )
            WaitForPage( pls );
    }
    fprintf( pls->OutFile, CLEAR_VIEW );          // erase and home
}

//--------------------------------------------------------------------------
// plD_bop_tek()
//
// Set up for the next page.  Advance to next family file if necessary
// (file output).  Devices that share graphics/alpha screens need a page
// clear.
//--------------------------------------------------------------------------

void
plD_bop_tek( PLStream *pls )
{
    TekDev *dev = (TekDev *) pls->dev;

    dev->xold = PL_UNDEFINED;
    dev->yold = PL_UNDEFINED;

    if ( pls->termin )
    {
        switch ( pls->dev_minor )
        {
        case mskermit:
            fprintf( pls->OutFile, CLEAR_VIEW ); // erase and home
            break;
        }
    }
    else
    {
        plGetFam( pls );
    }
    pls->page++;

// Initialize palette

    if ( pls->color & 0x01 )
        setcmap( pls );
}

//--------------------------------------------------------------------------
// plD_tidy_tek()
//
// Close graphics file or otherwise clean up.
//--------------------------------------------------------------------------

void
plD_tidy_tek( PLStream *pls )
{
    if ( !pls->termin )
    {
        plCloseFile( pls );
    }
    else
    {
        tek_text( pls );
        fflush( pls->OutFile );
    }
}

//--------------------------------------------------------------------------
// tek_color()
//
// Change to specified color index.
//--------------------------------------------------------------------------

static void
tek_color( PLStream *pls, int icol )
{
    switch ( pls->dev_minor )
    {
#ifdef PLD_mskermit                     // Is this really necessary?
    case mskermit:
        printf( "\033[%sm", kermit_color[icol % 14] );
        break;
#endif
    default:
        pls->bytecnt += fprintf( pls->OutFile, "\033ML%c", icol + '0' );
    }
}

//--------------------------------------------------------------------------
// plD_state_tek()
//
// Handle change in PLStream state (color, pen width, fill attribute,
// etc).
//--------------------------------------------------------------------------

void
plD_state_tek( PLStream *pls, PLINT op )
{
    TekDev *dev = (TekDev *) pls->dev;

    switch ( op )
    {
    case PLSTATE_WIDTH:
        break;

    case PLSTATE_COLOR0:
        if ( pls->color )
        {
            int icol0 = pls->icol0;
            tek_graph( pls );
            if ( icol0 != PL_RGB_COLOR )
            {
                dev->curcolor = icol0;
                tek_color( pls, icol0 );
            }
        }
        break;

    case PLSTATE_COLOR1:
        if ( pls->color )
        {
            int icol1, ncol1;
            tek_graph( pls );
            if ( ( ncol1 = MIN( 16 - pls->ncol0, pls->ncol1 ) ) < 1 )
                break;

            icol1         = pls->ncol0 + ( pls->icol1 * ( ncol1 - 1 ) ) / ( pls->ncol1 - 1 );
            dev->curcolor = icol1;
            tek_color( pls, icol1 );
        }
        break;

    case PLSTATE_CMAP0:
    case PLSTATE_CMAP1:
        if ( pls->color & 0x01 )
            setcmap( pls );

        break;
    }
}

//--------------------------------------------------------------------------
// plD_esc_tek()
//
// Escape function.
//--------------------------------------------------------------------------

void
plD_esc_tek( PLStream *pls, PLINT op, void *ptr )
{
    switch ( op )
    {
    case PLESC_TEXT:
        tek_text( pls );
        break;

    case PLESC_GRAPH:
        tek_graph( pls );
        break;

    case PLESC_FILL:
        fill_polygon( pls );
        break;

    case PLESC_GETC:
        GetCursor( pls, (PLGraphicsIn *) ptr );
        break;
    }
}

//--------------------------------------------------------------------------
// GetCursor()
//
// Waits for a left button mouse event and returns coordinates.
// xterm doesn't handle GIN. I think all the rest do.
//--------------------------------------------------------------------------

static void
GetCursor( PLStream *pls, PLGraphicsIn *ptr )
{
#define MAX_GIN    10
    char input_string[MAX_GIN];
    int  i = 0;

    plGinInit( ptr );

    if ( pls->termin && pls->dev_minor != xterm )
    {
        tek_graph( pls );

