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XmScale
NAME
XmScale - The Scale widget class
SYNOPSIS
#include <Xm/Scale.h>
DESCRIPTION
Scale is used by an application to indicate a value from within a
range of values, and it allows the user to input or modify a value
from the same range.
A Scale has an elongated rectangular region similar to a
ScrollBar. A slider inside this region indicates the current value
along the Scale. The user can also modify the Scale's value by moving
the slider within the rectangular region of the Scale. A Scale can
also include a label set located outside the Scale region. These can
indicate the relative value at various positions along the scale.
A Scale can be either input/output or output only. An input/output
Scale's value can be set by the application and also modified by the
user with the slider. An output-only Scale is used strictly as an
indicator of the current value of something and cannot be modified
interactively by the user. The Core resource XmNsensitive specifies
whether the user can interactively modify the Scale's value.
The user can specify resources in a resource file for the
automatically created gadget that contains the title of the Scale
widget. The name of the gadget is "Title".
Classes
Scale inherits behavior and resources from Core, Composite, Constraint, and XmManager classes.
The class pointer is xmScaleWidgetClass.
The class name is XmScale.
New Resources
The following table defines a set of widget resources used by the
programmer to specify data. The programmer can also set the resource
values for the inherited classes to set attributes for this widget. To
reference a resource by name or by class in a .Xdefaults
file, remove the XmN or XmC prefix
and use the remaining letters. To specify one of the defined values
for a resource in a .Xdefaults file, remove the
Xm prefix and use the remaining letters (in either
lowercase or uppercase, but include any underscores between words).
The codes in the access column indicate if the given resource can be
set at creation time (C), set by using XtSetValues
(S), retrieved by using XtGetValues (G), or is not
applicable (N/A).
- XmNdecimalPoints
- Specifies the number of decimal points to shift the slider
value when displaying it. For example, a slider value of 2,350 and an
XmNdecimalPoints value of 2 results in a display
value of 23.50. The value must not be negative.
- XmNdragCallback
- Specifies the list of callbacks that is called when the slider
position changes as the slider is being dragged. The reason sent by
the callback is XmCR_DRAG.
- XmNfontList
- Specifies the font list to use for the title text string
specified by XmNtitleString, and the label
displayed when XmNshowValue is True. If this value
is NULL at initialization, the font list is initialized by looking up
the parent hierarchy of the widget for an ancestor that is a subclass
of the XmBulletinBoard, VendorShell, or XmMenuShell widget class. If such an
ancestor is found, the font list is initialized to the XmNlabelFontList
of the ancestor widget. If no such ancestor is found, the default is
implementation dependent. Refer to XmFontList(3X) for more
information on the creation and structure of a font list.
- XmNhighlightOnEnter
- Specifies whether the highlighting rectangle is drawn when the
cursor moves into the widget. If the shell's focus policy is
XmEXPLICIT, this resource is ignored, and the widget
is highlighted when it has the focus. If the shell's focus policy is
XmPOINTER and if this resource is True, the
highlighting rectangle is drawn when the the cursor moves into the
widget. If the shell's focus policy is XmPOINTER and
if this resource is False, the highlighting rectangle is not drawn
when the the cursor moves into the widget. The default is False.
- XmNhighlightThickness
- Specifies the size of the slider's border drawing rectangle
used for enter window and traversal highlight drawing.
- XmNmaximum
- Specifies the slider's maximum value.
XmNmaximum must be greater than XmNminimum.
- XmNminimum
- Specifies the slider's minimum value. XmNmaximum must be greater than
XmNminimum.
- XmNorientation
- Displays Scale vertically or horizontally. This resource can
have values of XmVERTICAL and XmHORIZONTAL.
- XmNprocessingDirection
- Specifies whether the value for XmNmaximum is on the right or left
side of XmNminimum for
horizontal Scales or above or below XmNminimum for vertical Scales. This
resource can have values of XmMAX_ON_TOP,
XmMAX_ON_BOTTOM,XmMAX_ON_LEFT, and
XmMAX_ON_RIGHT. If the XmScale is oriented
vertically, the default value is XmMAX_ON_TOP. If
the XmScale is oriented horizontally, the default value may depend on
the value of the XmNstringDirection
resource.
- XmNscaleHeight
- Specifies the height of the slider area. The value should be
in the specified unit type (the default is pixels). If no value is
specified a default height is computed.
- XmNscaleMultiple
- Specifies the amount to move the slider when the user takes an
action that moves the slider by a multiple increment. The default is
(XmNmaximum - XmNminimum) divided by
10, with a minimum of 1.
- XmNscaleWidth
- Specifies the width of the slider area. The value should be in
the specified unit type (the default is pixels). If no value is
specified a default width is computed.
- XmNshowValue
- Specifies whether a label for
the current slider value should be displayed next to the slider. If
the value is True, the current slider value is displayed.
- XmNtitleString
- Specifies the title text string to appear in the Scale widget
window.
- XmNvalue
- Specifies the slider's current position along the scale,
between XmNminimum and XmNmaximum.
The value is constrained to be within these inclusive bounds. The
initial value of this resource is the larger of 0 and
XmNminimum.
- XmNvalueChangedCallback
- Specifies the list of callbacks that is called when the value
of the slider has changed. The reason sent by the callback is
XmCR_VALUE_CHANGED.
Inherited Resources
Scale inherits behavior and resources from the following
superclasses. For a complete description of each resource, refer to
the man page for that superclass.
