Tk Source Code

Specifies the desired long dimension of the scale in screen units
(i.e. any of the forms acceptable to \fBTk_GetPixels\fR).
For vertical scales this is the scale's height;  for horizontal scales
it is the scale's width.
.OP \-resolution resolution Resolution
A real value specifying the resolution for the scale.
If this value is greater than zero then the scale's value will always be
rounded to an even multiple of this value, as will tick marks and
rounded to an even multiple of this value, as will
the endpoints of the scale.  If the value is less than zero then no
rounding occurs.  Defaults to 1 (i.e., the value will be integral).
.OP \-showvalue showValue ShowValue
Specifies a boolean value indicating whether or not the current
value of the scale is to be displayed.
.OP \-sliderlength sliderLength SliderLength
Specifies the size of the slider, measured in screen units along the slider's

If the scale is disabled then the value may not be changed and the scale
will not activate.
If the scale is active, the slider is displayed using the color
specified by the \fB\-activebackground\fR option.
.OP \-tickinterval tickInterval TickInterval
Must be a real value.
Determines the spacing between numerical
tick marks displayed below or to the left of the slider.
tick marks displayed below or to the left of the slider. The values will all be displayed with the same number of decimal places, which will be enough to ensure they are all accurate to within 20% of a tick interval. 
If 0, no tick marks will be displayed.
.OP \-to to To
Specifies a real value corresponding
to the right or bottom end of the scale.
This value may be either less than or greater than the \fB\-from\fR option.
.OP \-variable variable Variable
Specifies the name of a global variable to link to the scale.  Whenever the

    COMMAND_IDENTIFY, COMMAND_SET
};

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

static void		ComputeFormat(TkScale *scalePtr);
static void		ComputeFormat(TkScale *scalePtr, int forTicks);
static void		ComputeScaleGeometry(TkScale *scalePtr);
static int		ConfigureScale(Tcl_Interp *interp, TkScale *scalePtr,
			    int objc, Tcl_Obj *const objv[]);
static void		DestroyScale(char *memPtr);
static double		MaxTickRoundingError(TkScale *scalePtr,
			    double tickResolution);
static void		ScaleCmdDeletedProc(ClientData clientData);
static void		ScaleEventProc(ClientData clientData,
			    XEvent *eventPtr);
static char *		ScaleVarProc(ClientData clientData,
			    Tcl_Interp *interp, const char *name1,
			    const char *name2, int flags);
static int		ScaleWidgetObjCmd(ClientData clientData,
			    Tcl_Interp *interp, int objc,
			    Tcl_Obj *const objv[]);
static void		ScaleWorldChanged(ClientData instanceData);
static void		ScaleSetVariable(TkScale *scalePtr);

/*
 * The structure below defines scale class behavior by means of procedures
 * that can be invoked from generic window code.
 */

static const Tk_ClassProcs scaleClass = {
    sizeof(Tk_ClassProcs),	/* size */
    ScaleWorldChanged,		/* worldChangedProc */
    NULL,					/* createProc */
    NULL					/* modalProc */
    NULL,			/* createProc */
    NULL			/* modalProc */
};

/*
 *--------------------------------------------------------------
 *
 * ScaleDigit, ScaleMax, ScaleMin, ScaleRound --
 *
 *	Simple math helper functions, designed to be automatically inlined by
 *	the compiler most of the time.
 *
 *--------------------------------------------------------------
 */

static inline int
ScaleDigit(
    double value)
{
    return (int) floor(log10(fabs(value)));
}

static inline double
ScaleMax(
    double a,
    double b)
{
    return (a > b) ? a : b;
}

static inline double
ScaleMin(
    double a,
    double b)
{
    return (a < b) ? a : b;
}

static inline int
ScaleRound(
    double value)
{
    return (int) floor(value + 0.5);
}

/*
 *--------------------------------------------------------------
 *
 * Tk_ScaleObjCmd --
 *
 *	This procedure is invoked to process the "scale" Tcl command. See the

