/[dtapublic]/projs/trunk/shared_source/c_tk_base_7_5_w_mods/tkscale.c

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-revision 69 by dashley,
Sat Nov  5 10:54:17 2016 UTC
+revision 71 by dashley,
Sat Nov  5 11:07:06 2016 UTC
 Line 1
  /* $Header$ */
  /*
   * tkScale.c --
   *
   *      This module implements a scale widgets for the Tk toolkit.
   *      A scale displays a slider that can be adjusted to change a
   *      value;  it also displays numeric labels and a textual label,
   *      if desired.
   *
   *      The modifications to use floating-point values are based on
   *      an implementation by Paul Mackerras.  The -variable option
   *      is due to Henning Schulzrinne.  All of these are used with
   *      permission.
   *
   * Copyright (c) 1990-1994 The Regents of the University of California.
   * Copyright (c) 1994-1997 Sun Microsystems, Inc.
   * Copyright (c) 1998-2000 by Scriptics Corporation.
   *
   * See the file "license.terms" for information on usage and redistribution
   * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
   *
   * RCS: @(#) $Id: tkscale.c,v 1.1.1.1 2001/06/13 05:07:45 dtashley Exp $
   */
  #include "tkPort.h"
  #include "default.h"
  #include "tkInt.h"
  #include "tclMath.h"
  #include "tkScale.h"
  /*
   * The following table defines the legal values for the -orient option.
   * It is used together with the "enum orient" declaration in tkScale.h.
   */
  static char *orientStrings[] = {
      "horizontal", "vertical", (char *) NULL
  };
  /*
   * The following table defines the legal values for the -state option.
   * It is used together with the "enum state" declaration in tkScale.h.
   */
  static char *stateStrings[] = {
      "active", "disabled", "normal", (char *) NULL
  };
  static Tk_OptionSpec optionSpecs[] = {
      {TK_OPTION_BORDER, "-activebackground", "activeBackground", "Foreground",
          DEF_SCALE_ACTIVE_BG_COLOR, -1, Tk_Offset(TkScale, activeBorder),
 , (ClientData) DEF_SCALE_ACTIVE_BG_MONO, 0},
      {TK_OPTION_BORDER, "-background", "background", "Background",
          DEF_SCALE_BG_COLOR, -1, Tk_Offset(TkScale, bgBorder),
 , (ClientData) DEF_SCALE_BG_MONO, 0},
      {TK_OPTION_DOUBLE, "-bigincrement", "bigIncrement", "BigIncrement",
          DEF_SCALE_BIG_INCREMENT, -1, Tk_Offset(TkScale, bigIncrement),
 , 0, 0},
      {TK_OPTION_SYNONYM, "-bd", (char *) NULL, (char *) NULL,
          (char *) NULL, 0, -1, 0, (ClientData) "-borderwidth", 0},
      {TK_OPTION_SYNONYM, "-bg", (char *) NULL, (char *) NULL,
          (char *) NULL, 0, -1, 0, (ClientData) "-background", 0},
      {TK_OPTION_PIXELS, "-borderwidth", "borderWidth", "BorderWidth",
          DEF_SCALE_BORDER_WIDTH, -1, Tk_Offset(TkScale, borderWidth),
 , 0, 0},
      {TK_OPTION_STRING, "-command", "command", "Command",
          DEF_SCALE_COMMAND, -1, Tk_Offset(TkScale, command),
          TK_OPTION_NULL_OK, 0, 0},
      {TK_OPTION_CURSOR, "-cursor", "cursor", "Cursor",
          DEF_SCALE_CURSOR, -1, Tk_Offset(TkScale, cursor),
          TK_OPTION_NULL_OK, 0, 0},
      {TK_OPTION_INT, "-digits", "digits", "Digits",
          DEF_SCALE_DIGITS, -1, Tk_Offset(TkScale, digits),
 , 0, 0},
      {TK_OPTION_SYNONYM, "-fg", "foreground", (char *) NULL,
          (char *) NULL, 0, -1, 0, (ClientData) "-foreground", 0},
      {TK_OPTION_FONT, "-font", "font", "Font",
          DEF_SCALE_FONT, -1, Tk_Offset(TkScale, tkfont), 0, 0, 0},
      {TK_OPTION_COLOR, "-foreground", "foreground", "Foreground",
          DEF_SCALE_FG_COLOR, -1, Tk_Offset(TkScale, textColorPtr), 0,
          (ClientData) DEF_SCALE_FG_MONO, 0},
      {TK_OPTION_DOUBLE, "-from", "from", "From", DEF_SCALE_FROM, -1,
          Tk_Offset(TkScale, fromValue), 0, 0, 0},
      {TK_OPTION_BORDER, "-highlightbackground", "highlightBackground",
          "HighlightBackground", DEF_SCALE_HIGHLIGHT_BG_COLOR,
          -1, Tk_Offset(TkScale, highlightBorder),
 , (ClientData) DEF_SCALE_HIGHLIGHT_BG_MONO, 0},
      {TK_OPTION_COLOR, "-highlightcolor", "highlightColor", "HighlightColor",
          DEF_SCALE_HIGHLIGHT, -1, Tk_Offset(TkScale, highlightColorPtr),
 , 0, 0},
      {TK_OPTION_PIXELS, "-highlightthickness", "highlightThickness",
          "HighlightThickness", DEF_SCALE_HIGHLIGHT_WIDTH, -1,
          Tk_Offset(TkScale, highlightWidth), 0, 0, 0},
      {TK_OPTION_STRING, "-label", "label", "Label",
          DEF_SCALE_LABEL, -1, Tk_Offset(TkScale, label),
          TK_OPTION_NULL_OK, 0, 0},
      {TK_OPTION_PIXELS, "-length", "length", "Length",
          DEF_SCALE_LENGTH, -1, Tk_Offset(TkScale, length), 0, 0, 0},
      {TK_OPTION_STRING_TABLE, "-orient", "orient", "Orient",
          DEF_SCALE_ORIENT, -1, Tk_Offset(TkScale, orient),
 , (ClientData) orientStrings, 0},
      {TK_OPTION_RELIEF, "-relief", "relief", "Relief",
          DEF_SCALE_RELIEF, -1, Tk_Offset(TkScale, relief), 0, 0, 0},
      {TK_OPTION_INT, "-repeatdelay", "repeatDelay", "RepeatDelay",
          DEF_SCALE_REPEAT_DELAY, -1, Tk_Offset(TkScale, repeatDelay),
 , 0, 0},
      {TK_OPTION_INT, "-repeatinterval", "repeatInterval", "RepeatInterval",
          DEF_SCALE_REPEAT_INTERVAL, -1, Tk_Offset(TkScale, repeatInterval),
 , 0, 0},
      {TK_OPTION_DOUBLE, "-resolution", "resolution", "Resolution",
          DEF_SCALE_RESOLUTION, -1, Tk_Offset(TkScale, resolution),
 , 0, 0},
      {TK_OPTION_BOOLEAN, "-showvalue", "showValue", "ShowValue",
          DEF_SCALE_SHOW_VALUE, -1, Tk_Offset(TkScale, showValue),
 , 0, 0},
      {TK_OPTION_PIXELS, "-sliderlength", "sliderLength", "SliderLength",
