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events.c

/*========================================================================*\

Copyright (c) 1990-1999  Paul Vojta

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to
deal in the Software without restriction, including without limitation the
rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
sell copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
PAUL VOJTA BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

NOTE:
      xdvi is based on prior work, as noted in the modification history
      in xdvi.c.

\*========================================================================*/

#include "xdvi-config.h"


/* Xlib and Xutil are already included */

#ifdef      TOOLKIT

#ifdef      OLD_X11_TOOLKIT
#include <X11/Atoms.h>
#else /* not OLD_X11_TOOLKIT */
#include <X11/Xatom.h>
#include <X11/StringDefs.h>
#endif /* not OLD_X11_TOOLKIT */

#include <X11/Shell.h>  /* needed for def. of XtNiconX */

#ifndef     XtSpecificationRelease
#define     XtSpecificationRelease  0
#endif
#if   XtSpecificationRelease >= 4
#ifndef MOTIF
#include <X11/Xaw/Viewport.h>
#ifdef HTEX
#include <X11/Xaw/Dialog.h>
#include <X11/Xaw/Text.h>
#endif
#else /* MOTIF */
#include <Xm/MainW.h>
#include <Xm/ToggleB.h>
#include <Xm/RowColumn.h>
#include <Xm/MenuShell.h>
#endif /* MOTIF */

#ifdef      BUTTONS
#ifndef MOTIF
#include <X11/Xaw/Command.h>
#define     PANEL_WIDGET_CLASS      compositeWidgetClass
#define     BUTTON_WIDGET_CLASS     commandWidgetClass
#else /* MOTIF */
#include <Xm/Form.h>
#include <Xm/BulletinB.h>
#include <Xm/PushB.h>
#define     PANEL_WIDGET_CLASS      xmBulletinBoardWidgetClass
#define     BUTTON_WIDGET_CLASS     xmPushButtonWidgetClass
#endif /* MOTIF */
#endif /* BUTTONS */

#else /* XtSpecificationRelease < 4 */

#define     XtPointer caddr_t
#include <X11/Viewport.h>
#ifdef      BUTTONS
#include <X11/Command.h>
#define     PANEL_WIDGET_CLASS      compositeWidgetClass
#define     BUTTON_WIDGET_CLASS     commandWidgetClass
#endif

#endif      /* XtSpecificationRelease */

#else /* not TOOLKIT */

typedef     int         Position;
#define     XtPending() XPending(DISP)

#endif      /* not TOOLKIT */

#include <signal.h>
#include <sys/file.h>   /* this defines FASYNC */

#if !defined(FLAKY_SIGPOLL) && !HAVE_STREAMS && !defined(FASYNC)
#define     FLAKY_SIGPOLL     1
#endif

#ifndef FLAKY_SIGPOLL

#ifndef SIGPOLL
#define     SIGPOLL     SIGIO
#endif

#ifndef SA_RESTART
#define SA_RESTART 0
#endif

#if HAVE_STREAMS
#include <stropts.h>

#ifndef S_RDNORM
#define     S_RDNORM S_INPUT
#endif

#ifndef S_RDBAND
#define     S_RDBAND 0
#endif

#ifndef S_HANGUP
#define     S_HANGUP 0
#endif

#ifndef S_WRNORM
#define     S_WRNORM S_OUTPUT
#endif
#endif /* HAVE_STREAMS */

#endif /* not FLAKY_SIGPOLL */

#if HAVE_POLL
# include <poll.h>
#else
# if HAVE_SYS_SELECT_H
#  include <sys/select.h>
# else
#  if HAVE_SELECT_H
#   include <select.h>
#  endif
# endif
#endif

#include <errno.h>

#ifdef      X_NOT_STDC_ENV
extern      int   errno;
#endif      /* X_NOT_STDC_ENV */

#ifndef     X11HEIGHT
#define     X11HEIGHT   8     /* Height of server default font */
#endif

#define     MAGBORD     1     /* border size for magnifier */

/*
 * Command line flags.
 */

#define delay_rulers    resource._delay_rulers
#define tick_units      resource._tick_units
#define tick_length     resource._tick_length
#define     fore_Pixel  resource._fore_Pixel
#define     back_Pixel  resource._back_Pixel
#ifdef      TOOLKIT
extern      struct _resource  resource;
#define     brdr_Pixel  resource._brdr_Pixel
#endif      /* TOOLKIT */

#define     clip_w      mane.width
#define     clip_h      mane.height
static      Position main_x, main_y;
static      Position mag_x, mag_y, new_mag_x, new_mag_y;
static      Boolean     mag_moved   = False;
static      Boolean     busycurs    = False;

#ifndef FLAKY_SIGPOLL
sigset_t          sigpollusrterm;
#endif

#if HAVE_POLL
static      struct pollfd     fds[1]      = {{0, POLLIN, 0}};
#else
static      fd_set            readfds;
#endif

#ifdef      TOOLKIT
#ifdef      BUTTONS
static      Widget      line_widget;
static      Widget      panel_widget;
static      int   destroy_count     = 0;
#endif /* BUTTONS */

#ifndef MOTIF
static      Widget      x_bar, y_bar;     /* horizontal and vertical scroll bars */
#endif

static      Arg   resize_args[] = {
      {XtNwidth,  (XtArgVal) 0},
      {XtNheight, (XtArgVal) 0},
};

#define     XdviResizeWidget(widget, w, h)      \
            (resize_args[0].value = (XtArgVal) (w), \
            resize_args[1].value = (XtArgVal) (h), \
            XtSetValues(widget, resize_args, XtNumber(resize_args)) )

#ifdef      BUTTONS

#ifndef MOTIF
static      Arg   resizable_on[] = {
      {XtNresizable,    (XtArgVal) True},
};

static      Arg   resizable_off[] = {
      {XtNresizable,    (XtArgVal) False},
};
#endif

static      Arg   line_args[] = {
      {XtNbackground,         (XtArgVal) 0},
      {XtNwidth,        (XtArgVal) 1},
#ifndef MOTIF
      {XtNheight,       (XtArgVal) 0},
      {XtNfromHoriz,          (XtArgVal) NULL},
      {XtNborderWidth,  (XtArgVal) 0},
      {XtNtop,          (XtArgVal) XtChainTop},
      {XtNbottom,       (XtArgVal) XtChainBottom},
      {XtNleft,         (XtArgVal) XtChainRight},
      {XtNright,        (XtArgVal) XtChainRight},
#else /* MOTIF */
      {XmNleftWidget,         (XtArgVal) NULL},
      {XmNleftAttachment,     (XtArgVal) XmATTACH_WIDGET},
      {XmNtopAttachment,      (XtArgVal) XmATTACH_FORM},
      {XmNbottomAttachment,   (XtArgVal) XmATTACH_FORM},
#endif /* MOTIF */
};

static      Arg   panel_args[] = {
      {XtNwidth,        (XtArgVal) (XTRA_WID - 1)},
#ifndef MOTIF
      {XtNheight,       (XtArgVal) 0},
      {XtNborderWidth,  (XtArgVal) 0},
      {XtNfromHoriz,          (XtArgVal) NULL},
      {XtNtop,          (XtArgVal) XtChainTop},
      {XtNbottom,       (XtArgVal) XtChainBottom},
      {XtNleft,         (XtArgVal) XtChainRight},
      {XtNright,        (XtArgVal) XtChainRight},
#else /* MOTIF */
      {XmNleftAttachment,     (XtArgVal) XmATTACH_FORM},
      {XmNtopAttachment,      (XtArgVal) XmATTACH_FORM},
      {XmNbottomAttachment,   (XtArgVal) XmATTACH_FORM},
#endif /* MOTIF */
};

static      struct {
      _Xconst     char  *label;
      _Xconst     char  *name;
      int   closure;
      int   y_pos;
      }
#define BPOS(n) (10 + (n)*28)
      command_table[] = {
            {"Quit",    "quit",           'q',        BPOS(1)},
            {"Abort",   "abort",    'Q',        BPOS(2)},
            {"Again",   "again",    '\001',           BPOS(3)},
            {"Help",    "help",           '?',        BPOS(4)},
            {"Reread",  "reread",   'R',        BPOS(5)},
            {"100%",    "sh1",            1 << 8 | 's',     BPOS(7)},
#define LOWRES_s_COMMANDS     6
            /* Good for 300dpi */
            {"50%",     "sh2",            2 << 8 | 's',     BPOS(8)},
            {"33%",     "sh3",            3 << 8 | 's',     BPOS(9)},
            {"25%",     "sh4",            4 << 8 | 's',     BPOS(10)},
#define HIRES_s_COMMANDS      9
            /* Good for 600dpi */
            {"33%",     "sh2",            3 << 8 | 's',     BPOS(8)},
            {"25%",     "sh3",            4 << 8 | 's',     BPOS(9)},
            {"17%",     "sh4",            6 << 8 | 's',     BPOS(10)},

            /* What's good for 1200dpi? */

#define PAGE_BUTTONS 12
            {"First",   "next0",    1 << 8 | 'g',   BPOS(12)},
            {"Page-10", "prev10",   10 << 8 | 'p',    BPOS(13)},
            {"Page-5",  "prev5",    5 << 8 | 'p',     BPOS(14)},
            {"Prev",    "prev",           'p',        BPOS(15)},
            {"Next",    "next",           'n',        BPOS(16)},
            {"Page+5",  "next5",    5 << 8 | 'n',     BPOS(17)},
            {"Page+10", "next10",   10 << 8 | 'n',    BPOS(18)},
            {"Last",    "next999",  'g',            BPOS(19)},
#if   PS
            {"View PS", "postscript",     'v',        BPOS(21)},
#endif
#ifdef HTEX
            {"Back",    "back",           'B',        BPOS(23)},
#endif
#ifdef SELFILE
            {"File",    "file",     '\006',             BPOS(24)},
#endif  /* SELFILE */
};

static      void  handle_command();

static      XtCallbackRec     command_call[] = {
      {handle_command, NULL},
      {NULL,            NULL},
};

static      Arg   command_args[] = {
#ifndef MOTIF
      {XtNlabel,  (XtArgVal) NULL},
#else
      {XmNlabelString, (XtArgVal) NULL},
#endif
      {XtNx,            (XtArgVal) 6},
      {XtNy,            (XtArgVal) 0},
#ifndef MOTIF
      {XtNwidth,  (XtArgVal) 64},
#else
      {XtNwidth,  (XtArgVal) 90},
#endif
      {XtNheight, (XtArgVal) 30},
#ifndef MOTIF
      {XtNcallback,     (XtArgVal) command_call},
#else
      {XmNactivateCallback, (XtArgVal) command_call},
#endif
};

void
create_buttons(h)
      XtArgVal    h;
{
  int i;

  line_args[0].value = (XtArgVal) resource._hl_Pixel;
#ifndef MOTIF
  line_args[2].value = h;
  line_args[3].value = (XtArgVal) vport_widget;
  line_widget = XtCreateManagedWidget("line", widgetClass,
                              form_widget, line_args, 
                              XtNumber(line_args));
  panel_args[1].value = h;
  panel_args[3].value = (XtArgVal) line_widget;
#endif
  panel_widget = XtCreateManagedWidget("panel", PANEL_WIDGET_CLASS,
                               form_widget, panel_args, 
                               XtNumber(panel_args));

  /* This adjusts the command table according to any shrinkbutton
     resources */
  for (i = 0; i <= XtNumber(command_table) - 4; ++i) {
    if (strncmp(command_table[i].name, "sh1",2) == 0) {
      /* It's a shrink command.  Check if the resources tell us to 
       modify it, and how */
      int j,k;

      j = atoi(&command_table[i].name[2]);
      k = resource.shrinkbutton[j-1];
      
      if (k != 0) {
      char *s = xmalloc(9);
        
      if (k < 1)
        k = 1;
      else if (k > 99)
        k = 99;

      if (k<16) {
        Sprintf(s, "%d%%", (int) 100/k);
      } else {
        /* Need more precition */
        Sprintf(s, "%.2f%%", (double) 100/k);
      }
      command_table[i].label = s;
      command_table[i].closure = k << 8 | 's';
      } /* if k != 0 */
    } /* if strncmp */
  } /* For */

  command_args[2].value = (XtArgVal) vport_widget;