Callback Information
A pointer to the following structure is passed to each callback:
typedef struct
{
int reason;
XEvent * event;
int value;
} XmScaleCallbackStruct;
- reason
- Indicates why the callback was invoked
- event
- Points to the XEvent that triggered the
callback
- value
- Is the new slider value
Behavior
XmScale behavior is described below:
- BSelect Press or BDrag Press:
- (in region between an end of the Scale and the slider): Moves
the slider by one multiple increment in the direction of the end of
the Scale and calls the XmNvalueChangedCallback
callbacks. If XmNprocessingDirection is
XmMAX_ON_RIGHT or XmMAX_ON_BOTTOM,
movement toward the right or bottom increments the Scale value, and
movement toward the left or top decrements the Scale value. If
XmNprocessingDirection is
XmMAX_ON_LEFT or XmMAX_ON_TOP,
movement toward the right or bottom decrements the Scale value, and
movement toward the left or top increments the Scale value. If the
button is held down longer than a delay period, the slider is moved
again by the same increment and the same callbacks are called.
(in slider): Activates the interactive dragging of the slider.
- BSelect Motion or BDrag Motion:
- If the button press occurs within the slider, the subsequent
motion events move the slider to the position of the pointer and call
the callbacks for XmNdragCallback.
- BSelect Release or BDrag Release:
- If the button press occurs within the slider and the slider
position is changed, the callbacks for
XmNvalueChangedCallback are called.
- MCtrl BSelect Press:
- (in region between an end of the Scale and the
slider): Moves the slider to that end of the Scale and calls
the XmNvalueChangedCallback callbacks. If
XmNprocessingDirection is
XmMAX_ON_RIGHT or XmMAX_ON_BOTTOM,
movement toward the right or bottom increments the Scale value, and
movement toward the left or top decrements the Scale value. If
XmNprocessingDirection is
XmMAX_ON_LEFT or XmMAX_ON_TOP,
movement toward the right or bottom decrements the Scale value, and
movement toward the left or top increments the Scale value.
- KUp:
- For vertical Scales, moves the slider up one increment and
calls the XmNvalueChangedCallback callbacks. If
XmNprocessingDirection is
XmMAX_ON_TOP, movement toward the top increments the
Scale value. If XmNprocessingDirection is
XmMAX_ON_BOTTOM, movement toward the top decrements
the Scale value.
- KDown:
- For vertical Scales, moves the slider down one increment and
calls the XmNvalueChangedCallback callbacks. If
XmNprocessingDirection is
XmMAX_ON_BOTTOM, movement toward the bottom
increments the Scale value. If
XmNprocessingDirection is
XmMAX_ON_TOP, movement toward the bottom decrements
the Scale value.
- KLeft:
- For horizontal Scales, moves the slider one increment to the
left and calls the XmNvalueChangedCallback callbacks.
If XmNprocessingDirection is
XmMAX_ON_LEFT, movement toward the left increments
the Scale value. If XmNprocessingDirection is
XmMAX_ON_RIGHT, movement toward the left decrements
the Scale value.
- KRight:
- For horizontal Scales, moves the slider one increment to the
right and calls the XmNvalueChangedCallback
callbacks. If XmNprocessingDirection is
XmMAX_ON_RIGHT, movement toward the right increments
the Scale value. If XmNprocessingDirection is
XmMAX_ON_LEFT, movement toward the right decrements
the Scale value.
- MCtrl KUp or KPageUp:
- For vertical Scales, moves the slider up one multiple increment
and calls the XmNvalueChangedCallback callbacks. If
XmNprocessingDirection is
XmMAX_ON_TOP, movement toward the top increments the
Scale value. If XmNprocessingDirection is
XmMAX_ON_BOTTOM, movement toward the top decrements
the Scale value.
- MCtrl KDown or KPageDown:
- For vertical Scales, moves the slider down one multiple
increment and calls the XmNvalueChangedCallback
callbacks. If XmNprocessingDirection is
XmMAX_ON_BOTTOM, movement toward the bottom
increments the Scale value. If
XmNprocessingDirection is
XmMAX_ON_TOP, movement toward the bottom decrements
the Scale value.
- MCtrl KLeft or KPageLeft:
- For horizontal Scales, moves the slider one multiple increment
to the left and calls the XmNvalueChangedCallback
callbacks. If XmNprocessingDirection is
XmMAX_ON_LEFT, movement toward the left increments
the Scale value. If XmNprocessingDirection is
XmMAX_ON_RIGHT, movement toward the left decrements
the Scale value.
- MCtrl KRight or KPageRight:
- For horizontal Scales, moves the slider one multiple increment
to the right and calls the XmNvalueChangedCallback
callbacks. If XmNprocessingDirection is
XmMAX_ON_RIGHT, movement toward the right increments
the Scale value. If XmNprocessingDirection is
XmMAX_ON_LEFT, movement toward the right decrements
the Scale value.
- KBeginLine or KBeginData:
- Moves the slider to the minimum value and calls the
XmNvalueChangedCallback callbacks.
- KEndLine or KEndData:
- Moves the slider to the maximum value and calls the
XmNvalueChangedCallback callbacks.
- KNextField:
- Traverses to the first item in the next tab group. If the
current tab group is the last entry in the tab group list, it wraps to
the beginning of the tab group list.
- KPrevField:
- Traverses to the first item in the previous tab group. If the
beginning of the tab group list is reached, it wraps to the end of the
tab group list.
- KHelp:
- Calls the callbacks for XmNhelpCallback
if any exist. If there are no help callbacks for this widget, this
action calls the help callbacks for the nearest ancestor that has
them.
Virtual Bindings
The bindings for virtual keys are vendor specific. For information
about bindings for virtual buttons and keys, see VirtualBindings(3X).
RELATED INFORMATION
Composite(3X),
Constraint(3X),
Core(3X), XmCreateScale(3X), XmManager(3X), XmScaleGetValue(3X), and
XmScaleSetValue(3X).