          DEF_SCALE_SLIDER_LENGTH, -1, Tk_Offset(TkScale, sliderLength),
 , 0, 0},
      {TK_OPTION_RELIEF, "-sliderrelief", "sliderRelief", "SliderRelief",
          DEF_SCALE_SLIDER_RELIEF, -1, Tk_Offset(TkScale, sliderRelief),
 , 0, 0},
      {TK_OPTION_STRING_TABLE, "-state", "state", "State",
          DEF_SCALE_STATE, -1, Tk_Offset(TkScale, state),
 , (ClientData) stateStrings, 0},
      {TK_OPTION_STRING, "-takefocus", "takeFocus", "TakeFocus",
          DEF_SCALE_TAKE_FOCUS, Tk_Offset(TkScale, takeFocusPtr), -1,
          TK_OPTION_NULL_OK, 0, 0},
      {TK_OPTION_DOUBLE, "-tickinterval", "tickInterval", "TickInterval",
          DEF_SCALE_TICK_INTERVAL, -1, Tk_Offset(TkScale, tickInterval),
 , 0, 0},
      {TK_OPTION_DOUBLE, "-to", "to", "To",
          DEF_SCALE_TO, -1, Tk_Offset(TkScale, toValue), 0, 0, 0},
      {TK_OPTION_COLOR, "-troughcolor", "troughColor", "Background",
          DEF_SCALE_TROUGH_COLOR, -1, Tk_Offset(TkScale, troughColorPtr),
 , (ClientData) DEF_SCALE_TROUGH_MONO, 0},
      {TK_OPTION_STRING, "-variable", "variable", "Variable",
          DEF_SCALE_VARIABLE, Tk_Offset(TkScale, varNamePtr), -1,
          TK_OPTION_NULL_OK, 0, 0},
      {TK_OPTION_PIXELS, "-width", "width", "Width",
          DEF_SCALE_WIDTH, -1, Tk_Offset(TkScale, width), 0, 0, 0},
      {TK_OPTION_END, (char *) NULL, (char *) NULL, (char *) NULL,
          (char *) NULL, 0, -1, 0, 0, 0}
  };
  /*
   * The following tables define the scale widget commands and map the
   * indexes into the string tables into a single enumerated type used
   * to dispatch the scale widget command.
   */
  static char *commandNames[] = {
      "cget", "configure", "coords", "get", "identify", "set", (char *) NULL
  };
  enum command {
      COMMAND_CGET, COMMAND_CONFIGURE, COMMAND_COORDS, COMMAND_GET,
      COMMAND_IDENTIFY, COMMAND_SET
  };
  /*
   * Forward declarations for procedures defined later in this file:
   */
  static void             ComputeFormat _ANSI_ARGS_((TkScale *scalePtr));
  static void             ComputeScaleGeometry _ANSI_ARGS_((TkScale *scalePtr));
  static int              ConfigureScale _ANSI_ARGS_((Tcl_Interp *interp,
                              TkScale *scalePtr, int objc,
                              Tcl_Obj *CONST objv[]));
  static void             DestroyScale _ANSI_ARGS_((char *memPtr));
  static void             ScaleCmdDeletedProc _ANSI_ARGS_((
                              ClientData clientData));
  static void             ScaleEventProc _ANSI_ARGS_((ClientData clientData,
                              XEvent *eventPtr));
  static char *           ScaleVarProc _ANSI_ARGS_((ClientData clientData,
                              Tcl_Interp *interp, char *name1, char *name2,
                              int flags));
  static int              ScaleWidgetObjCmd _ANSI_ARGS_((ClientData clientData,
                              Tcl_Interp *interp, int objc,
                              Tcl_Obj *CONST objv[]));
  static void             ScaleWorldChanged _ANSI_ARGS_((
                              ClientData instanceData));
  static void             ScaleSetVariable _ANSI_ARGS_((TkScale *scalePtr));
  /*
   * The structure below defines scale class behavior by means of procedures
   * that can be invoked from generic window code.
   */
  static TkClassProcs scaleClass = {
      NULL,                       /* createProc. */
      ScaleWorldChanged,          /* geometryProc. */
      NULL                        /* modalProc. */
  };
  /*
   *--------------------------------------------------------------
   *
   * Tk_ScaleObjCmd --
   *
   *      This procedure is invoked to process the "scale" Tcl
   *      command.  See the user documentation for details on what
   *      it does.
   *
   * Results:
   *      A standard Tcl result.
   *
   * Side effects:
   *      See the user documentation.
   *
   *--------------------------------------------------------------
   */
  int
  Tk_ScaleObjCmd(clientData, interp, objc, objv)
      ClientData clientData;      /* Either NULL or pointer to option table. */
      Tcl_Interp *interp;         /* Current interpreter. */
      int objc;                   /* Number of arguments. */
      Tcl_Obj *CONST objv[];      /* Argument values. */
  {
      register TkScale *scalePtr;
      Tk_OptionTable optionTable;
      Tk_Window tkwin;
      optionTable = (Tk_OptionTable) clientData;
      if (optionTable == NULL) {
          Tcl_CmdInfo info;
          char *name;
          /*
           * We haven't created the option table for this widget class
           * yet.  Do it now and save the table as the clientData for
           * the command, so we'll have access to it in future
           * invocations of the command.
           */
          optionTable = Tk_CreateOptionTable(interp, optionSpecs);
          name = Tcl_GetString(objv[0]);
          Tcl_GetCommandInfo(interp, name, &info);
          info.objClientData = (ClientData) optionTable;
          Tcl_SetCommandInfo(interp, name, &info);
      }
      if (objc < 2) {
          Tcl_WrongNumArgs(interp, 1, objv, "pathName ?options?");
          return TCL_ERROR;
      }
      tkwin = Tk_CreateWindowFromPath(interp, Tk_MainWindow(interp),
              Tcl_GetString(objv[1]), (char *) NULL);
      if (tkwin == NULL) {
          return TCL_ERROR;
      }
      Tk_SetClass(tkwin, "Scale");
      scalePtr = TkpCreateScale(tkwin);
      /*
       * Initialize fields that won't be initialized by ConfigureScale,
       * or which ConfigureScale expects to have reasonable values
       * (e.g. resource pointers).
