DwtScrollBar(3Dwt) DwtScrollBar(3Dwt)
Name
DwtScrollBar, DwtScrollBarCreate - Creates a scroll bar widget for the application to display and process scroll bar screen operations.
Syntax
Widget DwtScrollBar(parent_widget, name, x, y,
width, height, inc, page_inc,
shown, value, min_value, max_value,
orientation, callback, help_callback,
unit_inc_callback, unit_dec_callback,
page_inc_callback, page_dec_callback,
to_top_callback, to_bottom_callback)
drag_callback)
Widget parent_widget;
char *name;
Position x, y;
Dimension width, height;
int inc, page_inc;
int shown;
int value;
int min_value, max_value;
int orientation;
DwtCallbackPtr callback, help_callback;
DwtCallbackPtr unit_inc_callback, unit_dec_callback;
DwtCallbackPtr page_inc_callback, page_dec_callback;
DwtCallbackPtr to_top_callback, to_bottom_callback;
DwtCallbackPtr drag_callback;
Widget DwtScrollBarCreate (parent_widget, name,
override_arglist, override_argcount)
Widget parent_widget;
char *name;
ArgList override_arglist;
int override_argcount;
Arguments
parent_widget
Specifies the parent widget ID.
name Specifies the name of the created widget.
x Specifies the placement, in pixels, of the left side of the widget window relative to the inner upper left corner of the parent
window. This argument sets the DwtNx core widget attribute.
y Specifies, in pixels, the placement of the upper left corner of the widget window relative to the inner upper left corner of the
parent window. This argument sets the DwtNy core widget attribute.
width Specifies the width of the widget window. This argument sets the DwtNwidth core widget attribute.
height Specifies the height of the widget window. This argument sets the DwtNheight core widget attribute.
inc Specifies the amount of button increment and decrement. If this argument is nonzero, the scroll bar widget automatically adjusts
the slider when an increment or decrement action occurs. This argument sets the DwtNinc attribute associated with DwtScrollBar-
Create.
page_inc Specifies the amount of page increment and decrement. If this argument is nonzero, the scroll bar widget automatically adjusts
the slider when an increment or decrement action occurs. This argument sets the DwtNpageInc attribute associated with DwtScroll-
BarCreate.
shown Specifies the size of the slider as a value between zero and the absolute value of DwtNmaxValue minus DwtNminValue. The size of
the slider varies, depending on how much of the slider scroll area it represents. This argument sets the DwtNshown attribute
associated with DwtScrollBarCreate.
value Specifies the scroll bar's top thumb position between DwtNminValue and DwtNmaxValue. This sets the DwtNvalue attribute associ-
ated with DwtScrollBarCreate.
min_value Specifies the scroll bar's minimum value. This argument sets the DwtNminValue attribute associated with DwtScrollBarCreate.
max_value Specifies the scroll bar's maximum value. This argument sets the DwtNmaxValue attribute associated with DwtScrollBarCreate.
orientation
Specifies whether the scroll bar is displayed vertically or horizontally. You can pass DwtOrientationHorizontal or DwtOrienta-
tionVertical. This argument sets the DwtNorientation attribute associated with DwtScrollBarCreate.
callback Specifies the callback function or functions called back when the value of the scroll bar changes. This argument sets the Dwt-
NvalueChangedCallback attribute associated with DwtScrollBarCreate.
help_callback
Specifies the callback function or functions called when a help request is made. This argument sets the DwtNhelpCallback common
widget attribute.
unit_inc_callback
Specifies the callback function or functions called when the user selected the down or right unit scroll function. For this
callback, the reason is DwtCRUnitInc. This argument sets the DwtNunitIncCallback attribute associated with DwtScrollBarCreate.
unit_dec_callback
Specifies the callback function or functions called when the user selected the above or left unit scroll function. For this
callback, the reason is DwtCRUnitDec. This argument sets the DwtNunitDecCallback attribute associated with DwtScrollBarCreate.
page_inc_callback
Specifies the callback function or functions called when the user selected the below or right page scroll function. For this
callback, the reason is DwtCRPageInc. This argument sets the DwtNpageIncCallback attribute associated with DwtScrollBarCreate.
page_dec_callback
Specifies the callback function or functions called when the user selected the above or left page scroll function. For this
callback, the reason is DwtCRPageDec. This argument sets the DwtNpageDecCallback attribute associated with DwtScrollBarCreate.
to_top_callback
Specifies the callback function or functions called when the user selected the current line to top scroll function. For this
callback, the reason is DwtCRToTop. The scroll bar does not automatically change the scroll bar's DwtNvalue for this callback.
