//  Copyright 1993, 1994, 1995
//  Maurice LeBrun			mjl@dino.ph.utexas.edu
//  Institute for Fusion Studies	University of Texas at Austin
//
//  Copyright (C) 2004  Joao Cardoso
//  Copyright (C) 2004  Andrew Ross
//
//  This file is part of PLplot.
//
//  PLplot is free software; you can redistribute it and/or modify
//  it under the terms of the GNU Library General Public License as published
//  by the Free Software Foundation; either version 2 of the License, or
//  (at your option) any later version.
//
//  PLplot is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU Library General Public License for more details.
//
//  You should have received a copy of the GNU Library General Public License
//  along with PLplot; if not, write to the Free Software
//  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
//
//
//  Based upon tkFrame.c from the TK 3.2 distribution:
//
//  Copyright 1990 Regents of the University of California.
//  Permission to use, copy, modify, and distribute this
//  software and its documentation for any purpose and without
//  fee is hereby granted, provided that the above copyright
//  notice appear in all copies.  The University of California
//  makes no representations about the suitability of this
//  software for any purpose.  It is provided "as is" without
//  express or implied warranty.
//
//--------------------------------------------------------------------------
//
//  This module implements "plframe" widgets for the Tk toolkit.  These are
//  frames that have extra logic to allow them to be interfaced with the
//  PLplot X driver.  These are then drawn into and respond to keyboard and
//  mouse events.
//
//
// #define DEBUG_ENTER
// #define DEBUG
//

#define DEBUGx

#define NEED_PLDEBUG
#include "plserver.h"
#include "plxwd.h"
#include "tcpip.h"

#ifdef PL_HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <fcntl.h>

#undef HAVE_ITCL

#define NDEV    100             // Max number of output device types in menu

// If set, BUFFER_FIFO causes FIFO i/o to be buffered

#define BUFFER_FIFO    1

// If set, causes a file handler to be used with FIFO

#define FH_FIFO    0

// A handy command wrapper

#define plframe_cmd( code ) \
    if ( ( code ) == TCL_ERROR ) return ( TCL_ERROR );

// Backward compatibility junk

#if TCL_MAJOR_VERSION <= 7 && TCL_MINOR_VERSION <= 4
#define Tk_Cursor    Cursor
#endif

//
// A data structure of the following type is kept for each
// plframe that currently exists for this process:
//

typedef struct
{
// This is stuff taken from tkFrame.c

    Tk_Window tkwin;            // Window that embodies the frame.  NULL
                                // means that the window has been destroyed
                                // but the data structures haven't yet been
                                // cleaned up.
    Display    *display;        // Display containing widget.  Used, among
                                // other things, so that resources can be
                                // freed even after tkwin has gone away.
    Tcl_Interp *interp;         // Interpreter associated with
                                // widget.  Used to delete widget
                                // command.
#ifdef HAVE_ITCL
    Tcl_Command widgetCmd;      // Token for frame's widget command.
#endif
    Tk_3DBorder border;         // Structure used to draw 3-D border and
                                // background.
    int         borderWidth;    // Width of 3-D border (if any).
    int         relief;         // 3-d effect: TK_RELIEF_RAISED etc.
    int         width;          // Width to request for window.  <= 0 means
                                // don't request any size.
    int         height;         // Height to request for window.  <= 0 means
                                // don't request any size.
    Tk_Cursor   cursor;         // Current cursor for window, or None.
    int         flags;          // Various flags;  see below for
                                // definitions.

// These are new to plframe widgets

// control stuff

    int      tkwin_initted;     // Set first time widget is mapped
    PLStream *pls;              // PLplot stream pointer
    PLINT    ipls;              // PLplot stream number
    PLINT    ipls_save;         // PLplot stream number, save files

    PLRDev   *plr;              // Renderer state information.  Malloc'ed
    XColor   *bgColor;          // Background color
    char     *plpr_cmd;         // Holds print command name.  Malloc'ed

// Used to handle resize and expose events

    PLDisplay pldis;            // Info about the display window
    int       prevWidth;        // Previous window width
    int       prevHeight;       // Previous window height

// Support for save operations

    char       *SaveFnam;       // File name we are currently saving to.
                                // Malloc'ed.
    const char **devDesc;       // Descriptive names for file-oriented
                                // devices.  Malloc'ed.
    const char **devName;       // Keyword names of file-oriented devices.
                                // Malloc'ed.

// Used in selecting & modifying plot or device area

    GC        xorGC;            // GC used for rubber-band drawing
    XPoint    pts[5];           // Points for rubber-band drawing
    int       continue_draw;    // Set when doing rubber-band draws
    Tk_Cursor xhair_cursor;     // cursor used for drawing
    PLFLT     xl, xr, yl, yr;   // Bounds on plot viewing area
    char      *xScrollCmd;      // Command prefix for communicating with
                                // horizontal scrollbar.  NULL means no
                                // command to issue.  Malloc'ed.
    char      *yScrollCmd;      // Command prefix for communicating with
                                // vertical scrollbar.  NULL means no
                                // command to issue.  Malloc'ed.

// Used for flashing bop or eop condition

    char *bopCmd;               // Proc to call at bop
    char *eopCmd;               // Proc to call at eop

// Used for drawing graphic crosshairs

    int    xhairs;              // Configuration option to turn on xhairs
    int    drawing_xhairs;      // Set if we are currently drawing xhairs
    XPoint xhair_x[2];          // Points for horizontal xhair line
    XPoint xhair_y[2];          // Points for vertical xhair line

// Used for drawing a rubber band lilne segment

    int    rband;               // Configuration option to turn on rband
    int    drawing_rband;       // See if we are currently drawing rband
    XPoint rband_pt[2];         // Ends of rubber band line
} PlFrame;

//
// Flag bits for plframes:
//
// REFRESH_PENDING:		Non-zero means a DoWhenIdle handler
//				has already been queued to refresh
//				this window.
// RESIZE_PENDING;		Used to reschedule resize events
// REDRAW_PENDING;		Used to redraw contents of plot buffer
// UPDATE_V_SCROLLBAR:		Non-zero means vertical scrollbar needs
//				to be updated.
// UPDATE_H_SCROLLBAR:		Non-zero means horizontal scrollbar needs
//				to be updated.
//

#define REFRESH_PENDING       1
#define RESIZE_PENDING        2
#define REDRAW_PENDING        4
#define UPDATE_V_SCROLLBAR    8
#define UPDATE_H_SCROLLBAR    16

// Defaults for plframes:

#define DEF_PLFRAME_BG_COLOR        "Black"
#define DEF_PLFRAME_BG_MONO         "White"
#define DEF_PLFRAME_BORDER_WIDTH    "0"
#define DEF_PLFRAME_CURSOR          ( (char *) NULL )
#define DEF_PLFRAME_HEIGHT          "0"
#define DEF_PLFRAME_RELIEF          "flat"
#define DEF_PLFRAME_WIDTH           "0"

// Configuration info

static Tk_ConfigSpec configSpecs[] = {
    { TK_CONFIG_BORDER,        "-background",     "background",     "Background",
      DEF_PLFRAME_BG_COLOR, Tk_Offset( PlFrame, border ),
      TK_CONFIG_COLOR_ONLY, NULL },
//
//  {TK_CONFIG_COLOR, (char *) NULL, (char *) NULL, (char *) NULL,
//      (char *) NULL, Tk_Offset(PlFrame, bgColor),
//      TK_CONFIG_COLOR_ONLY},
//
#ifndef MAC_TCL
    { TK_CONFIG_COLOR,         "-plbg",           "plbackground",   "Plbackground",
      DEF_PLFRAME_BG_COLOR, Tk_Offset( PlFrame, bgColor ),
      TK_CONFIG_COLOR_ONLY, NULL },
#endif
    { TK_CONFIG_BORDER,        "-background",     "background",     "Background",
      DEF_PLFRAME_BG_MONO, Tk_Offset( PlFrame, border ),
      TK_CONFIG_MONO_ONLY, NULL },
//
//  {TK_CONFIG_COLOR, (char *) NULL, (char *) NULL, (char *) NULL,
//      (char *) NULL, Tk_Offset(PlFrame, bgColor),
//      TK_CONFIG_MONO_ONLY},
//
#ifndef MAC_TCL
    { TK_CONFIG_COLOR,         "-plbg",           (char *) NULL,    (char *) NULL,
      DEF_PLFRAME_BG_MONO, Tk_Offset( PlFrame, bgColor ),
      TK_CONFIG_MONO_ONLY, NULL },
#endif
    { TK_CONFIG_SYNONYM,       "-bd",             "borderWidth",    (char *) NULL,
      (char *) NULL, 0, 0, NULL },
    { TK_CONFIG_SYNONYM,       "-bg",             "background",     (char *) NULL,
      (char *) NULL, 0, 0, NULL },
    { TK_CONFIG_PIXELS,        "-borderwidth",    "borderWidth",    "BorderWidth",
      DEF_PLFRAME_BORDER_WIDTH, Tk_Offset( PlFrame, borderWidth ), 0, NULL },
    { TK_CONFIG_ACTIVE_CURSOR, "-cursor",         "cursor",         "Cursor",
      DEF_PLFRAME_CURSOR, Tk_Offset( PlFrame, cursor ), TK_CONFIG_NULL_OK, NULL },
    { TK_CONFIG_STRING,        "-bopcmd",         "bopcmd",         "PgCommand",
      (char *) NULL, Tk_Offset( PlFrame, bopCmd ), TK_CONFIG_NULL_OK, NULL },
    { TK_CONFIG_STRING,        "-eopcmd",         "eopcmd",         "PgCommand",
      (char *) NULL, Tk_Offset( PlFrame, eopCmd ), TK_CONFIG_NULL_OK, NULL },
    { TK_CONFIG_PIXELS,        "-height",         "height",         "Height",
      DEF_PLFRAME_HEIGHT, Tk_Offset( PlFrame, height ), 0, NULL },
    { TK_CONFIG_RELIEF,        "-relief",         "relief",         "Relief",
      DEF_PLFRAME_RELIEF, Tk_Offset( PlFrame, relief ), 0, NULL },
    { TK_CONFIG_PIXELS,        "-width",          "width",          "Width",
      DEF_PLFRAME_WIDTH, Tk_Offset( PlFrame, width ), 0, NULL },
    { TK_CONFIG_BOOLEAN,       "-xhairs",         (char *) NULL,    (char *) NULL,
      "0", Tk_Offset( PlFrame, xhairs ), TK_CONFIG_DONT_SET_DEFAULT, NULL },
    { TK_CONFIG_BOOLEAN,       "-rubberband",     (char *) NULL,    (char *) NULL,
      "0", Tk_Offset( PlFrame, rband ), TK_CONFIG_DONT_SET_DEFAULT, NULL },
    { TK_CONFIG_STRING,        "-xscrollcommand", "xScrollCommand", "ScrollCommand",
      (char *) NULL, Tk_Offset( PlFrame, xScrollCmd ), TK_CONFIG_NULL_OK, NULL },
    { TK_CONFIG_STRING,        "-yscrollcommand", "yScrollCommand", "ScrollCommand",
      (char *) NULL, Tk_Offset( PlFrame, yScrollCmd ), TK_CONFIG_NULL_OK, NULL },
    { TK_CONFIG_END,           (char *) NULL,     (char *) NULL,    (char *) NULL,
      (char *) NULL, 0, 0, NULL }
};

// Forward declarations for procedures defined later in this file:

// Externals

int   plFrameCmd( ClientData, Tcl_Interp *, int, const char ** );

// These are invoked by the TK dispatcher

#if TK_MAJOR_VERSION < 4 || ( TK_MAJOR_VERSION == 4 && TK_MINOR_VERSION == 0 )
#define FreeProcArg    ClientData
#else
#define FreeProcArg    char *
#endif

static void  DestroyPlFrame( FreeProcArg );
static void  DisplayPlFrame( ClientData );
static void  PlFrameInit( ClientData );
static void  PlFrameConfigureEH( ClientData, XEvent * );
static void  PlFrameExposeEH( ClientData, XEvent * );
static void  PlFrameMotionEH( ClientData, register XEvent * );
static void  PlFrameEnterEH( ClientData, register XEvent * );
static void  PlFrameLeaveEH( ClientData, register XEvent * );
static void  PlFrameKeyEH( ClientData, register XEvent * );
static int   PlFrameWidgetCmd( ClientData, Tcl_Interp *, int, const char ** );
static int   ReadData( ClientData, int );
static void  Install_cmap( PlFrame *plFramePtr );

// These are invoked by PlFrameWidgetCmd to process widget commands

static int   Closelink( Tcl_Interp *, PlFrame *, int, const char ** );
static int   Cmd( Tcl_Interp *, PlFrame *, int, const char ** );
static int   ColorManip( Tcl_Interp *, PlFrame *, int, const char ** );
static int   ConfigurePlFrame( Tcl_Interp *, PlFrame *, int, const char **, int );
static int   Draw( Tcl_Interp *, PlFrame *, int, const char ** );
static int   Info( Tcl_Interp *, PlFrame *, int, const char ** );
static int   Openlink( Tcl_Interp *, PlFrame *, int, const char ** );
static int   Orient( Tcl_Interp *, PlFrame *, int, const char ** );
static int   Page( Tcl_Interp *, PlFrame *, int, const char ** );
static int   Print( Tcl_Interp *, PlFrame *, int, const char ** );
static int   Redraw( Tcl_Interp *, PlFrame *, int, const char ** );
static int   Save( Tcl_Interp *, PlFrame *, int, const char ** );
static int   View( Tcl_Interp *, PlFrame *, int, const char ** );
static int   xScroll( Tcl_Interp *, PlFrame *, int, const char ** );
static int   yScroll( Tcl_Interp *, PlFrame *, int, const char ** );
static int   report( Tcl_Interp *, PlFrame *, int, const char ** );

// Routines for manipulating graphic crosshairs

static void  CreateXhairs( PlFrame * );
static void  DestroyXhairs( PlFrame * );
static void  DrawXhairs( PlFrame *, int, int );
static void  UpdateXhairs( PlFrame * );