       */
      scalePtr->tkwin             = tkwin;
      scalePtr->display           = Tk_Display(tkwin);
      scalePtr->interp            = interp;
      scalePtr->widgetCmd         = Tcl_CreateObjCommand(interp,
              Tk_PathName(scalePtr->tkwin), ScaleWidgetObjCmd,
              (ClientData) scalePtr, ScaleCmdDeletedProc);
      scalePtr->optionTable       = optionTable;
      scalePtr->orient            = ORIENT_VERTICAL;
      scalePtr->width             = 0;
      scalePtr->length            = 0;
      scalePtr->value             = 0.0;
      scalePtr->varNamePtr        = NULL;
      scalePtr->fromValue         = 0.0;
      scalePtr->toValue           = 0.0;
      scalePtr->tickInterval      = 0.0;
      scalePtr->resolution        = 1.0;
      scalePtr->digits            = 0;
      scalePtr->bigIncrement      = 0.0;
      scalePtr->command           = NULL;
      scalePtr->repeatDelay       = 0;
      scalePtr->repeatInterval    = 0;
      scalePtr->label             = NULL;
      scalePtr->labelLength       = 0;
      scalePtr->state             = STATE_NORMAL;
      scalePtr->borderWidth       = 0;
      scalePtr->bgBorder          = NULL;
      scalePtr->activeBorder      = NULL;
      scalePtr->sliderRelief      = TK_RELIEF_RAISED;
      scalePtr->troughColorPtr    = NULL;
      scalePtr->troughGC          = None;
      scalePtr->copyGC            = None;
      scalePtr->tkfont            = NULL;
      scalePtr->textColorPtr      = NULL;
      scalePtr->textGC            = None;
      scalePtr->relief            = TK_RELIEF_FLAT;
      scalePtr->highlightWidth    = 0;
      scalePtr->highlightBorder   = NULL;
      scalePtr->highlightColorPtr = NULL;
      scalePtr->inset             = 0;
      scalePtr->sliderLength      = 0;
      scalePtr->showValue         = 0;
      scalePtr->horizLabelY       = 0;
      scalePtr->horizValueY       = 0;
      scalePtr->horizTroughY      = 0;
      scalePtr->horizTickY        = 0;
      scalePtr->vertTickRightX    = 0;
      scalePtr->vertValueRightX   = 0;
      scalePtr->vertTroughX       = 0;
      scalePtr->vertLabelX        = 0;
      scalePtr->fontHeight        = 0;
      scalePtr->cursor            = None;
      scalePtr->takeFocusPtr      = NULL;
      scalePtr->flags             = NEVER_SET;
      TkSetClassProcs(scalePtr->tkwin, &scaleClass, (ClientData) scalePtr);
      Tk_CreateEventHandler(scalePtr->tkwin,
              ExposureMask|StructureNotifyMask|FocusChangeMask,
              ScaleEventProc, (ClientData) scalePtr);
      if ((Tk_InitOptions(interp, (char *) scalePtr, optionTable, tkwin)
              != TCL_OK) ||
              (ConfigureScale(interp, scalePtr, objc - 2, objv + 2) != TCL_OK)) {
          Tk_DestroyWindow(scalePtr->tkwin);
          return TCL_ERROR;
      }
      Tcl_SetResult(interp, Tk_PathName(scalePtr->tkwin), TCL_STATIC);
      return TCL_OK;
  }
  /*
   *--------------------------------------------------------------
   *
   * ScaleWidgetObjCmd --
   *
   *      This procedure is invoked to process the Tcl command
   *      that corresponds to a widget managed by this module.
   *      See the user documentation for details on what it does.
   *
   * Results:
   *      A standard Tcl result.
   *
   * Side effects:
   *      See the user documentation.
   *
   *--------------------------------------------------------------
   */
  static int
  ScaleWidgetObjCmd(clientData, interp, objc, objv)
      ClientData clientData;              /* Information about scale
                                           * widget. */
      Tcl_Interp *interp;                 /* Current interpreter. */
      int objc;                           /* Number of arguments. */
      Tcl_Obj *CONST objv[];              /* Argument strings. */
  {
      TkScale *scalePtr = (TkScale *) clientData;
      Tcl_Obj *objPtr;
      int index, result;
      if (objc < 2) {
          Tcl_WrongNumArgs(interp, 1, objv, "option ?arg arg ...?");
          return TCL_ERROR;
      }
      result = Tcl_GetIndexFromObj(interp, objv[1], commandNames,
              "option", 0, &index);
      if (result != TCL_OK) {
          return result;
      }
      Tcl_Preserve((ClientData) scalePtr);
      switch (index) {
          case COMMAND_CGET: {
              if (objc != 3) {
                  Tcl_WrongNumArgs(interp, 1, objv, "cget option");
                  goto error;
              }
              objPtr = Tk_GetOptionValue(interp, (char *) scalePtr,
                      scalePtr->optionTable, objv[2], scalePtr->tkwin);
              if (objPtr == NULL) {
                   goto error;
              } else {
                  Tcl_SetObjResult(interp, objPtr);
              }
              break;
          }
          case COMMAND_CONFIGURE: {
              if (objc <= 3) {
                  objPtr = Tk_GetOptionInfo(interp, (char *) scalePtr,
                          scalePtr->optionTable,
                          (objc == 3) ? objv[2] : (Tcl_Obj *) NULL,
                          scalePtr->tkwin);
                  if (objPtr == NULL) {
                      goto error;
                  } else {
                      Tcl_SetObjResult(interp, objPtr);
                  }
              } else {
                  result = ConfigureScale(interp, scalePtr, objc-2, objv+2);
              }
              break;
          }
          case COMMAND_COORDS: {
              int x, y ;
              double value;
              char buf[TCL_INTEGER_SPACE * 2];
              if ((objc != 2) && (objc != 3)) {
                  Tcl_WrongNumArgs(interp, 1, objv, "coords ?value?");
                  goto error;
              }
              if (objc == 3) {
                  if (Tcl_GetDoubleFromObj(interp, objv[2], &value)
                          != TCL_OK) {
                      goto error;
                  }
              } else {
                  value = scalePtr->value;
              }
              if (scalePtr->orient == ORIENT_VERTICAL) {
                  x = scalePtr->vertTroughX + scalePtr->width/2
                          + scalePtr->borderWidth;
                  y = TkScaleValueToPixel(scalePtr, value);
              } else {
                  x = TkScaleValueToPixel(scalePtr, value);
                  y = scalePtr->horizTroughY + scalePtr->width/2
                          + scalePtr->borderWidth;
              }
              sprintf(buf, "%d %d", x, y);
              Tcl_SetResult(interp, buf, TCL_VOLATILE);
              break;
          }
          case COMMAND_GET: {
              double value;
              int x, y;