	} 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);
	}
	Tcl_SetObjResult(interp, Tcl_ObjPrintf(scalePtr->format, value));
	Tcl_SetObjResult(interp, Tcl_ObjPrintf(scalePtr->valueFormat, value));
	break;
    }
    case COMMAND_IDENTIFY: {
	int x, y;
	const char *zone = "";

	if (objc != 4) {

	 */

	if ((scalePtr->tickInterval < 0)
		^ ((scalePtr->toValue - scalePtr->fromValue) < 0)) {
	    scalePtr->tickInterval = -scalePtr->tickInterval;
	}

	ComputeFormat(scalePtr);
	ComputeFormat(scalePtr, 0);
	ComputeFormat(scalePtr, 1);

	scalePtr->labelLength = scalePtr->label ? (int)strlen(scalePtr->label) : 0;

	Tk_SetBackgroundFromBorder(scalePtr->tkwin, scalePtr->bgBorder);

	if (scalePtr->highlightWidth < 0) {
	    scalePtr->highlightWidth = 0;

     * know how much space is needed now.
     */

    ComputeScaleGeometry(scalePtr);

    TkEventuallyRedrawScale(scalePtr, REDRAW_ALL);
}

/*
 *----------------------------------------------------------------------
 *
 /*
  *----------------------------------------------------------------------
  *
  * MaxTickRoundingError --
  *
  *      Given the separation between values that can be displayed on ticks,
  *      this calculates the maximum magnitude of error for the displayed
  *      value. Tries to be clever by working out the increment in error
  *      between ticks rather than testing all of them, so may overestimate
  *      error if it is greater than 0.25 x the value separation.
  *
  * Results:
  *      Maximum error magnitude of tick numbers.
  *
  * Side effects:
  *      None.
  *
  *----------------------------------------------------------------------
  */

static double
MaxTickRoundingError(
    TkScale *scalePtr,		/* Information about scale widget. */
    double tickResolution)      /* Separation between displayable values. */
{
    double tickPosn, firstTickError, lastTickError, intervalError;
    int tickCount;

    /*
     * Compute the error for each tick-related measure.
     */

    tickPosn = scalePtr->fromValue / tickResolution;
    firstTickError = tickPosn - ScaleRound(tickPosn);

    tickPosn = scalePtr->tickInterval / tickResolution;
    intervalError = tickPosn - ScaleRound(tickPosn);

    tickCount = (int) ((scalePtr->toValue - scalePtr->fromValue) /
	    scalePtr->tickInterval);	/* not including first */
    lastTickError = ScaleMin(0.5,
	    fabs(firstTickError + tickCount * intervalError));

    /*
     * Compute the maximum cumulative rounding error.
     */

    return ScaleMax(fabs(firstTickError), lastTickError) * tickResolution;
}

/*
 *----------------------------------------------------------------------
 *
 * 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.
 *	This procedure is invoked to recompute the "valueFormat" or
 *	"tickFormat" field of a scale's widget record, which determines how
 *	the value of the scale or one of its ticks is converted to a string.
 *
 * Results:
 *	None.
 *
 * Side effects:
 * Side effects: The valueFormat or tickFormat field of scalePtr is modified.
 *	The format field of scalePtr is modified.
 *
 *----------------------------------------------------------------------
 */

static void
ComputeFormat(
    TkScale *scalePtr)		/* Information about scale widget. */
    TkScale *scalePtr,		/* Information about scale widget. */
    int forTicks)               /* Do for ticks rather than value */
{
    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));
    mostSigDigit = ScaleDigit(maxValue);

    if (forTicks) {
    /*
     * 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.
     */
	/*
	 * Display only enough digits to ensure adjacent ticks have different
	 * values.
	 */

	if (scalePtr->tickInterval != 0) {
	    leastSigDigit = ScaleDigit(scalePtr->tickInterval);