        // Enter GIN mode

        printf( GIN_MODE );
        fflush( stdout );

        // Read & decode report

        while ( ++i < MAX_GIN && ( input_string[i - 1] = getchar() ) != '\n' )
            ;

        input_string[i - 1] = '\0';
        ptr->keysym         = input_string[0];
        decode_gin( &input_string[1], ptr );

        // Switch out of GIN mode

        printf( VECTOR_MODE );
    }
}

//--------------------------------------------------------------------------
// fill_polygon()
//
// Fill polygon described in points pls->dev_x[] and pls->dev_y[].
//--------------------------------------------------------------------------

static void
fill_polygon( PLStream *pls )
{
    TekDev *dev = (TekDev *) pls->dev;
    int    i;
    char   fillcol[4], firstpoint[5];

    if ( pls->dev_npts < 1 )
        return;

    tek_graph( pls );

    encode_int( fillcol, -dev->curcolor );
    encode_vector( firstpoint, pls->dev_x[0], pls->dev_y[0] );

// Select the fill pattern

    pls->bytecnt += fprintf( pls->OutFile, "\033MP%s", fillcol );

// Begin panel boundary
// Set pls->debug to see the boundary of each fill box -- cool!

    if ( pls->debug )
        pls->bytecnt += fprintf( pls->OutFile, "\033LP%s1", firstpoint );
    else
        pls->bytecnt += fprintf( pls->OutFile, "\033LP%s0", firstpoint );

// Specify boundary (in vector mode)

    pls->bytecnt += fprintf( pls->OutFile, VECTOR_MODE );
    for ( i = 1; i < pls->dev_npts; i++ )
        tek_vector( pls, pls->dev_x[i], pls->dev_y[i] );

// End panel

    pls->bytecnt += fprintf( pls->OutFile, "\033LE" );
}

//--------------------------------------------------------------------------
// tek_text()
//
// Switch to text screen (or alpha mode, for vanilla tek's).  Restore
// terminal to its original state, to better handle user input if
// necessary.
//
// Note: xterm behaves strangely in the following circumstance: switch to
// the text screen, print a string, and switch to the graphics screen, all
// done in quick succession.  The first character of the printed string
// usually comes out blank -- but only apparently so, because if you force
// a refresh of the screen in this area it will reappear.  This is a
// reproducible bug on the HP 720 under X11R5.  If you insert a sleep(1)
// after the switch to text screen or before the switch to graphics
// screen, the string is printed correctly.  I've been unable to find a
// workaround for this problem (and I've tried, you can believe eet man).
//--------------------------------------------------------------------------

static void
tek_text( PLStream *pls )
{
    if ( pls->termin && ( pls->graphx == GRAPHICS_MODE ) )
    {
        tty_reset();
        pls->graphx = TEXT_MODE;
        switch ( pls->dev_minor )
        {
        case xterm:
            printf( "\033\003" );         // vt100 mode (xterm) = ESC ETX
            break;

        case mskermit:
        case vlt:
            printf( "\033[?38l" );        // vt100 screen
            break;

        case versaterm:
            printf( "\033%%!2" );         // vt100 screen
            break;

        case tek4107:
            printf( "\033LV1" );          // set dialog visible
            printf( "\033%%!1" );         // set ansi mode
            break;

        default:
            printf( ALPHA_MODE );         // enter alpha mode
        }
        fflush( stdout );
    }
}

//--------------------------------------------------------------------------
// tek_graph()
//
// Switch to graphics screen.  Also switch terminal to cbreak mode, to allow
// single keystrokes to govern actions at end of page.
//--------------------------------------------------------------------------

static void
tek_graph( PLStream *pls )
{
    if ( pls->termin && ( pls->graphx == TEXT_MODE ) )
    {
        tty_cbreak();
        pls->graphx = GRAPHICS_MODE;
        switch ( pls->dev_minor )
        {
        case xterm:
        case mskermit:
        case vlt:
            printf( "\033[?38h" );        // switch to tek screen
            break;

        case versaterm:
            printf( "\033%%!0" );         // switch to tek4107 screen
            break;

        case tek4107:
            printf( "\033%%!0" );         // set tek mode
            printf( CLEAR_VIEW );         // clear screen
            printf( "\033LV0" );          // set dialog invisible
            break;
        }
    }
}