              char buf[TCL_DOUBLE_SPACE];
              if ((objc != 2) && (objc != 4)) {
                  Tcl_WrongNumArgs(interp, 1, objv, "get ?x y?");
                  goto error;
              }
              if (objc == 2) {
                  value = scalePtr->value;
              } else {
                  if ((Tcl_GetIntFromObj(interp, objv[2], &x) != TCL_OK)
                          || (Tcl_GetIntFromObj(interp, objv[3], &y)
                          != TCL_OK)) {
                      goto error;
                  }
                  value = TkScalePixelToValue(scalePtr, x, y);
              }
              sprintf(buf, scalePtr->format, value);
              Tcl_SetResult(interp, buf, TCL_VOLATILE);
              break;
          }
          case COMMAND_IDENTIFY: {
              int x, y, thing;
              if (objc != 4) {
                  Tcl_WrongNumArgs(interp, 1, objv, "identify x y");
                  goto error;
              }
              if ((Tcl_GetIntFromObj(interp, objv[2], &x) != TCL_OK)
                      || (Tcl_GetIntFromObj(interp, objv[3], &y) != TCL_OK)) {
                  goto error;
              }
              thing = TkpScaleElement(scalePtr, x,y);
              switch (thing) {
                  case TROUGH1:
                      Tcl_SetResult(interp, "trough1", TCL_STATIC);
                      break;
                  case SLIDER:
                      Tcl_SetResult(interp, "slider", TCL_STATIC);
                      break;
                  case TROUGH2:
                      Tcl_SetResult(interp, "trough2", TCL_STATIC);
                      break;
              }
              break;
          }
          case COMMAND_SET: {
              double value;
              if (objc != 3) {
                  Tcl_WrongNumArgs(interp, 1, objv, "set value");
                  goto error;
              }
              if (Tcl_GetDoubleFromObj(interp, objv[2], &value) != TCL_OK) {
                  goto error;
              }
              if (scalePtr->state != STATE_DISABLED) {
                TkScaleSetValue(scalePtr, value, 1, 1);
              }
              break;
          }
      }
      Tcl_Release((ClientData) scalePtr);
      return result;
      error:
      Tcl_Release((ClientData) scalePtr);
      return TCL_ERROR;
  }
  /*
   *----------------------------------------------------------------------
   *
   * DestroyScale --
   *
   *      This procedure is invoked by Tcl_EventuallyFree or Tcl_Release
   *      to clean up the internal structure of a button at a safe time
   *      (when no-one is using it anymore).
   *
   * Results:
   *      None.
   *
   * Side effects:
   *      Everything associated with the scale is freed up.
   *
   *----------------------------------------------------------------------
   */
  static void
  DestroyScale(memPtr)
      char *memPtr;       /* Info about scale widget. */
  {
      register TkScale *scalePtr = (TkScale *) memPtr;
      scalePtr->flags |= SCALE_DELETED;
      Tcl_DeleteCommandFromToken(scalePtr->interp, scalePtr->widgetCmd);
      if (scalePtr->flags & REDRAW_PENDING) {
          Tcl_CancelIdleCall(TkpDisplayScale, (ClientData) scalePtr);
      }
      /*
       * Free up all the stuff that requires special handling, then
       * let Tk_FreeOptions handle all the standard option-related
       * stuff.
       */
      if (scalePtr->varNamePtr != NULL) {
          Tcl_UntraceVar(scalePtr->interp, Tcl_GetString(scalePtr->varNamePtr),
                  TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
                  ScaleVarProc, (ClientData) scalePtr);
      }
      if (scalePtr->troughGC != None) {
          Tk_FreeGC(scalePtr->display, scalePtr->troughGC);
      }
      if (scalePtr->copyGC != None) {
          Tk_FreeGC(scalePtr->display, scalePtr->copyGC);
      }
      if (scalePtr->textGC != None) {
          Tk_FreeGC(scalePtr->display, scalePtr->textGC);
      }
      Tk_FreeConfigOptions((char *) scalePtr, scalePtr->optionTable,
              scalePtr->tkwin);
      scalePtr->tkwin = NULL;
      TkpDestroyScale(scalePtr);
  }
  /*
   *----------------------------------------------------------------------
   *
   * ConfigureScale --
   *
   *      This procedure is called to process an argv/argc list, plus
   *      the Tk option database, in order to configure (or
   *      reconfigure) a scale widget.
   *
   * Results:
   *      The return value is a standard Tcl result.  If TCL_ERROR is
   *      returned, then the interp's result contains an error message.
   *
   * Side effects:
   *      Configuration information, such as colors, border width,
   *      etc. get set for scalePtr;  old resources get freed,
   *      if there were any.
   *
   *----------------------------------------------------------------------
   */
  static int
  ConfigureScale(interp, scalePtr, objc, objv)
      Tcl_Interp *interp;         /* Used for error reporting. */
      register TkScale *scalePtr; /* Information about widget;  may or may
                                   * not already have values for some fields. */
      int objc;                   /* Number of valid entries in objv. */
      Tcl_Obj *CONST objv[];      /* Argument values. */
  {
      Tk_SavedOptions savedOptions;
      Tcl_Obj *errorResult = NULL;
      int error;
      double oldValue = scalePtr->value;
      /*
       * Eliminate any existing trace on a variable monitored by the scale.
       */
      if (scalePtr->varNamePtr != NULL) {
          Tcl_UntraceVar(interp, Tcl_GetString(scalePtr->varNamePtr),
                  TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
                  ScaleVarProc, (ClientData) scalePtr);
      }
      for (error = 0; error <= 1; error++) {
          if (!error) {
              /*
               * First pass: set options to new values.
               */
              if (Tk_SetOptions(interp, (char *) scalePtr,
                      scalePtr->optionTable, objc, objv,
                      scalePtr->tkwin, &savedOptions, (int *) NULL) != TCL_OK) {
                  continue;
              }
          } else {
              /*
               * Second pass: restore options to old values.
               */
              errorResult = Tcl_GetObjResult(interp);
              Tcl_IncrRefCount(errorResult);
              Tk_RestoreSavedOptions(&savedOptions);
          }
          /*
           * If the scale is tied to the value of a variable, then set
           * the scale's value from the value of the variable, if it exists
           * and it holds a valid double value.