  /* This loop sets up the buttons */
  for (i = 0; i < XtNumber(command_table); ++i) {
    if ( ((i==HIRES_s_COMMANDS)&&(pixels_per_inch<600)) ||
       ((i==LOWRES_s_COMMANDS)&&(pixels_per_inch>=600)) ) i+=3;
#ifndef MOTIF
    command_args[0].value = (XtArgVal) command_table[i].label;
#else /* MOTIF */
    command_args[0].value = (XtArgVal)
      XmCvtCTToXmString((char *) command_table[i].label);
#endif /* MOTIF */
    command_args[2].value = (XtArgVal) command_table[i].y_pos;
    command_call[0].closure = (XtPointer) &command_table[i].closure;
    (void) XtCreateManagedWidget(command_table[i].name,
                         BUTTON_WIDGET_CLASS, panel_widget,
                         command_args, XtNumber(command_args));
  }
#ifdef MOTIF
  line_args[2].value = (XtArgVal) panel_widget;
  line_widget = XtCreateManagedWidget("line", widgetClass, form_widget,
                              line_args, XtNumber(line_args));
  XtVaSetValues(vport_widget, XmNleftAttachment, XmATTACH_WIDGET,
            XmNleftWidget, line_widget, NULL);
#endif
}
#endif      /* BUTTONS */

#else /* !TOOLKIT */
static      Window      x_bar, y_bar;
static      int   x_bgn, x_end, y_bgn, y_end;   /* scrollbar positions */
#endif      /* TOOLKIT */

/* We split this help string into smaller pieces, because some C
implementations have been known to croak on large strings. */

static char* help_string[] =
{
    "",
    "----------------------------Help and Exiting----------------------------",
    "",
    "h or H or ? or Help",
    "     Displays this help text.",
    "",
    "q or Control-C or Control-D or Cancel or Stop or Control-Z (VAX VMS)",
    "     Quits the program.",
    "",
    "------------------------------Page Motion-------------------------------",
    "",
    "n or f or Space or Return or LineFeed or PgDn",
    "     Moves to the next page (or to the nth next page if a",
    "     number is given).",
    "",
    "p or b or Control-H or BackSpace or DELete or PgUp",
    "     Moves to the previous page (or back n pages).",
    "",
    "u or Up-arrow",
    "     Moves up two thirds of a window-full.",
    "",
    "d or Down-arrow",
    "     Moves down two thirds of a window-full.",
    "",
    "l or Left-arrow",
    "     Moves left two thirds of a window-full.",
    "",
    "r or Right-arrow",
    "     Moves right two thirds of a window-full.",
    "",
    "g or j or End",
    "     Moves to the page with the given number.  Initially,",
    "     the first page is assumed to be page number 1, but this",
    "     can be changed with the `P' keystroke, below.  If no",
    "     page number is given, then it goes to the last page.",
    "",
    "<    Move to first page in document.",
    ">    Move to last page in document.",
    "",
    "-----------------------------Other Commands-----------------------------",
    "",
    "Control-A or Again",
    "     Repeat last command (including its argument).",
    "",
    "Control-L or Clear",
    "     Redisplays the current page.",
    "",
    "Control-P",
    "     Prints bitmap unit, bit order, and byte order.",
    "",
    "^ or Home",
    "     Move to the ``home'' position of the page.  This is",
    "     normally the upper left-hand corner of the page,",
    "     depending on the margins as described in the -margins",
    "     option, above.",
    "",
    "c    Moves the page so that the point currently beneath the",
    "     cursor is moved to the middle of the window.  It also",
    "     (gasp!) warps the cursor to the same place.",
    "",
    "G    This key toggles the use of greyscale anti-aliasing for",
    "     displaying shrunken bitmaps.  In addition, the key",
    "     sequences `0G' and `1G' clear and set this flag,",
    "     respectively.  See also the -nogrey option.",
    "",
    "k    Normally when xdvi switches pages, it moves to the home",
    "     position as well.  The `k' keystroke toggles a `keep-",
    "     position' flag which, when set, will keep the same",
    "     position when moving between pages.  Also `0k' and `1k'",
    "     clear and set this flag, respectively.  See also the",
    "     -keep option.",
    "",
    "M    Sets the margins so that the point currently under the",
    "     cursor is the upper left-hand corner of the text in the",
    "     page.  Note that this command itself does not move the",
    "     image at all.  For details on how the margins are used,",
    "     see the -margins option.",
    "",
    "P    ``This is page number n.''  This can be used to make",
    "     the `g' keystroke refer to actual page numbers instead",
    "     of absolute page numbers.",
    "",
    "R    Forces the dvi file to be reread.  This allows you to",
    "     preview many versions of the same file while running",
    "     xdvi only once.",
    "",
    "s    Changes the shrink factor to the given number.  If no",
    "     number is given, the smallest factor that makes the",
    "     entire page fit in the window will be used.  (Margins",
    "     are ignored in this computation.)",
    "",
    "S    Sets the density factor to be used when shrinking",
    "     bitmaps.  This should be a number between 0 and 100;",
    "     higher numbers produce lighter characters.",
    "",
    "t    Toggles to the next unit in a sorted list of TeX dimension",
    "     units for the popup magnifier ruler.",
    "",
    "x    Toggles expert mode (in which the buttons do not appear).",
    "     Also `0x' and `1x' clear and enable this mode,",
    "     respectively.  See also the -expert option.",
    "",
    "V    Toggles Ghostscript anti-aliasing.  Also `0V' and `1V' clear",
    "     and enables this mode, respectively.  See also the the -gsalpha",
    "     option.",
    "",
#ifdef SELFILE
    "Control-F     Find another DVI file.",
    "",
#endif
#ifdef HTEX
    "B    Go back to the previous anchor.",
    "F    Follow hyperlink forward.",
    "",
#endif
    "------------------------------------------------------------------------",
};

static void
show_help()
{
    int k;

    for (k = 0; k < (sizeof(help_string)/sizeof(help_string[0])); ++k)
      (void)puts(help_string[k]);
}

/*
 *    Mechanism to keep track of the magnifier window.  The problems are,
 *    (a) if the button is released while the window is being drawn, this
 *    could cause an X error if we continue drawing in it after it is
 *    destroyed, and
 *    (b) creating and destroying the window too quickly confuses the window
 *    manager, which is avoided by waiting for an expose event before
 *    destroying it.
 */
static      short alt_stat;   /* 1 = wait for expose, */
                        /* -1 = destroy upon expose */
static      Boolean     alt_canit;  /* stop drawing this window */

/*
 *    Data for buffered events.
 */

#ifndef FLAKY_SIGPOLL
static      VOLATILE short    event_freq  = 70;
#else
#define     event_freq  70
#endif

static      void  can_exposures(), keystroke();

#ifdef      GREY
#define     gamma resource._gamma

static      void
mask_shifts(mask, pshift1, pshift2)
      Pixel mask;
      int   *pshift1, *pshift2;
{
      int   k, l;

      for (k = 0; (mask & 1) == 0; ++k)
          mask >>= 1;
      for (l = 0; (mask & 1) == 1; ++l)
          mask >>= 1;
      *pshift1 = sizeof(short) * 8 - l;
      *pshift2 = k;
}

/*
 *    Try to allocate 4 color planes for 16 colors (for GXor drawing)
 */

void
init_plane_masks()
{
      Pixel pixel;

      if (copy || plane_masks[0] != 0)
          return;

      if (XAllocColorCells(DISP, our_colormap, False, plane_masks, 4,
        &pixel, 1)) {
          /* Make sure fore_Pixel and back_Pixel are a part of the palette */
          back_Pixel = pixel;
          fore_Pixel = pixel | plane_masks[0] | plane_masks[1]
            | plane_masks[2] | plane_masks[3];
          if (mane.win != (Window) 0)
            XSetWindowBackground(DISP, mane.win, back_Pixel);
      }
      else {
          copy = True;
          puts("\
Greyscaling is running in copy mode:  your display can only display\n\
a limited number of colors at a time (typically 256), and other applications\n\
(such as netscape) are using many of them.  Running in copy mode will\n\
cause overstrike characters to appear incorrectly, and may result in\n\
poor display quality.\n\
\n\
See the section ``GREYSCALING AND COLORMAPS'' in the xdvi manual page\n\
for more details.");
          fflush(stdout);     /* useful if called by netscape */
      }
}

extern      double      pow();

#ifndef TOOLKIT
#define     XtWindow(win)     win
#endif

#define     MakeGC(fcn, fg, bg)     (values.function = fcn, \
        values.foreground=fg, values.background=bg, \
        XCreateGC(DISP, XtWindow(top_level), \
          GCFunction | GCForeground | GCBackground, &values))

void
init_pix()
{
      static      int   shrink_allocated_for = 0;
      static      float oldgamma    = 0.0;
      static      Pixel palette[17];
      XGCValues   values;
      int   i;

      if (fore_color_data.pixel == back_color_data.pixel) {
          /* get foreground and background RGB values for interpolating */
          fore_color_data.pixel = fore_Pixel;
          XQueryColor(DISP, our_colormap, &fore_color_data);
          back_color_data.pixel = back_Pixel;
          XQueryColor(DISP, our_colormap, &back_color_data);
      }

      if (our_visual->class == TrueColor) {
          /* This mirrors the non-grey code in xdvi.c */
          static int          shift1_r, shift1_g, shift1_b;
          static int          shift2_r, shift2_g, shift2_b;
          static Pixel  set_bits;
          static Pixel  clr_bits;
          unsigned int  sf_squared;

          if (oldgamma == 0.0) {
            mask_shifts(our_visual->red_mask,   &shift1_r, &shift2_r);
            mask_shifts(our_visual->green_mask, &shift1_g, &shift2_g);
            mask_shifts(our_visual->blue_mask,  &shift1_b, &shift2_b);

            set_bits = fore_color_data.pixel & ~back_color_data.pixel;
            clr_bits = back_color_data.pixel & ~fore_color_data.pixel;

            if (set_bits & our_visual->red_mask)
                set_bits |= our_visual->red_mask;
            if (clr_bits & our_visual->red_mask)
                clr_bits |= our_visual->red_mask;
            if (set_bits & our_visual->green_mask)
                set_bits |= our_visual->green_mask;
            if (clr_bits & our_visual->green_mask)
                clr_bits |= our_visual->green_mask;
            if (set_bits & our_visual->blue_mask)
                set_bits |= our_visual->blue_mask;
            if (clr_bits & our_visual->blue_mask)
                clr_bits |= our_visual->blue_mask;

            /*
             * Make the GCs
             */

            foreGC = foreGC2 = ruleGC = NULL;
            if (copy || (set_bits && clr_bits)) {
                ruleGC = MakeGC(GXcopy, fore_Pixel, back_Pixel);
                if (!resource.thorough) copy = True;
            }
            if (copy) {
                foreGC = ruleGC;
                if (!resource.copy)
                  Puts("Note:  overstrike characters may be incorrect.");
            }
            else {
                if (set_bits)
                  foreGC = MakeGC(GXor,
                    set_bits & fore_color_data.pixel, 0);
                if (clr_bits || !set_bits)
                  *(foreGC ? &foreGC2 : &foreGC) = MakeGC(GXandInverted,
                    clr_bits & ~fore_color_data.pixel, 0);
                if (!ruleGC) ruleGC = foreGC;
            }
          }

          if (mane.shrinkfactor == 1) return;
          sf_squared = mane.shrinkfactor * mane.shrinkfactor;

          if (shrink_allocated_for < mane.shrinkfactor) {
            if (pixeltbl != NULL) {
                free((char *) pixeltbl);
                if (pixeltbl_t != NULL)
                  free((char *) pixeltbl_t);
            }
            pixeltbl = xmalloc((sf_squared + 1) * sizeof(Pixel));
            if (foreGC2 != NULL)
                pixeltbl_t = xmalloc((sf_squared + 1) * sizeof(Pixel));
            shrink_allocated_for = mane.shrinkfactor;
          }