//--------------------------------------------------------------------------
// encode_int()
//
// Encodes a single int into standard tek integer format, storing into a
// NULL-terminated character string (must be length 4 or greater).  This
// scheme does not work for negative integers less than 15.
//--------------------------------------------------------------------------

static void
encode_int( char *c, int i )
{
    int negative = 0;

    if ( i > 0 )
    {
        if ( i & 0x7C00 )                       // are any of bits 10-14 set?
            *c++ = ( ( i >> 10 ) & 0x1F ) | 0x40;
        if ( i & 0x03F0 )                       // are any of bits 4-9 set?
            *c++ = ( ( i >> 4 ) & 0x3F ) | 0x40;
    }
    else
    {
        i        = -i;
        negative = 1;
    }

    if ( i & 0x000F )                           // are any of bits 0-3 set?
        *c = ( i & 0x0F ) | 0x20;
    else                                        // if not, put in a space
        *c = 0x20;

    if ( !negative )                            // if positive, set sign bit
        *c |= 0x10;

    c++; *c = '\0';                             // NULL-terminate
    return;
}

//--------------------------------------------------------------------------
// decode_gin()
//
// Decodes a GIN tek vector string into an xy pair of relative device
// coordinates.  It's best to not use absolute device coordinates since the
// coordinate bounds are different depending on the report encoding used.
//
// Standard:	<HiX><LoX><HiY><LoY>
// Extended:	<HiY><Extra><LoY><HiX><LoX>
//
// where <Extra> holds the two low order bits for each coordinate.
//--------------------------------------------------------------------------

static void
decode_gin( char *c, PLGraphicsIn *gin )
{
    int x, y, lc = strlen( c );

    if ( lc == 4 )
    {
        x = ( ( c[0] & 0x1f ) << 5 ) +
            ( ( c[1] & 0x1f ) );

        y = ( ( c[2] & 0x1f ) << 5 ) +
            ( ( c[3] & 0x1f ) );

        gin->pX = x;
        gin->pY = y;
        gin->dX = x / (double) TEKX;
        gin->dY = y / (double) TEKY;
    }
    else if ( lc == 5 )
    {
        y = ( ( c[0] & 0x1f ) << 7 ) +
            ( ( c[2] & 0x1f ) << 2 ) +
            ( ( c[1] & 0x06 ) >> 2 );

        x = ( ( c[3] & 0x1f ) << 7 ) +
            ( ( c[4] & 0x1f ) << 2 ) +
            ( ( c[1] & 0x03 ) );

        gin->pX = x;
        gin->pY = y;
        gin->dX = x / (double) ( TEKX << 2 );
        gin->dY = y / (double) ( TEKY << 2 );
    }
    else                        // Illegal encoding
    {
        gin->pX = 0;
        gin->pY = 0;
        gin->dY = 0;
        gin->dX = 0;
    }
}

//--------------------------------------------------------------------------
// encode_vector()
//
// Encodes an xy vector (2 ints) into standard tek vector format, storing
// into a NULL-terminated character string of length 5.  Note that the y
// coordinate always comes first.
//--------------------------------------------------------------------------

static void
encode_vector( char *c, int x, int y )
{
    c[0] = ( y >> 5 ) + 0x20;             // hy
    c[1] = ( y & 0x1f ) + 0x60;           // ly
    c[2] = ( x >> 5 ) + 0x20;             // hx
    c[3] = ( x & 0x1f ) + 0x40;           // lx
    c[4] = '\0';                          // NULL
}

//--------------------------------------------------------------------------
// tek_vector()
//
// Issues a vector draw command, assuming we are in vector plot mode.  XY
// coordinates are encoded according to the standard xy encoding scheme.
//--------------------------------------------------------------------------

static void
tek_vector( PLStream *pls, int x, int y )
{
    char c[5];

    encode_vector( c, x, y );
    pls->bytecnt += fprintf( pls->OutFile, "%s", c );
}

