NAME

XwrowColWidgetClass − the X Widgets row/column manager widget. 

SYNOPSIS

#include <X11/StringDefs.h>
#include <X11/Intrinsic.h>
#include <Xw/Xw.h>
#include <Xw/RCManager.h>

CLASSES

The row column manager widget is built from the Core, Composite, Constraint and XwManager classes.  Note that the Constraint fields are not used in this widget and so is not listed in the resource tables below.  Also, since the Composite class contains no user settable resources, there is no table for Composite class resources. 

The widget class to use when creating a row column manager is XwrowColWidgetClass.  The class name is RowCol. 

DESCRIPTION

The row/column widget is a composite widget which supports 3 types of row/column layouts for its children.  They are: requested columns, maximum columns, and maximum unaligned.  With the first layout type, requested columns, the application specifies the number of columns (the default is one) to be used in laying out the data.  The children are laid out rowwise.  Columns are as wide as the widest element in the column and all elements are left justified.  Row height is determined by the largest element in the row and all elements are centered in the row.  The second layout type, maximum columns, automatically calculates the maximum number of columns that can fit within the manager and lays the children out accordingly.  The last layout type, maximum unaligned, does not force any columnar alignment.  A child being positioned is placed to the immediately right of previous child until a row is full, then a new row is started at the left edge of the manager immediately below the previous row. 

In addition to the row/column ordering, this manager widget supports 3 different layout policies: minimize (the default), maximize and ignore.  When the layout policy is set to minimize, the manager will create a box which is just large enough to contain all of its children, regardless of any provided width and height values.  When the given width and height values would create a box larger than needed, the maximize setting will use this additional space as padding between elements.  Note that, with the maximize setting, if one or both of the height/width values are too small, the box will grow the manager to honor the given width and height, it will not grow or shrink in response to the addition, deletion or altering of its children. 

The row/column widget also implements two selection policies.  The default is n_of_many, and the alternative is one_of_many.  The n_of_many policy does not require any action on the part of the manager widget.  It allows any or all of its children to be selected and performs no action in response to their selection.  The one_of_many policy ONLY applies to to children widgets which are subclasses of the XwPrimitive class.  When one_of_many is the active policy, a callback (of type XtNselect) is added to each child widget. Then, when a child is selected the manager is informed.  The manager keeps track of the previously active child and directly invokes a release procedure in that child so that it becomes unselected.  The one_of_many mode will not activate a child if none are active and will not disallow the selection of an active child causing it to become deactive.  Thus, if a strict one of many mode is desired, the application will have to enforce it. 

NEW RESOURCES

The row/column manager defines a set of resource types used by the programmer to specify data for the manager widget.  The programmer can also set the values for the Core, Composite and XwManager widget classes to set attributes for this widget.  The following table contains the settable resources defined by the row/column manager. The string to be used when setting any of these resources in an application defaults file (like .Xdefaults) can be obtained by stripping the preface "XtN" off of the resource name.  For instance, XtNvSpace becomes vSpace.   

XtNhSpace
The application may determine the number of pixels of space left between each element within a given row.  This defines a minimum spacing.

XtNvSpace
The application may determine the number of pixels of space left between each column.  This defines a minimum spacing.

XtNlayoutType
The application can specify the type of layout the row column manager is to perform.  Allowable argument list settings are XwREQUESTED_COLUMNS, XwMAXIMUM_COLUMNS and XwMAXIMUM_UNALIGNED. To set this value in .Xdefaults or another resource file use the strings requested_columns, maximum_columns and maximum_unaligned.

XtNcolumns
The application can specify the number of columns to be used when laying out the widgets children.

XtNforceSize
The application has the option of forcing the widths of each widget in a column and the heights of each widget in a row to be the same.  This can be used, for example to enforce an orderly layout for a group of buttons. For the layout type of maximum unaligned, only the heights of the widgets in a row are forced to the same size.

XtNsingleRow
For layout types of maximum columns and maximum unaligned, the application has the option of having the row column manager to try to lay itself out in a single row whenever one of its children makes a geometry request.

XtNmode
The application can specify whether the selection policy is n_of_many or one_of_many. Allowable argument list settings are XwONE_OF_MANY and XwN_OF_MANY.  To set this value in .Xdefaults or another resource file use the strings one_of_many and n_of_many.

INHERITED RESOURCES

The following resources are inherited from the named superclasses:  

KEYBOARD TRAVERSAL

If the XtNtraversalOn resource is set to TRUE at either create time or during a call to XtSetValues, the XwManager superclass will automatically augment the manager widget’s translations to support keyboard traversal.  Refer to the XwManager man page for a complete description of these translations. 

ORIGIN

Hewlett-Packard Company. 

SEE ALSO

CORE(3X), XWMANAGER(3X), XWPRIMITIVE(3X)

September 29, 2021