XmForm(3)

NAME
XmForm — The Form widget class

SYNOPSIS

#include <Xm/Form.h>

DESCRIPTION

Form is a container widget with no input semantics of its own. Constraints are placed on children of the Form to define attachments for each of the child's four sides. These attachments can be to the Form, to another child widget or gadget, to a relative position within the Form, or to the initial position of the child. The attachments determine the layout behavior of the Form when resizing occurs.

The default value for XmNinitialFocus is the value of XmNdefaultButton.

Following are some important considerations in using a Form:

•   Every child must have an attachment on either the left or the right. If initialization or XtSetValues leaves a widget without such an attachment, the result depends upon the value of XmNrubberPositioning.

    If XmNrubberPositioning is False, the child is given an XmNleftAttachment of XmATTACH_FORM and an XmNleftOffset equal to its current x value.

    If XmNrubberPositioning is True, the child is given an XmNleftAttachment of XmATTACH_POSITION and an XmNleftPosition proportional to the current x value divided by the width of the Form.

    In either case, if the child has not been previously given an x value, its x value is taken to be 0 (zero), which places the child at the left side of the Form.

•   If you want to create a child without any attachments, and then later (for example, after creating and managing it, but before realizing it) give it a right attachment through XtSetValues, you must set its XmNleftAttachment to XmATTACH_NONE at the same time.

•   The XmNresizable resource controls only whether a geometry request by the child will be granted. It has no effect on whether the child's size can be changed because of changes in geometry of the Form or of other children.

•   Every child has a preferred width, based on geometry requests it makes (whether they are granted or not).

•   If a child has attachments on both the left and the right sides, its size is completely controlled by the Form. It can be shrunk below its preferred width or enlarged above it, if necessary, due to other constraints. In addition, the child's geometry requests to change its own width may be refused.

•   If a child has attachments on only its left or right side, it will always be at its preferred width (if resizable, otherwise at is current width). This may cause it to be clipped by the Form or by other children.

•   If a child's left (or right) attachment is set to XmATTACH_SELF, its corresponding left (or right) offset is forced to 0 (zero). The attachment is then changed to XmATTACH_POSITION, with a position that corresponds to the x value of the child's left (or right) edge. To fix the position of a side at a specific x value, use XmATTACH_FORM or XmATTACH_OPPOSITE_FORM with the x value as the left (or right) offset.

•   Unmapping a child has no effect on the Form except that the child is not mapped.

•   Unmanaging a child unmaps it. If no other child is attached to it, or if all children attached to it and all children recursively attached to them are also all unmanaged, all of those children are treated as if they did not exist in determining the size of the Form.

•   When using XtSetValues to change the XmNx resource of a child, you must simultaneously set its left attachment to either XmATTACH_SELF or XmATTACH_NONE. Otherwise, the request is not granted. If XmNresizable is False, the request is granted only if the child's size can remain the same.

•   A left (or right) attachment of XmATTACH_WIDGET, where XmNleftWidget (or XmNrightWidget) is NULL, acts like an attachment of XmATTACH_FORM.

•   If an attachment is made to a widget that is not a child of the Form, but an ancestor of the widget is a child of the Form, the attachment is made to the ancestor.

All these considerations are true of top and bottom attachments as well, with top acting like left, bottom acting like right, y acting like x, and height acting like width.

  Classes

Form inherits behavior, resources, and traits from Core, Composite, Constraint, XmManager, and XmBulletinBoard.

The class pointer is xmFormWidgetClass.

The class name is XmForm.

  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).

XmNfractionBase
    Specifies the denominator used in calculating the relative position of a child widget using XmATTACH_POSITION constraints. The value must not be 0 (zero).

    If the value of a child's XmNleftAttachment (or XmNrightAttachment) is XmATTACH_POSITION, the position of the left (or right) side of the child is relative to the left side of the Form and is a fraction of the width of the Form. This fraction is the value of the child's XmNleftPosition (or XmNrightPosition) resource divided by the value of the Form's XmNfractionBase.

    If the value of a child's XmNtopAttachment (or XmNbottomAttachment) is XmATTACH_POSITION, the position of the top (or bottom) side of the child is relative to the top side of the Form and is a fraction of the height of the Form. This fraction is the value of the child's XmNtopPosition (or XmNbottomPosition) resource divided by the value of the Form's XmNfractionBase.