          /*
           * Compute pixel values directly.
           */

#define     SHIFTIFY(x, shift1, shift2)   ((((Pixel)(x)) >> (shift1)) << (shift2))

          for (i = 0; i <= sf_squared; ++i) {
            double            frac  = gamma > 0
                ? pow((double) i / sf_squared, 1 / gamma)
                : 1 - pow((double) (sf_squared - i) / sf_squared, -gamma);
            unsigned int      red, green, blue;
            Pixel       pixel;

            red = frac
              * ((double) fore_color_data.red - back_color_data.red)
              + back_color_data.red;
            green = frac
              * ((double) fore_color_data.green - back_color_data.green)
              + back_color_data.green;
            blue = frac
              * ((double) fore_color_data.blue - back_color_data.blue)
              + back_color_data.blue;

            pixel = SHIFTIFY(red,   shift1_r, shift2_r) |
                  SHIFTIFY(green, shift1_g, shift2_g) |
                  SHIFTIFY(blue,  shift1_b, shift2_b);

            if (copy) pixeltbl[i] = pixel;
            else {
                pixeltbl[i] = set_bits ? pixel & set_bits
                  : ~pixel & clr_bits;
                if (pixeltbl_t != NULL)
                  pixeltbl_t[i] = ~pixel & clr_bits;
            }
          }

#undef      SHIFTIFY

          return;
      }

      /* if not TrueColor ... */

      if (gamma != oldgamma) {
          XColor  color;

          if (oldgamma == 0.0)
            init_plane_masks();

          for (i = 0; i < 16; ++i) {
            double      frac = gamma > 0 ? pow((double) i / 15, 1 / gamma)
                : 1 - pow((double) (15 - i) / 15, -gamma);

            color.red = frac
              * ((double) fore_color_data.red - back_color_data.red)
              + back_color_data.red;
            color.green = frac
              * ((double) fore_color_data.green - back_color_data.green)
              + back_color_data.green;
            color.blue = frac
              * ((double) fore_color_data.blue - back_color_data.blue)
              + back_color_data.blue;

            color.pixel = back_Pixel;
            color.flags = DoRed | DoGreen | DoBlue;

            if (!copy) {
                if (i & 1) color.pixel |= plane_masks[0];
                if (i & 2) color.pixel |= plane_masks[1];
                if (i & 4) color.pixel |= plane_masks[2];
                if (i & 8) color.pixel |= plane_masks[3];
                XStoreColor(DISP, our_colormap, &color);
                palette[i] = color.pixel;
            }
            else {
                if (XAllocColor(DISP, our_colormap, &color))
                  palette[i] = color.pixel;
                else
                  palette[i] = (i * 100 >= density * 15)
                      ? fore_Pixel : back_Pixel;
            }
          }

          foreGC = ruleGC = MakeGC(copy ? GXcopy : GXor,
            fore_Pixel, back_Pixel);
          foreGC2 = NULL;

          oldgamma = gamma;
      }

      if (mane.shrinkfactor == 1) return;

      if (shrink_allocated_for < mane.shrinkfactor) {
          if (pixeltbl != NULL) free((char *) pixeltbl);
          pixeltbl = xmalloc((unsigned)
            (mane.shrinkfactor * mane.shrinkfactor + 1) * sizeof(Pixel));
          shrink_allocated_for = mane.shrinkfactor;
      }

      for (i = 0; i <= mane.shrinkfactor * mane.shrinkfactor; ++i)
          pixeltbl[i] =
            palette[(i * 30 + mane.shrinkfactor * mane.shrinkfactor)
                / (2 * mane.shrinkfactor * mane.shrinkfactor)];
}

#undef MakeGC

void
init_colors()
{
      static      Boolean     warn_done = False;
      Boolean     warn = False;

      copy = resource.copy;

#ifdef      GREY
      if (use_grey)
          init_pix();
      else
#endif
      {
          XGCValues     values;
          Pixel   set_bits = (Pixel) (fore_Pixel & ~back_Pixel);
          Pixel   clr_bits = (Pixel) (back_Pixel & ~fore_Pixel);

          if (copy == Maybe)
            copy = (!resource.thorough
                && DefaultDepthOfScreen(SCRN) > 1);

#define     MakeGC(fcn, fg, bg)     (values.function = fcn, values.foreground=fg,\
            values.background=bg,\
            XCreateGC(DISP, RootWindowOfScreen(SCRN),\
                  GCFunction|GCForeground|GCBackground, &values))

          foreGC = foreGC2 = ruleGC = NULL;
          if (copy || (set_bits && clr_bits))
            ruleGC = MakeGC(GXcopy, fore_Pixel, back_Pixel);
          if (copy) foreGC = ruleGC;
          else if (!resource.thorough && ruleGC) {
            foreGC = ruleGC;
            warn = True;
          }
          else {
            if (set_bits) foreGC = MakeGC(GXor, set_bits, 0);
            if (clr_bits || !set_bits)
                *(foreGC ? &foreGC2 : &foreGC) =
                  MakeGC(GXandInverted, clr_bits, 0);
            if (!ruleGC) ruleGC = foreGC;
          }
      }

      if (warn && !warn_done) {
          Puts("Note:  overstrike characters may be incorrect.");
          warn_done = True; /* Print warning only once. */
      }
}

/*
 *    Ruler routines
 */

static int
tick_scale(k)
      int         k;
{
    if (k == 0)
      return 3;
    else if ((k % 1000) == 0)
      return 7;
    else if ((k % 500) == 0)
      return 6;
    else if ((k % 100) == 0)
      return 5;
    else if ((k % 50) == 0)
      return 4;
    else if ((k % 10) == 0)
      return 3;
    else if ((k % 5) == 0)
      return 2;
    else
      return 1;
}


static void
draw_rulers(width, height, ourGC)
      unsigned int      width, height;
      GC          ourGC;
{
    int           k;                /* tick counter */
    double  old_pixels_per_tick;
    double  pixels_per_tick;
    int           scale;
    int           tick_offset;            /* offset along axes */
    int           x;                /* coordinates of top-left popup */
    int           y;                /* window corner */
    double  xx;               /* coordinates of tick */
    double  yy;               /* coordinates of tick */
    static char *last_tick_units = "";    /* memory of last tick units */

    if (tick_length <= 0)           /* user doesn't want tick marks */
      return;

    x = 0;        /* the pop-up window always has origin (0,0)  */
    y = 0;

    /* We need to clear the existing window to remove old rulers.  I think
       that this could be avoided if draw_rulers() could be invoked earlier.
       The expose argument in XClearArea() must be True to force redrawing
       of the text inside the popup window. Also, it would be better to draw
       the rulers before painting the text, so that rulers would not
       overwrite the text, but I haven't figured out yet how to arrange
       that. */

    XClearArea(DISP, alt.win, x, y, width, height, True);

    /* The global resource._pixels_per_inch tells us how to find the ruler
    scale.  For example, 300dpi corresponds to these TeX units:

      1 TeX point (pt)  =   4.151      pixels
      1 big point (bp)  =   4.167      pixels
      1 pica (pc)             =  49.813      pixels
      1 cicero (cc)           =  53.501      pixels
        1 didot point (dd)    =   4.442      pixels
      1 millimeter (mm)       =  11.811      pixels
      1 centimeter (cm)       = 118.110      pixels
      1 inch (in)             = 300.000      pixels
        1 scaled point (sp)   =   0.00006334 pixels

    The user can select the units via a resource (e.g. XDvi*tickUnits: bp),
    or a command-line option (e.g. -xrm '*tickUnits: cm').  The length of
    the ticks can be controlled by a resource (e.g. XDvi*tickLength: 10), or
    a command-line option (e.g. -xrm '*tickLength: 10000').  If the tick
    length exceeds the popup window size, then a graph-paper grid is drawn
    over the whole window.  Zero, or negative, tick length completely
    suppresses rulers. */

    pixels_per_tick = (double)resource._pixels_per_inch;
    if (strcmp(tick_units,"pt") == 0)
      pixels_per_tick /= 72.27;
    else if (strcmp(tick_units,"bp") == 0)
      pixels_per_tick /= 72.0;
    else if (strcmp(tick_units,"in") == 0)
      /* NO-OP */;
    else if (strcmp(tick_units,"cm") == 0)
      pixels_per_tick /= 2.54;
    else if (strcmp(tick_units,"mm") == 0)
      pixels_per_tick /= 25.4;
    else if (strcmp(tick_units,"dd") == 0)
      pixels_per_tick *= (1238.0 / 1157.0) / 72.27;
    else if (strcmp(tick_units,"cc") == 0)
      pixels_per_tick *= 12.0 * (1238.0 / 1157.0) / 72.27;
    else if (strcmp(tick_units,"pc") == 0)
      pixels_per_tick *= 12.0 /72.27;
    else if (strcmp(tick_units,"sp") == 0)
      pixels_per_tick /= (65536.0 * 72.27);
    else
    {
      Printf("Unrecognized tickUnits [%s]: defaulting to TeX points [pt]\n",
            tick_units);
      tick_units = "pt";
      pixels_per_tick /= 72.27;
    }

    /* To permit accurate measurement in the popup window, we can reasonably
    place tick marks about 3 to 10 pixels apart, so we scale the computed
    pixels_per_tick by a power of ten to bring it into that range. */

    old_pixels_per_tick = pixels_per_tick; /* remember the original scale */
    while (pixels_per_tick < 3.0)
      pixels_per_tick *= 10.0;
    while (pixels_per_tick > 30.0)
      pixels_per_tick /= 10.0;
    if (strcmp(last_tick_units, tick_units) != 0)
    { /* tell user what the ruler scale is, but only when it changes */
      if (old_pixels_per_tick != pixels_per_tick)
          Printf("Ruler tick interval adjusted to represent %.2f%s\n",
               pixels_per_tick/old_pixels_per_tick, tick_units);
      else if (debug & DBG_EVENT)
          Printf("Ruler tick interval represents 1%s\n", tick_units);
    }

    /* In order to make the ruler as accurate as possible, given the coarse
    screen resolution, we compute tick positions in floating-point
    arithmetic, then round to nearest integer values. */

    for (k = 0, xx = 0.0; xx < (double)width; k++, xx += pixels_per_tick)
    {                   /* draw vertical ticks on top and bottom */
      tick_offset = (int)(0.5 + xx);      /* round to nearest pixel */
      scale = tick_scale(k);
      XDrawLine(DISP, alt.win, ourGC,
              x + tick_offset, y,
              x + tick_offset, y + scale*tick_length);
      XDrawLine(DISP, alt.win, ourGC,
              x + tick_offset, y + height,
              x + tick_offset, y + height - scale*tick_length);
    }

    for (k = 0, yy = 0.0; yy < (double)height; k++, yy += pixels_per_tick)
    {                   /* draw horizontal ticks on left and right */
      tick_offset = (int)(0.5 + yy);      /* round to nearest pixel */
      scale = tick_scale(k);
      XDrawLine(DISP, alt.win, ourGC,
              x,                     y + tick_offset,
              x + scale*tick_length, y + tick_offset);
      XDrawLine(DISP, alt.win, ourGC,
              x + width,                     y + tick_offset,
              x + width - scale*tick_length, y + tick_offset);
    }

    last_tick_units = tick_units;