//--------------------------------------------------------------------------
// scolor()
//
// Sets a color by tek-encoded RGB values.  Need to convert PLplot RGB
// color range (0 to 255) to Tek RGB color range (0 to 100).
//--------------------------------------------------------------------------

static void
scolor( PLStream *pls, int icol, int r, int g, int b )
{
    char tek_col[4], tek_r[4], tek_g[4], tek_b[4];

    encode_int( tek_col, icol );
    encode_int( tek_r, ( 100 * r ) / 255 );
    encode_int( tek_g, ( 100 * g ) / 255 );
    encode_int( tek_b, ( 100 * b ) / 255 );

    pls->bytecnt += fprintf( pls->OutFile, "\033TG14%s%s%s%s",
        tek_col, tek_r, tek_g, tek_b );
}

//--------------------------------------------------------------------------
// setcmap()
//
// Sets up color palette.
//--------------------------------------------------------------------------

static void
setcmap( PLStream *pls )
{
    int     i, ncol1 = MIN( 16 - pls->ncol0, pls->ncol1 );
    PLColor cmap1col;

    tek_graph( pls );

// Initialize cmap 0 colors

    for ( i = 0; i < pls->ncol0; i++ )
        scolor( pls, i, pls->cmap0[i].r, pls->cmap0[i].g, pls->cmap0[i].b );

// Initialize any remaining slots for cmap1

    for ( i = 0; i < ncol1; i++ )
    {
        plcol_interp( pls, &cmap1col, i, ncol1 );
        scolor( pls, i + pls->ncol0, cmap1col.r, cmap1col.g, cmap1col.b );
    }
}

//--------------------------------------------------------------------------
// WaitForPage()
//
// This routine waits for the user to advance the plot, while handling
// all other events.
//--------------------------------------------------------------------------

static void
WaitForPage( PLStream *pls )
{
    TekDev *dev = (TekDev *) pls->dev;

    printf( ALPHA_MODE );         // Switch to alpha mode (necessary)
    printf( RING_BELL );          // and ring bell
    printf( VECTOR_MODE );        // Switch out of alpha mode
    fflush( stdout );

    while ( !dev->exit_eventloop )
    {
        LookupEvent( pls );
        if ( dev->locate_mode )
            LocateEH( pls );
        else
            InputEH( pls );
    }
    dev->exit_eventloop = FALSE;
}

//--------------------------------------------------------------------------
// LookupEvent()
//
// Fills in the PLGraphicsIn from an input event.
//--------------------------------------------------------------------------

static void
LookupEvent( PLStream *pls )
{
    TekDev       *dev = (TekDev *) pls->dev;
    PLGraphicsIn *gin = &( dev->gin );

    if ( dev->locate_mode )
    {
        GetCursor( pls, gin );
    }
    else
    {
        plGinInit( gin );
        gin->keysym = getchar();
    }

    if ( isprint( gin->keysym ) )
    {
        gin->string[0] = gin->keysym;
        gin->string[1] = '\0';
    }
    else
    {
        gin->string[0] = '\0';
    }

    pldebug( "LookupEvent",
        "Keycode %x, string: %s\n", gin->keysym, gin->string );
}

//--------------------------------------------------------------------------
// LocateEH()
//
// Handles locate mode events.
//
// In locate mode: move cursor to desired location and select by pressing a
// key or by clicking on the mouse (if available).  Typically the world
// coordinates of the selected point are reported.
//
// There are two ways to enter Locate mode -- via the API, or via a driver
// command.  The API entry point is the call plGetCursor(), which initiates
// locate mode and does not return until input has been obtained.  The
// driver entry point is by entering a 'L' while the driver is waiting for
// events.
//
// Locate mode input is reported in one of three ways:
// 1. Through a returned PLGraphicsIn structure, when user has specified a
//    locate handler via (*pls->LocateEH).
// 2. Through a returned PLGraphicsIn structure, when locate mode is invoked
//    by a plGetCursor() call.
// 3. Through writes to stdout, when locate mode is invoked by a driver
//    command and the user has not supplied a locate handler.
//
// Hitting <Escape> will at all times end locate mode.  Other keys will
// typically be interpreted as locator input.  Selecting a point out of
// bounds will end locate mode unless the user overrides with a supplied
// Locate handler.
//--------------------------------------------------------------------------

static void
LocateEH( PLStream *pls )
{
    TekDev       *dev = (TekDev *) pls->dev;
    PLGraphicsIn *gin = &( dev->gin );