// Routines for manipulating the rubberband line

static void  CreateRband( PlFrame * );
static void  DestroyRband( PlFrame * );
static void  DrawRband( PlFrame *, int, int );
static void  UpdateRband( PlFrame * );

// Callbacks from plplot library

static void  process_bop( void *, int * );
static void  process_eop( void *, int * );

// Utility routines

static void  gbox( PLFLT *, PLFLT *, PLFLT *, PLFLT *, const char ** );
static void  UpdateVScrollbar( register PlFrame * );
static void  UpdateHScrollbar( register PlFrame * );

//
//--------------------------------------------------------------------------
//
// plFrameCmd --
//
//	This procedure is invoked to process the "plframe" Tcl
//	command.  See the user documentation for details on what it
//	does.
//
// Results:
//	A standard Tcl result.
//
// Side effects:
//	See the user documentation.
//
//--------------------------------------------------------------------------
//

int
plFrameCmd( ClientData PL_UNUSED( clientData ), Tcl_Interp *interp,
            int argc, const char **argv )
{
    Tk_Window        new;
    register PlFrame *plFramePtr;
    register PLRDev  *plr;
    int i, ndev;

    dbug_enter( "plFrameCmd" );

    if ( argc < 2 )
    {
        Tcl_AppendResult( interp, "wrong # args: should be \"",
            argv[0], " pathName ?options?\"", (char *) NULL );
        return TCL_ERROR;
    }

// Create the window.

    new = Tk_CreateWindowFromPath( interp, Tk_MainWindow( interp ),
        argv[1], (char *) NULL );
    if ( new == NULL )
    {
        return TCL_ERROR;
    }

    plFramePtr = (PlFrame *) ckalloc( sizeof ( PlFrame ) );

    // Initialize in the same order as the members of the struct just
    // to keep track of what is initialized and what not.

    plFramePtr->tkwin   = new;
    plFramePtr->display = Tk_Display( new );
    plFramePtr->interp  = interp;
    //plFramePtr->widgetCMD    = <initialized below for HAVE_ITCL case>
    plFramePtr->border = NULL;
    //plFramePtr->borderWidth  = <uninitialized>
    //plFramePtr->relief       = <uninitialized>
    plFramePtr->width         = Tk_Width( plFramePtr->tkwin );
    plFramePtr->height        = Tk_Height( plFramePtr->tkwin );
    plFramePtr->cursor        = None;
    plFramePtr->flags         = 0;
    plFramePtr->tkwin_initted = 0;
    // Associate new PLplot stream with this widget
    plmkstrm( &plFramePtr->ipls );
    plgpls( &plFramePtr->pls );
    plFramePtr->ipls_save    = 0;
    plFramePtr->plr          = (PLRDev *) ckalloc( sizeof ( PLRDev ) );
    plFramePtr->bgColor      = NULL;
    plFramePtr->plpr_cmd     = NULL;
    plFramePtr->pldis.x      = 0;
    plFramePtr->pldis.y      = 0;
    plFramePtr->pldis.width  = 0;
    plFramePtr->pldis.height = 0;
    plFramePtr->prevWidth    = 0;
    plFramePtr->prevHeight   = 0;
    plFramePtr->SaveFnam     = NULL;
    // plFramePtr->devDesc     = <uninitialized, to be malloced?>;
    // plFramePtr->devName     = <uninitialized, to be malloced?>;
    plFramePtr->xorGC = NULL;
    // plFram Ptr->pts         = <uninitialized array>;
    plFramePtr->continue_draw  = 0;
    plFramePtr->xhair_cursor   = None;
    plFramePtr->xl             = 0.;
    plFramePtr->yl             = 0.;
    plFramePtr->xr             = 1.;
    plFramePtr->yr             = 1.;
    plFramePtr->xScrollCmd     = NULL;
    plFramePtr->yScrollCmd     = NULL;
    plFramePtr->bopCmd         = NULL;
    plFramePtr->eopCmd         = NULL;
    plFramePtr->xhairs         = 0;
    plFramePtr->drawing_xhairs = 0;
    // plFram Ptr->xhair_x     = <uninitialized array>;
    // plFram Ptr->xhair_y     = <uninitialized array>;
    plFramePtr->rband         = 0;
    plFramePtr->drawing_rband = 0;
    // plFram Ptr->rband_pt    = <uninitialized array>;

    plr         = plFramePtr->plr;
    plr->pdfs   = NULL;
    plr->at_bop = 0;
    plr->at_eop = 0;
    plr->iodev  = (PLiodev *) ckalloc( sizeof ( PLiodev ) );
    plr_start( plr );

// Set up stuff for rubber-band drawing

    plFramePtr->xhair_cursor =
        Tk_GetCursor( plFramePtr->interp, plFramePtr->tkwin, "crosshair" );

// Partially initialize X driver.

    pllib_init();

    plsdev( "xwin" );
    pllib_devinit();
    plP_esc( PLESC_DEVINIT, NULL );

// Create list of valid device names and keywords for page dumps

    plFramePtr->devDesc = (const char **) ckalloc( NDEV * sizeof ( char ** ) );
    plFramePtr->devName = (const char **) ckalloc( NDEV * sizeof ( char ** ) );
    for ( i = 0; i < NDEV; i++ )
    {
        plFramePtr->devDesc[i] = NULL;
        plFramePtr->devName[i] = NULL;
    }
    ndev = NDEV;
    plgFileDevs( &plFramePtr->devDesc, &plFramePtr->devName, &ndev );

// Start up event handlers and other good stuff

    Tk_SetClass( plFramePtr->tkwin, "Plframe" );

    Tk_CreateEventHandler( plFramePtr->tkwin, StructureNotifyMask,
        PlFrameConfigureEH, (ClientData) plFramePtr );

    Tk_CreateEventHandler( plFramePtr->tkwin, ExposureMask,
        PlFrameExposeEH, (ClientData) plFramePtr );

#ifdef HAVE_ITCL
    plFramePtr->widgetCmd =
#endif
    Tcl_CreateCommand( interp, Tk_PathName( plFramePtr->tkwin ),
        (Tcl_CmdProc *) PlFrameWidgetCmd, (ClientData) plFramePtr, (Tcl_CmdDeleteProc *) NULL );
#ifdef HAVE_ITCL
    Itk_SetWidgetCommand( plFramePtr->tkwin, plFramePtr->widgetCmd );
#endif

    if ( ConfigurePlFrame( interp, plFramePtr, argc - 2, argv + 2, 0 ) != TCL_OK )
    {
#ifdef HAVE_ITCL
        Itk_SetWidgetCommand( plFramePtr->tkwin, (Tcl_Command) NULL );
#endif
        Tk_DestroyWindow( plFramePtr->tkwin );
        return TCL_ERROR;
    }
    Tcl_SetResult( interp, Tk_PathName( plFramePtr->tkwin ), TCL_VOLATILE );

    return TCL_OK;
}

//
//--------------------------------------------------------------------------
//
// PlFrameWidgetCmd --
//
//	This procedure is invoked to process the Tcl command that
//	corresponds to a plframe widget.  See the user
//	documentation for details on what it does.
//
// Results:
//	A standard Tcl result.
//
// Side effects:
//	See the user documentation.
//
//--------------------------------------------------------------------------
//

static int
PlFrameWidgetCmd( ClientData clientData, Tcl_Interp *interp,
                  int argc, const char **argv )
{
    register PlFrame *plFramePtr = (PlFrame *) clientData;
    int  result = TCL_OK;
    int  length;
    char c;
    char res[20];

    dbug_enter( "PlFrameWidgetCmd" );

#ifdef DEBUG
    {
        int      i;
        PLStream *pls;
        plgpls( pls );
        printf( "Current stream %d, frame stream %d\n",
            pls->ipls, plFramePtr->ipls );
        printf( "PlFrameWidgetCmd: " );
        for ( i = 0; i < argc; i++ )
            printf( " %s", argv[i] );
        printf( "\n" );
    }
#endif

    if ( argc < 2 )
    {
        Tcl_AppendResult( interp, "wrong # args: should be \"",
            argv[0], " option ?arg arg ...?\"", (char *) NULL );
        return TCL_ERROR;
    }
    Tk_Preserve( (ClientData) plFramePtr );
    c      = argv[1][0];
    length = (int) strlen( argv[1] );

// First, before anything else, we have to set the stream to be the one that
// corresponds to this widget.
    plsstrm( plFramePtr->ipls );

// cmd -- issue a command to the PLplot library

    if ( ( c == 'c' ) && ( strncmp( argv[1], "cmd", (size_t) length ) == 0 ) )
    {
        result = Cmd( interp, plFramePtr, argc - 2, argv + 2 );
    }

// cget

    else if ( ( c == 'c' ) && ( strncmp( argv[1], "cget", (size_t) length ) == 0 ) )
    {
        if ( argc > 2 )
        {
            Tcl_AppendResult( interp, "wrong # args: should be \"",
                argv[0], " cget <option>\"", (char *) NULL );
            result = TCL_ERROR;
            goto done;
        }
        else
        {
            result = Tk_ConfigureInfo( interp, plFramePtr->tkwin, configSpecs,
                (char *) plFramePtr, (char *) NULL, 0 );
        }
    }

// configure

    else if ( ( c == 'c' ) && ( strncmp( argv[1], "configure", (size_t) length ) == 0 ) )
    {
        if ( argc == 2 )
        {
            result = Tk_ConfigureInfo( interp, plFramePtr->tkwin, configSpecs,
                (char *) plFramePtr, (char *) NULL, 0 );
        }
        else if ( argc == 3 )
        {
            result = Tk_ConfigureInfo( interp, plFramePtr->tkwin, configSpecs,
                (char *) plFramePtr, argv[2], 0 );
        }
        else
        {
            result = ConfigurePlFrame( interp, plFramePtr, argc - 2, argv + 2,
                TK_CONFIG_ARGV_ONLY );
        }
    }

// double buffering

    else if ( ( c == 'd' ) &&
              ( ( strncmp( argv[1], "db", (size_t) length ) == 0 ) ||
                ( strncmp( argv[1], "doublebuffering", (size_t) length == 0 ) ) ) )
    {
        PLBufferingCB bcb;

        if ( argc == 3 )
        {
            if ( strcmp( argv[2], "on" ) == 0 )
            {
                bcb.cmd = PLESC_DOUBLEBUFFERING_ENABLE;
                pl_cmd( PLESC_DOUBLEBUFFERING, &bcb );
            }
            if ( strcmp( argv[2], "off" ) == 0 )
            {
                bcb.cmd = PLESC_DOUBLEBUFFERING_DISABLE;
                pl_cmd( PLESC_DOUBLEBUFFERING, &bcb );
            }
            if ( strcmp( argv[2], "query" ) == 0 )
            {
                bcb.cmd = PLESC_DOUBLEBUFFERING_QUERY;
                pl_cmd( PLESC_DOUBLEBUFFERING, &bcb );
                snprintf( res, 20, "%d", bcb.result );
                Tcl_SetResult( interp, res, TCL_VOLATILE );
            }
        }

        result = TCL_OK;
    }

// closelink -- Close a binary data link previously opened with openlink

    else if ( ( c == 'c' ) && ( strncmp( argv[1], "closelink", (size_t) length ) == 0 ) )
    {
        if ( argc > 2 )
        {
            Tcl_AppendResult( interp, "wrong # args: should be \"",
                argv[0], (char *) NULL );
            result = TCL_ERROR;
            goto done;
        }
        else
        {
            result = Closelink( interp, plFramePtr, argc - 2, argv + 2 );
        }
    }

// draw -- rubber-band draw used in region selection

    else if ( ( c == 'd' ) && ( strncmp( argv[1], "draw", (size_t) length ) == 0 ) )
    {
        if ( argc == 2 )
        {
            Tcl_AppendResult( interp, "wrong # args: should be \"",
                argv[0], " draw op ?options?\"", (char *) NULL );
            result = TCL_ERROR;
            goto done;
        }
        else
        {
            result = Draw( interp, plFramePtr, argc - 2, argv + 2 );
        }
    }

// color-manipulating commands, grouped together for convenience

    else if ( ( ( c == 'g' ) && ( ( strncmp( argv[1], "gcmap0", (size_t) length ) == 0 ) ||
                                  ( strncmp( argv[1], "gcmap1", (size_t) length ) == 0 ) ) ) ||
              ( ( c == 's' ) && ( ( strncmp( argv[1], "scmap0", (size_t) length ) == 0 ) ||
                                  ( strncmp( argv[1], "scmap1", (size_t) length ) == 0 ) ||
                                  ( strncmp( argv[1], "scol0", (size_t) length ) == 0 ) ||
                                  ( strncmp( argv[1], "scol1", (size_t) length ) == 0 ) ) ) )
        result = ColorManip( interp, plFramePtr, argc - 1, argv + 1 );

// info -- returns requested info

    else if ( ( c == 'i' ) && ( strncmp( argv[1], "info", (size_t) length ) == 0 ) )
    {
        result = Info( interp, plFramePtr, argc - 2, argv + 2 );
    }

// orient -- Set plot orientation

    else if ( ( c == 'o' ) && ( strncmp( argv[1], "orient", (size_t) length ) == 0 ) )
    {
        result = Orient( interp, plFramePtr, argc - 2, argv + 2 );
    }

// openlink -- Open a binary data link (FIFO or socket)

    else if ( ( c == 'o' ) && ( strncmp( argv[1], "openlink", (size_t) length ) == 0 ) )
    {
        if ( argc < 3 )
        {
            Tcl_AppendResult( interp, "wrong # args: should be \"",
                argv[0], " option ?arg arg ...?\"", (char *) NULL );
            result = TCL_ERROR;
            goto done;
        }
        else
        {
            result = Openlink( interp, plFramePtr, argc - 2, argv + 2 );
        }
    }

// page -- change or return output page setup

    else if ( ( c == 'p' ) && ( strncmp( argv[1], "page", (size_t) length ) == 0 ) )
    {
        result = Page( interp, plFramePtr, argc - 2, argv + 2 );
    }

// print -- prints plot

    else if ( ( c == 'p' ) && ( strncmp( argv[1], "print", (size_t) length ) == 0 ) )
    {
        result = Print( interp, plFramePtr, argc - 2, argv + 2 );
    }