           */
          if (scalePtr->varNamePtr != NULL) {
              double value;
              Tcl_Obj *valuePtr;
              valuePtr = Tcl_ObjGetVar2(interp, scalePtr->varNamePtr, NULL,
                      TCL_GLOBAL_ONLY);
              if ((valuePtr != NULL) &&
                      (Tcl_GetDoubleFromObj(NULL, valuePtr, &value) == TCL_OK)) {
                  scalePtr->value = TkRoundToResolution(scalePtr, value);
              }
          }
          /*
           * Several options need special processing, such as parsing the
           * orientation and creating GCs.
           */
          scalePtr->fromValue = TkRoundToResolution(scalePtr,
                  scalePtr->fromValue);
          scalePtr->toValue = TkRoundToResolution(scalePtr, scalePtr->toValue);
          scalePtr->tickInterval = TkRoundToResolution(scalePtr,
                  scalePtr->tickInterval);
          /*
           * Make sure that the tick interval has the right sign so that
           * addition moves from fromValue to toValue.
           */
          if ((scalePtr->tickInterval < 0)
                  ^ ((scalePtr->toValue - scalePtr->fromValue) <  0)) {
            scalePtr->tickInterval = -scalePtr->tickInterval;
          }
          ComputeFormat(scalePtr);
          scalePtr->labelLength = scalePtr->label ? strlen(scalePtr->label) : 0;
          Tk_SetBackgroundFromBorder(scalePtr->tkwin, scalePtr->bgBorder);
          if (scalePtr->highlightWidth < 0) {
              scalePtr->highlightWidth = 0;
          }
          scalePtr->inset = scalePtr->highlightWidth + scalePtr->borderWidth;
          break;
      }
      if (!error) {
          Tk_FreeSavedOptions(&savedOptions);
      }
      /*
       * Set the scale value to itself;  all this does is to make sure
       * that the scale's value is within the new acceptable range for
       * the scale.  We don't set the var here because we need to make
       * special checks for possibly changed varNamePtr.
       */
      TkScaleSetValue(scalePtr, scalePtr->value, 0, 1);
      /*
       * Reestablish the variable trace, if it is needed.
       */
      if (scalePtr->varNamePtr != NULL) {
          Tcl_Obj *valuePtr;
          /*
           * Set the associated variable only when the new value differs
           * from the current value, or the variable doesn't yet exist
           */
          valuePtr = Tcl_ObjGetVar2(interp, scalePtr->varNamePtr, NULL,
                  TCL_GLOBAL_ONLY);
          if ((valuePtr == NULL) || (scalePtr->value != oldValue)
                  || (Tcl_GetDoubleFromObj(NULL, valuePtr, &oldValue) != TCL_OK)
                  || (scalePtr->value != oldValue)) {
              ScaleSetVariable(scalePtr);
          }
          Tcl_TraceVar(interp, Tcl_GetString(scalePtr->varNamePtr),
                  TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
                  ScaleVarProc, (ClientData) scalePtr);
      }
      ScaleWorldChanged((ClientData) scalePtr);
      if (error) {
          Tcl_SetObjResult(interp, errorResult);
          Tcl_DecrRefCount(errorResult);
          return TCL_ERROR;
      } else {
          return TCL_OK;
      }
  }
  /*
   *---------------------------------------------------------------------------
   *
   * ScaleWorldChanged --
   *
   *      This procedure is called when the world has changed in some
   *      way and the widget needs to recompute all its graphics contexts
   *      and determine its new geometry.
   *
   * Results:
   *      None.
   *
   * Side effects:
   *      Scale will be relayed out and redisplayed.
   *
   *---------------------------------------------------------------------------
   */
  static void
  ScaleWorldChanged(instanceData)
      ClientData instanceData;    /* Information about widget. */
  {
      XGCValues gcValues;
      GC gc;
      TkScale *scalePtr;
      scalePtr = (TkScale *) instanceData;
      gcValues.foreground = scalePtr->troughColorPtr->pixel;
      gc = Tk_GetGC(scalePtr->tkwin, GCForeground, &gcValues);
      if (scalePtr->troughGC != None) {
          Tk_FreeGC(scalePtr->display, scalePtr->troughGC);
      }
      scalePtr->troughGC = gc;
      gcValues.font = Tk_FontId(scalePtr->tkfont);
      gcValues.foreground = scalePtr->textColorPtr->pixel;
      gc = Tk_GetGC(scalePtr->tkwin, GCForeground | GCFont, &gcValues);
      if (scalePtr->textGC != None) {
          Tk_FreeGC(scalePtr->display, scalePtr->textGC);
      }
      scalePtr->textGC = gc;
      if (scalePtr->copyGC == None) {
          gcValues.graphics_exposures = False;
          scalePtr->copyGC = Tk_GetGC(scalePtr->tkwin, GCGraphicsExposures,
              &gcValues);
      }
      scalePtr->inset = scalePtr->highlightWidth + scalePtr->borderWidth;
      /*
       * Recompute display-related information, and let the geometry
       * manager know how much space is needed now.
       */
      ComputeScaleGeometry(scalePtr);
      TkEventuallyRedrawScale(scalePtr, REDRAW_ALL);
  }
  /*
   *----------------------------------------------------------------------
   *
   * ComputeFormat --
   *
   *      This procedure is invoked to recompute the "format" field
   *      of a scale's widget record, which determines how the value
   *      of the scale is converted to a string.
   *
   * Results:
   *      None.
   *
   * Side effects:
   *      The format field of scalePtr is modified.
   *
   *----------------------------------------------------------------------
   */
  static void
  ComputeFormat(scalePtr)
      TkScale *scalePtr;                  /* Information about scale widget. */
  {
      double maxValue, x;
      int mostSigDigit, numDigits, leastSigDigit, afterDecimal;
      int eDigits, fDigits;
      /*
       * Compute the displacement from the decimal of the most significant
       * digit required for any number in the scale's range.
       */
      maxValue = fabs(scalePtr->fromValue);
      x = fabs(scalePtr->toValue);
      if (x > maxValue) {
          maxValue = x;
      }
      if (maxValue == 0) {
          maxValue = 1;
      }
      mostSigDigit = (int) floor(log10(maxValue));
      /*
       * If the number of significant digits wasn't specified explicitly,
       * compute it. It's the difference between the most significant
       * digit needed to represent any number on the scale and the
       * most significant digit of the smallest difference between
       * numbers on the scale.  In other words, display enough digits so
       * that at least one digit will be different between any two adjacent
       * positions of the scale.
