# Dialog Widget

    Application Header file	<X11/Xaw/Dialog.h>

    Class Header file	<X11/Xaw/DialogP.h>

    Class		dialogWidgetClass

    Class Name	Dialog

    Superclass	Form

The Dialog widget implements a commonly used interaction semantic to prompt for auxiliary input from a user. For example, you can use a Dialog widget when an application requires a small piece of information, such as a filename, from the user. A Dialog widget, which is simply a special case of the Form widget, provides a convenient way to create a preconfigured form.

The typical Dialog widget contains three areas. The first line contains a description of the function of the Dialog widget, for example, the string Filename:. The second line contains an area into which the user types input. The third line can contain buttons that let the user confirm or cancel the Dialog input. Any of these areas may be omitted by the application.

## Resources

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

Name | Class | Type | Notes | Default Value
accelerators | Accelerators | AcceleratorTable |  | NULL
ancestorSensitive | AncestorSensitive | Boolean | D | True
background | Background | Pixel |  | XtDefaultBackground
backgroundPixmap | Pixmap | Pixmap |  | XtUnspecifiedPixmap
borderColor | BorderColor | Pixel |  | XtDefaultForeground
borderPixmap | Pixmap | Pixmap |  | XtUnspecifiedPixmap
borderWidth | BorderWidth | Dimension |  | 1
children | ReadOnly | WidgetList | R | NULL
colormap | Colormap | Colormap |  | Parent's Colormap
defaultDistance | Thickness | int |  | 4
depth | Depth | int | C | Parent's Depth
destroyCallback | Callback | XtCallbackList |  | NULL
height | Height | Dimension | A | Enough space to contain all children
icon | Icon | Bitmap |  | None
label | Label | String |  | "label"
mappedWhenManaged | MappedWhenManaged | Boolean |  | True
numChildren | ReadOnly | Cardinal | R | 0
screen | Screen | Screen | R | Parent's Screen
sensitive | Sensitive | Boolean |  | True
translations | Translations | TranslationTable |  | NULL
value | Value | String |  | no value widget
width | Width | Dimension | A | Enough space to contain all children
x | Position | Position |  | 0
y | Position | Position |  | 0
_

`icon`

- A pixmap image to be displayed immediately to the left of the Dialog widget's label.

`label`

- A string to be displayed at the top of the Dialog widget.

`value`

- An initial value for the string field that the user will enter text into. By default, no text entry field is available to the user. Specifying an initial value for `value` activates the text entry field. If string input is desired, but no initial value is to be specified then set this resource to "" (empty string).

## Constraint Resources

Each child of the Dialog widget may request special layout resources be applied to it. These constraint resources allow the Dialog widget's children to specify individual layout requirements.

Name | Class | Type | Notes | Default Value
bottom | Edge | XawEdgeType |  | XawRubber
fromHoriz | Widget | Widget |  | NULL (left edge of Dialog)
fromVert | Widget | Widget |  | NULL (top edge of Dialog)
horizDistance | Thickness | int |  | `defaultDistance` resource
left | Edge | XawEdgeType |  | XawRubber
resizable | Boolean | Boolean |  | FALSE
right | Edge | XawEdgeType |  | XawRubber
top | Edge | XawEdgeType |  | XawRubber
vertDistance | Thickness | int |  | `defaultDistance` resource

    bottom
    left
    right
    top            What to do with this edge of the child when
                   the parent is resized.  This resource may be
                   any edgeType.  See Layout Semantics for
                   details.

    fromHoriz
    fromVert       Which widget this child should be placed
                   underneath (or to the right of).  If a value
                   of NULL is specified then this widget will be
                   positioned relative to the edge of the par-
                   ent.

    horizDistance
    vertDistance   The amount of space, in pixels, between this
                   child and its left or upper neighbor.

    resizable      If this resource is False then the parent
                   widget will ignore all geometry request made
                   by this child.  The parent may still resize
                   this child itself, however.

## Layout Semantics

The Dialog widget uses two different sets of layout seman- tics. One is used when initially laying out the children. The other is used when the Dialog is resized.