XmNhorizontalSpacing
    Specifies the offset for right and left attachments. This resource is only used if no offset resource is specified (when attaching to a widget), or if no margin resource is specified (when attaching to the Form).

XmNrubberPositioning
    Indicates the default near (left) and top attachments for a child of the Form. (Note that whether this resource actually applies to the left or right side of the child and its attachment depends on the value of the XmNlayoutDirection.)

    The default left attachment is applied whenever initialization or XtSetValues leaves the child without either a left or right attachment. The default top attachment is applied whenever initialization or XtSetValues leaves the child without either a top or bottom attachment.

    If this Boolean resource is set to False, XmNleftAttachment and XmNtopAttachment default to XmATTACH_FORM, XmNleftOffset defaults to the current x value of the left side of the child, and XmNtopOffset defaults to the current y value of the child. The effect is to position the child according to its absolute distance from the left or top side of the Form.

    If this resource is set to True, XmNleftAttachment and XmNtopAttachment default to XmATTACH_POSITION, XmNleftPosition defaults to a value proportional to the current x value of the left side of the child divided by the width of the Form, and XmNtopPosition defaults to a value proportional to the current y value of the child divided by the height of the Form. The effect is to position the child relative to the left or top side of the Form and in proportion to the width or height of the Form.

XmNverticalSpacing
    Specifies the offset for top and bottom attachments. This resource is only used if no offset resource is specified (when attaching to a widget), or if no margin resource is specified (when attaching to the Form).

XmNbottomAttachment
    Specifies attachment of the bottom side of the child. It can have the following values:

    XmATTACH_NONE
        Do not attach the bottom side of the child.

    XmATTACH_FORM
        Attach the bottom side of the child to the bottom side of the Form.

    XmATTACH_OPPOSITE_FORM
        Attach the bottom side of the child to the top side of the Form. XmNbottomOffset can be used to determine the visibility of the child.

    XmATTACH_WIDGET
        Attach the bottom side of the child to the top side of the widget or gadget specified in the XmNbottomWidget resource. If XmNbottomWidget is NULL, XmATTACH_WIDGET is replaced by XmATTACH_FORM, and the child is attached to the bottom side of the Form.

    XmATTACH_OPPOSITE_WIDGET
        Attach the bottom side of the child to the bottom side of the widget or gadget specified in the XmNbottomWidget resource.

    XmATTACH_POSITION
        Attach the bottom side of the child to a position that is relative to the top side of the Form and in proportion to the height of the Form. This position is determined by the XmNbottomPosition and XmNfractionBase resources.

    XmATTACH_SELF
        Attach the bottom side of the child to a position that is proportional to the current y value of the bottom of the child divided by the height of the Form. This position is determined by the XmNbottomPosition and XmNfractionBase resources. XmNbottomPosition is set to a value proportional to the current y value of the bottom of the child divided by the height of the Form.

XmNbottomOffset
    Specifies the constant offset between the bottom side of the child and the object to which it is attached. The relationship established remains, regardless of any resizing operations that occur. When this resource is explicitly set, the value of XmNverticalSpacing is ignored.

XmNbottomPosition
    This resource is used to determine the position of the bottom side of the child when the child's XmNbottomAttachment is set to XmATTACH_POSITION. In this case the position of the bottom side of the child is relative to the top side of the Form and is a fraction of the height of the Form. This fraction is the value of the child's XmNbottomPosition resource divided by the value of the Form's XmNfractionBase. For example, if the child's XmNbottomPosition is 50, the Form's XmNfractionBase is 100, and the Form's height is 200, the position of the bottom side of the child is 100.

XmNbottomWidget
    Specifies the widget or gadget to which the bottom side of the child is attached. This resource is used if the XmNbottomAttachment resource is set to either XmATTACH_WIDGET or XmATTACH_OPPOSITE_WIDGET.

    A string-to-widget resource converter is automatically installed for use with this resource. With this converter, the widget that is to be the value of the resource must exist at the time the widget that has the resource is created.

XmNleftAttachment
    Specifies attachment of the near (left) side of the child. (Note that whether this resource actually applies to the left or right side of the child and its attachment depends on the value of the XmNlayoutDirection resource.) It can have the following values:

    XmATTACH_NONE
        Do not attach the left side of the child. If XmNrightAttachment is also XmATTACH_NONE, this value is ignored and the child is given a default left attachment.

    XmATTACH_FORM
        Attach the left side of the child to the left side of the Form.