    XFlush(DISP);             /* bring window up-to-date */
}

#undef      MakeGC

#endif      /* GREY */

/*
 *    Event-handling routines
 */

static      void
expose(windowrec, x, y, w, h)
      register struct WindowRec *windowrec;
      int         x, y;
      unsigned int      w, h;
{
      if (windowrec->min_x > x) windowrec->min_x = x;
      if (windowrec->max_x < x + w)
          windowrec->max_x = x + w;
      if (windowrec->min_y > y) windowrec->min_y = y;
      if (windowrec->max_y < y + h)
          windowrec->max_y = y + h;
}

static      void
clearexpose(windowrec, x, y, w, h)
      struct WindowRec *windowrec;
      int         x, y;
      unsigned int      w, h;
{
      XClearArea(DISP, windowrec->win, x, y, w, h, False);
      expose(windowrec, x, y, w, h);
}

static      void
scrollwindow(windowrec, x0, y0)
      register struct WindowRec *windowrec;
      int   x0, y0;
{
      int   x, y;
      int   x2 = 0, y2 = 0;
      int   ww, hh;

      x = x0 - windowrec->base_x;
      y = y0 - windowrec->base_y;
      ww = windowrec->width - x;
      hh = windowrec->height - y;
      windowrec->base_x = x0;
      windowrec->base_y = y0;
      if (currwin.win == windowrec->win) {
          currwin.base_x = x0;
          currwin.base_y = y0;
      }
      windowrec->min_x -= x;
      if (windowrec->min_x < 0) windowrec->min_x = 0;
      windowrec->max_x -= x;
      if (windowrec->max_x > windowrec->width)
          windowrec->max_x = windowrec->width;
      windowrec->min_y -= y;
      if (windowrec->min_y < 0) windowrec->min_y = 0;
      windowrec->max_y -= y;
      if (windowrec->max_y > windowrec->height)
          windowrec->max_y = windowrec->height;
      if (x < 0) {
          x2 = -x;
          x = 0;
          ww = windowrec->width - x2;
      }
      if (y < 0) {
          y2 = -y;
          y = 0;
          hh = windowrec->height - y2;
      }
      if (ww <= 0 || hh <= 0) {
          XClearWindow(DISP, windowrec->win);
          windowrec->min_x = windowrec->min_y = 0;
          windowrec->max_x = windowrec->width;
          windowrec->max_y = windowrec->height;
      }
      else {
          XCopyArea(DISP, windowrec->win, windowrec->win, copyGC,
            x, y, (unsigned int) ww, (unsigned int) hh, x2, y2);
          if (x > 0)
            clearexpose(windowrec, ww, 0,
                (unsigned int) x, windowrec->height);
          if (x2 > 0)
            clearexpose(windowrec, 0, 0,
                (unsigned int) x2, windowrec->height);
          if (y > 0)
            clearexpose(windowrec, 0, hh,
                windowrec->width, (unsigned int) y);
          if (y2 > 0)
            clearexpose(windowrec, 0, 0,
                windowrec->width, (unsigned int) y2);
      }
}

#ifdef      TOOLKIT

/*
 *    routines for X11 toolkit
 */

static      Arg   arg_wh[] = {
      {XtNwidth,  (XtArgVal) &window_w},
      {XtNheight, (XtArgVal) &window_h},
};

static      Position    window_x, window_y;
static      Arg   arg_xy[] = {
      {XtNx,            (XtArgVal) &window_x},
      {XtNy,            (XtArgVal) &window_y},
};

#define     get_xy()    XtGetValues(draw_widget, arg_xy, XtNumber(arg_xy))

#define     mane_base_x 0
#define     mane_base_y 0


#ifdef MOTIF

static      int
set_bar_value(bar, value, max)
      Widget      bar;
      int   value;
      int   max;
{
      XmScrollBarCallbackStruct     call_data;

      if (value > max) value = max;
      if (value < 0) value = 0;
      call_data.value = value;
      XtVaSetValues(bar, XmNvalue, value, NULL);
      XtCallCallbacks(bar, XmNvalueChangedCallback, &call_data);
      return value;
}

#endif /* MOTIF */

/* not static because SELFILE stuff in dvi_init.c needs it */
void 
home(scrl)
      Boolean     scrl;
{
#if   PS
      psp.interrupt();
#endif
      if (!scrl) XUnmapWindow(DISP, mane.win);
#ifndef MOTIF
      get_xy();
      if (x_bar != NULL) {
          register int coord = (page_w - clip_w) / 2;

          if (coord > home_x / mane.shrinkfactor)
            coord = home_x / mane.shrinkfactor;
          XtCallCallbacks(x_bar, XtNscrollProc,
            (XtPointer) (window_x + coord));
      }
      if (y_bar != NULL) {
          register int coord = (page_h - clip_h) / 2;

          if (coord > home_y / mane.shrinkfactor)
            coord = home_y / mane.shrinkfactor;
          XtCallCallbacks(y_bar, XtNscrollProc,
            (XtPointer) (window_y + coord));
      }
#else /* MOTIF */
      {
          int value;

          value = (page_w - clip_w) / 2;
          if (value > home_x / mane.shrinkfactor)
            value = home_x / mane.shrinkfactor;
          (void) set_bar_value(x_bar, value, (int) (page_w - clip_w));

          value = (page_h - clip_h) / 2;
          if (value > home_y / mane.shrinkfactor)
            value = home_y / mane.shrinkfactor;
          (void) set_bar_value(y_bar, value, (int) (page_h - clip_h));
      }
#endif /* MOTIF */
      if (!scrl) {
          XMapWindow(DISP, mane.win);
          /* Wait for the server to catch up---this eliminates flicker. */
          XSync(DISP, False);
      }
}


#ifndef MOTIF
      /*ARGSUSED*/
static      void
handle_destroy_bar(w, client_data, call_data)
      Widget            w;
      XtPointer   client_data;
      XtPointer   call_data;
{
      * (Widget *) client_data = NULL;
}
#endif


static      Boolean resized = False;

static      void
get_geom()
{
      static      Dimension   new_clip_w, new_clip_h;
      static      Arg         arg_wh_clip[] = {
            {XtNwidth,  (XtArgVal) &new_clip_w},
            {XtNheight, (XtArgVal) &new_clip_h},
      };
      register int      old_clip_w;

      XtGetValues(vport_widget, arg_wh, XtNumber(arg_wh));
      XtGetValues(clip_widget, arg_wh_clip, XtNumber(arg_wh_clip));
#ifndef MOTIF
      /* Note:  widgets may be destroyed but not forgotten */
      if (x_bar == NULL) {
          x_bar = XtNameToWidget(vport_widget, "horizontal");
          if (x_bar != NULL)
            XtAddCallback(x_bar, XtNdestroyCallback, handle_destroy_bar,
                (XtPointer) &x_bar);
      }
      if (y_bar == NULL) {
          y_bar = XtNameToWidget(vport_widget, "vertical");
          if (y_bar != NULL)
            XtAddCallback(y_bar, XtNdestroyCallback, handle_destroy_bar,
                (XtPointer) &y_bar);
      }
#endif
      old_clip_w = clip_w;
                  /* we need to do this because */
                  /* sizeof(Dimension) != sizeof(int) */
      clip_w = new_clip_w;
      clip_h = new_clip_h;
      if (old_clip_w == 0) home(False);
      resized = False;
}

/*
 *    callback routines
 */

      /*ARGSUSED*/
void
handle_resize(widget, junk, event, cont)
      Widget      widget;
      XtPointer junk;
      XEvent      *event;
      Boolean     *cont;            /* unused */
{
      resized = True;
}

#ifdef      BUTTONS
      /*ARGSUSED*/
static      void
handle_command(widget, client_data_p, call_data)
      Widget      widget;
      XtPointer client_data_p;
      XtPointer call_data;
{
      int   client_data = * (int *) client_data_p;

      keystroke((client_data) & 0xff, (client_data) >> 8,
            ((client_data) >> 8) != 0, (XEvent *) NULL);
}

      /*ARGSUSED*/
static      void
handle_destroy_buttons(w, client_data, call_data)
      Widget            w;
      XtPointer   client_data;
      XtPointer   call_data;
{
      if (--destroy_count != 0) return;
#ifndef MOTIF
      XtSetValues(vport_widget, resizable_on, XtNumber(resizable_on));
      if (resource.expert) {
          XtGetValues(form_widget, arg_wh, XtNumber(arg_wh));
          XdviResizeWidget(vport_widget, window_w, window_h);
      }
      else {
          XdviResizeWidget(vport_widget, window_w -= XTRA_WID, window_h);
          create_buttons((XtArgVal) window_h);
      }
#else /* MOTIF */
      if (resource.expert)
          XtVaSetValues(vport_widget,
            XmNleftAttachment, XmATTACH_FORM,
            XmNleftOffset, 0,
            NULL);
      else {
          create_buttons((XtArgVal) 0);   /* the argument is ignored */
          window_w -= XTRA_WID;
      }
#endif /* MOTIF */
}

#endif      /* BUTTONS */

void
reconfig()
{
#ifdef      BUTTONS
#ifndef MOTIF
      XtSetValues(vport_widget, resizable_off, XtNumber(resizable_off));
#endif
#endif
      XdviResizeWidget(draw_widget, page_w, page_h);
      get_geom();
}


#ifdef HTEX

#define BIGBUF 32768
char anchorpaintstring[BIGBUF];
static Arg new_paint_args[] = {
      {XtNstring, (XtArgVal) anchorpaintstring},
};

/* Using Text widget ??? - see if this works... */
void paint_anchor(text)
char *text;
{
      static long pos = 0; /* Keep track of how many characters we've added */
      int len;
      char *firstnl;

      if (text == NULL) { /* Not on anchor any more */
            if ((pos > 0) && (pos < BIGBUF) && (anchorpaintstring[pos-1] != '\n')) {
                  anchorpaintstring[pos]= '\n'; /* But we were */
                  anchorpaintstring[pos+1]= '\0';
                  pos += 1;
                  XtSetValues(anchor_info, new_paint_args,
                        XtNumber(new_paint_args));
                  XawTextSetInsertionPoint(anchor_info, pos);
            }
            return;
      } /* There IS some anchor text under the mouse */
      len = strlen(text);
      if (!strcmp(text, anchorpaintstring+pos-len)) { /* Still on same anchor */
            return;
      }
      if (len > BIGBUF) { /* Try it anyway: */
            text[BIGBUF-1] = '\0';
            len = BIGBUF;
      }
      if ((pos + len) > BIGBUF) { /* Fix in case of overflows... */
            firstnl = strchr(anchorpaintstring+pos+len-BIGBUF, '\n');
            if (firstnl == NULL) {
                  pos = 0;
            } else {
                  strcpy(anchorpaintstring,firstnl+1);
                  pos -= 1 + firstnl - anchorpaintstring;
            }
      }
      if (pos < 0) pos = 0; /* Shouldn't happen but... */
      sprintf(anchorpaintstring+pos,"\n%s", text);
      pos += len+1;

      XtSetValues(anchor_info, new_paint_args, XtNumber(new_paint_args));
      XawTextSetInsertionPoint(anchor_info, pos);
      XawTextDisplay(anchor_info);
}

extern char anchorsearchstring[]; /* not being used? */

/* Callback for anchor search: */
void search_callback(w, c_p, call_data)
Widget w;
XtPointer c_p, call_data;
{
      int len;
      char *cp;

      cp = XawDialogGetValueString(anchor_search);
      if (cp == NULL) return;
      len = strlen(cp);
      strcpy(anchorsearchstring,cp);
      if (strchr(cp,'\n') == NULL) {
            anchorsearchstring[len] = '\n';
            anchorsearchstring[len+1] = '\0';
      }
      len = strchr(anchorsearchstring,'\n') - anchorsearchstring + 1;
      add_search(anchorsearchstring, len);
}
#endif

#else /* not TOOLKIT */

#ifdef HTEX
/* The anchor window stuff: */

void paint_anchor(text)
char *text;
{
      ClearArea(anchor_info, 1, 1, clip_w/2, BAR_THICK);
      if (text != NULL) XDrawString(DISP, anchor_info, foreGC,
            1 , BAR_WID, text, strlen(text));
}