This argument sets the DwtNtoTopCallback attribute associated with DwtScrollBarCreate.
to_bottom_callback
Specifies the callback function or functions called when the user selected the current line to bottom scroll function. For this
callback, the reason is DwtCRToBottom. The scroll bar does not automatically change the scroll bar's DwtNvalue for this call-
back. This argument sets the DwtNtoBottomCallback attribute associated with DwtScrollBarCreate.
drag_callback
Specifies the callback function or functions called when the user is dragging the scroll bar slider. For this callback, the rea-
son is DwtCRDrag. This argument sets the DwtNdragCallback attribute associated with DwtScrollBarCreate.
override_arglist
Specifies the application override argument list.
override_argcount
Specifies the number of attributes in the application override argument list (override_arglist).
Description
The DwtScrollBar and DwtScrollBarCreate functions create an instance of a scroll bar widget and return its associated widget ID. The
scroll bar widget is a screen object that the application or user uses to scroll through display data too large for the screen. This wid-
get consists of two stepping arrows at either end of an elongated rectangle called the scroll region. The scroll region is overlaid with a
slider bar (thumb) that is adjusted in size and position (thumb shown) as scrolling occurs using the function attributes. The stepping
arrows and the exposed scroll areas behind the slider are the scroll activator objects providing the user interface syntax ``feel.''
If the default core widget attributes DwtNwidth or DwtNheight(0) are used, the scroll bar is set to the DwtNheight of the parent window
(vertical) or to the DwtNwidth of the parent window (horizontal). If the default core widget attributes DwtNx or DwtNy(0) are used, the
scroll bar is set to the right of the parent window (vertical) or to the bottom of the parent window (horizontal). This is also true if
you specify DwtNwidth, DwtNheight, DwtNx, or DwtNy in the call to XtSetValues.
Note that the DwtNtoTopCallback and DwtNtoBottomCallback callbacks do not automatically set the thumb as the other callbacks do.
Inherited Attributes
------------------------------------------------------------------
Attribute Name Data Type Default
------------------------------------------------------------------
Core Attributes
DwtNx Position Determined by the geome-
try manager
DwtNy Position Determined by the geome-
try manager
DwtNwidth Dimension For vertical scroll
bars, 17 pixels.
For horizontal scroll
bars, the width of the
parent minus 17 pixels.
DwtNheight Dimension For horizontal scroll
bars, 17 pixels.
For vertical scroll
bars, the height of the
parent minus 17 pixels.
DwtNborderWidth Dimension One pixel
DwtNborder Pixel Default foreground color
DwtNborderPixmap Pixmap NULL
DwtNbackground Pixel Default background color
DwtNbackgroundPixmap Pixmap NULL
DwtNcolormap Colormap Default color map
DwtNsensitive Boolean True
DwtNancestorSensitive Boolean The bitwise AND of the
parent widget's DwtNsen-
sitive and DwtNances-
torSensitive attributes
DwtNaccelerators XtTranslations NULL
DwtNdepth int Depth of the parent win-
dow
DwtNtranslations XtTranslations NULL
DwtNmappedWhenManaged Boolean True
DwtNscreen Screen * The parent screen
DwtNdestroyCallback DwtCallbackPtr NULL
Common Attributes
DwtNforeground Pixel Default foreground color
DwtNhighlight Pixel Default foreground color
DwtNhighlightPixmap Pixmap NULL
DwtNuserData Opaque * NULL
DwtNdirectionRToL unsigned char DwtDirectionRightDown
DwtNfont NOT SUPPORTED
DwtNhelpCallback DwtCallbackPtr NULL
------------------------------------------------------------------
Widget-Specific Attributes
------------------------------------------------------------
Attribute Name Data Type Default
------------------------------------------------------------
DwtNvalue int Zero
DwtNminValue int Zero
DwtNmaxValue int 100
DwtNorientation unsigned char DwtOrientation-
Vertical
DwtNtranslations1 XtTranslations NULL
DwtNtranslations2 XtTranslations NULL
DwtNshown int 10 units
DwtNinc int 10 units
DwtNpageInc int 10 units
DwtNvalueChangedCallback DwtCallbackPtr NULL
DwtNunitIncCallback DwtCallbackPtr NULL
DwtNunitDecCallback DwtCallbackPtr NULL
DwtNpageIncCallback DwtCallbackPtr NULL
DwtNpageDecCallback DwtCallbackPtr NULL
DwtNtoTopCallback DwtCallbackPtr NULL
DwtNtoBottomCallback DwtCallbackPtr NULL
DwtNdragCallback DwtCallbackPtr NULL
DwtNshowArrows Boolean True
------------------------------------------------------------
DwtNvalue Specifies the scroll bar's top thumb position between DwtNminValue and DwtNmaxValue. This attribute also appears as a mem-
ber in DwtScrollBarCallbackStruct.