	    /*
	     * Now add more digits until max error is less than
	     * TICK_VALUES_DISPLAY_ACCURACY intervals
	     */

	    while (MaxTickRoundingError(scalePtr, pow(10, leastSigDigit))
		    > fabs(TICK_VALUES_DISPLAY_ACCURACY * scalePtr->tickInterval)) {
		--leastSigDigit;
	    }
	    numDigits = 1 + mostSigDigit - leastSigDigit;
	} else {
	    numDigits = 1;
	}
    } else {
	/*
	 * 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 > TCL_MAX_PREC) {
	numDigits = 0;
    }
    if (numDigits <= 0) {
	if (scalePtr->resolution > 0) {
	    /*
	     * A resolution was specified for the scale, so just use it.
	     */
	numDigits = scalePtr->digits;
	if (numDigits > TCL_MAX_PREC) {
	    numDigits = 0;
	}
	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.
	     */
		leastSigDigit = ScaleDigit(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;
		x = fabs(scalePtr->fromValue - scalePtr->toValue);
		if (scalePtr->length > 0) {
		    x /= scalePtr->length;
		}
		if (x > 0) {
		    leastSigDigit = ScaleDigit(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.
     */

    fDigits = (mostSigDigit >= 0) ? mostSigDigit + afterDecimal : afterDecimal;
    if (afterDecimal > 0) {
	fDigits++;			/* Decimal point. */
    }
    if (mostSigDigit < 0) {
	fDigits++;			/* Zero to left of decimal point. */
    }

    if (forTicks) {
    if (fDigits <= eDigits) {
	sprintf(scalePtr->format, "%%.%df", afterDecimal);
    } else {
	sprintf(scalePtr->format, "%%.%de", numDigits-1);
	if (fDigits <= eDigits) {
	    sprintf(scalePtr->tickFormat, "%%.%df", afterDecimal);
	} else {
	    sprintf(scalePtr->tickFormat, "%%.%de", numDigits - 1);
	}
    } else {
	if (fDigits <= eDigits) {
	    sprintf(scalePtr->valueFormat, "%%.%df", afterDecimal);
	} else {
	    sprintf(scalePtr->valueFormat, "%%.%de", numDigits - 1);
	}
    }
}

/*
 *----------------------------------------------------------------------
 *
 * ComputeScaleGeometry --

 */

static void
ComputeScaleGeometry(
    register TkScale *scalePtr)	/* Information about widget. */
{
    char valueString[TCL_DOUBLE_SPACE];
    int tmp, valuePixels, x, y, extraSpace;
    int tmp, valuePixels, tickPixels, 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

    /*
     * 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.
     */

    if (snprintf(valueString, TCL_DOUBLE_SPACE, scalePtr->format,
    if (snprintf(valueString, TCL_DOUBLE_SPACE, scalePtr->valueFormat,
            scalePtr->fromValue) < 0) {
        valueString[TCL_DOUBLE_SPACE - 1] = '\0';
    }
    valuePixels = Tk_TextWidth(scalePtr->tkfont, valueString, -1);

    if (snprintf(valueString, TCL_DOUBLE_SPACE, scalePtr->format,
    if (snprintf(valueString, TCL_DOUBLE_SPACE, scalePtr->valueFormat,
            scalePtr->toValue) < 0) {
        valueString[TCL_DOUBLE_SPACE - 1] = '\0';
    }
    tmp = Tk_TextWidth(scalePtr->tkfont, valueString, -1);
    if (valuePixels < tmp) {
	valuePixels = tmp;
    }

    /*
     * Now do the same thing for the tick values
     */

    if (snprintf(valueString, TCL_DOUBLE_SPACE, scalePtr->tickFormat,
            scalePtr->fromValue) < 0) {
        valueString[TCL_DOUBLE_SPACE - 1] = '\0';
    }
    tickPixels = Tk_TextWidth(scalePtr->tkfont, valueString, -1);