       */
      numDigits = scalePtr->digits;
      if (numDigits <= 0) {
          if  (scalePtr->resolution > 0) {
              /*
               * A resolution was specified for the scale, so just use it.
               */
              leastSigDigit = (int) floor(log10(scalePtr->resolution));
          } else {
              /*
               * No resolution was specified, so compute the difference
               * in value between adjacent pixels and use it for the least
               * significant digit.
               */
              x = fabs(scalePtr->fromValue - scalePtr->toValue);
              if (scalePtr->length > 0) {
                  x /= scalePtr->length;
              }
              if (x > 0){
                  leastSigDigit = (int) floor(log10(x));
              } else {
                  leastSigDigit = 0;
              }
          }
          numDigits = mostSigDigit - leastSigDigit + 1;
          if (numDigits < 1) {
              numDigits = 1;
          }
      }
      /*
       * Compute the number of characters required using "e" format and
       * "f" format, and then choose whichever one takes fewer characters.
       */
      eDigits = numDigits + 4;
      if (numDigits > 1) {
          eDigits++;                      /* Decimal point. */
      }
      afterDecimal = numDigits - mostSigDigit - 1;
      if (afterDecimal < 0) {
          afterDecimal = 0;
      }
      fDigits = (mostSigDigit >= 0) ? mostSigDigit + afterDecimal : afterDecimal;
      if (afterDecimal > 0) {
          fDigits++;                      /* Decimal point. */
      }
      if (mostSigDigit < 0) {
          fDigits++;                      /* Zero to left of decimal point. */
      }
      if (fDigits <= eDigits) {
          sprintf(scalePtr->format, "%%.%df", afterDecimal);
      } else {
          sprintf(scalePtr->format, "%%.%de", numDigits-1);
      }
  }
  /*
   *----------------------------------------------------------------------
   *
   * ComputeScaleGeometry --
   *
   *      This procedure is called to compute various geometrical
   *      information for a scale, such as where various things get
   *      displayed.  It's called when the window is reconfigured.
   *
   * Results:
   *      None.
   *
   * Side effects:
   *      Display-related numbers get changed in *scalePtr.  The
   *      geometry manager gets told about the window's preferred size.
   *
   *----------------------------------------------------------------------
   */
  static void
  ComputeScaleGeometry(scalePtr)
      register TkScale *scalePtr;         /* Information about widget. */
  {
      char valueString[PRINT_CHARS];
      int tmp, valuePixels, x, y, extraSpace;
      Tk_FontMetrics fm;
      Tk_GetFontMetrics(scalePtr->tkfont, &fm);
      scalePtr->fontHeight = fm.linespace + SPACING;
      /*
       * Horizontal scales are simpler than vertical ones because
       * all sizes are the same (the height of a line of text);
       * handle them first and then quit.
       */
      if (scalePtr->orient == ORIENT_HORIZONTAL) {
          y = scalePtr->inset;
          extraSpace = 0;
          if (scalePtr->labelLength != 0) {
              scalePtr->horizLabelY = y + SPACING;
              y += scalePtr->fontHeight;
              extraSpace = SPACING;
          }
          if (scalePtr->showValue) {
              scalePtr->horizValueY = y + SPACING;
              y += scalePtr->fontHeight;
              extraSpace = SPACING;
          } else {
              scalePtr->horizValueY = y;
          }
          y += extraSpace;
          scalePtr->horizTroughY = y;
          y += scalePtr->width + 2*scalePtr->borderWidth;
          if (scalePtr->tickInterval != 0) {
              scalePtr->horizTickY = y + SPACING;
              y += scalePtr->fontHeight + SPACING;
          }
          Tk_GeometryRequest(scalePtr->tkwin,
                  scalePtr->length + 2*scalePtr->inset, y + scalePtr->inset);
          Tk_SetInternalBorder(scalePtr->tkwin, scalePtr->inset);
          return;
      }
      /*
       * Vertical scale:  compute the amount of space needed to display
       * the scales value by formatting strings for the two end points;
       * use whichever length is longer.
       */
      sprintf(valueString, scalePtr->format, scalePtr->fromValue);
      valuePixels = Tk_TextWidth(scalePtr->tkfont, valueString, -1);
      sprintf(valueString, scalePtr->format, scalePtr->toValue);
      tmp = Tk_TextWidth(scalePtr->tkfont, valueString, -1);
      if (valuePixels < tmp) {
          valuePixels = tmp;
      }
      /*
       * Assign x-locations to the elements of the scale, working from
       * left to right.
       */
      x = scalePtr->inset;
      if ((scalePtr->tickInterval != 0) && (scalePtr->showValue)) {
          scalePtr->vertTickRightX = x + SPACING + valuePixels;
          scalePtr->vertValueRightX = scalePtr->vertTickRightX + valuePixels
                  + fm.ascent/2;
          x = scalePtr->vertValueRightX + SPACING;
      } else if (scalePtr->tickInterval != 0) {
          scalePtr->vertTickRightX = x + SPACING + valuePixels;
          scalePtr->vertValueRightX = scalePtr->vertTickRightX;
          x = scalePtr->vertTickRightX + SPACING;
      } else if (scalePtr->showValue) {
          scalePtr->vertTickRightX = x;
          scalePtr->vertValueRightX = x + SPACING + valuePixels;
          x = scalePtr->vertValueRightX + SPACING;
      } else {
          scalePtr->vertTickRightX = x;
          scalePtr->vertValueRightX = x;
      }
      scalePtr->vertTroughX = x;
      x += 2*scalePtr->borderWidth + scalePtr->width;
      if (scalePtr->labelLength == 0) {
          scalePtr->vertLabelX = 0;
      } else {
          scalePtr->vertLabelX = x + fm.ascent/2;
          x = scalePtr->vertLabelX + fm.ascent/2
              + Tk_TextWidth(scalePtr->tkfont, scalePtr->label,
                      scalePtr->labelLength);
      }
      Tk_GeometryRequest(scalePtr->tkwin, x + scalePtr->inset,
              scalePtr->length + 2*scalePtr->inset);
      Tk_SetInternalBorder(scalePtr->tkwin, scalePtr->inset);
  }
  /*
   *--------------------------------------------------------------
   *
   * ScaleEventProc --
   *
   *      This procedure is invoked by the Tk dispatcher for various
   *      events on scales.
   *
   * Results:
   *      None.
   *
   * Side effects:
   *      When the window gets deleted, internal structures get
   *      cleaned up.  When it gets exposed, it is redisplayed.