// End locate mode on <Escape>

    if ( gin->keysym == PLK_Escape )
    {
        dev->locate_mode = 0;
        return;
    }

// Call user locate mode handler if provided

    if ( pls->LocateEH != NULL )
        ( *pls->LocateEH )( gin, pls->LocateEH_data, &dev->locate_mode );

// Use default procedure

    else
    {
        // Try to locate cursor

        if ( plTranslateCursor( gin ) )
        {
            // Successful, so send report to stdout

            pltext();
            if ( isprint( gin->keysym ) )
                printf( "%f %f %c\n", gin->wX, gin->wY, gin->keysym );
            else
                printf( "%f %f\n", gin->wX, gin->wY );

            plgra();
        }
        else
        {
            // Selected point is out of bounds, so end locate mode

            dev->locate_mode = 0;
        }
    }
}

//--------------------------------------------------------------------------
// InputEH()
//
// Event handler routine for xterm.  Just reacts to keyboard input.
//
// In locate mode: move cursor to desired location and select by pressing a
// key or by clicking on the mouse (if available).  The world coordinates of
// the selected point are output on the text screen.  Terminate by picking a
// point out of bounds, hitting page advance, or the escape key.  If you
// want to customize this, write an event handler to do it.
//--------------------------------------------------------------------------

static void
InputEH( PLStream *pls )
{
    TekDev       *dev = (TekDev *) pls->dev;
    PLGraphicsIn *gin = &( dev->gin );

// Call user event handler.
// Since this is called first, the user can disable all PLplot internal
// event handling by setting gin->keysym to 0 and gin->string to '\0'.
//
    if ( pls->KeyEH != NULL )
        ( *pls->KeyEH )( gin, pls->KeyEH_data, &dev->exit_eventloop );

// Remaining internal event handling

    switch ( gin->keysym )
    {
    case PLK_Linefeed:
        // Advance to next page (i.e. terminate event loop) on a <eol>
        dev->exit_eventloop = TRUE;
        break;

    case 'Q':
        // Terminate on a 'Q' (not 'q', since it's too easy to hit by mistake)
        pls->nopause = TRUE;
        plexit( "" );
        break;

    case 'L':
        // Begin locate mode
        dev->locate_mode = 1;
        break;
    }
}

//--------------------------------------------------------------------------
// tty cbreak-mode handlers
//
// Taken from "Advanced Programming in the UNIX(R) Environment",
// by W. Richard Stevens.
//--------------------------------------------------------------------------

#ifdef HAVE_TERMIOS_H

static void
tty_setup( void )                         // setup for terminal operations
{
    if ( tcgetattr( STDIN_FILENO, &termios_reset ) < 0 )
    {
        fprintf( stderr, "Unable to set up cbreak mode.\n" );
        return;
    }

    termios_cbreak = termios_reset;             // structure copy

    termios_cbreak.c_lflag    &= ~( ICANON );   // canonical mode off
    termios_cbreak.c_cc[VMIN]  = 1;             // 1 byte at a time
    termios_cbreak.c_cc[VTIME] = 0;             // no timer

#ifdef STDC_HEADERS
    if ( atexit( tty_atexit ) )
        fprintf( stderr, "Unable to set up atexit handler.\n" );
#endif
    return;
}

static int
tty_cbreak( void )                        // put terminal into a cbreak mode
{
    if ( ttystate != CBREAK )
    {
        if ( tcsetattr( STDIN_FILENO, TCSAFLUSH, &termios_cbreak ) < 0 )
            return -1;

        ttystate = CBREAK;
    }
    return 0;
}

static int
tty_reset( void )                         // restore terminal's mode
{
    if ( ttystate != RESET )
    {
        if ( tcsetattr( STDIN_FILENO, TCSAFLUSH, &termios_reset ) < 0 )
            return -1;

        ttystate = RESET;
    }
    return 0;
}

static void
tty_atexit( void )                        // exit handler
{
    tty_reset();
}

#endif                  // HAVE_TERMIOS_H

#else
int pldummy_tek()
{
    return 0;
}

#endif  //  defined(PLD_xterm) || ...