    if (snprintf(valueString, TCL_DOUBLE_SPACE, scalePtr->tickFormat,
            scalePtr->toValue) < 0) {
        valueString[TCL_DOUBLE_SPACE - 1] = '\0';
    }
    tmp = Tk_TextWidth(scalePtr->tkfont, valueString, -1);
    if (tickPixels < tmp) {
	tickPixels = 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->vertTickRightX = x + SPACING + tickPixels;
	scalePtr->vertValueRightX = scalePtr->vertTickRightX + valuePixels
		+ fm.ascent/2;
	x = scalePtr->vertValueRightX + SPACING;
    } else if (scalePtr->tickInterval != 0) {
	scalePtr->vertTickRightX = x + SPACING + valuePixels;
	scalePtr->vertTickRightX = x + SPACING + tickPixels;
	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 {

static void
ScaleSetVariable(
    register TkScale *scalePtr)	/* Info about widget. */
{
    if (scalePtr->varNamePtr != NULL) {
	char string[TCL_DOUBLE_SPACE];

        if (snprintf(string, TCL_DOUBLE_SPACE, scalePtr->format,
        if (snprintf(string, TCL_DOUBLE_SPACE, scalePtr->valueFormat,
                scalePtr->value) < 0) {
            string[TCL_DOUBLE_SPACE - 1] = '\0';
        }
	scalePtr->flags |= SETTING_VAR;
	Tcl_ObjSetVar2(scalePtr->interp, scalePtr->varNamePtr, NULL,
		Tcl_NewStringObj(string, -1), TCL_GLOBAL_ONLY);
	scalePtr->flags &= ~SETTING_VAR;

    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);
	y = ScaleRound((value - scalePtr->fromValue) * pixelRange
		/ valueRange);
	if (y < 0) {
	    y = 0;
	} else if (y > pixelRange) {
	    y = pixelRange;
	}
    }
    y += scalePtr->sliderLength/2 + scalePtr->inset + scalePtr->borderWidth;

				 * display any tick marks. */
    double resolution;		/* If > 0, all values are rounded to an even
				 * multiple of this value. */
    int digits;			/* Number of significant digits to print in
				 * values. 0 means we get to choose the number
				 * based on resolution and/or the range of the
				 * scale. */
    char format[16];		/* Sprintf conversion specifier computed from
    char valueFormat[16];	/* Sprintf conversion specifier computed from
				 * digits and other information. */
    char tickFormat[16];	/* Sprintf conversion specifier computed from
				 * tick interval. */
    double bigIncrement;	/* Amount to use for large increments to scale
				 * value. (0 means we pick a value). */
    char *command;		/* Command prefix to use when invoking Tcl
				 * commands because the scale value changed.
				 * NULL means don't invoke commands. */
    int repeatDelay;		/* How long to wait before auto-repeating on
				 * scrolling actions (in ms). */

/*
 * Space to leave between scale area and text, and between text and edge of
 * window.
 */

#define SPACING 2

/*
 * The tick values are all displayed with the same number of decimal places.
 * This number of decimal places is such that the displayed values are all
 * accurate to within the following proportion of a tick interval.
 */

#define TICK_VALUES_DISPLAY_ACCURACY 0.2

/*
 * Declaration of procedures used in the implementation of the scale widget.
 */

MODULE_SCOPE void	TkEventuallyRedrawScale(TkScale *scalePtr, int what);
MODULE_SCOPE double	TkRoundValueToResolution(TkScale *scalePtr, double value);
MODULE_SCOPE double	TkRoundIntervalToResolution(TkScale *scalePtr, double value);

/*
 * Forward declarations for functions defined later in this file:
 */

static void		DisplayHorizontalScale(TkScale *scalePtr,
			    Drawable drawable, XRectangle *drawnAreaPtr);
static void		DisplayHorizontalValue(TkScale *scalePtr,
			    Drawable drawable, double value, int top);
			    Drawable drawable, double value, int top,
			    const char *format);
static void		DisplayVerticalScale(TkScale *scalePtr,
			    Drawable drawable, XRectangle *drawnAreaPtr);
static void		DisplayVerticalValue(TkScale *scalePtr,
			    Drawable drawable, double value, int rightEdge);
			    Drawable drawable, double value, int rightEdge,
			    const char *format);

/*
 *----------------------------------------------------------------------
 *
 * TkpCreateScale --
 *
 *	Allocate a new TkScale structure.