    XmATTACH_OPPOSITE_FORM
        Attach the left side of the child to the right side of the Form. XmNleftOffset can be used to determine the visibility of the child.

    XmATTACH_WIDGET
        Attach the left side of the child to the right side of the widget or gadget specified in the XmNleftWidget resource. If XmNleftWidget is NULL, XmATTACH_WIDGET is replaced by XmATTACH_FORM, and the child is attached to the left side of the Form.

    XmATTACH_OPPOSITE_WIDGET
        Attach the left side of the child to the left side of the widget or gadget specified in the XmNleftWidget resource.

    XmATTACH_POSITION
        Attach the left side of the child to a position that is relative to the left side of the Form and in proportion to the width of the Form. This position is determined by the XmNleftPosition and XmNfractionBase resources.

    XmATTACH_SELF
        Attach the left side of the child to a position that is proportional to the current x value of the left side of the child divided by the width of the Form. This position is determined by the XmNleftPosition and XmNfractionBase resources. XmNleftPosition is set to a value proportional to the current x value of the left side of the child divided by the width of the Form.

XmNleftOffset
    Specifies the constant offset between the near (left) side of the child and the object to which it is attached. (Note that whether this resource actually applies to the left or right side of the child and its attachment depends on the value of the XmNlayoutDirection resource.) The relationship established remains, regardless of any resizing operations that occur. When this resource is explicitly set, the value of XmNhorizontalSpacing is ignored.

XmNleftPosition
    This resource is used to determine the position of the near (left) side of the child when the child's XmNleftAttachment is set to XmATTACH_POSITION. (Note that whether this resource actually applies to the left or right side of the child and its attachment depends on the value of the XmNlayoutDirection resource.)

    In this case, the position of the left side of the child is relative to the left side of the Form and is a fraction of the width of the Form. This fraction is the value of the child's XmNleftPosition resource divided by the value of the Form's XmNfractionBase. For example, if the child's XmNleftPosition is 50, the Form's XmNfractionBase is 100, and the Form's width is 200, the position of the left side of the child is 100.

XmNleftWidget
    Specifies the widget or gadget to which the near (left) side of the child is attached. (Note that whether this resource actually applies to the left or right side of the child and its attachment depends on the value of the XmNlayoutDirection resource.) The XmNleftWidget resource is used if the XmNleftAttachment resource is set to either XmATTACH_WIDGET or XmATTACH_OPPOSITE_WIDGET.

    A string-to-widget resource converter is automatically installed for use with this resource. With this converter, the widget that is to be the value of the resource must exist at the time the widget that has the resource is created.

XmNresizable
    This Boolean resource specifies whether or not a child's request for a new size is (conditionally) granted by the Form. If this resource is set to True the request is granted if possible. If this resource is set to False the request is always refused.

    If a child has both left and right attachments, its width is completely controlled by the Form, regardless of the value of the child's XmNresizable resource. If a child has a left or right attachment but not both, the child's XmNwidth is used in setting its width if the value of the child's XmNresizable resource is True. These conditions are also true for top and bottom attachments, with height acting like width.

XmNrightAttachment
    Specifies attachment of the far (right) side of the child. (Note that whether this resource actually applies to the left or right side of the child and its attachment depends on the value of the XmNlayoutDirection resource.) It can have the following values:

    XmATTACH_NONE
        Do not attach the right side of the child.

    XmATTACH_FORM
        Attach the right side of the child to the right side of the Form.

    XmATTACH_OPPOSITE_FORM
        Attach the right side of the child to the left side of the Form. XmNrightOffset can be used to determine the visibility of the child.

    XmATTACH_WIDGET
        Attach the right side of the child to the left side of the widget or gadget specified in the XmNrightWidget resource. If XmNrightWidget is NULL, XmATTACH_WIDGET is replaced by XmATTACH_FORM, and the child is attached to the right side of the Form.

    XmATTACH_OPPOSITE_WIDGET
        Attach the right side of the child to the right side of the widget or gadget specified in the XmNrightWidget resource.

    XmATTACH_POSITION
        Attach the right side of the child to a position that is relative to the left side of the Form and in proportion to the width of the Form. This position is determined by the XmNrightPosition and XmNfractionBase resources.

    XmATTACH_SELF
        Attach the right side of the child to a position that is proportional to the current x value of the right side of the child divided by the width of the Form. This position is determined by the XmNrightPosition and XmNfractionBase resources. XmNrightPosition is set to a value proportional to the current x value of the right side of the child divided by the width of the Form.