DwtNminValue Specifies the scroll bar's minimum value.
DwtNmaxValue Specifies the scroll bar's maximum value.
DwtNorientation
Specifies whether the scroll bar is displayed vertically or horizontally. You can pass DwtOrientationHorizontal or DwtOri-
entationVertical.
DwtNtranslations1
Specifies the translation table for events after being parsed by the X intrinsics function XtParseTranslationTable for the
decrement button.
DwtNtranslations2
Specifies the translation table for events after being parsed by the X intrinsics function XtParseTranslationTable for the
increment button.
DwtNshown Specifies the size of the slider as a value between zero and the absolute value of DwtNmaxValue minus DwtNminValue. The
size of the slider varies, depending on how much of the slider scroll area it represents.
DwtNinc Specifies the amount of button increment and decrement. If this argument is nonzero, the scroll bar widget automatically
adjusts the slider when an increment or decrement action occurs.
DwtNpageInc Specifies the amount of page increment and decrement. If this argument is nonzero, the scroll bar widget automatically
adjusts the slider when an increment or decrement action occurs.
DwtNvalueChangedCallback
Specifies the callback function or functions called when the value of the scroll bar slider was changed. For this callback,
the reason is DwtCRValueChanged.
DwtNunitIncCallback
Specifies the callback function or functions called when the user selected the down or right unit scroll function. For this
callback, the reason is DwtCRUnitInc.
DwtNunitDecCallback
Specifies the callback function or functions called when the user selected the above or left unit scroll function. For this
callback, the reason is DwtCRUnitDec.
DwtNpageIncCallback
Specifies the callback function or functions called when the user selected the below or right page scroll function. For
this callback, the reason is DwtCRPageInc.
DwtNpageDecCallback
Specifies the callback function or functions called when the user selected the above or left page scroll function. For this
callback, the reason is DwtCRPageDec.
DwtNtoTopCallback
Specifies the callback function or functions called when the user selected the current line to top scroll function. For
this callback, the reason is DwtCRToTop. The scroll bar does not automatically change the scroll bar's DwtNvalue for this
callback.
DwtNtoBottomCallback
Specifies the callback function or functions called when the user selected the current line to bottom scroll function. For
this callback, the reason is DwtCRToBottom. The scroll bar does not automatically change the scroll bar's DwtNvalue for
this callback.
DwtNdragCallback
Specifies the callback function or functions called when the user is dragging the scroll bar slider. For this callback, the
reason is DwtCRDrag. The scroll bar does not automatically change the scroll bar's DwtNvalue for this callback.
DwtNshowArrows Specifies a boolean value that, when True, indicates there are arrows. If False, there are no arrows.
Return Values
These functions return the ID of the created widget.
Callback Information
The following structure is returned to your callback:
typedef struct {
int reason;
XEvent *event;
int value;
int pixel;
} DwtScrollBarCallbackStruct;
The reason member is set to a constant that represents the reason why this callback was invoked. For this callback, the reason member can
be set to:
DwtCRValueChanged The user changed the
value of the scroll bar
slider.
DwtCRUnitInc The user selected the
down or right unit scroll
function.
DwtCRUnitDec The user selected the up
or left unit scroll func-
tion.
DwtCRPageDec The user selected the
above or left page scroll
function.
DwtCRPageInc The user selected the
below or right page
scroll function.
DwtCRToTop The user selected the
current line to top
scroll function.
DwtCRToBottom The user selected the
current line to bottom
scroll function.
DwtCRDrag The user is dragging the
scroll bar slider.
DwtCRHelpRequested The user selected help.
The event member is a pointer to the Xlib structure XEvent, which describes the event that generated this callback. This structure is a
union of the individual structures declared for each event type. For information on XEvent and event processing, see the Guide to the Xlib
Library: C Language Binding. The value member is set to the slider's current value and maps to the DwtNvalue attribute. The pixel member
is set to the pixel value from the top right of the scroll bar where the event occurred. This pixel value is used for the DwtNtoTopCall-
back and DwtNtoBottomCallback attributes.
See Also
Guide to the XUI Toolkit: C Language Binding
Guide to the XUI Toolkit Intrinsics: C Language Binding
DwtScrollBar(3Dwt)