// redraw -- redraw plot

    else if ( ( c == 'r' ) && ( strncmp( argv[1], "redraw", (size_t) length ) == 0 ) )
    {
        if ( argc > 2 )
        {
            Tcl_AppendResult( interp, "wrong # args: should be \"",
                argv[0], " redraw\"", (char *) NULL );
            result = TCL_ERROR;
            goto done;
        }
        else
        {
            result = Redraw( interp, plFramePtr, argc - 2, argv + 2 );
        }
    }

// report -- find out useful info about the plframe (GMF)

    else if ( ( c == 'r' ) && ( strncmp( argv[1], "report", (size_t) length ) == 0 ) )
    {
        result = report( interp, plFramePtr, argc - 2, argv + 2 );
    }

// save -- saves plot to the specified plot file type

    else if ( ( c == 's' ) && ( strncmp( argv[1], "save", (size_t) length ) == 0 ) )
    {
        result = Save( interp, plFramePtr, argc - 2, argv + 2 );
    }

// view -- change or return window into plot

    else if ( ( c == 'v' ) && ( strncmp( argv[1], "view", (size_t) length ) == 0 ) )
    {
        result = View( interp, plFramePtr, argc - 2, argv + 2 );
    }

// xscroll -- horizontally scroll window into plot

    else if ( ( c == 'x' ) && ( strncmp( argv[1], "xscroll", (size_t) length ) == 0 ) )
    {
        if ( argc == 2 || argc > 3 )
        {
            Tcl_AppendResult( interp, "wrong # args: should be \"",
                argv[0], " xscroll pixel\"", (char *) NULL );
            result = TCL_ERROR;
            goto done;
        }
        else
        {
            result = xScroll( interp, plFramePtr, argc - 2, argv + 2 );
        }
    }

// yscroll -- vertically scroll window into plot

    else if ( ( c == 'y' ) && ( strncmp( argv[1], "yscroll", (size_t) length ) == 0 ) )
    {
        if ( argc == 2 || argc > 3 )
        {
            Tcl_AppendResult( interp, "wrong # args: should be \"",
                argv[0], " yscroll pixel\"", (char *) NULL );
            result = TCL_ERROR;
            goto done;
        }
        else
        {
            result = yScroll( interp, plFramePtr, argc - 2, argv + 2 );
        }
    }

// unrecognized widget command

    else
    {
        Tcl_AppendResult( interp, "bad option \"", argv[1],
            "\":  must be closelink, cmd, configure, draw, ",
            "gcmap0, gcmap1, ",
            "info, openlink, orient, page, print, redraw, save, ",
            "scmap0, scmap1, scol0, scol1, ",
            "view, xscroll, or yscroll", (char *) NULL );

        result = TCL_ERROR;
#ifdef DEBUG
        printf( "bad option!\n" );
#endif
    }

#ifdef DEBUG
    printf( "result=%d current stream=%d\n", result, plsc->ipls );
#endif

done:
    Tk_Release( (ClientData) plFramePtr );
    return result;
}

//
//--------------------------------------------------------------------------
//
// DestroyPlFrame --
//
//	This procedure is invoked by Tk_EventuallyFree or Tk_Release to
//	clean up the internal structure of a plframe at a safe time
//	(when no-one is using it anymore).
//
// Results:
//	None.
//
// Side effects:
//	Everything associated with the plframe is freed up.
//
//--------------------------------------------------------------------------
//

static void
DestroyPlFrame( FreeProcArg clientData )
{
    register PlFrame *plFramePtr = (PlFrame *) clientData;
    register PLRDev  *plr        = plFramePtr->plr;

    dbug_enter( "DestroyPlFrame" );

    if ( plFramePtr->border != NULL )
    {
        Tk_Free3DBorder( plFramePtr->border );
    }
    if ( plFramePtr->bgColor != NULL )
    {
        Tk_FreeColor( plFramePtr->bgColor );
    }
    if ( plFramePtr->plpr_cmd != NULL )
    {
        ckfree( (char *) plFramePtr->plpr_cmd );
    }
    if ( plFramePtr->cursor != None )
    {
        Tk_FreeCursor( plFramePtr->display, plFramePtr->cursor );
    }
    if ( plFramePtr->xhair_cursor != None )
    {
        Tk_FreeCursor( plFramePtr->display, plFramePtr->xhair_cursor );
    }
    if ( plFramePtr->xorGC != NULL )
    {
        Tk_FreeGC( plFramePtr->display, plFramePtr->xorGC );
    }
    if ( plFramePtr->yScrollCmd != NULL )
    {
        ckfree( (char *) plFramePtr->yScrollCmd );
    }
    if ( plFramePtr->xScrollCmd != NULL )
    {
        ckfree( (char *) plFramePtr->xScrollCmd );
    }
    if ( plFramePtr->SaveFnam != NULL )
    {
        ckfree( (char *) plFramePtr->SaveFnam );
    }
    if ( plFramePtr->devDesc != NULL )
    {
        ckfree( (char *) plFramePtr->devDesc );
    }
    if ( plFramePtr->devName != NULL )
    {
        ckfree( (char *) plFramePtr->devName );
    }

// Clean up data connection

    pdf_close( plr->pdfs );
    ckfree( (char *) plFramePtr->plr->iodev );

// Tell PLplot to clean up

    plsstrm( plFramePtr->ipls );
    plend1();

// Delete main data structures

    ckfree( (char *) plFramePtr->plr );
    ckfree( (char *) plFramePtr );
}

//
//--------------------------------------------------------------------------
//
// PlFrameConfigureEH --
//
//	Invoked by the Tk dispatcher on structure changes to a plframe.
//
// Results:
//	None.
//
// Side effects:
//	When the window gets deleted, internal structures get cleaned up.
//	When it gets resized, it is redrawn.
//
//--------------------------------------------------------------------------
//

static void
PlFrameConfigureEH( ClientData clientData, register XEvent *eventPtr )
{
    register PlFrame   *plFramePtr = (PlFrame *) clientData;
    register Tk_Window tkwin       = plFramePtr->tkwin;

    dbug_enter( "PlFrameConfigureEH" );

    switch ( eventPtr->type )
    {
    case ConfigureNotify:
        pldebug( "PLFrameConfigureEH", "ConfigureNotify\n" );
        plFramePtr->flags |= RESIZE_PENDING;
        plFramePtr->width  = Tk_Width( tkwin );
        plFramePtr->height = Tk_Height( tkwin );
        if ( ( tkwin != NULL ) && !( plFramePtr->flags & REFRESH_PENDING ) )
        {
            Tk_DoWhenIdle( DisplayPlFrame, (ClientData) plFramePtr );
            plFramePtr->flags |= REFRESH_PENDING;
            plFramePtr->flags |= UPDATE_V_SCROLLBAR | UPDATE_H_SCROLLBAR;
        }
        break;

    case DestroyNotify:
        pldebug( "PLFrameConfigureEH", "DestroyNotify\n" );
#ifdef HAVE_ITCL
        Itk_SetWidgetCommand( plFramePtr->tkwin, (Tcl_Command) NULL );
        Tcl_DeleteCommand2( plFramePtr->interp, plFramePtr->widgetCmd );
#else
        Tcl_DeleteCommand( plFramePtr->interp, Tk_PathName( tkwin ) );
#endif
        plFramePtr->tkwin = NULL;
        if ( plFramePtr->flags & REFRESH_PENDING )
        {
            Tk_CancelIdleCall( DisplayPlFrame, (ClientData) plFramePtr );
        }
        Tk_EventuallyFree( (ClientData) plFramePtr, DestroyPlFrame );
        break;

    case MapNotify:
        pldebug( "PLFrameConfigureEH", "MapNotify\n" );
        if ( plFramePtr->flags & REFRESH_PENDING )
        {
            Tk_CancelIdleCall( DisplayPlFrame, (ClientData) plFramePtr );
        }

        // For some reason, "." must be mapped or PlFrameInit will die (Note:
        // mapped & withdrawn or mapped in the withdrawn state is OK). Issuing
        // an update fixes this.  I'd love to know why this occurs.
        //

        if ( !plFramePtr->tkwin_initted )
        {
            Tcl_VarEval( plFramePtr->interp, "update", (char *) NULL );
        }
        Tk_DoWhenIdle( PlFrameInit, (ClientData) plFramePtr );
        break;
    }
}

//
//--------------------------------------------------------------------------
//
// PlFrameExposeEH --
//
//	Invoked by the Tk dispatcher on exposes of a plframe.
//
// Results:
//	None.
//
// Side effects:
//	Widget is redisplayed.
//
// Note: it's customary in Tk to collapse multiple exposes, so for best
// performance without losing the window contents, I keep track of the
// smallest single rectangle that can satisfy all expose events.  If there
// are any overlaid graphics (like crosshairs), however, we need to refresh
// the entire plot in order to have a predictable outcome.
//
//--------------------------------------------------------------------------

static void
PlFrameExposeEH( ClientData clientData, register XEvent *eventPtr )
{
    register PlFrame   *plFramePtr = (PlFrame *) clientData;
    XExposeEvent       *event      = (XExposeEvent *) eventPtr;
    register Tk_Window tkwin       = plFramePtr->tkwin;

    dbug_enter( "PlFrameExposeEH" );

    pldebug( "PLFrameExposeEH", "Expose\n" );

// Set up the area to refresh

    if ( !( plFramePtr->drawing_xhairs || plFramePtr->drawing_rband ) )
    {
        int x0_old, x1_old, y0_old, y1_old, x0_new, x1_new, y0_new, y1_new;

        x0_old = (int) plFramePtr->pldis.x;
        y0_old = (int) plFramePtr->pldis.y;
        x1_old = x0_old + (int) plFramePtr->pldis.width;
        y1_old = y0_old + (int) plFramePtr->pldis.height;

        x0_new = event->x;
        y0_new = event->y;
        x1_new = x0_new + event->width;
        y1_new = y0_new + event->height;

        plFramePtr->pldis.x      = (unsigned int) MIN( x0_old, x0_new );
        plFramePtr->pldis.y      = (unsigned int) MIN( y0_old, y0_new );
        plFramePtr->pldis.width  = (unsigned int) MAX( x1_old, x1_new ) - plFramePtr->pldis.x;
        plFramePtr->pldis.height = (unsigned int) MAX( y1_old, y1_new ) - plFramePtr->pldis.y;
    }

// Invoke DoWhenIdle handler to redisplay widget.

    if ( event->count == 0 )
    {
        if ( ( tkwin != NULL ) && !( plFramePtr->flags & REFRESH_PENDING ) )
        {
            Tk_DoWhenIdle( DisplayPlFrame, (ClientData) plFramePtr );
            plFramePtr->width  = Tk_Width( tkwin );
            plFramePtr->height = Tk_Height( tkwin );
            plFramePtr->flags |= REFRESH_PENDING;
        }
    }
}

//
//--------------------------------------------------------------------------
//
// PlFrameMotionEH --
//
//	Invoked by the Tk dispatcher on MotionNotify events in a plframe.
//	Not invoked unless we are drawing graphic crosshairs.
//
// Results:
//	None.
//
// Side effects:
//	Graphic crosshairs are drawn.
//
//--------------------------------------------------------------------------
//

static void
PlFrameMotionEH( ClientData clientData, register XEvent *eventPtr )
{
    register PlFrame *plFramePtr = (PlFrame *) clientData;
    XMotionEvent     *event      = (XMotionEvent *) eventPtr;

    dbug_enter( "PlFrameMotionEH" );

    if ( plFramePtr->drawing_xhairs )
    {
        DrawXhairs( plFramePtr, event->x, event->y );
    }
    if ( plFramePtr->drawing_rband )
    {
        DrawRband( plFramePtr, event->x, event->y );
    }
}

//
//--------------------------------------------------------------------------
//
// PlFrameEnterEH --
//
//	Invoked by the Tk dispatcher on EnterNotify events in a plframe.
//	Not invoked unless we are drawing graphic crosshairs.
//
// Results:
//	None.
//
// Side effects:
//	Graphic crosshairs are updated.
//
//--------------------------------------------------------------------------

static void
PlFrameEnterEH( ClientData clientData, register XEvent *eventPtr )
{
    register PlFrame *plFramePtr    = (PlFrame *) clientData;
    XCrossingEvent   *crossingEvent = (XCrossingEvent *) eventPtr;

    dbug_enter( "PlFrameEnterEH" );

    if ( plFramePtr->xhairs )
    {
        DrawXhairs( plFramePtr, crossingEvent->x, crossingEvent->y );
        plFramePtr->drawing_xhairs = 1;
    }
    if ( plFramePtr->rband )
    {
        plFramePtr->drawing_rband = 1;
        UpdateRband( plFramePtr );
        DrawRband( plFramePtr, crossingEvent->x, crossingEvent->y );
    }
}

//
//--------------------------------------------------------------------------
//
// PlFrameLeaveEH --
//
//	Invoked by the Tk dispatcher on LeaveNotify events in a plframe.
//	Not invoked unless we are drawing graphic crosshairs.
//
// Results:
//	None.
//
// Side effects:
//	Graphic crosshairs are updated.
//
//--------------------------------------------------------------------------

static void
PlFrameLeaveEH( ClientData clientData, register XEvent * PL_UNUSED( eventPtr ) )
{
    register PlFrame *plFramePtr = (PlFrame *) clientData;

    dbug_enter( "PlFrameLeaveEH" );

    if ( plFramePtr->drawing_xhairs )
    {
        UpdateXhairs( plFramePtr );
        plFramePtr->drawing_xhairs = 0;
    }
    if ( plFramePtr->drawing_rband )
    {
        UpdateRband( plFramePtr );
        plFramePtr->drawing_rband = 0;
    }
}

//
//--------------------------------------------------------------------------
//
// PlFrameKeyEH --
//
//	Invoked by the Tk dispatcher on Keypress events in a plframe.
//	Not invoked unless we are drawing graphic crosshairs.
//
// Results:
//	None.
//
// Side effects:
//	Keypress events get filtered.  If a cursor key is pushed, the
//	graphic crosshairs are moved in the appropriate direction.  Using a
//	modifier key multiplies the movement a factor of 5 for each key
//	added.
//
//--------------------------------------------------------------------------
//

static void
PlFrameKeyEH( ClientData clientData, register XEvent *eventPtr )
{
    register PlFrame   *plFramePtr = (PlFrame *) clientData;
    XKeyEvent          *event      = (XKeyEvent *) eventPtr;
    register Tk_Window tkwin       = plFramePtr->tkwin;