   *
   *--------------------------------------------------------------
   */
  static void
  ScaleEventProc(clientData, eventPtr)
      ClientData clientData;      /* Information about window. */
      XEvent *eventPtr;           /* Information about event. */
  {
      TkScale *scalePtr = (TkScale *) clientData;
      if ((eventPtr->type == Expose) && (eventPtr->xexpose.count == 0)) {
          TkEventuallyRedrawScale(scalePtr, REDRAW_ALL);
      } else if (eventPtr->type == DestroyNotify) {
          DestroyScale((char *) clientData);
      } else if (eventPtr->type == ConfigureNotify) {
          ComputeScaleGeometry(scalePtr);
          TkEventuallyRedrawScale(scalePtr, REDRAW_ALL);
      } else if (eventPtr->type == FocusIn) {
          if (eventPtr->xfocus.detail != NotifyInferior) {
              scalePtr->flags |= GOT_FOCUS;
              if (scalePtr->highlightWidth > 0) {
                  TkEventuallyRedrawScale(scalePtr, REDRAW_ALL);
              }
          }
      } else if (eventPtr->type == FocusOut) {
          if (eventPtr->xfocus.detail != NotifyInferior) {
              scalePtr->flags &= ~GOT_FOCUS;
              if (scalePtr->highlightWidth > 0) {
                  TkEventuallyRedrawScale(scalePtr, REDRAW_ALL);
              }
          }
      }
  }
  /*
   *----------------------------------------------------------------------
   *
   * ScaleCmdDeletedProc --
   *
   *      This procedure is invoked when a widget command is deleted.  If
   *      the widget isn't already in the process of being destroyed,
   *      this command destroys it.
   *
   * Results:
   *      None.
   *
   * Side effects:
   *      The widget is destroyed.
   *
   *----------------------------------------------------------------------
   */
  static void
  ScaleCmdDeletedProc(clientData)
      ClientData clientData;      /* Pointer to widget record for widget. */
  {
      TkScale *scalePtr = (TkScale *) clientData;
      Tk_Window tkwin = scalePtr->tkwin;
      /*
       * This procedure could be invoked either because the window was
       * destroyed and the command was then deleted (in which case tkwin
       * is NULL) or because the command was deleted, and then this procedure
       * destroys the widget.
       */
      if (!(scalePtr->flags & SCALE_DELETED)) {
          scalePtr->flags |= SCALE_DELETED;
          Tk_DestroyWindow(tkwin);
      }
  }
  /*
   *--------------------------------------------------------------
   *
   * TkEventuallyRedrawScale --
   *
   *      Arrange for part or all of a scale widget to redrawn at
   *      the next convenient time in the future.
   *
   * Results:
   *      None.
   *
   * Side effects:
   *      If "what" is REDRAW_SLIDER then just the slider and the
   *      value readout will be redrawn;  if "what" is REDRAW_ALL
   *      then the entire widget will be redrawn.
   *
   *--------------------------------------------------------------
   */
  void
  TkEventuallyRedrawScale(scalePtr, what)
      register TkScale *scalePtr; /* Information about widget. */
      int what;                   /* What to redraw:  REDRAW_SLIDER
                                   * or REDRAW_ALL. */
  {
      if ((what == 0) || (scalePtr->tkwin == NULL)
              || !Tk_IsMapped(scalePtr->tkwin)) {
          return;
      }
      if (!(scalePtr->flags & REDRAW_PENDING)) {
          scalePtr->flags |= REDRAW_PENDING;
          Tcl_DoWhenIdle(TkpDisplayScale, (ClientData) scalePtr);
      }
      scalePtr->flags |= what;
  }
  /*
   *--------------------------------------------------------------
   *
   * TkRoundToResolution --
   *
   *      Round a given floating-point value to the nearest multiple
   *      of the scale's resolution.
   *
   * Results:
   *      The return value is the rounded result.
   *
   * Side effects:
   *      None.
   *
   *--------------------------------------------------------------
   */
  double
  TkRoundToResolution(scalePtr, value)
      TkScale *scalePtr;          /* Information about scale widget. */
      double value;               /* Value to round. */
  {
      double rem, new, tick;
      if (scalePtr->resolution <= 0) {
          return value;
      }
      tick = floor(value/scalePtr->resolution);
      new = scalePtr->resolution * tick;
      rem = value - new;
      if (rem < 0) {
          if (rem <= -scalePtr->resolution/2) {
              new = (tick - 1.0) * scalePtr->resolution;
          }
      } else {
          if (rem >= scalePtr->resolution/2) {
              new = (tick + 1.0) * scalePtr->resolution;
          }
      }
      return new;
  }
  /*
   *----------------------------------------------------------------------
   *
   * ScaleVarProc --
   *
   *      This procedure is invoked by Tcl whenever someone modifies a
   *      variable associated with a scale widget.
   *
   * Results:
   *      NULL is always returned.
   *
   * Side effects:
   *      The value displayed in the scale will change to match the
   *      variable's new value.  If the variable has a bogus value then
   *      it is reset to the value of the scale.
   *
   *----------------------------------------------------------------------
   */
      /* ARGSUSED */
  static char *
  ScaleVarProc(clientData, interp, name1, name2, flags)
      ClientData clientData;      /* Information about button. */
      Tcl_Interp *interp;         /* Interpreter containing variable. */
      char *name1;                /* Name of variable. */
      char *name2;                /* Second part of variable name. */
      int flags;                  /* Information about what happened. */
  {
      register TkScale *scalePtr = (TkScale *) clientData;
      char *resultStr;
      double value;
      Tcl_Obj *valuePtr;
      int result;
      /*
       * If the variable is unset, then immediately recreate it unless
       * the whole interpreter is going away.
       */
      if (flags & TCL_TRACE_UNSETS) {
          if ((flags & TCL_TRACE_DESTROYED) && !(flags & TCL_INTERP_DESTROYED)) {
              Tcl_TraceVar(interp, Tcl_GetString(scalePtr->varNamePtr),
                      TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
                      ScaleVarProc, clientData);
              scalePtr->flags |= NEVER_SET;
              TkScaleSetValue(scalePtr, scalePtr->value, 1, 0);
          }
          return (char *) NULL;
      }
      /*
       * If we came here because we updated the variable (in TkScaleSetValue),
       * then ignore the trace.  Otherwise update the scale with the value
       * of the variable.