#endif

/*
 *    brute force scrollbar routines
 */

static      void
paint_x_bar()
{
      register int      new_x_bgn = mane.base_x * clip_w / page_w;
      register int      new_x_end = (mane.base_x + clip_w) * clip_w / page_w;

      if (new_x_bgn >= x_end || x_bgn >= new_x_end) { /* no overlap */
          XClearArea(DISP, x_bar, x_bgn, 1, x_end - x_bgn, BAR_WID, False);
          XFillRectangle(DISP, x_bar, ruleGC,
            new_x_bgn, 1, new_x_end - new_x_bgn, BAR_WID);
      }
      else {            /* this stuff avoids flicker */
          if (x_bgn < new_x_bgn)
            XClearArea(DISP, x_bar, x_bgn, 1, new_x_bgn - x_bgn,
                BAR_WID, False);
          else
            XFillRectangle(DISP, x_bar, ruleGC,
                new_x_bgn, 1, x_bgn - new_x_bgn, BAR_WID);
          if (new_x_end < x_end)
            XClearArea(DISP, x_bar, new_x_end, 1, x_end - new_x_end,
                BAR_WID, False);
          else
            XFillRectangle(DISP, x_bar, ruleGC,
                x_end, 1, new_x_end - x_end, BAR_WID);
      }
      x_bgn = new_x_bgn;
      x_end = new_x_end;
}

static      void
paint_y_bar()
{
      register int      new_y_bgn = mane.base_y * clip_h / page_h;
      register int      new_y_end = (mane.base_y + clip_h) * clip_h / page_h;

      if (new_y_bgn >= y_end || y_bgn >= new_y_end) { /* no overlap */
          XClearArea(DISP, y_bar, 1, y_bgn, BAR_WID, y_end - y_bgn, False);
          XFillRectangle(DISP, y_bar, ruleGC,
            1, new_y_bgn, BAR_WID, new_y_end - new_y_bgn);
      }
      else {            /* this stuff avoids flicker */
          if (y_bgn < new_y_bgn)
            XClearArea(DISP, y_bar, 1, y_bgn, BAR_WID, new_y_bgn - y_bgn,
                False);
          else
            XFillRectangle(DISP, y_bar, ruleGC,
                1, new_y_bgn, BAR_WID, y_bgn - new_y_bgn);
          if (new_y_end < y_end)
            XClearArea(DISP, y_bar, 1, new_y_end,
                BAR_WID, y_end - new_y_end, False);
          else
            XFillRectangle(DISP, y_bar, ruleGC,
                1, y_end, BAR_WID, new_y_end - y_end);
      }
      y_bgn = new_y_bgn;
      y_end = new_y_end;
}

static      void
scrollmane(x, y)
      int   x, y;
{
      register int      old_base_x = mane.base_x;
      register int      old_base_y = mane.base_y;

#if   PS
      psp.interrupt();
#endif
      if (x > (int) (page_w - clip_w)) x = page_w - clip_w;
      if (x < 0) x = 0;
      if (y > (int) (page_h - clip_h)) y = page_h - clip_h;
      if (y < 0) y = 0;
      scrollwindow(&mane, x, y);
      if (old_base_x != mane.base_x && x_bar) paint_x_bar();
      if (old_base_y != mane.base_y && y_bar) paint_y_bar();
}

void
reconfig()
{
      int   x_thick = 0;
      int   y_thick = 0;

            /* determine existence of scrollbars */
      if (window_w < page_w) x_thick = BAR_THICK;
      if (window_h - x_thick < page_h) y_thick = BAR_THICK;
      clip_w = window_w - y_thick;
      if (clip_w < page_w) x_thick = BAR_THICK;
      clip_h = window_h - x_thick;

            /* process drawing (clip) window */
      if (mane.win == (Window) 0) { /* initial creation */
          XWindowAttributes attrs;

          mane.win = XCreateSimpleWindow(DISP, top_level, y_thick, x_thick,
                  (unsigned int) clip_w, (unsigned int) clip_h, 0,
                  brdr_Pixel, back_Pixel);
          XSelectInput(DISP, mane.win, ExposureMask |
#ifdef HTEX
                  PointerMotionMask | PointerMotionHintMask |
                  ButtonPressMask | ButtonReleaseMask);
#else
                  ButtonPressMask | ButtonMotionMask | ButtonReleaseMask);
#endif
          (void) XGetWindowAttributes(DISP, mane.win, &attrs);
          backing_store = attrs.backing_store;
          XMapWindow(DISP, mane.win);
      }
      else
          XMoveResizeWindow(DISP, mane.win, y_thick, x_thick, clip_w, clip_h);

#ifdef HTEX
      if (anchor_info) {
            XMoveResizeWindow(DPY anchor_info,
                y_thick - 1, x_thick - BAR_THICK - 1,
                               clip_w/2, BAR_THICK - 1);
            paint_anchor(NULL);
            XMoveResizeWindow(DPY anchor_search,
                y_thick + clip_w/2 - 1, x_thick - BAR_THICK - 1,
                                     clip_w/2, BAR_THICK - 1);
      } else {
            anchor_info = XCreateSimpleWindow(DISP, top_level, y_thick - 1,
                        x_thick - BAR_THICK -1,
                        (unsigned int) clip_w/2, BAR_THICK - 1, 1,
                        brdr_Pixel, back_Pixel);
            XSelectInput(DISP, anchor_info, ExposureMask);
            anchor_search = XCreateSimpleWindow(DISP, top_level,
                        y_thick + clip_w/2 - 1,
                        x_thick - BAR_THICK -1,
                        (unsigned int) clip_w/2, BAR_THICK - 1, 1,
                        brdr_Pixel, back_Pixel);
            XSelectInput(DISP, anchor_search, ExposureMask|KeyPressMask);
            XMapWindow(DPY anchor_info);
            XMapWindow(DPY anchor_search);
      }
#endif
            /* process scroll bars */
      if (x_thick) {
          if (x_bar) {
            XMoveResizeWindow(DISP, x_bar,
                y_thick - 1, -1, clip_w, BAR_THICK - 1);
            paint_x_bar();
          }
          else {
            x_bar = XCreateSimpleWindow(DISP, top_level, y_thick - 1, -1,
                        (unsigned int) clip_w, BAR_THICK - 1, 1,
                        brdr_Pixel, back_Pixel);
            XSelectInput(DISP, x_bar,
                  ExposureMask | ButtonPressMask | Button2MotionMask);
            XMapWindow(DISP, x_bar);
          }
          x_bgn = mane.base_x * clip_w / page_w;
          x_end = (mane.base_x + clip_w) * clip_w / page_w;
      }
      else
          if (x_bar) {
            XDestroyWindow(DISP, x_bar);
            x_bar = (Window) 0;
          }

      if (y_thick) {
          if (y_bar) {
            XMoveResizeWindow(DISP, y_bar,
                -1, x_thick - 1, BAR_THICK - 1, clip_h);
            paint_y_bar();
          }
          else {
            y_bar = XCreateSimpleWindow(DISP, top_level, -1, x_thick - 1,
                        BAR_THICK - 1, (unsigned int) clip_h, 1,
                        brdr_Pixel, back_Pixel);
            XSelectInput(DISP, y_bar,
                  ExposureMask | ButtonPressMask | Button2MotionMask);
            XMapWindow(DISP, y_bar);
          }
          y_bgn = mane.base_y * clip_h / page_h;
          y_end = (mane.base_y + clip_h) * clip_h / page_h;
      }
      else
          if (y_bar) {
            XDestroyWindow(DISP, y_bar);
            y_bar = (Window) 0;
          }
}

static      void
home(scrl)
      Boolean     scrl;
{
      int   x = 0, y = 0;

      if (page_w > clip_w) {
          x = (page_w - clip_w) / 2;
          if (x > home_x / mane.shrinkfactor)
            x = home_x / mane.shrinkfactor;
      }
      if (page_h > clip_h) {
          y = (page_h - clip_h) / 2;
          if (y > home_y / mane.shrinkfactor)
            y = home_y / mane.shrinkfactor;
      }
      if (scrl)
          scrollmane(x, y);
      else {
          mane.base_x = x;
          mane.base_y = y;
          if (currwin.win == mane.win) {
            currwin.base_x = x;
            currwin.base_y = y;
          }
          if (x_bar) paint_x_bar();
          if (y_bar) paint_y_bar();
      }
}

#define     get_xy()
#define     window_x 0
#define     window_y 0
#define     mane_base_x mane.base_x
#define     mane_base_y mane.base_y
#endif      /* not TOOLKIT */

static      void
compute_mag_pos(xp, yp)
      int   *xp, *yp;
{
      register int t;

      t = mag_x + main_x - alt.width/2;
      if (t > WidthOfScreen(SCRN) - (int) alt.width - 2*MAGBORD)
          t = WidthOfScreen(SCRN) - (int) alt.width - 2*MAGBORD;
      if (t < 0) t = 0;
      *xp = t;
      t = mag_y + main_y - alt.height/2;
      if (t > HeightOfScreen(SCRN) - (int) alt.height - 2*MAGBORD)
          t = HeightOfScreen(SCRN) - (int) alt.height - 2*MAGBORD;
      if (t < 0) t = 0;
      *yp = t;
}


#define     TRSIZE      100

#ifdef      TOOLKIT
      /*ARGSUSED*/
void
handle_key(widget, junk, eventp, cont)
      Widget      widget;
      XtPointer junk;
      XEvent      *eventp;
      Boolean     *cont;            /* unused */
#else /* !TOOLKIT */
void
handle_key(eventp)
      XEvent *eventp;
#endif      /* TOOLKIT */
{
      static      Boolean     has_arg           = False;
      static      int   number            = 0;
      static      int   sign        = 1;
      char  ch;
      Boolean     arg0;
      int   number0;
      char  trbuf[TRSIZE];
      int   nbytes;

      nbytes = XLookupString(&eventp->xkey, trbuf, TRSIZE, (KeySym *) NULL,
          (XComposeStatus *) NULL);
      if (nbytes == 0) return;
      ch = '\0';
      if (nbytes == 1) ch = *trbuf;
      if (ch >= '0' && ch <= '9') {
          has_arg = True;
          number = number * 10 + sign * (ch - '0');
          return;
      }
      else if (ch == '-') {
          has_arg = True;
          sign = -1;
          number = 0;
          return;
      }
      number0 = number;
      number = 0;
      sign = 1;
      arg0 = has_arg;
      has_arg = False;
      keystroke(ch, number0, arg0, eventp);
}

#ifdef      TOOLKIT
      /*ARGSUSED*/
void
handle_button(widget, junk, ev, cont)
      Widget      widget;
      XtPointer junk;
      XEvent *ev;
#define     event (&(ev->xbutton))
      Boolean     *cont;            /* unused */
#else /* !TOOLKIT */
void
handle_button(event)
      XButtonEvent *event;
#endif      /* TOOLKIT */
{
      int   x, y;
      struct mg_size_rec      *size_ptr = mg_size + event->button - 1;
      XSetWindowAttributes attr;

#ifdef HTEX
      if ((event->button == 1)||(event->button == 2)) {
            if (pointerlocate(&x, &y)) {
      /* Only do this if there's actually an href right there */
                  int ret;
                  /* screen_to_page(&mane,x,y,&page,&px,&py); */
                  if (event->button == 2) HTeXnext_extern = 1;
                  ret = htex_handleref(current_page, x, y);
                  HTeXnext_extern = 0;
                  if (ret == 1) return;
            }
      }
#endif
      if (alt.win != (Window) 0 || mane.shrinkfactor == 1 || size_ptr->w <= 0)
          XBell(DISP, 20);
      else {
          mag_x = event->x;
          mag_y = event->y;
          alt.width = size_ptr->w;
          alt.height = size_ptr->h;
          main_x = event->x_root - mag_x;
          main_y = event->y_root - mag_y;
          compute_mag_pos(&x, &y);
          alt.base_x = (event->x + mane_base_x) * mane.shrinkfactor -
            alt.width/2;
          alt.base_y = (event->y + mane_base_y) * mane.shrinkfactor -
            alt.height/2;
          attr.save_under = True;
          attr.border_pixel = brdr_Pixel;
          attr.background_pixel = back_Pixel;
          attr.override_redirect = True;
#ifdef GREY
          attr.colormap = our_colormap;
#endif
          alt.win = XCreateWindow(DISP, RootWindowOfScreen(SCRN),
                  x, y, alt.width, alt.height, MAGBORD,
                  our_depth, InputOutput, our_visual,
                  CWSaveUnder | CWBorderPixel | CWBackPixel |
#ifdef GREY
                  CWColormap |
#endif
                  CWOverrideRedirect, &attr);
          XSelectInput(DISP, alt.win, ExposureMask);
          XMapWindow(DISP, alt.win);

          /*****************************************************************
          This call will draw the point rulers when the magnifier first
          pops up, if the XDvi*delayRulers resource is false.  Some users
          may prefer rulers to remain invisible until the magnifier is
          moved, so the default is true.  Rulers can be suppressed entirely
          by setting the XDvi*tickLength resource to zero or negative.