    KeySym             keysym;
    int            nchars;
    char           string[11];
    XComposeStatus cs;

    dbug_enter( "PlFrameKeyEH" );

#if !defined ( _WIN32 )
    nchars = XLookupString( event, string, 10, &keysym, &cs );
#else
    nchars = 0;
#endif
    string[nchars] = '\0';
    pldebug( "PlFrameKeyEH", "Keysym %x, translation: %s\n", keysym, string );

    if ( IsModifierKey( keysym ) )
    {
        eventPtr->type = 0;
    }
    else if ( IsCursorKey( keysym ) )
    {
        int x1, y1, dx = 0, dy = 0;
        int x0   = event->x, y0 = event->y;
        int xmin = 0, xmax = Tk_Width( tkwin ) - 1;
        int ymin = 0, ymax = Tk_Height( tkwin ) - 1;

        switch ( keysym )
        {
        case XK_Left:
            dx = -1;
            break;
        case XK_Right:
            dx = 1;
            break;
        case XK_Up:
            dy = -1;
            break;
        case XK_Down:
            dy = 1;
            break;
        }

        // Each modifier key added increases the multiplication factor by 5

        // Shift

        if ( event->state & 0x01 )
        {
            dx *= 5;
            dy *= 5;
        }

        // Caps Lock

        if ( event->state & 0x02 )
        {
            dx *= 5;
            dy *= 5;
        }

        // Control

        if ( event->state & 0x04 )
        {
            dx *= 5;
            dy *= 5;
        }

        // Alt

        if ( event->state & 0x08 )
        {
            dx *= 5;
            dy *= 5;
        }

        // Bounds checking so that we don't send cursor out of window

        x1 = x0 + dx;
        y1 = y0 + dy;

        if ( x1 < xmin )
            dx = xmin - x0;
        if ( y1 < ymin )
            dy = ymin - y0;
        if ( x1 > xmax )
            dx = xmax - x0;
        if ( y1 > ymax )
            dy = ymax - y0;

        // Engage...

        XWarpPointer( plFramePtr->display, Tk_WindowId( tkwin ),
            None, 0, 0, 0, 0, dx, dy );
        eventPtr->type = 0;
    }
}

//--------------------------------------------------------------------------
// CreateXhairs()
//
// Creates graphic crosshairs at current pointer location.
//--------------------------------------------------------------------------

static void
CreateXhairs( PlFrame *plFramePtr )
{
    register Tk_Window tkwin = plFramePtr->tkwin;
    Window             root, child;
    int root_x, root_y, win_x, win_y;
    unsigned int       mask;

// Switch to crosshair cursor.

    Tk_DefineCursor( tkwin, plFramePtr->xhair_cursor );

// Find current pointer location and draw graphic crosshairs if pointer is
// inside our window.

    if ( XQueryPointer( plFramePtr->display, Tk_WindowId( tkwin ),
             &root, &child, &root_x, &root_y, &win_x, &win_y,
             &mask ) )
    {
        if ( win_x >= 0 && win_x < Tk_Width( tkwin ) &&
             win_y >= 0 && win_y < Tk_Height( tkwin ) )
        {
            DrawXhairs( plFramePtr, win_x, win_y );
            plFramePtr->drawing_xhairs = 1;
        }
    }

// Catch PointerMotion and crossing events so we can update them properly

    if ( !plFramePtr->drawing_rband )
    {
        Tk_CreateEventHandler( tkwin, PointerMotionMask,
            PlFrameMotionEH, (ClientData) plFramePtr );

        Tk_CreateEventHandler( tkwin, EnterWindowMask,
            PlFrameEnterEH, (ClientData) plFramePtr );

        Tk_CreateEventHandler( tkwin, LeaveWindowMask,
            PlFrameLeaveEH, (ClientData) plFramePtr );
    }

// Catch KeyPress events so we can filter them

    Tk_CreateEventHandler( tkwin, KeyPressMask,
        PlFrameKeyEH, (ClientData) plFramePtr );
}

//--------------------------------------------------------------------------
// DestroyXhairs()
//
// Destroys graphic crosshairs.
//--------------------------------------------------------------------------

static void
DestroyXhairs( PlFrame *plFramePtr )
{
    register Tk_Window tkwin = plFramePtr->tkwin;

// Switch back to boring old pointer

    Tk_DefineCursor( tkwin, plFramePtr->cursor );

// Don't catch PointerMotion or crossing events any more

    if ( !plFramePtr->drawing_rband )
    {
        Tk_DeleteEventHandler( tkwin, PointerMotionMask,
            PlFrameMotionEH, (ClientData) plFramePtr );

        Tk_DeleteEventHandler( tkwin, EnterWindowMask,
            PlFrameEnterEH, (ClientData) plFramePtr );

        Tk_DeleteEventHandler( tkwin, LeaveWindowMask,
            PlFrameLeaveEH, (ClientData) plFramePtr );
    }

    Tk_DeleteEventHandler( tkwin, KeyPressMask,
        PlFrameKeyEH, (ClientData) plFramePtr );

// This draw removes the last set of graphic crosshairs

    UpdateXhairs( plFramePtr );
    plFramePtr->drawing_xhairs = 0;
}

//--------------------------------------------------------------------------
// DrawXhairs()
//
// Draws graphic crosshairs at (x0, y0).  The first draw erases the old set.
//--------------------------------------------------------------------------

static void
DrawXhairs( PlFrame *plFramePtr, int x0, int y0 )
{
    register Tk_Window tkwin = plFramePtr->tkwin;
    int xmin = 0, xmax = Tk_Width( tkwin ) - 1;
    int ymin = 0, ymax = Tk_Height( tkwin ) - 1;

    if ( plFramePtr->drawing_xhairs )
        UpdateXhairs( plFramePtr );

    plFramePtr->xhair_x[0].x = (short) xmin; plFramePtr->xhair_x[0].y = (short) y0;
    plFramePtr->xhair_x[1].x = (short) xmax; plFramePtr->xhair_x[1].y = (short) y0;

    plFramePtr->xhair_y[0].x = (short) x0; plFramePtr->xhair_y[0].y = (short) ymin;
    plFramePtr->xhair_y[1].x = (short) x0; plFramePtr->xhair_y[1].y = (short) ymax;

    UpdateXhairs( plFramePtr );
}

//--------------------------------------------------------------------------
// UpdateXhairs()
//
// Updates graphic crosshairs.  If already there, they are erased.
//--------------------------------------------------------------------------

static void
UpdateXhairs( PlFrame *plFramePtr )
{
    register Tk_Window tkwin = plFramePtr->tkwin;

    XDrawLines( Tk_Display( tkwin ), Tk_WindowId( tkwin ),
        plFramePtr->xorGC, plFramePtr->xhair_x, 2,
        CoordModeOrigin );

    XDrawLines( Tk_Display( tkwin ), Tk_WindowId( tkwin ),
        plFramePtr->xorGC, plFramePtr->xhair_y, 2,
        CoordModeOrigin );
}

//--------------------------------------------------------------------------
// CreateRband()
//
// Initiate rubber banding.
//--------------------------------------------------------------------------

static void
CreateRband( PlFrame *plFramePtr )
{
    register Tk_Window tkwin = plFramePtr->tkwin;
    Window             root, child;
    int root_x, root_y, win_x, win_y;
    unsigned int       mask;

// Find current pointer location, and initiate rubber banding.

    if ( XQueryPointer( plFramePtr->display, Tk_WindowId( tkwin ),
             &root, &child, &root_x, &root_y, &win_x, &win_y,
             &mask ) )
    {
        if ( win_x >= 0 && win_x < Tk_Width( tkwin ) &&
             win_y >= 0 && win_y < Tk_Height( tkwin ) )
        {
            // Okay, pointer is in our window.
            plFramePtr->rband_pt[0].x = (short) win_x;
            plFramePtr->rband_pt[0].y = (short) win_y;

            DrawRband( plFramePtr, win_x, win_y );
            plFramePtr->drawing_rband = 1;
        }
        else
        {
            // Hmm, somehow they turned it on without even being in the window.
            // Just put the anchor in top left, they'll soon realize this is a
            // mistake...

            plFramePtr->rband_pt[0].x = 0;
            plFramePtr->rband_pt[0].y = 0;

            DrawRband( plFramePtr, win_x, win_y );
            plFramePtr->drawing_rband = 1;
        }
    }

// Catch PointerMotion and crossing events so we can update them properly

    if ( !plFramePtr->drawing_xhairs )
    {
        Tk_CreateEventHandler( tkwin, PointerMotionMask,
            PlFrameMotionEH, (ClientData) plFramePtr );

        Tk_CreateEventHandler( tkwin, EnterWindowMask,
            PlFrameEnterEH, (ClientData) plFramePtr );

        Tk_CreateEventHandler( tkwin, LeaveWindowMask,
            PlFrameLeaveEH, (ClientData) plFramePtr );
    }
}

//--------------------------------------------------------------------------
// DestroyRband()
//
// Turn off rubber banding.
//--------------------------------------------------------------------------

static void
DestroyRband( PlFrame *plFramePtr )
{
    register Tk_Window tkwin = plFramePtr->tkwin;

// Don't catch PointerMotion or crossing events any more

    if ( !plFramePtr->drawing_xhairs )
    {
        Tk_DeleteEventHandler( tkwin, PointerMotionMask,
            PlFrameMotionEH, (ClientData) plFramePtr );

        Tk_DeleteEventHandler( tkwin, EnterWindowMask,
            PlFrameEnterEH, (ClientData) plFramePtr );

        Tk_DeleteEventHandler( tkwin, LeaveWindowMask,
            PlFrameLeaveEH, (ClientData) plFramePtr );
    }

// This draw removes the residual rubber band.

    UpdateRband( plFramePtr );
    plFramePtr->drawing_rband = 0;
}

//--------------------------------------------------------------------------
// DrawRband()
//
// Draws a rubber band from the anchor to the current cursor location.
//--------------------------------------------------------------------------

static void
DrawRband( PlFrame *plFramePtr, int x0, int y0 )
{
// If the line is already up, clear it.

    if ( plFramePtr->drawing_rband )
        UpdateRband( plFramePtr );

    plFramePtr->rband_pt[1].x = (short) x0; plFramePtr->rband_pt[1].y = (short) y0;

    UpdateRband( plFramePtr );
}

//--------------------------------------------------------------------------
// UpdateRband()
//
// Updates rubber band.  If already there, it is erased.
//--------------------------------------------------------------------------

static void
UpdateRband( PlFrame *plFramePtr )
{
    register Tk_Window tkwin = plFramePtr->tkwin;

    XDrawLines( Tk_Display( tkwin ), Tk_WindowId( tkwin ),
        plFramePtr->xorGC, plFramePtr->rband_pt, 2,
        CoordModeOrigin );
}

//
//--------------------------------------------------------------------------
//
// PlFrameInit --
//
//	Invoked to handle miscellaneous initialization after window gets
//	mapped.
//
// Results:
//	None.
//
// Side effects:
//	PLplot internal parameters and device driver are initialized.
//
//--------------------------------------------------------------------------

static void
PlFrameInit( ClientData clientData )
{
    register PlFrame   *plFramePtr = (PlFrame *) clientData;
    register Tk_Window tkwin       = plFramePtr->tkwin;

// Set up window parameters and arrange for window to be refreshed

    plFramePtr->flags |= REFRESH_PENDING;
    plFramePtr->flags |= UPDATE_V_SCROLLBAR | UPDATE_H_SCROLLBAR;

// First-time initialization

    if ( !plFramePtr->tkwin_initted )
    {
        plsstrm( plFramePtr->ipls );
        plsxwin( (PLINT) Tk_WindowId( tkwin ) );
        plspause( 0 );
        plinit();
// plplot_ccmap is statically defined in plxwd.h.  Note that
// xwin.c also includes that header and uses that variable.
        if ( plplot_ccmap )
        {
            Install_cmap( plFramePtr );
        }
        if ( plFramePtr->bopCmd != NULL )
            plsbopH( process_bop, (void *) plFramePtr );
        if ( plFramePtr->eopCmd != NULL )
            plseopH( process_eop, (void *) plFramePtr );

        plbop();

        plFramePtr->tkwin_initted = 1;
        plFramePtr->width         = Tk_Width( tkwin );
        plFramePtr->height        = Tk_Height( tkwin );
        plFramePtr->prevWidth     = plFramePtr->width;
        plFramePtr->prevHeight    = plFramePtr->height;
    }

// Draw plframe

    DisplayPlFrame( clientData );

    if ( plFramePtr->xhairs )
        CreateXhairs( plFramePtr );

    if ( plFramePtr->rband )
        CreateRband( plFramePtr );
}

//
//--------------------------------------------------------------------------
//
// Install_cmap --
//
//	Installs X driver color map as necessary when custom color maps
//	are used.
//
// Results:
//	None.
//
// Side effects:
//	Parent color maps may get changed.
//
//--------------------------------------------------------------------------
//

static void
Install_cmap( PlFrame *plFramePtr )
{
    XwDev *dev;

#define INSTALL_COLORMAP_IN_TK
#ifdef  INSTALL_COLORMAP_IN_TK
    dev = (XwDev *) plFramePtr->pls->dev;
    Tk_SetWindowColormap( Tk_MainWindow( plFramePtr->interp ), dev->xwd->map );

//
// If the colormap is local to this widget, the WM must be informed that
// it should be installed when the widget gets the focus.  The top level
// window must be added to the end of its own list, because otherwise the
// window manager adds it to the front (as required by the ICCCM).  Thanks
// to Paul Mackerras for providing this info in his TK photo widget.
//

#else
    int    count = 0;
    Window top, colormap_windows[5];

    top = Tk_WindowId( Tk_MainWindow( plFramePtr->interp ) );

    colormap_windows[count++] = Tk_WindowId( plFramePtr->tkwin );
    colormap_windows[count++] = top;

    if ( !XSetWMColormapWindows( plFramePtr->display,
             top, colormap_windows, count ) )
        fprintf( stderr, "Unable to set color map property!\n" );
#endif
}

