Tree(3X) — DeltaWindows 1.3.3 Release 4 Version 4.3

NAME

Tree widget − a constraint widget that arranges its children in a tree.

SYNOPSIS

Public Headers:<X11/StringDefs.h> <X11/Xaw/Tree.h>

Private Header:<X11/Xaw/TreeP.h>

Class Name:Tree

Class Pointer:treeWidgetClass

Instantiation:widget = XtCreateWidget(name, treeWidgetClass, ...)

CLASS HIERARCHY

Core → Composite → Constraint → Tree

AVAILABILITY

Release 5 and later.

DESCRIPTION

The Tree widget provides geometry management of arbitrary widgets arranged in a directed, acyclic graph (i.e., a tree). The hierarchy is constructed by attaching a constraint resource called XtNtreeParent to each child indicating which other node in the tree should be treated as the child’s superior. The structure of the tree is shown by laying out the nodes in the standard format for tree diagrams with lines drawn to connect each node with its children.

The Tree sizes itself according to the needs of its children and is not intended to be resized by its parent. Instead, it should be placed inside another composite widget (such as the Porthole or Viewport) that can be used to scroll around in the tree.

RESOURCES

When creating a Tree widget instance, the following resources are retrieved from the argument list or from the resource database:

Name	Type	Default	Description

XtNaccelerators	Accelerator- Table	NULL	Accelerators for this widget.
XtNancestor− Sensitive	Boolean	True	Sensitivity state of the ancestors of this widget.
XtNautoReconfigure	Boolean	False	Whether to re-layout the tree when each new child is added.
XtNbackground	Pixel	XtDefault− Background	Window background color.
XtNbackground− Pixmap	Pixmap	XtUnspecified− Pixmap	Window background pixmap.
XtNborderColor	Pixel	XtDefault− Foreground	Window border color.
XtNborderPixmap	Pixmap	XtUnspecified− Pixmap	Window border pixmap.
XtNborderWidth	Dimension	1	Width of border in pixels.
XtNchildren	WidgetList	NULL	List of all this composite widget’s current children.
XtNcolormap	Colormap	Parent’s colormap.	Colormap that this widget will use.
XtNdepth	int	Parent’s depth.	Depth of this widget’s window.
XtNdestroy− Callback	XtCallback- List	NULL	Callbacks for XtDestroyWidget().
XtNforeground	Pixel	XtDefault- Foreground	Widget foreground color.
XtNgravity	XtGravity	West	Window gravity of widget.
XtNheight	Dimension	Computed at realize.	Height of tree.
XtNhSpace	Dimension	20	Horizontal space between children.
XtNlineWidth	Dimension	0	Width of tree lines.
XtNmappedWhen− Managed	Boolean	TRUE	Whether XtMapWidget() is automatic.
XtNnumChildren	Cardinal	0	Number of children in this composite widget.
XtNscreen	Screen	Parent’s screen.	Screen on which this widget is displayed.
XtNsensitive	Boolean	TRUE	Whether widget receives input.
XtNtranslations	Translation- Table	NULL	Event-to-action translations.
XtNvSpace	Dimension	6	Vertical space between children.
XtNwidth	Dimension	Computed at realize.	Width of tree.
XtNx	Position	0	x-coordinate in pixels.
XtNy	Position	0	y-coordinate in pixels.

XtNautoReconfigure
Whether or not to lay out the tree every time a node is added or removed.

XtNforeground
Foreground color for the widget.

XtNgravity
Specifies the side of the widget from which the tree should grow. Valid values include WestGravity, NorthGravity, EastGravity, and SouthGravity.

XtNhSpace
Amount of horizontal space, in pixels, to leave between the children. This resource also specifies the amount of space between the outermost children and the edge of the box.

XtNlineWidth
The width of the lines drawn between nodes that do not have a XtNtreeGC constraint resource and their inferiors in the tree.

XtNvSpace
The amount of vertical space, in pixels, to leave between the children. This resource also specifies the amount of space left between the outermost children and the edge of the box.

CONSTRAINTS

When creating children to be added to a Tree, the following additional resources are retrieved from the argument list or from the resource database. Note that these resources are maintained by the Tree widget even though they are stored in the child.

Name	Type	Default	Description

XtNtreeGC	GC	NULL	GC used to draw lines between the child and its inferiors in the tree.
XtNtreeParent	Widget	NULL	The child’s superior node in the tree.

XtNtreeGC
This specifies the GC to use when drawing lines between this widget and its inferiors in the tree. If this resource is not specified, the Tree’s XtNforeground and XtNlineWidth will be used.

XtNtreeParent
This specifies the superior node in the tree for this widget. The default is for the node to have no superior (and to therefore be at the top of the tree).

The position of each child in the tree hierarchy (as opposed to the widget hierarchy) is determined by the value of the XtNtreeParent constraint resource. Each time a child is managed or unmanaged, the Tree widget will attempt to reposition the remaining children to fix the shape of the tree if the XtNautoReconfigure resource is set. Children at the root of the tree are drawn at the side specified by the XtNgravity resource. After positioning all children, the Tree widget attempts to shrink its own size to the minimum dimensions required for the layout.

PUBLIC FUNCTIONS

•XawTreeForceLayout() forces a Tree widget to re-layout its children. When adding several children to a Tree widget, it is most efficient to set XtNautoReconfigure to False and use this function once all the widgets have been added.

void XawTreeForceLayout(w) Widget w;

wspecifies the Tree widget.

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