		    }
		} else {
		    if (tickValue < scalePtr->toValue) {
			break;
		    }
		}
		DisplayVerticalValue(scalePtr, drawable, tickValue,
			scalePtr->vertTickRightX);
			scalePtr->vertTickRightX, scalePtr->tickFormat);
	    }
	}
    }

    /*
     * Display the value, if it is desired.
     */

    if (scalePtr->showValue) {
	DisplayVerticalValue(scalePtr, drawable, scalePtr->value,
		scalePtr->vertValueRightX);
		scalePtr->vertValueRightX, scalePtr->valueFormat);
    }

    /*
     * Display the trough and the slider.
     */

    Tk_Draw3DRectangle(tkwin, drawable,

    if ((scalePtr->flags & REDRAW_OTHER) && (scalePtr->labelLength != 0)) {
	Tk_FontMetrics fm;

	Tk_GetFontMetrics(scalePtr->tkfont, &fm);
	Tk_DrawChars(scalePtr->display, drawable, scalePtr->textGC,
		scalePtr->tkfont, scalePtr->label,
                scalePtr->labelLength, scalePtr->vertLabelX,
                scalePtr->inset + (3*fm.ascent)/2);
		scalePtr->labelLength, scalePtr->vertLabelX,
		scalePtr->inset + (3 * fm.ascent) / 2);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * DisplayVerticalValue --

    register TkScale *scalePtr,	/* Information about widget in which to
				 * display value. */
    Drawable drawable,		/* Pixmap or window in which to draw the
				 * value. */
    double value,		/* Y-coordinate of number to display,
				 * specified in application coords, not in
				 * pixels (we'll compute pixels). */
    int rightEdge)		/* X-coordinate of right edge of text,
    int rightEdge,		/* X-coordinate of right edge of text,
				 * specified in pixels. */
    const char *format)		/* Format string to use for the value */
{
    register Tk_Window tkwin = scalePtr->tkwin;
    int y, width, length;
    char valueString[TCL_DOUBLE_SPACE];
    Tk_FontMetrics fm;

    Tk_GetFontMetrics(scalePtr->tkfont, &fm);
    y = TkScaleValueToPixel(scalePtr, value) + fm.ascent/2;
    if (snprintf(valueString, TCL_DOUBLE_SPACE, scalePtr->format, value) < 0) {
        valueString[TCL_DOUBLE_SPACE - 1] = '\0';
    if (snprintf(valueString, TCL_DOUBLE_SPACE, format, value) < 0) {
	valueString[TCL_DOUBLE_SPACE - 1] = '\0';
    }
    length = (int) strlen(valueString);
    width = Tk_TextWidth(scalePtr->tkfont, valueString, length);

    /*
     * Adjust the y-coordinate if necessary to keep the text entirely inside
     * the window.
     */

    if ((y - fm.ascent) < (scalePtr->inset + SPACING)) {
    if (y - fm.ascent < scalePtr->inset + SPACING) {
	y = scalePtr->inset + SPACING + fm.ascent;
    }
    if ((y + fm.descent) > (Tk_Height(tkwin) - scalePtr->inset - SPACING)) {
    if (y + fm.descent > Tk_Height(tkwin) - scalePtr->inset - SPACING) {
	y = Tk_Height(tkwin) - scalePtr->inset - SPACING - fm.descent;
    }
    Tk_DrawChars(scalePtr->display, drawable, scalePtr->textGC,
	    scalePtr->tkfont, valueString, length, rightEdge - width, y);
}

/*

    XRectangle *drawnAreaPtr)	/* Initally contains area of window; if only a
				 * part of the scale is redrawn, gets modified
				 * to reflect the part of the window that was
				 * redrawn. */
{
    register Tk_Window tkwin = scalePtr->tkwin;
    int x, y, width, height, shadowWidth;
    double tickValue, tickInterval = scalePtr->tickInterval;
    double tickInterval = scalePtr->tickInterval;
    Tk_3DBorder sliderBorder;