          It is better to use highGC for draw_rulers() than foreGC,
          because this allows the ruler to be drawn in a different color,
          helping to distinguish ruler ticks from normal typeset text.
          *****************************************************************/
          if (!delay_rulers)
            draw_rulers(alt.width, alt.height, highGC);

          alt_stat = 1; /* waiting for exposure */
      }
}

#ifdef      TOOLKIT
#undef      event

      /*ARGSUSED*/
void
handle_motion(widget, junk, ev, cont)
      Widget      widget;
      XtPointer junk;
      XEvent *ev;
#define     event (&(ev->xmotion))
      Boolean     *cont;            /* unused */
{
#ifdef HTEX
      int x, y;

/* APS Modification required because of changes in motion events selected: */
      /* We asked only for hints, so check where pointer is: */
      if (pointerlocate(&x, &y)) {
            if ((event->state&(Button1Mask|Button2Mask|Button3Mask|
                              Button4Mask|Button5Mask)) == 0) {
                  htex_displayanchor(current_page, x, y);
                  return;
            }
      }
#endif
      new_mag_x = event->x;
      main_x = event->x_root - new_mag_x;
      new_mag_y = event->y;
      main_y = event->y_root - new_mag_y;
      mag_moved = (new_mag_x != mag_x || new_mag_y != mag_y);
}

#undef      event
#endif      /* TOOLKIT */

static      void
movemag(x, y)
      int   x, y;
{
      int   xx, yy;

      mag_x = x;
      mag_y = y;
      if (mag_x == new_mag_x && mag_y == new_mag_y) mag_moved = False;
      compute_mag_pos(&xx, &yy);
      XMoveWindow(DISP, alt.win, xx, yy);
      scrollwindow(&alt,
          (x + mane_base_x) * mane.shrinkfactor - (int) alt.width/2,
          (y + mane_base_y) * mane.shrinkfactor - (int) alt.height/2);
      draw_rulers(alt.width, alt.height, highGC);
}

#ifdef      TOOLKIT
      /*ARGSUSED*/
void
handle_release(widget, junk, ev, cont)
      Widget      widget;
      XtPointer junk;
      XEvent *ev;
#define     event (&(ev->xbutton))
      Boolean     *cont;            /* unused */
#else /* !TOOLKIT */
void
handle_release()
#endif      /* TOOLKIT */
{
      if (alt.win != (Window) 0) {
          if (alt_stat) alt_stat = -1;    /* destroy upon expose */
          else {
            XDestroyWindow(DISP, alt.win);
            if (currwin.win == alt.win) alt_canit = True;
            alt.win = (Window) 0;
            mag_moved = False;
            can_exposures(&alt);
          }
        }
}

#ifdef      TOOLKIT
#undef      event

      /*ARGSUSED*/
void
handle_exp(widget, closure, ev, cont)
      Widget      widget;
      XtPointer closure;
      register XEvent *ev;
#define     event (&(ev->xexpose))
      Boolean     *cont;            /* unused */
{
      struct WindowRec *windowrec = (struct WindowRec *) closure;

      if (windowrec == &alt) {
          if (alt_stat < 0) { /* destroy upon exposure */
            alt_stat = 0;
            handle_release(widget, (caddr_t) NULL, ev, (Boolean *) NULL);
            return;
          }
          else
            alt_stat = 0;
        }
      expose(windowrec, event->x, event->y,
          (unsigned int) event->width, (unsigned int) event->height);
}

#undef      event
#endif      /* TOOLKIT */

#ifdef MOTIF

/* ARGSUSED */
void
file_pulldown_callback(w, client_data, call_data)
      Widget            w;
      XtPointer   client_data;
      XtPointer   call_data;
{
      switch ((int) client_data) {
      case 0:
          keystroke('R', 0, False, (XEvent *) NULL);
          break;
      case 1:
          keystroke('q', 0, False, (XEvent *) NULL);
          break;
      }
}

/* ARGSUSED */
void
navigate_pulldown_callback(w, client_data, call_data)
      Widget            w;
      XtPointer   client_data;
      XtPointer   call_data;
{
      switch ((int) client_data) {
      case 0:
          keystroke('p', 10, True, (XEvent *) NULL);
          break;
      case 1:
          keystroke('p', 5, True, (XEvent *) NULL);
          break;
      case 2:
          keystroke('p', 0, False, (XEvent *) NULL);
          break;
      case 3:
          keystroke('n', 0, False, (XEvent *) NULL);
          break;
      case 4:
          keystroke('n', 5, True, (XEvent *) NULL);
          break;
      case 5:
          keystroke('n', 10, True, (XEvent *) NULL);
          break;
      }
}

/* ARGSUSED */
void
scale_pulldown_callback(w, client_data, call_data)
      Widget            w;
      XtPointer   client_data;
      XtPointer   call_data;
{
      int   data  = (int) client_data;

      if (data >= 0 && data < 4)
          keystroke('s', data + 1, True, (XEvent *) NULL);
}

void
set_shrink_factor(shrink)
      int   shrink;
{
      static      Widget      active_shrink_button    = NULL;
      Widget            new_shrink_button;

      mane.shrinkfactor = shrink;
      new_shrink_button = (shrink > 0 && shrink <= XtNumber(shrink_button)
        ? shrink_button[shrink - 1] : NULL);
      if (new_shrink_button != active_shrink_button) {
          if (active_shrink_button != NULL)
            XmToggleButtonSetState(active_shrink_button, False, False);
          if (new_shrink_button != NULL)
            XmToggleButtonSetState(new_shrink_button, True, False);
          active_shrink_button = new_shrink_button;
      }
}

#endif /* MOTIF */

void
showmessage(message)
      _Xconst     char  *message;
{
      get_xy();
      XDrawImageString(DISP, mane.win, foreGC,
          5 - window_x, 5 + X11HEIGHT - window_y, message, strlen(message));
}

/* |||
 *    Currently the event handler does not coordinate XCopyArea requests
 *    with GraphicsExpose events.  This can lead to problems if the window
 *    is partially obscured and one, for example, drags a scrollbar.
 */

static      void
keystroke(ch, number0, arg0, eventp)
      char  ch;
      int   number0;
      Boolean     arg0;
      XEvent      *eventp;
{
      static int last_number = 0;   /* memory for Again command */
      static char last_ch = '\0';   /* ditto */
      static Boolean last_arg = False; /* ditto */

      int   next_page;
#ifdef      TOOLKIT
      Window      ww;
#endif

      next_page = current_page;

#if DEBUG
      if (isprint(ch))
          fprintf(stderr,"<%c>",(int)ch);
      else
          fprintf(stderr,"<%03o>",(int)ch);
#endif

      if (ch == '\001')       /* Ctl-A or Again */
      {
          ch = last_ch;
          number0 = last_number;
          arg0 = last_arg;
      }
      else              /* remember key and arg for Again command */
      {
          last_ch = ch;
          last_number = number0;
          last_arg = arg0;
      }

      switch (ch) {
          case 'q':
          case 'Q':
          case '\003':  /* control-C */
          case '\004':  /* control-D */
#ifdef      VMS
          case '\032':  /* control-Z */
#endif
#if   PS
            ps_destroy();
#endif
#ifndef FLAKY_SIGPOLL
            if (debug & DBG_EVENT)
                puts(event_freq < 0
                  ? "SIGPOLL is working" : "no SIGPOLL signals received");
#endif
            exit((ch == 'Q') ? 2 : 0);

          case 'n':
          case 'f':
          case ' ':
          case '\r':
          case '\n':
            /* scroll forward; i.e. go to relative page */
            next_page = current_page + (arg0 ? number0 : 1);
            break;
#ifdef HTEX
          case 'F': /* Follow link forward! */
            {
                  int x, y;
                  if (pointerlocate(&x, &y)) {
                  /* screen_to_page(&mane,s_x,s_y,&page,&px,&py); */
                        (void) htex_handleref(current_page, x, y);
                  }
            }
            return; /* Should goto bad if problem arises? */
          case 'B': /* Go back to previous anchor. */
            htex_goback(); /* Should goto bad if problem arises? */
            return;
#endif
          case 'p':
          case 'b':
          case '\b':
          case '\177':  /* Del */
            /* scroll backward */
            next_page = current_page - (arg0 ? number0 : 1);
            break;
          case '<':
             next_page = 0;
             break;
          case 'g':
          case 'j':
          case '>':
            /* go to absolute page (last by default) */
            next_page = (arg0 ? number0 - pageno_correct :
                total_pages - 1);
            break;
          case '?':
          case 'h':
          case 'H':                 /* Help */
            show_help();
            return;
          case 'P':           /* declare current page */
            pageno_correct = arg0 * number0 - current_page;
            return;
          case 'k':           /* toggle keep-position flag */
            resource.keep_flag = (arg0 ? number0 : !resource.keep_flag);
            return;
          case '\f':
            /* redisplay current page */
            break;
          case '^':
            home(True);
            return;
#ifdef      TOOLKIT
#ifndef MOTIF
          case 'l':
            if (!x_bar) goto bad;
            XtCallCallbacks(x_bar, XtNscrollProc,
                (XtPointer) (-2 * (int) clip_w / 3));
            return;
          case 'r':
            if (!x_bar) goto bad;
            XtCallCallbacks(x_bar, XtNscrollProc,
                (XtPointer) (2 * (int) clip_w / 3));
            return;
          case 'u':
            if (!y_bar) goto bad;
            XtCallCallbacks(y_bar, XtNscrollProc,
                (XtPointer) (-2 * (int) clip_h / 3));
            return;
          case 'd':
            if (!y_bar) goto bad;
            XtCallCallbacks(y_bar, XtNscrollProc,
                (XtPointer) (2 * (int) clip_h / 3));
            return;
          case 'c':
            {
                int x, y;

                x = eventp->xkey.x - clip_w / 2;
                y = eventp->xkey.y - clip_h / 2;
                /* The clip widget gives a more exact value. */
                if (x_bar != NULL)
                  XtCallCallbacks(x_bar, XtNscrollProc, (XtPointer) x);
                if (y_bar != NULL)
                  XtCallCallbacks(y_bar, XtNscrollProc, (XtPointer) y);
                XWarpPointer(DISP, None, None, 0, 0, 0, 0, -x, -y);
            }
            return;
#else /* MOTIF */
          case 'c':
            {
                int x, y;

                get_xy();
                /* The clip widget gives a more exact value. */
                x = eventp->xkey.x - clip_w / 2;
                y = eventp->xkey.y - clip_h / 2;