//
//--------------------------------------------------------------------------
//
// DisplayPlFrame --
//
//	This procedure is invoked to display a plframe widget.
//
// Results:
//	None.
//
// Side effects:
//	Commands are output to X to display the plframe in its
//	current mode.
//
//--------------------------------------------------------------------------
//

static void
DisplayPlFrame( ClientData clientData )
{
    register PlFrame   *plFramePtr = (PlFrame *) clientData;
    register Tk_Window tkwin       = plFramePtr->tkwin;

    dbug_enter( "DisplayPlFrame" );

// Update scrollbars if needed

    if ( plFramePtr->flags & UPDATE_V_SCROLLBAR )
    {
        UpdateVScrollbar( plFramePtr );
    }
    if ( plFramePtr->flags & UPDATE_H_SCROLLBAR )
    {
        UpdateHScrollbar( plFramePtr );
    }
    plFramePtr->flags &= ~( UPDATE_V_SCROLLBAR | UPDATE_H_SCROLLBAR );

// If not mapped yet, just return and cancel pending refresh

    if ( ( plFramePtr->tkwin == NULL ) || !Tk_IsMapped( tkwin ) )
    {
        plFramePtr->flags &= ~REFRESH_PENDING;
        return;
    }

// Redraw border if necessary

    if ( ( plFramePtr->border != NULL ) &&
         ( plFramePtr->relief != TK_RELIEF_FLAT ) )
    {
#if TK_MAJOR_VERSION >= 4 && TK_MINOR_VERSION >= 0
        Tk_Draw3DRectangle( plFramePtr->tkwin, Tk_WindowId( tkwin ),
            plFramePtr->border, 0, 0, Tk_Width( tkwin ), Tk_Height( tkwin ),
            plFramePtr->borderWidth, plFramePtr->relief );
#else
        Tk_Draw3DRectangle( plFramePtr->display, Tk_WindowId( tkwin ),
            plFramePtr->border, 0, 0, Tk_Width( tkwin ), Tk_Height( tkwin ),
            plFramePtr->borderWidth, plFramePtr->relief );
#endif
    }

// All refresh events

    if ( plFramePtr->flags & REFRESH_PENDING )
    {
        plFramePtr->flags &= ~REFRESH_PENDING;

        // Reschedule resizes to avoid occasional ordering conflicts with
        // the packer's resize of the window (this call must come last).

        if ( plFramePtr->flags & RESIZE_PENDING )
        {
            plFramePtr->flags |= REFRESH_PENDING;
            plFramePtr->flags &= ~RESIZE_PENDING;
            Tk_DoWhenIdle( DisplayPlFrame, clientData );
            return;
        }

        // Redraw -- replay contents of plot buffer

        if ( plFramePtr->flags & REDRAW_PENDING )
        {
            plFramePtr->flags &= ~REDRAW_PENDING;
            plsstrm( plFramePtr->ipls );
            pl_cmd( PLESC_REDRAW, (void *) NULL );
        }

        // Resize -- if window bounds have changed

        else if ( ( plFramePtr->width != plFramePtr->prevWidth ) ||
                  ( plFramePtr->height != plFramePtr->prevHeight ) )
        {
            plFramePtr->pldis.width  = (unsigned int) plFramePtr->width;
            plFramePtr->pldis.height = (unsigned int) plFramePtr->height;

            plsstrm( plFramePtr->ipls );
            pl_cmd( PLESC_RESIZE, (void *) &( plFramePtr->pldis ) );
            plFramePtr->prevWidth  = plFramePtr->width;
            plFramePtr->prevHeight = plFramePtr->height;
        }

        // Expose -- if window bounds are unchanged

        else
        {
            plsstrm( plFramePtr->ipls );
            if ( plFramePtr->drawing_xhairs )
            {
                XClearWindow( plFramePtr->display, Tk_WindowId( tkwin ) );
                XFlush( plFramePtr->display );
                pl_cmd( PLESC_EXPOSE, NULL );
            }
            else
            {
                pl_cmd( PLESC_EXPOSE, (void *) &( plFramePtr->pldis ) );
            }

            // Reset window bounds so that next time they are set fresh

            plFramePtr->pldis.x      = (unsigned int) ( Tk_X( tkwin ) + Tk_Width( tkwin ) );
            plFramePtr->pldis.y      = (unsigned int) ( Tk_Y( tkwin ) + Tk_Height( tkwin ) );
            plFramePtr->pldis.width  = (unsigned int) ( -Tk_Width( tkwin ) );
            plFramePtr->pldis.height = (unsigned int) ( -Tk_Height( tkwin ) );
        }

        // Update graphic crosshairs if necessary

        if ( plFramePtr->drawing_xhairs )
        {
            UpdateXhairs( plFramePtr );
        }

        // Update rubber band if necessary.

        if ( plFramePtr->drawing_rband )
        {
            UpdateRband( plFramePtr );
        }
    }
}

//--------------------------------------------------------------------------
// Routines to process widget commands.
//--------------------------------------------------------------------------

//--------------------------------------------------------------------------
// scol0
//
// Sets a color in cmap0.
//--------------------------------------------------------------------------

static int
scol0( Tcl_Interp *interp, register PlFrame *plFramePtr,
       int i, const char *col, int *p_changed )
{
    PLStream *pls = plFramePtr->pls;
    XColor   xcol;
    PLINT    r, g, b;

    if ( col == NULL )
    {
        Tcl_AppendResult( interp, "color value not specified",
            (char *) NULL );
        return TCL_ERROR;
    }

    if ( !XParseColor( plFramePtr->display,
             Tk_Colormap( plFramePtr->tkwin ), col, &xcol ) )
    {
        Tcl_AppendResult( interp, "Couldn't parse color ", col,
            (char *) NULL );
        return TCL_ERROR;
    }

    r = (unsigned) ( xcol.red & 0xFF00 ) >> 8;
    g = (unsigned) ( xcol.green & 0xFF00 ) >> 8;
    b = (unsigned) ( xcol.blue & 0xFF00 ) >> 8;

    if ( ( pls->cmap0[i].r != r ) ||
         ( pls->cmap0[i].g != g ) ||
         ( pls->cmap0[i].b != b ) )
    {
        pls->cmap0[i].r = (unsigned char) r;
        pls->cmap0[i].g = (unsigned char) g;
        pls->cmap0[i].b = (unsigned char) b;
        *p_changed      = 1;
    }

    return TCL_OK;
}

//--------------------------------------------------------------------------
// scol1
//
// Sets a color in cmap1.
//--------------------------------------------------------------------------

static int
scol1( Tcl_Interp *interp, register PlFrame *plFramePtr,
       int i, const char *col, const char *pos, const char *rev, int *p_changed )
{
    PLStream *pls = plFramePtr->pls;
    XColor   xcol;
    PLFLT    h, l, s, r, g, b, p;
    int      reverse;

    if ( col == NULL )
    {
        Tcl_AppendResult( interp, "color value not specified",
            (char *) NULL );
        return TCL_ERROR;
    }

    if ( pos == NULL )
    {
        Tcl_AppendResult( interp, "control point position not specified",
            (char *) NULL );
        return TCL_ERROR;
    }

    if ( rev == NULL )
    {
        Tcl_AppendResult( interp, "interpolation sense not specified",
            (char *) NULL );
        return TCL_ERROR;
    }

    if ( !XParseColor( plFramePtr->display,
             Tk_Colormap( plFramePtr->tkwin ), col, &xcol ) )
    {
        Tcl_AppendResult( interp, "Couldn't parse color ", col,
            (char *) NULL );
        return TCL_ERROR;
    }

    r = ( (unsigned) ( xcol.red & 0xFF00 ) >> 8 ) / 255.0;
    g = ( (unsigned) ( xcol.green & 0xFF00 ) >> 8 ) / 255.0;
    b = ( (unsigned) ( xcol.blue & 0xFF00 ) >> 8 ) / 255.0;

    plrgbhls( r, g, b, &h, &l, &s );

    p       = atof( pos ) / 100.0;
    reverse = atoi( rev );

    if ( ( pls->cmap1cp[i].c1 != h ) ||
         ( pls->cmap1cp[i].c2 != l ) ||
         ( pls->cmap1cp[i].c3 != s ) ||
         ( pls->cmap1cp[i].p != p ) ||
         ( pls->cmap1cp[i].alt_hue_path != reverse ) )
    {
        pls->cmap1cp[i].c1           = h;
        pls->cmap1cp[i].c2           = l;
        pls->cmap1cp[i].c3           = s;
        pls->cmap1cp[i].p            = p;
        pls->cmap1cp[i].alt_hue_path = reverse;
        *p_changed = 1;
    }
    return TCL_OK;
}

//--------------------------------------------------------------------------
// ColorManip
//
// Processes color manipulation widget commands.
//
// This provides an alternate API for the plplot color handling functions
// (prepend a "pl" to get the corresponding plplot function).  They differ
// from the versions in the Tcl API in the following ways:
//
//  - X11 conventions are used rather than plplot ones.  XParseColor is used
//    to convert a string into its 3 rgb components.  This lets you use
//    symbolic names or hex notation for color values.
//
//  - these expect/emit Tcl array values in lists rather than in tclmatrix
//    form, like most "normal" Tcl tools.  For usage, see the examples in the
//    palette tools (plcolor.tcl).
//--------------------------------------------------------------------------

static int
ColorManip( Tcl_Interp *interp, register PlFrame *plFramePtr,
            int argc, const char **argv )
{
    PLStream *pls = plFramePtr->pls;
    int      length;
    char     c;
    int      result = TCL_OK;
    char     *tmpstring;

#ifdef DEBUG
    if ( pls->debug )
    {
        int i;
        fprintf( stderr, "There are %d arguments to ColorManip:", argc );
        for ( i = 0; i < argc; i++ )
        {
            fprintf( stderr, " %s", argv[i] );
        }
        fprintf( stderr, "\n" );
    }
#else
    (void) argc;       // Cast to void to suppress compiler warning about unused parameter
#endif

// Make sure widget has been initialized before going any further

    if ( !plFramePtr->tkwin_initted )
    {
        Tcl_VarEval( plFramePtr->interp, "update", (char *) NULL );
    }

// Set stream number and get ready to process the command

    plsstrm( plFramePtr->ipls );

    c      = argv[0][0];
    length = (int) strlen( argv[0] );

// gcmap0 -- get color map 0
// first arg is number of colors, the rest are hex number specifications

    if ( ( c == 'g' ) && ( strncmp( argv[0], "gcmap0", (size_t) length ) == 0 ) )
    {
        int           i;
        unsigned long plcolor;
        char          str[10];

        sprintf( str, "%d", (int) pls->ncol0 );
        Tcl_AppendElement( interp, str );
        for ( i = 0; i < pls->ncol0; i++ )
        {
            plcolor = (unsigned long) ( ( pls->cmap0[i].r << 16 ) |
                                        ( pls->cmap0[i].g << 8 ) |
                                        ( pls->cmap0[i].b ) );

            sprintf( str, "#%06lx", ( plcolor & 0xFFFFFF ) );
            Tcl_AppendElement( interp, str );
        }
        result = TCL_OK;
    }

// gcmap1 -- get color map 1
// first arg is number of control points
// the rest are hex number specifications followed by positions (0-100)

    else if ( ( c == 'g' ) && ( strncmp( argv[0], "gcmap1", (size_t) length ) == 0 ) )
    {
        int           i;
        unsigned long plcolor;
        char          str[10];
        PLFLT         h, l, s, r, g, b;
        int           r1, g1, b1;

        sprintf( str, "%d", (int) pls->ncp1 );
        Tcl_AppendElement( interp, str );
        for ( i = 0; i < pls->ncp1; i++ )
        {
            h = pls->cmap1cp[i].c1;
            l = pls->cmap1cp[i].c2;
            s = pls->cmap1cp[i].c3;

            plhlsrgb( h, l, s, &r, &g, &b );

            r1 = MAX( 0, MIN( 255, (int) ( 256. * r ) ) );
            g1 = MAX( 0, MIN( 255, (int) ( 256. * g ) ) );
            b1 = MAX( 0, MIN( 255, (int) ( 256. * b ) ) );

            plcolor = (unsigned long) ( ( r1 << 16 ) | ( g1 << 8 ) | ( b1 ) );

            sprintf( str, "#%06lx", ( plcolor & 0xFFFFFF ) );
            Tcl_AppendElement( interp, str );

            sprintf( str, "%02d", (int) ( 100 * pls->cmap1cp[i].p ) );
            Tcl_AppendElement( interp, str );

            sprintf( str, "%01d", (int) ( pls->cmap1cp[i].alt_hue_path ) );
            Tcl_AppendElement( interp, str );
        }
        result = TCL_OK;
    }

// scmap0 -- set color map 0
// first arg is number of colors, the rest are hex number specifications

    else if ( ( c == 's' ) && ( strncmp( argv[0], "scmap0", (size_t) length ) == 0 ) )
    {
        int  i, changed = 1, ncol0 = atoi( argv[1] );
        char *col;

        if ( ncol0 > 16 || ncol0 < 1 )
        {
            Tcl_AppendResult( interp, "illegal number of colors in cmap0: ",
                argv[1], (char *) NULL );
            return TCL_ERROR;
        }

        pls->ncol0 = ncol0;
        tmpstring  = (char *) malloc( strlen( argv[2] ) + 1 );
        strcpy( tmpstring, argv[2] );
        col = strtok( tmpstring, " " );
        for ( i = 0; i < pls->ncol0; i++ )
        {
            if ( col == NULL )
                break;

            if ( scol0( interp, plFramePtr, i, col, &changed ) != TCL_OK )
                return TCL_ERROR;

            col = strtok( NULL, " " );
        }
        free( tmpstring );

        if ( changed )
            plP_state( PLSTATE_CMAP0 );
    }

// scmap1 -- set color map 1
// first arg is number of colors, the rest are hex number specifications

    else if ( ( c == 's' ) && ( strncmp( argv[0], "scmap1", (size_t) length ) == 0 ) )
    {
        int  i, changed = 1, ncp1 = atoi( argv[1] );
        char *col, *pos, *rev;

        if ( ncp1 > 32 || ncp1 < 1 )
        {
            Tcl_AppendResult( interp,
                "illegal number of control points in cmap1: ",
                argv[1], (char *) NULL );
            return TCL_ERROR;
        }

        tmpstring = (char *) malloc( strlen( argv[2] ) + 1 );
        strcpy( tmpstring, argv[2] );
        col = strtok( tmpstring, " " );
        pos = strtok( NULL, " " );
        rev = strtok( NULL, " " );
        for ( i = 0; i < ncp1; i++ )
        {
            if ( col == NULL )
                break;

            if ( scol1( interp, plFramePtr,
                     i, col, pos, rev, &changed ) != TCL_OK )
                return TCL_ERROR;

            col = strtok( NULL, " " );
            pos = strtok( NULL, " " );
            rev = strtok( NULL, " " );
        }
        free( tmpstring );

        if ( changed )
        {
            plFramePtr->pls->ncp1 = ncp1;
            plcmap1_calc();
        }
    }