XmNrightOffset
    Specifies the constant offset between the far (right) side of the child and the object to which it is attached. (Note that whether this resource actually applies to the left or right side of the child and its attachment depends on the value of the XmNlayoutDirection resource.) The relationship established remains, regardless of any resizing operations that occur. When this resource is explicitly set, the value of XmNhorizontalSpacing is ignored.

XmNrightPosition
    This resource is used to determine the position of the far (right) side of the child when the child's XmNrightAttachment is set to XmATTACH_POSITION. (Note that whether this resource actually applies to the left or right side of the child and its attachment depends on the value of the XmNlayoutDirection resource.)

    In this case the position of the right side of the child is relative to the left side of the Form and is a fraction of the width of the Form. This fraction is the value of the child's XmNrightPosition resource divided by the value of the Form's XmNfractionBase. For example, if the child's XmNrightPosition is 50, the Form's XmNfractionBase is 100, and the Form's width is 200, the position of the right side of the child is 100.

XmNrightWidget
    Specifies the widget or gadget to which the far (right) side of the child is attached. (Note that whether this resource actually applies to the left or right side of the child and its attachment depends on the value of the XmNlayoutDirection resource.) The XmNrightWidget resource is used if the XmNrightAttachment resource is set to either XmATTACH_WIDGET or XmATTACH_OPPOSITE_WIDGET.

    A string-to-widget resource converter is automatically installed for use with this resource. With this converter, the widget that is to be the value of the resource must exist at the time the widget that has the resource is created.

XmNtopAttachment
    Specifies attachment of the top side of the child. It can have following values:

    XmATTACH_NONE
        Do not attach the top side of the child. If the XmNbottomAttachment resource is also XmATTACH_NONE, this value is ignored and the child is given a default top attachment.

    XmATTACH_FORM
        Attach the top side of the child to the top side of the Form.

    XmATTACH_OPPOSITE_FORM
        Attach the top side of the child to the bottom side of the Form. XmNtopOffset can be used to determine the visibility of the child.

    XmATTACH_WIDGET
        Attach the top side of the child to the bottom side of the widget or gadget specified in the XmNtopWidget resource. If XmNtopWidget is NULL, XmATTACH_WIDGET is replaced by XmATTACH_FORM and the child is attached to the top side of the Form.

    XmATTACH_OPPOSITE_WIDGET
        Attach the top side of the child to the top side of the widget or gadget specified in the XmNtopWidget resource.

    XmATTACH_POSITION
        Attach the top side of the child to a position that is relative to the top side of the Form and in proportion to the height of the Form. This position is determined by the XmNtopPosition and XmNfractionBase resources.

    XmATTACH_SELF
        Attach the top side of the child to a position that is proportional to the current y value of the child divided by the height of the Form. This position is determined by the XmNtopPosition and XmNfractionBase resources. XmNtopPosition is set to a value proportional to the current y value of the child divided by the height of the Form.

XmNtopOffset
    Specifies the constant offset between the top side of the child and the object to which it is attached. The relationship established remains, regardless of any resizing operations that occur. When this resource is explicitly set, the value of XmNverticalSpacing is ignored.

XmNtopPosition
    This resource is used to determine the position of the top side of the child when the child's XmNtopAttachment is set to XmATTACH_POSITION. In this case, the position of the top side of the child is relative to the top side of the Form and is a fraction of the height of the Form. This fraction is the value of the child's XmNtopPosition resource divided by the value of the Form's XmNfractionBase. For example, if the child's XmNtopPosition is 50, the Form's XmNfractionBase is 100, and the Form's height is 200, the position of the top side of the child is 100.

XmNtopWidget
    Specifies the widget or gadget to which the top side of the child is attached. This resource is used if XmNtopAttachment is set to a value of either XmATTACH_WIDGET or XmATTACH_OPPOSITE_WIDGET.

    A string-to-widget resource converter is automatically installed for use with this resource. With this converter, the widget that is to be the value of the resource must exist at the time the widget that has the resource is created.

  Inherited Resources

Form inherits behavior and resources from the superclasses described in the following tables. For a complete description of each resource, refer to the reference page for that superclass.

  Translations

XmForm inherits translations from XmBulletinBoard.

RELATED

Composite(3), Constraint(3), Core(3), XmBulletinBoard(3), XmCreateForm, XmCreateFormDialog(3), and XmManager(3).