    /*
     * Display the information from bottom to top across the window.
     */

    if (!(scalePtr->flags & REDRAW_OTHER)) {

    if (scalePtr->flags & REDRAW_OTHER) {
	/*
	 * Display the tick marks.
	 */

	if (tickInterval != 0) {
	    char valueString[TCL_DOUBLE_SPACE];
	    double ticks, maxTicks;
	    double ticks, maxTicks, tickValue;

	    /*
	     * Ensure that we will only draw enough of the tick values such
	     * that they don't overlap. We base this off the width that
	     * fromValue would take. Not exact, but better than no constraint.
	     */

	    ticks = fabs((scalePtr->toValue - scalePtr->fromValue)
		    / tickInterval);
            if (snprintf(valueString, TCL_DOUBLE_SPACE, scalePtr->format,
                    scalePtr->fromValue) < 0) {
                valueString[TCL_DOUBLE_SPACE - 1] = '\0';
            }
	    if (snprintf(valueString, TCL_DOUBLE_SPACE, scalePtr->tickFormat,
		    scalePtr->fromValue) < 0) {
		valueString[TCL_DOUBLE_SPACE - 1] = '\0';
	    }
	    maxTicks = (double) Tk_Width(tkwin)
		    / (double) Tk_TextWidth(scalePtr->tkfont, valueString, -1);
	    if (ticks > maxTicks) {
		tickInterval *= (ticks / maxTicks);
		tickInterval *= ticks / maxTicks;
	    }
	    for (tickValue = scalePtr->fromValue; ;
		 tickValue += tickInterval) {
	    tickValue = scalePtr->fromValue;
	    while (1) {
		/*
		 * The TkRoundValueToResolution call gets rid of accumulated
		 * round-off errors, if any.
		 */

		tickValue = TkRoundValueToResolution(scalePtr, tickValue);
		if (scalePtr->toValue >= scalePtr->fromValue) {
		    if (tickValue > scalePtr->toValue) {
			break;
		    }
		} else {
		    if (tickValue < scalePtr->toValue) {
			break;
		    }
		}
		DisplayHorizontalValue(scalePtr, drawable, tickValue,
			scalePtr->horizTickY);
			scalePtr->horizTickY, scalePtr->tickFormat);
		tickValue += tickInterval;
	    }
	}
    }

    /*
     * Display the value, if it is desired.
     */

    if (scalePtr->showValue) {
	DisplayHorizontalValue(scalePtr, drawable, scalePtr->value,
		scalePtr->horizValueY);
		scalePtr->horizValueY, scalePtr->valueFormat);
    }

    /*
     * Display the trough and the slider.
     */

    y = scalePtr->horizTroughY;

    if ((scalePtr->flags & REDRAW_OTHER) && (scalePtr->labelLength != 0)) {
	Tk_FontMetrics fm;

	Tk_GetFontMetrics(scalePtr->tkfont, &fm);
	Tk_DrawChars(scalePtr->display, drawable, scalePtr->textGC,
		scalePtr->tkfont, scalePtr->label,
                scalePtr->labelLength, scalePtr->inset + fm.ascent/2,
                scalePtr->horizLabelY + fm.ascent);
		scalePtr->labelLength, scalePtr->inset + fm.ascent/2,
		scalePtr->horizLabelY + fm.ascent);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * DisplayHorizontalValue --

    register TkScale *scalePtr,	/* Information about widget in which to
				 * display value. */
    Drawable drawable,		/* Pixmap or window in which to draw the
				 * value. */
    double value,		/* X-coordinate of number to display,
				 * specified in application coords, not in
				 * pixels (we'll compute pixels). */
    int top)			/* Y-coordinate of top edge of text, specified
    int top,			/* Y-coordinate of top edge of text, specified
				 * in pixels. */
    const char *format)		/* Format string to use for the value */
{
    register Tk_Window tkwin = scalePtr->tkwin;
    int x, y, length, width;
    char valueString[TCL_DOUBLE_SPACE];
    Tk_FontMetrics fm;