                x = set_bar_value(x_bar, x, (int) (page_w - clip_w));
                y = set_bar_value(y_bar, y, (int) (page_h - clip_h));
                XWarpPointer(DISP, None, None, 0, 0, 0, 0,
                  -x - window_x, -y - window_y);
            }
            return;
          /* These four won't be needed once translations are put in. */
          case 'l':
            get_xy();
            (void) set_bar_value(x_bar, -2 * (int) clip_w / 3 - window_x,
              (int) (page_w - clip_w));
            return;
          case 'r':
            get_xy();
            (void) set_bar_value(x_bar, 2 * (int) clip_w / 3 - window_x,
              (int) (page_w - clip_w));
            return;
          case 'u':
            get_xy();
            (void) set_bar_value(y_bar, -2 * (int) clip_h / 3 - window_y,
              (int) (page_h - clip_h));
            return;
          case 'd':
            get_xy();
            (void) set_bar_value(y_bar, 2 * (int) clip_h / 3 - window_y,
              (int) (page_h - clip_h));
            return;
#endif /* MOTIF */
          case 'M':
            (void) XTranslateCoordinates(DISP, eventp->xkey.window,
                  mane.win, eventp->xkey.x, eventp->xkey.y,
                  &home_x, &home_y, &ww); /* throw away last argument */
            home_x *= mane.shrinkfactor;
            home_y *= mane.shrinkfactor;
            return;
#ifdef      BUTTONS
          case 'x':
            if (arg0 && resource.expert == (number0 != 0)) return;
            if (resource.expert) {  /* create buttons */
                resource.expert = False;
                if (destroy_count != 0) return;
#ifndef MOTIF
                XtSetValues(vport_widget, resizable_on,
                  XtNumber(resizable_on));
                XdviResizeWidget(vport_widget,
                  window_w -= XTRA_WID, window_h);
                create_buttons((XtArgVal) window_h);
#else /* MOTIF */
                create_buttons((XtArgVal) 0);   /* the argument is ignored */
                window_w -= XTRA_WID;
#endif /* MOTIF */
            }
            else {            /* destroy buttons */
                resource.expert = True;
                if (destroy_count != 0) return;
                destroy_count = 2;
                XtAddCallback(panel_widget, XtNdestroyCallback,
                  handle_destroy_buttons, (XtPointer) 0);
                XtAddCallback(line_widget, XtNdestroyCallback,
                  handle_destroy_buttons, (XtPointer) 0);
                XtDestroyWidget(panel_widget);
                XtDestroyWidget(line_widget);
                window_w += XTRA_WID;
            }
            return;
#endif      /* BUTTONS */
#else /* not TOOLKIT */
          case 'l':
            if (mane.base_x <= 0) goto bad;
            scrollmane(mane.base_x - 2 * (int) clip_w / 3, mane.base_y);
            return;
          case 'r':
            if (mane.base_x >= page_w - clip_w) goto bad;
            scrollmane(mane.base_x + 2 * (int) clip_w / 3, mane.base_y);
            return;
          case 'u':
            if (mane.base_y <= 0) goto bad;
            scrollmane(mane.base_x, mane.base_y - 2 * (int) clip_h / 3);
            return;
          case 'd':
            if (mane.base_y >= page_h - clip_h) goto bad;
            scrollmane(mane.base_x, mane.base_y + 2 * (int) clip_h / 3);
            return;
          case 'c':     /* unchecked scrollmane() */
            scrollwindow(&mane, mane.base_x + eventp->xkey.x - clip_w/2,
                mane.base_y + eventp->xkey.y - clip_h/2);
            if (x_bar) paint_x_bar();
            if (y_bar) paint_y_bar();
            XWarpPointer(DISP, None, None, 0, 0, 0, 0,
                clip_w/2 - eventp->xkey.x, clip_h/2 - eventp->xkey.y);
            return;
          case 'M':
            home_x = (eventp->xkey.x - (y_bar ? BAR_THICK : 0)
                + mane.base_x) * mane.shrinkfactor;
            home_y = (eventp->xkey.y - (x_bar ? BAR_THICK : 0)
                + mane.base_y) * mane.shrinkfactor;
            return;
#endif      /* not TOOLKIT */

          case '\020':  /* Control P */
            Printf("Unit = %d, bitord = %d, byteord = %d\n",
                BitmapUnit(DISP), BitmapBitOrder(DISP),
                ImageByteOrder(DISP));
            return;
          case 's':
            if (!arg0) {
                int temp;

                number0 = ROUNDUP(unshrunk_page_w, window_w - 2);
#ifndef MOTIF
                temp = ROUNDUP(unshrunk_page_h, window_h - 2);
#else /* MOTIF */
                { /* account for menubar */
                  static      Dimension   new_h;

                  /* get rid of scrollbar */
                  XdviResizeWidget(draw_widget, 1, 1);
                  XtVaGetValues(clip_widget, XtNheight, &new_h, NULL);
                  temp = ROUNDUP(unshrunk_page_h, new_h - 2);
                }
#endif /* MOTIF */
                if (number0 < temp) number0 = temp;
            }
            if (number0 <= 0) goto bad;
            if (number0 == mane.shrinkfactor) return;
#ifndef MOTIF
            mane.shrinkfactor = number0;
#else
            set_shrink_factor(number0);
#endif
            init_page();
            if (number0 != 1 && number0 != bak_shrink) {
                bak_shrink = number0;
#ifdef      GREY
                if (use_grey) init_colors();
#endif
                reset_fonts();
            }
            reconfig();
            home(False);
            break;
          case 'S':
            if (!arg0) goto bad;
#ifdef      GREY
            if (use_grey) {
                float newgamma = number0 != 0 ? number0 / 100.0 : 1.0;

                if (newgamma == gamma) return;
                gamma = newgamma;
                init_colors();
                return;
            }
#endif
            if (number0 < 0) goto bad;
            if (number0 == density) return;
            density = number0;
            reset_fonts();
            if (mane.shrinkfactor == 1) return;
            break;

          case 't':
            {           /* toggle through magnifier ruler tick units */
                int k = 0;
                static char *TeX_units[] = {
                  "bp", "cc", "cm", "dd", "in", "mm", "pc", "pt", "sp",
                };
 
                for (k = 0; k < sizeof(TeX_units)/sizeof(TeX_units[0]); ++k)
                  if (strcmp(tick_units,TeX_units[k]) == 0)
                      break;
                k++;
                if (k >= sizeof(TeX_units)/sizeof(TeX_units[0]))
                  k = 0;
                tick_units = TeX_units[k];
                Printf("Ruler units = %s\n", tick_units);
            }
            return;

#ifdef      GREY
          case 'G':
            use_grey = (arg0 ? number0 : !use_grey);
            if (use_grey) init_colors();
            reset_fonts();
            break;
#endif
#ifdef GRID
          case 'D':
            grid_mode = (arg0 ? number0 : !grid_mode );
            init_page();
            reconfig();
            break;
#endif /* GRID */

#if   PS
          case 'v':
            if (!arg0 || resource._postscript != !number0) {
                resource._postscript = !resource._postscript;
                if (resource._postscript) scanned_page = scanned_page_bak;
                psp.toggle();
            }
            break;
#endif

#ifdef SELFILE
            case '\006': /* control-f */
            ++dvi_time ; /* notice we want a new file in check_dvi_file */
            break ;
#endif  /* SELFILE */

#if PS_GS
          case 'V':
            if (!arg0 || resource.gs_alpha != !number0)
                resource.gs_alpha = !resource.gs_alpha;
            break;
#endif

          case 'R':
            /* reread DVI file */
            --dvi_time; /* then it will notice a change */
            break;
          default:
            goto bad;
      }
      if (0 <= next_page && next_page < total_pages) {
          if (current_page != next_page) {
            current_page = next_page;
            warn_spec_now = warn_spec;
            if (!resource.keep_flag) home(False);
          }
          canit = True;
          XFlush(DISP);
          return; /* Don't use longjmp here:  it might be called from
                   * within the toolkit, and we don't want to longjmp out
                   * of Xt routines. */
      }
      bad:  XBell(DISP, 10);
}

/*
 *    Since redrawing the screen is (potentially) a slow task, xdvi checks
 *    for incoming events while this is occurring.  It does not register
 *    a work proc that draws and returns every so often, as the toolkit
 *    documentation suggests.  Instead, it checks for events periodically
 *    (or not, if SIGPOLL can be used instead) and processes them in
 *    a subroutine called by the page drawing routine.  This routine (below)
 *    checks to see if anything has happened and processes those events and
 *    signals.  (Or, if it is called when there is no redrawing that needs
 *    to be done, it blocks until something happens.)
 */

void
#if   PS
ps_read_events(wait, allow_can)
      wide_bool   wait;
      wide_bool   allow_can;
#else
read_events(wait)
      wide_bool   wait;
#define     allow_can   True
#endif
{
      XEvent      event;

      alt_canit = False;
      for (;;) {
          event_counter = event_freq;
          /*
           * The above line clears the flag indicating that an event is
           * pending.  So if an event comes in right now, the flag will be
           * set again needlessly, but we just end up making an extra call.
           * Also, be careful about destroying the magnifying glass while
           * drawing on it.
           */

#ifndef FLAKY_SIGPOLL

          if (event_freq < 0) {     /* if SIGPOLL works */

            if (!XtPending()) {
                sigset_t oldsig;

                (void) sigprocmask(SIG_BLOCK, &sigpollusrterm, &oldsig);
                if (terminate_flag) {
#if   PS
                  ps_destroy();
#endif
                  exit(0);
                }
                while (!XtPending())
                {
                  /*
                   * The following code eliminates unnecessary calls to
                   * XDefineCursor, since this is a slow operation on 
                   * some hardware (e.g., S3 chips).
                   */
                  if (busycurs && wait && !canit && !mag_moved
                    && alt.min_x == MAXDIM && mane.min_x == MAXDIM) {
                      XSync(DISP, False);
                      if (XtPending()) break;
                      XDefineCursor(DISP, mane.win, ready_cursor);
                      XFlush(DISP);
                      busycurs = False;
                  }
                  if (!wait && (canit | alt_canit)) {
#if   PS
                      psp.interrupt();
#endif
                      if (allow_can) {
                        (void) sigprocmask(SIG_SETMASK, &oldsig,
                            (sigset_t *)NULL);
                        longjmp(canit_env, 1);
                      }
                  }
                  if (!wait || canit || mane.min_x < MAXDIM
                        || alt.min_x < MAXDIM || mag_moved) {
                      (void) sigprocmask(SIG_SETMASK, &oldsig,
                        (sigset_t *) NULL);
                      return;
                  }
                  (void) sigsuspend(&oldsig);
                  if (terminate_flag) {
#if   PS
                      ps_destroy();
#endif
                      exit(0);
                  }

                }
                (void) sigprocmask(SIG_SETMASK, &oldsig, (sigset_t *) NULL);
            }
          }
          else

#endif /* not FLAKY_SIGPOLL */

          {
            for (;;) {
#if HAVE_POLL
                int     retval;
#endif

                if (terminate_flag) {
#if   PS
                  ps_destroy();
#endif
                  exit(0);
                }

                if (XtPending())
                  break;

                /*
                 * The following code eliminates unnecessary calls to
                 * XDefineCursor, since this is a slow operation on some
                 * hardware (e.g., S3 chips).
                 */
                if (busycurs && wait && !canit && !mag_moved
                      && alt.min_x == MAXDIM && mane.min_x == MAXDIM) {
                  XSync(DISP, False);
                  if (XtPending()) break;
                  XDefineCursor(DISP, mane.win, ready_cursor);
                  XFlush(DISP);
                  busycurs = False;
                }
                if (!wait && (canit | alt_canit)) {
#if   PS
                  psp.interrupt();
#endif
                  if (allow_can) longjmp(canit_env, 1);
                }
                if (!wait || canit
                  || mane.min_x < MAXDIM || alt.min_x < MAXDIM || mag_moved)
                  return;
                /* If a SIGUSR1 signal comes right now, then it will wait
                   until an X event or another SIGUSR1 signal arrives. */

#if HAVE_POLL
                do {
                  retval = poll(fds, XtNumber(fds), -1);
                } while (retval < 0 && errno == EAGAIN);

                if (retval < 0 && errno != EINTR)
                  perror("poll (xdvi read_events)");
#else
                FD_SET(ConnectionNumber(DISP), &readfds);
                if (select(ConnectionNumber(DISP) + 1, &readfds,
                      (fd_set *) NULL, (fd_set *) NULL,
                      (struct timeval *) NULL) < 0 && errno != EINTR)
                  perror("select (xdvi read_events)");
#endif
            }
          }

#ifdef      TOOLKIT

          XtNextEvent(&event);
          if (resized) get_geom();
          if (event.xany.window == alt.win && event.type == Expose) {
            handle_exp((Widget) NULL, (XtPointer) &alt, &event,
                (Boolean *) NULL);
            continue;
          }
          (void) XtDispatchEvent(&event);

