WIDGET CLASS NAME

Slider

SYNOPSIS

f4#include <Intrinsic.h>
#include <StringDefs.h>
#include <OpenLook.h>
#include <Slider.h>

widget = XtCreateWidget(name, sliderWidgetClass, ...)

DESCRIPTION

Slider Components

The Slider widget controls the setting of a numeric value;  a horizontal slider is shown in the diagram Horizontal Slider. 

  Figure 1 Horizontal Slider

It consists of the following elements:

—Top (Left) Anchor

—Bottom (Right) Anchor

—Drag Box

—Bar (typically)

—Shaded Bar (typically)

—Current Value (not visible)

—Minimum Value (not visible)

—Maximum Value (not visible)

The Current Value is the numeric value a user attempts to change with the Slider widget.  Drag Box Motion

As visual feedback to the user, the Drag Box moves up or down (or left or right) along the Bar as the Current Value changes. 

  Figure 2 Vertical Slider Dragging SELECT

The user can change the Current Value by dragging the Drag Box with SELECT.  The pressing of SELECT must start with the pointer in the Drag Box, but the Drag Box (and the Current Value) track the pointer motion regardless of where it goes while SELECT is pressed.  This means it is not possible for the user to change the Current Value by first pressing SELECT outside the Drag Box and then moving the pointer into it.  Only the component of the pointer motion parallel to the Bar is tracked, and the motion of the Drag Box (and change in the Current Value) are limited by the length of the Bar.  Clicking SELECT

Clicking SELECT above the Drag Box for a vertical slider, or to the right for a horizontal slider, increases the Current Value by an application-specified amount, moves the Drag Box to correspond to the new Current Value, and moves the pointer to keep it on the Drag Box.  Clicking SELECT to the other side of the Drag Box decreases the value by the same amount and moves the Drag Box and pointer accordingly.  Pressing SELECT repeats this action.  Moving Drag Box to Limits

Clicking SELECT on one of the Bottom/Left or Top/Right Anchors causes the Current Value to take on the Minimum Value or Maximum Value, respectively, and moves the Drag Box to the limit in the direction of the Anchor.  If the Drag Box is already at the limit, nothing happens. 

Clicking SELECT on an Anchor highlights the Anchor while the Current Value is changed.  Application Notification

The application finds out about a change in the Current Value on the release of SELECT for either the drag or click.  It is responsible for providing any feedback to the end user deemed appropriate, such as updating the Current Value in a text field.  Slider Coloration

the diagram Slider Coloration illustrates the resources that affect the coloration of the Slider widget. 

  Figure 3 Slider Coloration

RESOURCES

  Table 1 Slider Resource Set Slider Resource Set\\∗(cO
                Name            Type       Default   Access XtNancestorSensitive         Boolean          TRUE       G∗
       XtNbackground           Pixel         White  SGI†
 XtNbackgroundPixmap          Pixmap        (none)  SGI†
            XtNdepth             int    (parent’s)       GI
  XtNdestroyCallback  XtCallbackList          NULL       SI
       XtNforeground           Pixel         Black  SGI†
      XtNgranularity             int             1      SGI
           XtNheight       Dimension  (calculated)      SGI
     XtNinitialDelay             int           500      SGI XtNmappedWhenManaged         Boolean          TRUE      SGI
       XtNrepeatRate             int           100      SGI
        XtNsensitive         Boolean          TRUE      GI∗
        XtNsliderMax             int           100      SGI
        XtNsliderMin             int             0      SGI
      XtNsliderMoved  XtCallbackList          NULL       SI
      XtNsliderValue             int             0      SGI
         XtNuserData       XtPointer          NULL      SGI
            XtNwidth       Dimension  (calculated)      SGI
                XtNx        Position             0      SGI
                XtNy        Position             0      SGI XtNforeground

This resource defines the foreground color for the widget. 

See the note about the interaction of this resource with other color resources under the description of the XtNbackground resource in CORE(3W).  XtNgranularity

Range of Values:

1 ≤ XtNgranularity ≤ (XtNsliderMax - XtNsliderMin)

Clicking SELECT on the Bar or Shaded Bar attempts to change the Current Value by the amount given in this resource.  Dragging the Drag Box with SELECT changes the Current Value by this amount before the XtNsliderMoved callbacks are issued.  XtNinitialDelay

Range of Values:

0 < XtNinitialDelay

This resource gives the time, in milliseconds, before the first action occurs when SELECT is pressed on the Bar or Shaded Bar.  Note that millisecond timing precision may not be possible for all implementations, so the value may be rounded up to the nearest available unit by the toolkit.  XtNorientation

Range of Values:

OL_HORIZONTAL/"horizontal"
OL_VERTICAL/"vertical"

This resource defines the direction for the visual presentation of the widget.  XtNrepeatRate

Range of Values:

0 < XtNrepeatRate

This resource gives the time, in milliseconds, between repeated actions when SELECT is pressed on the Bar or Shaded Bar.  Note that millisecond timing precision may not be possible for all implementations, so the value may be rounded up to the nearest available unit by the toolkit.  XtNsliderMax
XtNsliderMin

Range of Values:

XtNsliderMin < XtNsliderMax

These two resources give the range of values tracked by the Slider widget.  Mathematically, the range is open on the right; that is, the range is the following subset of the set of integers:

This is independent of the Drag Box displayed in the Slider

widget.  The Slider widget is responsible for taking into account the size of the Drag Box when relating the physical range of movement to the range of values. 

  Figure 4 Drag Box Range of Movement XtNsliderMoved

This resource defines the callback list used when the Slider widget is manipulated.  The call_data parameter is a pointer to the Current Value; an XtGetValue() inside the callback will return the previous an XtGetValue() inside the callback will return the previous value.  XtNsliderValue

Range of Values:

XtNsliderMin ≤ XtNsliderValue ≤ XtNsliderMax

This resource gives the current position of the Drag Box, in the range [ XtNsliderMin , XtNsliderMax ].  The Slider widget keeps this resource up to date; however, an application can also get the current value through the XtNsliderMoved callbacks. 

Sun Release 4.1  —  Last change: 1/8/90