    x = TkScaleValueToPixel(scalePtr, value);
    Tk_GetFontMetrics(scalePtr->tkfont, &fm);
    y = top + fm.ascent;
    if (snprintf(valueString, TCL_DOUBLE_SPACE, scalePtr->format, value) < 0) {
        valueString[TCL_DOUBLE_SPACE - 1] = '\0';
    if (snprintf(valueString, TCL_DOUBLE_SPACE, format, value) < 0) {
	valueString[TCL_DOUBLE_SPACE - 1] = '\0';
    }
    length = (int) strlen(valueString);
    width = Tk_TextWidth(scalePtr->tkfont, valueString, length);

    /*
     * Adjust the x-coordinate if necessary to keep the text entirely inside
     * the window.
     */

    x -= (width)/2;
    if (x < (scalePtr->inset + SPACING)) {
    x -= width / 2;
    if (x < scalePtr->inset + SPACING) {
	x = scalePtr->inset + SPACING;
    }

    /*
     * Check the right border so use starting point +text width for the check.
     */

    /*
     * Invoke the scale's command if needed.
     */

    Tcl_Preserve(scalePtr);
    if ((scalePtr->flags & INVOKE_COMMAND) && (scalePtr->command != NULL)) {
	Tcl_Preserve(interp);
        if (snprintf(string, TCL_DOUBLE_SPACE, scalePtr->format,
                scalePtr->value) < 0) {
            string[TCL_DOUBLE_SPACE - 1] = '\0';
        }
	if (snprintf(string, TCL_DOUBLE_SPACE, scalePtr->valueFormat,
		scalePtr->value) < 0) {
	    string[TCL_DOUBLE_SPACE - 1] = '\0';
	}
	Tcl_DStringInit(&buf);
	Tcl_DStringAppend(&buf, scalePtr->command, -1);
	Tcl_DStringAppend(&buf, " ", -1);
	Tcl_DStringAppend(&buf, string, -1);
	result = Tcl_EvalEx(interp, Tcl_DStringValue(&buf), -1, 0);
	Tcl_DStringFree(&buf);
	if (result != TCL_OK) {

	if (scalePtr->highlightWidth != 0) {
	    GC gc;

	    if (scalePtr->flags & GOT_FOCUS) {
		gc = Tk_GCForColor(scalePtr->highlightColorPtr, pixmap);
	    } else {
		gc = Tk_GCForColor(
                        Tk_3DBorderColor(scalePtr->highlightBorder), pixmap);
			Tk_3DBorderColor(scalePtr->highlightBorder), pixmap);
	    }
	    Tk_DrawFocusHighlight(tkwin, gc, scalePtr->highlightWidth, pixmap);
	}
    }

#ifndef TK_NO_DOUBLE_BUFFERING
    /*

	    return OTHER;
	}
	sliderFirst = TkScaleValueToPixel(scalePtr, scalePtr->value)
		- scalePtr->sliderLength/2;
	if (y < sliderFirst) {
	    return TROUGH1;
	}
	if (y < (sliderFirst+scalePtr->sliderLength)) {
	if (y < sliderFirst + scalePtr->sliderLength) {
	    return SLIDER;
	}
	return TROUGH2;
    }

    if ((y < scalePtr->horizTroughY)
	    || (y >= (scalePtr->horizTroughY + 2*scalePtr->borderWidth +
	    scalePtr->width))) {
	return OTHER;
    }
    if ((x < scalePtr->inset)
	    || (x >= (Tk_Width(scalePtr->tkwin) - scalePtr->inset))) {
	return OTHER;
    }
    sliderFirst = TkScaleValueToPixel(scalePtr, scalePtr->value)
	    - scalePtr->sliderLength/2;
    if (x < sliderFirst) {
	return TROUGH1;
    }
    if (x < (sliderFirst+scalePtr->sliderLength)) {
    if (x < sliderFirst + scalePtr->sliderLength) {
	return SLIDER;
    }
    return TROUGH2;
}

/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 4
 * fill-column: 78
 * End:
 */