#else /* not TOOLKIT */

          XNextEvent(DISP, &event);
          if (event.xany.window == mane.win || event.xany.window == alt.win) {
            struct WindowRec *wr = &mane;

            if (event.xany.window == alt.win) {
                wr = &alt;
                /* check in case we already destroyed the window */
                if (alt_stat < 0) { /* destroy upon exposure */
                  alt_stat = 0;
                  handle_release();
                  continue;
                }
                else
                  alt_stat = 0;
            }
            switch (event.type) {
            case GraphicsExpose:
            case Expose:
                expose(wr, event.xexpose.x, event.xexpose.y,
                  event.xexpose.width, event.xexpose.height);
                break;

            case MotionNotify:
#ifdef HTEX
/* APS Only using motion hints, so get the last pointer location: */
                while (XCheckMaskEvent(DISP, PointerMotionMask, &event));
                if ((keys_buttons&(Button1Mask|Button2Mask|Button3Mask|
                              Button4Mask|Button5Mask)) == 0) {
      /* None of the buttons was down, so this isn't a mag motion event: */
                  int x, y;
                  if (!pointerlocate(&x, &y)) break;
                  htex_displayanchor(current_page, x, y);
                  break;
                } 
#endif
                new_mag_x = event.xmotion.x;
                new_mag_y = event.xmotion.y;
                mag_moved = (new_mag_x != mag_x || new_mag_y != mag_y);
                break;

            case ButtonPress:
                handle_button(&event.xbutton);
                break;

            case ButtonRelease:
                handle_release();
                break;
            }     /* end switch */
          } /* end if window == {mane,alt}.win */

          else if (event.xany.window == x_bar) {
            if (event.type == Expose)
                XFillRectangle(DISP, x_bar, ruleGC,
                  x_bgn, 1, x_end - x_bgn, BAR_WID);
            else if (event.type == MotionNotify)
                scrollmane(event.xmotion.x * page_w / clip_w,
                  mane.base_y);
            else switch (event.xbutton.button)
            {
                case 1:
                  scrollmane(mane.base_x + event.xbutton.x, mane.base_y);
                  break;
                case 2:
                  scrollmane(event.xbutton.x * page_w / clip_w,
                      mane.base_y);
                  break;
                case 3:
                  scrollmane(mane.base_x - event.xbutton.x, mane.base_y);
            }
          }

          else if (event.xany.window == y_bar) {
            if (event.type == Expose)
                XFillRectangle(DISP, y_bar, ruleGC,
                  1, y_bgn, BAR_WID, y_end - y_bgn);
            else if (event.type == MotionNotify)
                scrollmane(mane.base_x,
                  event.xmotion.y * page_h / clip_h);
            else switch (event.xbutton.button)
            {
                case 1:
                  scrollmane(mane.base_x, mane.base_y + event.xbutton.y);
                  break;
                case 2:
                  scrollmane(mane.base_x,
                      event.xbutton.y * page_h / clip_h);
                  break;
                case 3:
                  scrollmane(mane.base_x, mane.base_y - event.xbutton.y);
            }
          }

          else if (event.xany.window == top_level)
            switch (event.type) {
            case ConfigureNotify:
                if (event.xany.window == top_level &&
                  (event.xconfigure.width != window_w ||
                  event.xconfigure.height != window_h)) {
                      register Window old_mane_win = mane.win;

                      window_w = event.xconfigure.width;
                      window_h = event.xconfigure.height;
                      reconfig();
                      if (old_mane_win == (Window) 0) home(False);
                }
                break;

            case MapNotify:         /* if running w/o WM */
                if (mane.win == (Window) 0) {
                  reconfig();
                  home(False);
                }
                break;

            case KeyPress:
                handle_key(&event);
                break;
            }

#endif      /* not TOOLKIT */

      }
}

static      void
redraw(windowrec)
      struct WindowRec *windowrec;
{

      currwin = *windowrec;
      min_x = currwin.min_x + currwin.base_x;
      min_y = currwin.min_y + currwin.base_y;
      max_x = currwin.max_x + currwin.base_x;
      max_y = currwin.max_y + currwin.base_y;
      can_exposures(windowrec);

      if (debug & DBG_EVENT)
          Printf("Redraw %d x %d at (%d, %d) (base=%d,%d)\n", max_x - min_x,
            max_y - min_y, min_x, min_y, currwin.base_x, currwin.base_y);
      if (!busycurs) {
          XDefineCursor(DISP, mane.win, redraw_cursor);
          XFlush(DISP);
          busycurs = True;
      }
      if (setjmp(dvi_env)) {
          XClearWindow(DISP, mane.win);
          showmessage(dvi_oops_msg);
          if (dvi_file) {
            Fclose(dvi_file);
            dvi_file = NULL;
          }
      }
      else {
          draw_page();
          warn_spec_now = False;
      }
}

void
redraw_page()
{
      if (debug & DBG_EVENT) Fputs("Redraw page:  ", stdout);
      XClearWindow(DISP, mane.win);
      if (backing_store != NotUseful) {
          mane.min_x = mane.min_y = 0;
          mane.max_x = page_w;
          mane.max_y = page_h;
      }
      else {
          get_xy();
          mane.min_x = -window_x;
          mane.max_x = -window_x + clip_w;
          mane.min_y = -window_y;
          mane.max_y = -window_y + clip_h;
      }
      redraw(&mane);
}

/*
 *    Interrupt system for receiving events.  The program sets a flag
 *    whenever an event comes in, so that at the proper time (i.e., when
 *    reading a new dvi item), we can check incoming events to see if we
 *    still want to go on printing this page.  This way, one can stop
 *    displaying a page if it is about to be erased anyway.  We try to read
 *    as many events as possible before doing anything and base the next
 *    action on all events read.
 *    Note that the Xlib and Xt routines are not reentrant, so the most we
 *    can do is set a flag in the interrupt routine and check it later.
 *    Also, sometimes the interrupts are not generated (some systems only
 *    guarantee that SIGIO is generated for terminal files, and on the system
 *    I use, the interrupts are not generated if I use "(xdvi foo &)" instead
 *    of "xdvi foo").  Therefore, there is also a mechanism to check the
 *    event queue every 70 drawing operations or so.  This mechanism is
 *    disabled if it turns out that the interrupts do work.
 *    For a fuller discussion of some of the above, see xlife in
 *    comp.sources.x.
 */

static      void
can_exposures(windowrec)
      struct WindowRec *windowrec;
{
      windowrec->min_x = windowrec->min_y = MAXDIM;
      windowrec->max_x = windowrec->max_y = 0;
}

#ifndef FLAKY_SIGPOLL
/* ARGSUSED */
static      RETSIGTYPE
handle_sigpoll(signo)
      int   signo;
{
      event_counter = 1;
      event_freq = -1;  /* forget Plan B */
#if !HAVE_SIGACTION
      (void) signal(SIGPOLL, handle_sigpoll);   /* reset the signal */
#endif
}
#endif      /* not FLAKY_SIGPOLL */

/* ARGSUSED */
static      RETSIGTYPE
handle_sigusr(signo)
      int   signo;
{
      event_counter = 1;
      canit = True;
      dvi_time = 0;
#if ! HAVE_SIGACTION
      (void) signal(SIGUSR1, handle_sigusr);    /* reset the signal */
#endif
}

/* ARGSUSED */
static      RETSIGTYPE
handle_sigterm(signo)
      int   signo;
{
      terminate_flag = True;
}

static      void
enable_intr() {
#ifndef FLAKY_SIGPOLL
      int   sock_fd     = ConnectionNumber(DISP);
#endif
#if HAVE_SIGACTION
      struct sigaction a;
#endif

#ifndef FLAKY_SIGPOLL
#if HAVE_SIGACTION
      /* Subprocess handling, e.g., mktexpk, fails on the Alpha without
         this, because SIGPOLL interrupts the call of system(3), since OSF/1
         doesn't retry interrupted wait calls by default.  From code by
         maj@cl.cam.ac.uk.  */
      a.sa_handler = handle_sigpoll;
      (void) sigemptyset(&a.sa_mask);
      (void) sigaddset(&a.sa_mask, SIGPOLL);
      a.sa_flags = SA_RESTART;
      sigaction(SIGPOLL, &a, NULL);
#else /* not HAVE_SIGACTION */
      (void) signal(SIGPOLL, handle_sigpoll);
#endif /* not HAVE_SIGACTION */

#if HAVE_STREAMS
      if (isastream(sock_fd) > 0) {
          if (ioctl(sock_fd, I_SETSIG,
            S_RDNORM | S_RDBAND | S_HANGUP | S_WRNORM) == -1)
            perror("ioctl I_SETSIG (xdvi)");
      }
      else
#endif
      {
#ifdef FASYNC
          if (fcntl(sock_fd, F_SETOWN, getpid()) == -1)
            perror("fcntl F_SETOWN (xdvi)");
          if (fcntl(sock_fd, F_SETFL, fcntl(sock_fd, F_GETFL, 0) | FASYNC)
            == -1)
            perror("fcntl F_SETFL (xdvi)");
#endif
      }
#endif      /* not FLAKY_SIGPOLL */

#if HAVE_SIGACTION
      a.sa_handler = handle_sigusr;
      (void) sigemptyset(&a.sa_mask);
      (void) sigaddset(&a.sa_mask, SIGUSR1);
      a.sa_flags = 0;
      sigaction(SIGUSR1, &a, NULL);
#else /* not HAVE_SIGACTION */
      (void) signal(SIGUSR1, handle_sigusr);
#endif /* not HAVE_SIGACTION */

#if HAVE_SIGACTION
      a.sa_handler = handle_sigterm;
      (void) sigemptyset(&a.sa_mask);
      (void) sigaddset(&a.sa_mask, SIGINT);
      (void) sigaddset(&a.sa_mask, SIGQUIT);
      (void) sigaddset(&a.sa_mask, SIGTERM);
      a.sa_flags = 0;
      sigaction(SIGINT, &a, NULL);
      sigaction(SIGQUIT, &a, NULL);
      sigaction(SIGTERM, &a, NULL);
#else /* not HAVE_SIGACTION */
      (void) signal(SIGINT, handle_sigterm);
      (void) signal(SIGQUIT, handle_sigterm);
      (void) signal(SIGTERM, handle_sigterm);
#endif /* not HAVE_SIGACTION */

#ifndef FLAKY_SIGPOLL

      (void) sigemptyset(&sigpollusrterm);
      (void) sigaddset(&sigpollusrterm, SIGPOLL);
      (void) sigaddset(&sigpollusrterm, SIGUSR1);
      (void) sigaddset(&sigpollusrterm, SIGINT);
      (void) sigaddset(&sigpollusrterm, SIGQUIT);
      (void) sigaddset(&sigpollusrterm, SIGTERM);

#endif

#if HAVE_POLL
      fds[0].fd = ConnectionNumber(DISP);
#else
      FD_ZERO(&readfds);
#endif

}

void
do_pages()
{
      enable_intr();
      if (debug & DBG_BATCH) {
#ifdef      TOOLKIT
          while (mane.min_x == MAXDIM) read_events(True);
#else /* !TOOLKIT */
          while (mane.min_x == MAXDIM)
            if (setjmp(canit_env)) break;
            else read_events(True);
#endif      /* TOOLKIT */
          for (current_page = 0; current_page < total_pages; ++current_page) {
#ifdef      __convex__
            /* convex C turns off optimization for the entire function
               if setjmp return value is discarded.*/
            if (setjmp(canit_env))  /*optimize me*/;
#else
            (void) setjmp(canit_env);
#endif
            canit = False;
            redraw_page();
          }
      }
      else {      /* normal operation */
#ifdef      __convex__
          /* convex C turns off optimization for the entire function
             if setjmp return value is discarded.*/
          if (setjmp(canit_env))    /*optimize me*/;
#else
          (void) setjmp(canit_env);
#endif
          for (;;) {
            read_events(True);
            if (canit) {
                canit = False;
                can_exposures(&mane);
                can_exposures(&alt);
                redraw_page();
            }
            else if (mag_moved) {
                if (alt.win == (Window) 0) mag_moved = False;
                else if (abs(new_mag_x - mag_x) >
                  2 * abs(new_mag_y - mag_y))
                      movemag(new_mag_x, mag_y);
                else if (abs(new_mag_y - mag_y) >
                  2 * abs(new_mag_x - mag_x))
                      movemag(mag_x, new_mag_y);
                else movemag(new_mag_x, new_mag_y);
            }
            else if (alt.min_x < MAXDIM) redraw(&alt);
            else if (mane.min_x < MAXDIM) redraw(&mane);
            XFlush(DISP);
          }
      }
}

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