// scol0 -- set single color in cmap0
// first arg is the color number, the next is the color in hex

    else if ( ( c == 's' ) && ( strncmp( argv[0], "scol0", (size_t) length ) == 0 ) )
    {
        int i = atoi( argv[1] ), changed = 1;

        if ( i > pls->ncol0 || i < 0 )
        {
            Tcl_AppendResult( interp, "illegal color number in cmap0: ",
                argv[1], (char *) NULL );
            return TCL_ERROR;
        }

        if ( scol0( interp, plFramePtr, i, argv[2], &changed ) != TCL_OK )
            return TCL_ERROR;

        if ( changed )
            plP_state( PLSTATE_CMAP0 );
    }

// scol1 -- set color of control point in cmap1
// first arg is the control point, the next two are the color in hex and pos

    else if ( ( c == 's' ) && ( strncmp( argv[0], "scol1", (size_t) length ) == 0 ) )
    {
        int i = atoi( argv[1] ), changed = 1;

        if ( i > pls->ncp1 || i < 0 )
        {
            Tcl_AppendResult( interp, "illegal control point number in cmap1: ",
                argv[1], (char *) NULL );
            return TCL_ERROR;
        }

        if ( scol1( interp, plFramePtr,
                 i, argv[2], argv[3], argv[4], &changed ) != TCL_OK )
            return TCL_ERROR;

        if ( changed )
            plcmap1_calc();
    }

    plflush();
    return result;
}

//--------------------------------------------------------------------------
// Cmd
//
// Processes "cmd" widget command.
// Handles commands that go more or less directly to the PLplot library.
// Most of these come out of the PLplot Tcl API support file.
//--------------------------------------------------------------------------

static int
Cmd( Tcl_Interp *interp, register PlFrame *plFramePtr,
     int argc, const char **argv )
{
    int  result    = TCL_OK;
    char cmdlist[] = "";

#ifdef DEBUG
    PLStream *pls = plFramePtr->pls;
    if ( pls->debug )
    {
        int i;
        fprintf( stderr, "There are %d arguments to Cmd:", argc );
        for ( i = 0; i < argc; i++ )
        {
            fprintf( stderr, " %s", argv[i] );
        }
        fprintf( stderr, "\n" );
    }
#endif

// no option -- return list of available PLplot commands

    if ( argc == 0 )
        return plTclCmd( cmdlist, interp, argc, argv );

// Make sure widget has been initialized before going any further

    if ( !plFramePtr->tkwin_initted )
    {
        Tcl_VarEval( plFramePtr->interp, "update", (char *) NULL );
    }

// Set stream number and get ready to process the command

    plsstrm( plFramePtr->ipls );

// Process command

    result = plTclCmd( cmdlist, interp, argc, argv );

    plflush();
    return result;
}

//
//--------------------------------------------------------------------------
//
// ConfigurePlFrame --
//
//	This procedure is called to process an argv/argc list, plus the Tk
//	option database, in order to configure (or reconfigure) a
//	plframe widget.
//
// Results:
//	The return value is a standard Tcl result.  If TCL_ERROR is
//	returned, then interp->result contains an error message.
//
// Side effects:
//	Configuration information, such as text string, colors, font, etc.
//	get set for plFramePtr; old resources get freed, if there were
//	any.
//
//--------------------------------------------------------------------------
//

static int
ConfigurePlFrame( Tcl_Interp *interp, register PlFrame *plFramePtr,
                  int argc, const char **argv, int flags )
{
    register Tk_Window tkwin = plFramePtr->tkwin;
    PLStream           *pls  = plFramePtr->pls;
    XwDev              *dev  = (XwDev *) pls->dev;
    XwDisplay          *xwd  = (XwDisplay *) dev->xwd;
    XGCValues          gcValues;
    unsigned long      mask;
    int need_redisplay = 0;

#ifdef DEBUG
    if ( pls->debug )
    {
        int i;
        fprintf( stderr, "Arguments to configure are:" );
        for ( i = 0; i < argc; i++ )
        {
            fprintf( stderr, " %s", argv[i] );
        }
        fprintf( stderr, "\n" );
    }
#endif

    dbug_enter( "ConfigurePlFrame" );

    if ( Tk_ConfigureWidget( interp, tkwin, configSpecs,
             argc, (CONST char **) argv, (char *) plFramePtr, flags ) != TCL_OK )
    {
        return TCL_ERROR;
    }

//
// Set background color using xwin driver's pixel value.  Done this way so
// that (a) we can use r/w color cells, and (b) the BG pixel values as set
// here and in the xwin driver are consistent.
//

    plsstrm( plFramePtr->ipls );
    plP_esc( PLESC_DEV2PLCOL, (void *) plFramePtr->bgColor );
    pl_cpcolor( &pls->cmap0[0], &pls->tmpcolor );
    plP_esc( PLESC_SETBGFG, NULL );

    Tk_SetWindowBackground( tkwin, xwd->cmap0[0].pixel );
    Tk_SetWindowBorder( tkwin, xwd->cmap0[0].pixel );

// Set up GC for rubber-band draws

    gcValues.background = xwd->cmap0[0].pixel;
    gcValues.foreground = 0xFF;
    gcValues.function   = GXxor;
    mask = GCForeground | GCBackground | GCFunction;

    if ( plFramePtr->xorGC != NULL )
        Tk_FreeGC( plFramePtr->display, plFramePtr->xorGC );

    plFramePtr->xorGC = Tk_GetGC( plFramePtr->tkwin, mask, &gcValues );

// Geometry settings

    Tk_SetInternalBorder( tkwin, plFramePtr->borderWidth );
    if ( ( plFramePtr->width > 0 ) || ( plFramePtr->height > 0 ) )
    {
        Tk_GeometryRequest( tkwin, plFramePtr->width, plFramePtr->height );
        if ( ( plFramePtr->width != plFramePtr->prevWidth ) ||
             ( plFramePtr->height != plFramePtr->prevHeight ) )
            need_redisplay = 1;
    }

// Create or destroy graphic crosshairs as specified

    if ( Tk_IsMapped( tkwin ) )
    {
        if ( plFramePtr->xhairs )
        {
            if ( !plFramePtr->drawing_xhairs )
                CreateXhairs( plFramePtr );
        }
        else
        {
            if ( plFramePtr->drawing_xhairs )
                DestroyXhairs( plFramePtr );
        }
    }

// Create or destroy rubber band as specified

    if ( Tk_IsMapped( tkwin ) )
    {
        if ( plFramePtr->rband )
        {
            if ( !plFramePtr->drawing_rband )
                CreateRband( plFramePtr );
        }
        else
        {
            if ( plFramePtr->drawing_rband )
                DestroyRband( plFramePtr );
        }
    }

// Arrange for window to be refreshed if necessary

    if ( need_redisplay && Tk_IsMapped( tkwin )
         && !( plFramePtr->flags & REFRESH_PENDING ) )
    {
        Tk_DoWhenIdle( DisplayPlFrame, (ClientData) plFramePtr );
        plFramePtr->flags |= REFRESH_PENDING;
        plFramePtr->flags |= UPDATE_V_SCROLLBAR | UPDATE_H_SCROLLBAR;
    }

    return TCL_OK;
}

//--------------------------------------------------------------------------
// Draw
//
// Processes "draw" widget command.
// Handles rubber-band drawing.
//--------------------------------------------------------------------------

static int
Draw( Tcl_Interp *interp, register PlFrame *plFramePtr,
      int argc, const char **argv )
{
    register Tk_Window tkwin = plFramePtr->tkwin;
    int  result = TCL_OK;
    char c      = argv[0][0];
    int  length = (int) strlen( argv[0] );

// Make sure widget has been initialized before going any further

    if ( !plFramePtr->tkwin_initted )
    {
        Tcl_VarEval( plFramePtr->interp, "update", (char *) NULL );
    }

// init -- sets up for rubber-band drawing

    if ( ( c == 'i' ) && ( strncmp( argv[0], "init", (size_t) length ) == 0 ) )
    {
        Tk_DefineCursor( tkwin, plFramePtr->xhair_cursor );
    }

// end -- ends rubber-band drawing

    else if ( ( c == 'e' ) && ( strncmp( argv[0], "end", (size_t) length ) == 0 ) )
    {
        Tk_DefineCursor( tkwin, plFramePtr->cursor );
        if ( plFramePtr->continue_draw )
        {
            XDrawLines( Tk_Display( tkwin ), Tk_WindowId( tkwin ),
                plFramePtr->xorGC, plFramePtr->pts, 5,
                CoordModeOrigin );
            XSync( Tk_Display( tkwin ), 0 );
        }

        plFramePtr->continue_draw = 0;
    }

// rect -- draw a rectangle, used to select rectangular areas
// first draw erases old outline

    else if ( ( c == 'r' ) && ( strncmp( argv[0], "rect", (size_t) length ) == 0 ) )
    {
        if ( argc < 5 )
        {
            Tcl_AppendResult( interp, "wrong # args: should be \"",
                " draw rect x0 y0 x1 y1\"", (char *) NULL );
            result = TCL_ERROR;
        }
        else
        {
            int x0, y0, x1, y1;
            int xmin = 0, xmax = Tk_Width( tkwin ) - 1;
            int ymin = 0, ymax = Tk_Height( tkwin ) - 1;

            x0 = atoi( argv[1] );
            y0 = atoi( argv[2] );
            x1 = atoi( argv[3] );
            y1 = atoi( argv[4] );

            x0 = MAX( xmin, MIN( xmax, x0 ) );
            y0 = MAX( ymin, MIN( ymax, y0 ) );
            x1 = MAX( xmin, MIN( xmax, x1 ) );
            y1 = MAX( ymin, MIN( ymax, y1 ) );

            if ( plFramePtr->continue_draw )
            {
                XDrawLines( Tk_Display( tkwin ), Tk_WindowId( tkwin ),
                    plFramePtr->xorGC, plFramePtr->pts, 5,
                    CoordModeOrigin );
                XSync( Tk_Display( tkwin ), 0 );
            }

            plFramePtr->pts[0].x = (short) x0; plFramePtr->pts[0].y = (short) y0;
            plFramePtr->pts[1].x = (short) x1; plFramePtr->pts[1].y = (short) y0;
            plFramePtr->pts[2].x = (short) x1; plFramePtr->pts[2].y = (short) y1;
            plFramePtr->pts[3].x = (short) x0; plFramePtr->pts[3].y = (short) y1;
            plFramePtr->pts[4].x = (short) x0; plFramePtr->pts[4].y = (short) y0;

            XDrawLines( Tk_Display( tkwin ), Tk_WindowId( tkwin ),
                plFramePtr->xorGC, plFramePtr->pts, 5,
                CoordModeOrigin );
            XSync( Tk_Display( tkwin ), 0 );

            plFramePtr->continue_draw = 1;
        }
    }

    return result;
}

//--------------------------------------------------------------------------
// Info
//
// Processes "info" widget command.
// Returns requested info.
//--------------------------------------------------------------------------

static int
Info( Tcl_Interp *interp, register PlFrame *plFramePtr,
      int argc, const char **argv )
{
    int  length;
    char c;
    int  result = TCL_OK;

// no option -- return list of available info commands

    if ( argc == 0 )
    {
        Tcl_SetResult( interp, "devkeys devnames", TCL_STATIC );
        return TCL_OK;
    }

    c      = argv[0][0];
    length = (int) strlen( argv[0] );

// devkeys -- return list of supported device keywords

    if ( ( c == 'd' ) && ( strncmp( argv[0], "devkeys", (size_t) length ) == 0 ) )
    {
        int i = 0;
        while ( plFramePtr->devName[i] != NULL )
            Tcl_AppendElement( interp, plFramePtr->devName[i++] );

        result = TCL_OK;
    }

// devkeys -- return list of supported device types

    else if ( ( c == 'd' ) && ( strncmp( argv[0], "devnames", (size_t) length ) == 0 ) )
    {
        int i = 0;
        while ( plFramePtr->devDesc[i] != NULL )
            Tcl_AppendElement( interp, plFramePtr->devDesc[i++] );

        result = TCL_OK;
    }

// unrecognized

    else
    {
        Tcl_AppendResult( interp, "bad option to \"info\": must be ",
            "devkeys, devnames", (char *) NULL );

        result = TCL_ERROR;
    }

    return result;
}

//--------------------------------------------------------------------------
// Openlink
//
// Processes "openlink" widget command.
// Opens channel (FIFO or socket) for binary data transfer between client
// and server.
//--------------------------------------------------------------------------

static int
Openlink( Tcl_Interp *interp, register PlFrame *plFramePtr,
          int argc, const char **argv )
{
    register PLRDev  *plr   = plFramePtr->plr;
    register PLiodev *iodev = plr->iodev;

    char             c = argv[0][0];
    int length         = (int) strlen( argv[0] );

    dbug_enter( "Openlink" );