       */
      if (scalePtr->flags & SETTING_VAR) {
          return (char *) NULL;
      }
      resultStr = NULL;
      valuePtr = Tcl_ObjGetVar2(interp, scalePtr->varNamePtr, NULL,
              TCL_GLOBAL_ONLY);
      result = Tcl_GetDoubleFromObj(interp, valuePtr, &value);
      if (result != TCL_OK) {
          resultStr = "can't assign non-numeric value to scale variable";
          ScaleSetVariable(scalePtr);
      } else {
          scalePtr->value = TkRoundToResolution(scalePtr, value);
          /*
           * This code is a bit tricky because it sets the scale's value before
           * calling TkScaleSetValue.  This way, TkScaleSetValue won't bother
           * to set the variable again or to invoke the -command.  However, it
           * also won't redisplay the scale, so we have to ask for that
           * explicitly.
           */
          TkScaleSetValue(scalePtr, scalePtr->value, 1, 0);
      }
      TkEventuallyRedrawScale(scalePtr, REDRAW_SLIDER);
      return resultStr;
  }
  /*
   *--------------------------------------------------------------
   *
   * TkScaleSetValue --
   *
   *      This procedure changes the value of a scale and invokes
   *      a Tcl command to reflect the current position of a scale
   *
   * Results:
   *      None.
   *
   * Side effects:
   *      A Tcl command is invoked, and an additional error-processing
   *      command may also be invoked.  The scale's slider is redrawn.
   *
   *--------------------------------------------------------------
   */
  void
  TkScaleSetValue(scalePtr, value, setVar, invokeCommand)
      register TkScale *scalePtr; /* Info about widget. */
      double value;               /* New value for scale.  Gets adjusted
                                   * if it's off the scale. */
      int setVar;                 /* Non-zero means reflect new value through
                                   * to associated variable, if any. */
      int invokeCommand;          /* Non-zero means invoked -command option
                                   * to notify of new value, 0 means don't. */
  {
      value = TkRoundToResolution(scalePtr, value);
      if ((value < scalePtr->fromValue)
              ^ (scalePtr->toValue < scalePtr->fromValue)) {
          value = scalePtr->fromValue;
      }
      if ((value > scalePtr->toValue)
              ^ (scalePtr->toValue < scalePtr->fromValue)) {
          value = scalePtr->toValue;
      }
      if (scalePtr->flags & NEVER_SET) {
          scalePtr->flags &= ~NEVER_SET;
      } else if (scalePtr->value == value) {
          return;
      }
      scalePtr->value = value;
      if (invokeCommand) {
          scalePtr->flags |= INVOKE_COMMAND;
      }
      TkEventuallyRedrawScale(scalePtr, REDRAW_SLIDER);
      if (setVar && scalePtr->varNamePtr) {
          ScaleSetVariable(scalePtr);
      }
  }
  /*
   *--------------------------------------------------------------
   *
   * ScaleSetVariable --
   *
   *      This procedure sets the variable associated with a scale, if any.
   *
   * Results:
   *      None.
   *
   * Side effects:
   *      Other write traces on the variable will trigger.
   *
   *--------------------------------------------------------------
   */
  static void
  ScaleSetVariable(scalePtr)
      register TkScale *scalePtr; /* Info about widget. */
  {
      if (scalePtr->varNamePtr != NULL) {
          char string[PRINT_CHARS];
          sprintf(string, scalePtr->format, scalePtr->value);
          scalePtr->flags |= SETTING_VAR;
          Tcl_ObjSetVar2(scalePtr->interp, scalePtr->varNamePtr, NULL,
                  Tcl_NewStringObj(string, -1), TCL_GLOBAL_ONLY);
          scalePtr->flags &= ~SETTING_VAR;
      }
  }
  /*
   *----------------------------------------------------------------------
   *
   * TkScalePixelToValue --
   *
   *      Given a pixel within a scale window, return the scale
   *      reading corresponding to that pixel.
   *
   * Results:
   *      A double-precision scale reading.  If the value is outside
   *      the legal range for the scale then it's rounded to the nearest
   *      end of the scale.
   *
   * Side effects:
   *      None.
   *
   *----------------------------------------------------------------------
   */
  double
  TkScalePixelToValue(scalePtr, x, y)
      register TkScale *scalePtr;         /* Information about widget. */
      int x, y;                           /* Coordinates of point within
                                           * window. */
  {
      double value, pixelRange;
      if (scalePtr->orient == ORIENT_VERTICAL) {
          pixelRange = Tk_Height(scalePtr->tkwin) - scalePtr->sliderLength
                  - 2*scalePtr->inset - 2*scalePtr->borderWidth;
          value = y;
      } else {
          pixelRange = Tk_Width(scalePtr->tkwin) - scalePtr->sliderLength
                  - 2*scalePtr->inset - 2*scalePtr->borderWidth;
          value = x;
      }
      if (pixelRange <= 0) {
          /*
           * Not enough room for the slider to actually slide:  just return
           * the scale's current value.
           */
          return scalePtr->value;
      }
      value -= scalePtr->sliderLength/2 + scalePtr->inset
                  + scalePtr->borderWidth;
      value /= pixelRange;
      if (value < 0) {
          value = 0;
      }
      if (value > 1) {
          value = 1;
      }
      value = scalePtr->fromValue +
                  value * (scalePtr->toValue - scalePtr->fromValue);
      return TkRoundToResolution(scalePtr, value);
  }
  /*
   *----------------------------------------------------------------------
   *
   * TkScaleValueToPixel --
   *
   *      Given a reading of the scale, return the x-coordinate or
   *      y-coordinate corresponding to that reading, depending on
   *      whether the scale is vertical or horizontal, respectively.
   *
   * Results:
   *      An integer value giving the pixel location corresponding
   *      to reading.  The value is restricted to lie within the
   *      defined range for the scale.
   *
   * Side effects:
   *      None.
   *
   *----------------------------------------------------------------------
   */
  int
  TkScaleValueToPixel(scalePtr, value)
      register TkScale *scalePtr;         /* Information about widget. */
      double value;                       /* Reading of the widget. */
  {
      int y, pixelRange;
      double valueRange;
      valueRange = scalePtr->toValue - scalePtr->fromValue;
      pixelRange = ((scalePtr->orient == ORIENT_VERTICAL)
              ? Tk_Height(scalePtr->tkwin) : Tk_Width(scalePtr->tkwin))
          - scalePtr->sliderLength - 2*scalePtr->inset - 2*scalePtr->borderWidth;
      if (valueRange == 0) {
          y = 0;
      } else {
          y = (int) ((value - scalePtr->fromValue) * pixelRange
                    / valueRange + 0.5);
          if (y < 0) {
              y = 0;
          } else if (y > pixelRange) {
              y = pixelRange;
          }
      }
      y += scalePtr->sliderLength/2 + scalePtr->inset + scalePtr->borderWidth;
      return y;
  }
  /* End of tkscale.c */

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