// Open fifo

    if ( ( c == 'f' ) && ( strncmp( argv[0], "fifo", (size_t) length ) == 0 ) )
    {
        if ( argc < 1 )
        {
            Tcl_AppendResult( interp, "bad command -- must be: ",
                "openlink fifo <pathname>",
                (char *) NULL );
            return TCL_ERROR;
        }
#if !defined ( _WIN32 )
        if ( ( iodev->fd = open( argv[1], O_RDONLY ) ) == -1 )
#else
        if ( 1 )
#endif
        {
            Tcl_AppendResult( interp, "cannot open fifo ", argv[1],
                " for read", (char *) NULL );
            return TCL_ERROR;
        }
        iodev->type     = 0;
        iodev->typeName = "fifo";
#if !defined ( _WIN32 )
        iodev->file = fdopen( iodev->fd, "rb" );
#else
        iodev->file = NULL;
#endif
    }

// Open socket

    else if ( ( c == 's' ) && ( strncmp( argv[0], "socket", (size_t) length ) == 0 ) )
    {
        if ( argc < 1 )
        {
            Tcl_AppendResult( interp, "bad command -- must be: ",
                "openlink socket <sock-id>",
                (char *) NULL );
            return TCL_ERROR;
        }
        iodev->type       = 1;
        iodev->typeName   = "socket";
        iodev->fileHandle = argv[1];

#if TCL_MAJOR_VERSION < 7 || ( TCL_MAJOR_VERSION == 7 && TCL_MINOR_VERSION == 4 )
#define FILECAST
#else
#define FILECAST    ( ClientData )
#endif

// Exclude UNIX-only feature
#if !defined ( MAC_TCL ) && !defined ( _WIN32 ) && !defined ( __CYGWIN__ )
        if ( Tcl_GetOpenFile( interp, iodev->fileHandle,
                 0, 1, FILECAST & iodev->file ) != TCL_OK )
        {
            return TCL_ERROR;
        }
#endif
        iodev->fd = fileno( iodev->file );
    }

// unrecognized

    else
    {
        Tcl_AppendResult( interp, "bad option to \"openlink\": must be ",
            "fifo or socket", (char *) NULL );

        return TCL_ERROR;
    }

    plr->pdfs = pdf_bopen( NULL, 4200 );
// Sheesh, what a mess.  I don't see how Tk4.1's converter macro could
// possibly work.
#if TK_MAJOR_VERSION < 4 ||                               \
    ( TK_MAJOR_VERSION == 4 && TK_MINOR_VERSION == 0 ) || \
    TK_MAJOR_VERSION > 7
#if !defined ( MAC_TCL ) && !defined ( _WIN32 ) && !defined ( __CYGWIN__ )
    Tk_CreateFileHandler( iodev->fd, TK_READABLE, (Tk_FileProc *) ReadData,
        (ClientData) plFramePtr );
#endif
#else
#if !defined ( MAC_TCL ) && !defined ( _WIN32 ) && !defined ( __CYGWIN__ )
    Tcl_CreateFileHandler( Tcl_GetFile( (ClientData) iodev->fd, TCL_UNIX_FD ),
        TK_READABLE, (Tk_FileProc *) ReadData,
        (ClientData) plFramePtr );
#endif
#endif

    return TCL_OK;
}

//--------------------------------------------------------------------------
// Closelink
//
// Processes "closelink" widget command.
// CLoses channel previously opened with the "openlink" widget command.
//--------------------------------------------------------------------------

static int
Closelink( Tcl_Interp *interp, register PlFrame *plFramePtr,
           int PL_UNUSED( argc ), const char ** PL_UNUSED( argv ) )
{
    register PLRDev  *plr   = plFramePtr->plr;
    register PLiodev *iodev = plr->iodev;

    dbug_enter( "Closelink" );

    if ( iodev->fd == 0 )
    {
        Tcl_AppendResult( interp, "no link currently open", (char *) NULL );
        return TCL_ERROR;
    }

#if TK_MAJOR_VERSION < 4 ||                               \
    ( TK_MAJOR_VERSION == 4 && TK_MINOR_VERSION == 0 ) || \
    TK_MAJOR_VERSION > 7
#if !defined ( MAC_TCL ) && !defined ( _WIN32 ) && !defined ( __CYGWIN__ )
    Tk_DeleteFileHandler( iodev->fd );
#endif
#else
//    Tk_DeleteFileHandler( iodev->file );
#if !defined ( MAC_TCL ) && !defined ( _WIN32 ) && !defined ( __CYGWIN__ )
    Tcl_DeleteFileHandler( Tcl_GetFile( (ClientData) iodev->fd,
            TCL_UNIX_FD ) );
#endif
#endif
    pdf_close( plr->pdfs );
    iodev->fd = 0;

    return TCL_OK;
}

//--------------------------------------------------------------------------
// process_data
//
// Utility function for processing data and other housekeeping.
//--------------------------------------------------------------------------

static int
process_data( Tcl_Interp *interp, register PlFrame *plFramePtr )
{
    register PLRDev  *plr   = plFramePtr->plr;
    register PLiodev *iodev = plr->iodev;
    int result = TCL_OK;

// Process data

    if ( plr_process( plr ) == -1 )
    {
        Tcl_AppendResult( interp, "unable to read from ", iodev->typeName,
            (char *) NULL );
        result = TCL_ERROR;
    }

// Signal bop if necessary

    if ( plr->at_bop && plFramePtr->bopCmd != NULL )
    {
        plr->at_bop = 0;
        if ( Tcl_Eval( interp, plFramePtr->bopCmd ) != TCL_OK )
            fprintf( stderr, "Command \"%s\" failed:\n\t %s\n",
                plFramePtr->bopCmd, Tcl_GetStringResult( interp ) );
    }

// Signal eop if necessary

    if ( plr->at_eop && plFramePtr->eopCmd != NULL )
    {
        plr->at_eop = 0;
        if ( Tcl_Eval( interp, plFramePtr->eopCmd ) != TCL_OK )
            fprintf( stderr, "Command \"%s\" failed:\n\t %s\n",
                plFramePtr->eopCmd, Tcl_GetStringResult( interp ) );
    }

    return result;
}

//--------------------------------------------------------------------------
// ReadData
//
// Reads & processes data.
// Intended to be installed as a filehandler command.
//--------------------------------------------------------------------------

static int
ReadData( ClientData clientData, int mask )
{
    register PlFrame    *plFramePtr = (PlFrame *) clientData;
    register Tcl_Interp *interp     = plFramePtr->interp;

    register PLRDev     *plr   = plFramePtr->plr;
    register PLiodev    *iodev = plr->iodev;
    register PDFstrm    *pdfs  = plr->pdfs;
    int result = TCL_OK;

    if ( mask & TK_READABLE )
    {
        // Read from FIFO or socket

        plsstrm( plFramePtr->ipls );
        if ( pl_PacketReceive( interp, iodev, pdfs ) )
        {
            Tcl_AppendResult( interp, "Packet receive failed:\n\t %s\n",
                (char *) NULL );
            return TCL_ERROR;
        }

        // If the packet isn't complete it will be put back and we just return.
        // Otherwise, the buffer pointer is saved and then cleared so that reads
        // from the buffer start at the beginning.
        //
        if ( pdfs->bp == 0 )
            return TCL_OK;

        plr->nbytes = (int) pdfs->bp;
        pdfs->bp    = 0;
        result      = process_data( interp, plFramePtr );
    }

    return result;
}

//--------------------------------------------------------------------------
// Orient
//
// Processes "orient" widget command.
// Handles orientation of plot.
//--------------------------------------------------------------------------

static int
Orient( Tcl_Interp *interp, register PlFrame *plFramePtr,
        int argc, const char **argv )
{
    int result = TCL_OK;

// orient -- return orientation of current plot window

    plsstrm( plFramePtr->ipls );

    if ( argc == 0 )
    {
        PLFLT rot;
        char  result_str[128];
        plgdiori( &rot );
        sprintf( result_str, "%f", rot );
        Tcl_SetResult( interp, result_str, TCL_VOLATILE );
    }

// orient <rot> -- Set orientation to <rot>

    else
    {
        plsdiori( atof( argv[0] ) );
        result = Redraw( interp, plFramePtr, argc - 1, argv + 1 );
    }

    return result;
}

//--------------------------------------------------------------------------
// Print
//
// Processes "print" widget command.
// Handles printing of plot, duh.
//
// Creates a temporary file, dumps the current plot to it in metafile
// form, and then execs the "plpr" script to actually print it.  Since we
// output it in metafile form here, plpr must invoke plrender to drive the
// output to the appropriate file type.  The script is responsible for the
// deletion of the plot metafile.
//--------------------------------------------------------------------------

static int
Print( Tcl_Interp *interp, register PlFrame *plFramePtr,
       int PL_UNUSED( argc ), const char ** PL_UNUSED( argv ) )
{
    PLINT ipls;
    int   result = TCL_OK;
    char  *sfnam;
    FILE  *sfile;
    pid_t pid;

// Make sure widget has been initialized before going any further

    if ( !plFramePtr->tkwin_initted )
    {
        Tcl_AppendResult( interp, "Error -- widget not plotted to yet",
            (char *) NULL );
        return TCL_ERROR;
    }

// Create stream for save

    plmkstrm( &ipls );
    if ( ipls < 0 )
    {
        Tcl_AppendResult( interp, "Error -- cannot create stream",
            (char *) NULL );
        return TCL_ERROR;
    }

// Open file for writes
    sfnam = NULL;

    // Create and open temporary file
    if ( ( sfile = pl_create_tempfile( &sfnam ) ) == NULL )
    {
        Tcl_AppendResult( interp,
            "Error -- cannot open plot file for writing",
            (char *) NULL );
        plend1();
        if ( sfnam != NULL )
            free( sfnam );
        return TCL_ERROR;
    }

// Initialize stream

    plsdev( "plmeta" );
    plsfile( sfile );
// FIXME: plmeta/plrender need to honor these, needed to preserve the aspect ratio
    plspage( 0., 0., plFramePtr->width, plFramePtr->height, 0, 0 );
    plcpstrm( plFramePtr->ipls, 0 );
    pladv( 0 );

// Remake current plot, close file, and switch back to original stream

    plreplot();
    plend1();
    plsstrm( plFramePtr->ipls );

// So far so good.  Time to exec the print script.

    if ( plFramePtr->plpr_cmd == NULL )
        plFramePtr->plpr_cmd = plFindCommand( "plpr" );

#if !defined ( _WIN32 )
    if ( ( plFramePtr->plpr_cmd == NULL ) || ( pid = fork() ) < 0 )
#else
    if ( 1 )
#endif
    {
        Tcl_AppendResult( interp,
            "Error -- cannot fork print process",
            (char *) NULL );
        result = TCL_ERROR;
    }
    else if ( pid == 0 )
    {
#if !defined ( _WIN32 )
        if ( execl( plFramePtr->plpr_cmd, plFramePtr->plpr_cmd, sfnam,
                 (char *) 0 ) )
#else
        if ( 1 )
#endif
        {
            fprintf( stderr, "Unable to exec print command.\n" );
            free( sfnam );
            _exit( 1 );
        }
    }

    free( sfnam );

    return result;
}

//--------------------------------------------------------------------------
// Page
//
// Processes "page" widget command.
// Handles parameters such as margin, aspect ratio, and justification
// of final plot.
//--------------------------------------------------------------------------

static int
Page( Tcl_Interp *interp, register PlFrame *plFramePtr,
      int argc, const char **argv )
{
// page -- return current device window parameters

    plsstrm( plFramePtr->ipls );

    if ( argc == 0 )
    {
        PLFLT mar, aspect, jx, jy;
        char  result_str[128];

        plgdidev( &mar, &aspect, &jx, &jy );
        sprintf( result_str, "%g %g %g %g", mar, aspect, jx, jy );
        Tcl_SetResult( interp, result_str, TCL_VOLATILE );
        return TCL_OK;
    }

// page <mar> <aspect> <jx> <jy> -- set up page

    if ( argc < 4 )
    {
        Tcl_AppendResult( interp, "wrong # args: should be \"",
            " page mar aspect jx jy\"", (char *) NULL );
        return TCL_ERROR;
    }

    plsdidev( atof( argv[0] ), atof( argv[1] ), atof( argv[2] ), atof( argv[3] ) );
    return ( Redraw( interp, plFramePtr, argc - 1, argv + 1 ) );
}

//--------------------------------------------------------------------------
// Redraw
//
// Processes "redraw" widget command.
// Turns loose a DoWhenIdle command to redraw plot by replaying contents
// of plot buffer.
//--------------------------------------------------------------------------

static int
Redraw( Tcl_Interp *PL_UNUSED( interp ), register PlFrame *plFramePtr,
        int PL_UNUSED( argc ), const char ** PL_UNUSED( argv ) )
{
    dbug_enter( "Redraw" );

    plFramePtr->flags |= REDRAW_PENDING;
    if ( ( plFramePtr->tkwin != NULL ) &&
         !( plFramePtr->flags & REFRESH_PENDING ) )
    {
        Tk_DoWhenIdle( DisplayPlFrame, (ClientData) plFramePtr );
        plFramePtr->flags |= REFRESH_PENDING;
    }

    return TCL_OK;
}

//--------------------------------------------------------------------------
// Save
//
// Processes "save" widget command.
// Saves plot to a file.
//--------------------------------------------------------------------------

static int
Save( Tcl_Interp *interp, register PlFrame *plFramePtr,
      int argc, const char **argv )
{
    int  length;
    char c;
    FILE *sfile;

// Make sure widget has been initialized before going any further

    if ( !plFramePtr->tkwin_initted )
    {
        Tcl_AppendResult( interp, "Error -- widget not plotted to yet",
            (char *) NULL );
        return TCL_ERROR;
    }

// save -- save to already open file

    if ( argc == 0 )
    {
        if ( !plFramePtr->ipls_save )
        {
            Tcl_AppendResult( interp, "Error -- no current save file",
                (char *) NULL );
            return TCL_ERROR;
        }
        plsstrm( plFramePtr->ipls_save );
        // Note: many drivers ignore these, needed to preserve the aspect ratio
        plspage( 0., 0., plFramePtr->width, plFramePtr->height, 0, 0 );
        plcpstrm( plFramePtr->ipls, 0 );
        pladv( 0 );
        plreplot();
        plflush();
        plsstrm( plFramePtr->ipls );
        return TCL_OK;
    }

    c      = argv[0][0];
    length = (int) strlen( argv[0] );

// save to specified device & file

    if ( ( c == 'a' ) && ( strncmp( argv[0], "as", (size_t) length ) == 0 ) )
    {
        if ( argc < 3 )
        {
            Tcl_AppendResult( interp, "wrong # args: should be \"",
                " save as device file\"", (char *) NULL );
            return TCL_ERROR;
        }

        // If save previously in effect, delete old stream

        if ( plFramePtr->ipls_save )
        {
            plsstrm( plFramePtr->ipls_save );
            plend1();
        }

        // Create stream for saves to selected device & file

        plmkstrm( &plFramePtr->ipls_save );
        if ( plFramePtr->ipls_save < 0 )
        {
            Tcl_AppendResult( interp, "Error -- cannot create stream",
                (char *) NULL );
            plFramePtr->ipls_save = 0;
            return TCL_ERROR;
        }

        // Open file for writes

        if ( ( sfile = fopen( argv[2], "wb+" ) ) == NULL )
        {
            Tcl_AppendResult( interp, "Error -- cannot open file ", argv[2],
                " for writing", (char *) NULL );
            plFramePtr->ipls_save = 0;
            plend1();
            return TCL_ERROR;
        }

        // Initialize stream

        plsdev( argv[1] );
        plsfile( sfile );
        // Note: many drivers ignore these, needed to preserve the aspect ratio
        plspage( 0., 0., plFramePtr->width, plFramePtr->height, 0, 0 );
        plcpstrm( plFramePtr->ipls, 0 );
        pladv( 0 );

        // Remake current plot and then switch back to original stream

        plreplot();
        plflush();
        plsstrm( plFramePtr->ipls );
    }

// close save file

    else if ( ( c == 'c' ) && ( strncmp( argv[0], "close", (size_t) length ) == 0 ) )
    {
        if ( !plFramePtr->ipls_save )
        {
            Tcl_AppendResult( interp, "Error -- no current save file",
                (char *) NULL );
            return TCL_ERROR;
        }
        else
        {
            plsstrm( plFramePtr->ipls_save );
            plend1();
            plFramePtr->ipls_save = 0;
            plsstrm( plFramePtr->ipls );
        }
    }

// unrecognized

    else
    {
        Tcl_AppendResult( interp, "bad option to \"save\": must be ",
            "as or close", (char *) NULL );

        return TCL_ERROR;
    }

    return TCL_OK;
}

//--------------------------------------------------------------------------
// View
//
// Processes "view" widget command.
// Handles translation & scaling of view into plot.
//--------------------------------------------------------------------------

static int
View( Tcl_Interp *interp, register PlFrame *plFramePtr,
      int argc, const char **argv )
{
    int   length;
    char  c;
    PLFLT xl, xr, yl, yr;

// view -- return current relative plot window coordinates

    plsstrm( plFramePtr->ipls );

    if ( argc == 0 )
    {
        char result_str[128];
        plgdiplt( &xl, &yl, &xr, &yr );
        sprintf( result_str, "%g %g %g %g", xl, yl, xr, yr );
        Tcl_SetResult( interp, result_str, TCL_VOLATILE );
        return TCL_OK;
    }

    c      = argv[0][0];
    length = (int) strlen( argv[0] );

// view bounds -- return relative device coordinates of bounds on current
// plot window

    if ( ( c == 'b' ) && ( strncmp( argv[0], "bounds", (size_t) length ) == 0 ) )
    {
        char result_str[128];
        xl = 0.; yl = 0.;
        xr = 1.; yr = 1.;
        pldip2dc( &xl, &yl, &xr, &yr );
        sprintf( result_str, "%g %g %g %g", xl, yl, xr, yr );
        Tcl_SetResult( interp, result_str, TCL_VOLATILE );
        return TCL_OK;
    }

// view reset -- Resets plot

    if ( ( c == 'r' ) && ( strncmp( argv[0], "reset", (size_t) length ) == 0 ) )
    {
        xl = 0.; yl = 0.;
        xr = 1.; yr = 1.;
        plsdiplt( xl, yl, xr, yr );
    }

// view select -- set window into plot space
// Specifies in terms of plot window coordinates, not device coordinates

    else if ( ( c == 's' ) && ( strncmp( argv[0], "select", (size_t) length ) == 0 ) )
    {
        if ( argc < 5 )
        {
            Tcl_AppendResult( interp, "wrong # args: should be \"",
                " view select xmin ymin xmax ymax\"",
                (char *) NULL );
            return TCL_ERROR;
        }
        else
        {
            gbox( &xl, &yl, &xr, &yr, argv + 1 );
            plsdiplt( xl, yl, xr, yr );
        }
    }

// view zoom -- set window into plot space incrementally (zoom)
// Here we need to take the page (device) offsets into account

    else if ( ( c == 'z' ) && ( strncmp( argv[0], "zoom", (size_t) length ) == 0 ) )
    {
        if ( argc < 5 )
        {
            Tcl_AppendResult( interp, "wrong # args: should be \"",
                " view zoom xmin ymin xmax ymax\"",
                (char *) NULL );
            return TCL_ERROR;
        }
        else
        {
            gbox( &xl, &yl, &xr, &yr, argv + 1 );
            pldid2pc( &xl, &yl, &xr, &yr );
            plsdiplz( xl, yl, xr, yr );
        }
    }

// unrecognized

    else
    {
        Tcl_AppendResult( interp, "bad option \"", argv[1],
            "\":  options to \"view\" are: bounds, reset, select, or zoom",
            (char *) NULL );

        return TCL_ERROR;
    }

// Update plot window bounds and arrange for plot to be updated

    plgdiplt( &xl, &yl, &xr, &yr );
    plFramePtr->xl     = xl;
    plFramePtr->yl     = yl;
    plFramePtr->xr     = xr;
    plFramePtr->yr     = yr;
    plFramePtr->flags |= UPDATE_V_SCROLLBAR | UPDATE_H_SCROLLBAR;

    return ( Redraw( interp, plFramePtr, argc, argv ) );
}

//--------------------------------------------------------------------------
// xScroll
//
// Processes "xscroll" widget command.
// Handles horizontal scroll-bar invoked translation of view into plot.
//--------------------------------------------------------------------------

static int
xScroll( Tcl_Interp *interp, register PlFrame *plFramePtr,
         int argc, const char **argv )
{
    int   x0, width = Tk_Width( plFramePtr->tkwin );
    PLFLT xl, xr, yl, yr, xlen;

    plsstrm( plFramePtr->ipls );

    xlen = plFramePtr->xr - plFramePtr->xl;
    x0   = atoi( argv[0] );
    xl   = x0 / (double) width;
    xl   = MAX( 0., MIN( ( 1. - xlen ), xl ) );
    xr   = xl + xlen;

    yl = plFramePtr->yl;
    yr = plFramePtr->yr;

    plFramePtr->xl = xl;
    plFramePtr->xr = xr;

    plsdiplt( xl, yl, xr, yr );

    plFramePtr->flags |= UPDATE_V_SCROLLBAR | UPDATE_H_SCROLLBAR;
    return ( Redraw( interp, plFramePtr, argc, argv ) );
}

//--------------------------------------------------------------------------
// yScroll
//
// Processes "yscroll" widget command.
// Handles vertical scroll-bar invoked translation of view into plot.
//--------------------------------------------------------------------------

static int
yScroll( Tcl_Interp *interp, register PlFrame *plFramePtr,
         int argc, const char **argv )
{
    int   y0, height = Tk_Height( plFramePtr->tkwin );
    PLFLT xl, xr, yl, yr, ylen;

    plsstrm( plFramePtr->ipls );

    ylen = plFramePtr->yr - plFramePtr->yl;
    y0   = atoi( argv[0] );
    yr   = 1. - y0 / (double) height;
    yr   = MAX( 0. + ylen, MIN( 1., yr ) );
    yl   = yr - ylen;

    xl = plFramePtr->xl;
    xr = plFramePtr->xr;

    plFramePtr->yl = yl;
    plFramePtr->yr = yr;

    plsdiplt( xl, yl, xr, yr );

    plFramePtr->flags |= UPDATE_V_SCROLLBAR | UPDATE_H_SCROLLBAR;
    return ( Redraw( interp, plFramePtr, argc, argv ) );
}

//--------------------------------------------------------------------------
// report
//
// 4/17/95 GMF
// Processes "report" widget command.
//--------------------------------------------------------------------------

static int
report( Tcl_Interp *interp, register PlFrame *plFramePtr,
        int argc, const char **argv )
{
    PLFLT x, y;
    char  tmpstring[50];
//    fprintf( stdout, "Made it into report, argc=%d\n", argc );

    if ( argc == 0 )
    {
        Tcl_SetResult( interp, "report what?", TCL_STATIC );
        return TCL_ERROR;
    }

    if ( !strcmp( argv[0], "wc" ) )
    {
        XwDev        *dev = (XwDev *) plFramePtr->pls->dev;
        PLGraphicsIn *gin = &( dev->gin );

        if ( argc != 3 )
        {
            Tcl_SetResult( interp, "Wrong # of args: report wc x y", TCL_STATIC );
            return TCL_ERROR;
        }

        x = atof( argv[1] );
        y = atof( argv[2] );

        gin->dX = (PLFLT) x / ( dev->width - 1 );
        gin->dY = 1.0 - (PLFLT) y / ( dev->height - 1 );

        // Try to locate cursor

        if ( plTranslateCursor( gin ) )
        {
            snprintf( tmpstring, 50, "%f %f", gin->wX, gin->wY );
            Tcl_SetResult( interp, tmpstring, TCL_VOLATILE );
            return TCL_OK;
        }

        Tcl_SetResult( interp, "Cannot locate", TCL_STATIC );
        return TCL_OK;
    }

    Tcl_SetResult( interp, "nonsensical request.", TCL_STATIC );
    return TCL_ERROR;
}

//--------------------------------------------------------------------------
// Custom bop handler.
// Mostly for support of multi-page Tcl scripts from plserver.
//--------------------------------------------------------------------------

static void
process_bop( void *clientData, int * PL_UNUSED( skip_driver_bop ) )
{
    register PlFrame *plFramePtr = (PlFrame *) clientData;

    if ( Tcl_Eval( plFramePtr->interp, plFramePtr->bopCmd ) != TCL_OK )
        fprintf( stderr, "Command \"%s\" failed:\n\t %s\n",
            plFramePtr->bopCmd, Tcl_GetStringResult( plFramePtr->interp ) );
}

//--------------------------------------------------------------------------
// Custom eop handler.
// Mostly for support of multi-page Tcl scripts from plserver.
//--------------------------------------------------------------------------

static void
process_eop( void *clientData, int * PL_UNUSED( skip_driver_eop ) )
{
    register PlFrame *plFramePtr = (PlFrame *) clientData;

    if ( Tcl_Eval( plFramePtr->interp, plFramePtr->eopCmd ) != TCL_OK )
        fprintf( stderr, "Command \"%s\" failed:\n\t %s\n",
            plFramePtr->eopCmd, Tcl_GetStringResult( plFramePtr->interp ) );
}

//--------------------------------------------------------------------------
// Utility routines
//--------------------------------------------------------------------------

//--------------------------------------------------------------------------
// UpdateVScrollbar
//
// Updates vertical scrollbar if needed.
//--------------------------------------------------------------------------

static void
UpdateVScrollbar( register PlFrame *plFramePtr )
{
    int  height = Tk_Height( plFramePtr->tkwin );
    char string[60];
    int  totalUnits, windowUnits, firstUnit, lastUnit, result;

    if ( plFramePtr->yScrollCmd == NULL )
        return;

    totalUnits  = height;
    firstUnit   = (int) ( 0.5 + (PLFLT) height * ( 1. - plFramePtr->yr ) );
    lastUnit    = (int) ( 0.5 + (PLFLT) height * ( 1. - plFramePtr->yl ) );
    windowUnits = lastUnit - firstUnit;
    sprintf( string, " %d %d %d %d",
        totalUnits, windowUnits, firstUnit, lastUnit );

    result = Tcl_VarEval( plFramePtr->interp, plFramePtr->yScrollCmd, string,
        (char *) NULL );

    if ( result != TCL_OK )
    {
        Tk_BackgroundError( plFramePtr->interp );
    }
}

//--------------------------------------------------------------------------
// UpdateHScrollbar
//
// Updates horizontal scrollbar if needed.
//--------------------------------------------------------------------------

static void
UpdateHScrollbar( register PlFrame *plFramePtr )
{
    int  width = Tk_Width( plFramePtr->tkwin );
    char string[60];
    int  totalUnits, windowUnits, firstUnit, lastUnit, result;

    if ( plFramePtr->xScrollCmd == NULL )
        return;

    totalUnits  = width;
    firstUnit   = (int) ( 0.5 + (PLFLT) width * plFramePtr->xl );
    lastUnit    = (int) ( 0.5 + (PLFLT) width * plFramePtr->xr );
    windowUnits = lastUnit - firstUnit;
    sprintf( string, " %d %d %d %d",
        totalUnits, windowUnits, firstUnit, lastUnit );

    result = Tcl_VarEval( plFramePtr->interp, plFramePtr->xScrollCmd, string,
        (char *) NULL );

    if ( result != TCL_OK )
    {
        Tk_BackgroundError( plFramePtr->interp );
    }
}

//--------------------------------------------------------------------------
// gbox
//
// Returns selection box coordinates.  It's best if the TCL script does
// bounds checking on the input but I do it here as well just to be safe.
//--------------------------------------------------------------------------

static void
gbox( PLFLT *xl, PLFLT *yl, PLFLT *xr, PLFLT *yr, const char **argv )
{
    PLFLT x0, y0, x1, y1;

    x0 = atof( argv[0] );
    y0 = atof( argv[1] );
    x1 = atof( argv[2] );
    y1 = atof( argv[3] );

    x0 = MAX( 0., MIN( 1., x0 ) );
    y0 = MAX( 0., MIN( 1., y0 ) );
    x1 = MAX( 0., MIN( 1., x1 ) );
    y1 = MAX( 0., MIN( 1., y1 ) );

// Only need two vertices, pick the lower left and upper right

    *xl = MIN( x0, x1 );
    *yl = MIN( y0, y1 );
    *xr = MAX( x0, x1 );
    *yr = MAX( y0, y1 );
}