The first layout method uses the `fromVert` mand `fromHoriz` resources to place the children of the Dialog. A single pass is made through the Dialog widget's children in the order that they were created. Each child is then placed in the Dialog widget below or to the right of the widget speci- fied by the `fromVert` mand `fromHoriz` mresources. The distance the new child is placed from its left or upper neighbor is determined by the `horizDistance` mand `vertDistance` mresources. This implies some things about how the order of creation affects the possible placement of the children. The Form widget registers a string to widget converter which does not postpone conversion and does not cache conversion results.

The second layout method is used when the Dialog is resized. It does not matter what causes this resize, and it is possi- ble for a resize to happen before the widget becomes visible (due to constraints imposed by the parent of the Dialog). This layout method uses the `bottom` , `top` , `left` , and `right` resources. These resources are used to determine what will happen to each edge of the child when the Dialog is resized. If a value of `XawChain` <something> is specified, the the edge of the child will remain a fixed distance from the chain edge of the Dialog. For example if `XawChainLeft` mis specified for the `right` mresource of a child then the right edge of that child will remain a fixed distance from the left edge of the Dialog widget. If a value of `XawRubber` mis spec- ified, that edge will grow by the same percentage that the Dialog grew. For instance if the Dialog grows by 50% the left edge of the child (if specified as `XawRubber` mwill be 50% farther from the left edge of the Dialog). One must be very careful when specifying these resources, for when they are specified incorrectly children may overlap or completely occlude other children when the Dialog widget is resized.

Edge Type | Resource Name | Description
XawChainBottom | ChainBottom | Edge remains a fixed distance from bottom of Dialog
XawChainLeft | ChainLeft | Edge remains a fixed distance from left of Dialog
XawChainRight | ChainRight | Edge remains a fixed distance from right of Dialog
XawChainTop | ChainTop | Edge remains a fixed distance from top of Dialog
XawRubber | Rubber | Edges will move a proportional distance

### Example

If you wish to force the Dialog to never resize one or more of its children then set `left` and `right` to `XawChainLeft` and `top` and `bottom` to `XawChainTop`. This will cause the child to remain a fixed distance from the top and left edges of the Dialog, and to never resize.

### Special Considerations

The Dialog widget automatically sets the `top` and `bottom` resources for all Children that are subclasses of the Command widget, as well as the widget children that are used to contain the `label`, `value`, and `icon`. This policy allows the buttons at the bottom of the Dialog to interact correctly with the predefined children, and makes it possible for a client to simply create and manage a new Command button without having to specify its constraints.

The Dialog will also set `fromLeft` to the last button in the Dialog for each new button added to the Dialog widget.

The automatically added constraints cannot be overridden, as they are policy decisions of the Dialog widget. If a more flexible Dialog is desired, the application is free to use the Form widget to create its own Dialog policy.

## Automatically Created Children.

The Dialog uses Label widgets to contain the `label` and `icon`. These widgets are named label and icon respectively. The Dialog `value` is contained in an AsciiText widget whose name is `value`. Using `XtNameToWidget` the application can change those resources associated with each of these widgets that are not available through the Dialog widget itself.

## Convenience Routines

To return the character string in the text field, use

      String XawDialogGetValueString
      Widget w

w

- Specifies the Dialog widget.

This function returns a copy of the value string of the Dialog widget. This string is allocated by the AsciiText widget and will remain valid and unchanged until another call to XawDialogGetValueString or an XtGetValues call on the `value` widget, when the string will be automatically freed, and a new string is returned. This string may be freed earlier by calling the function XawAsciiSourceFreeString.

To add a new button to the Dialog widget use XawDialogAddButton.

      void XawDialogAddButton
      Widget w
      String name
      XtCallbackProc func
      XtPointer client_data

w

- Specifies the Dialog widget.

name

- Specifies the name of the new Command button to be added to the Dialog.

func

- Specifies a callback function to be called when this button is activated. If NULL is specified then no callback is added.

client_data

- Specifies the client_data to be passed to the func.

This function is merely a shorthand for the code sequence:

    {
    	Widget button = XtCreateManagedWidget(name, commandWidgetClass, w, NULL, ZERO);
    	XtAddCallback(button, XtNcallback, func, client_data);
    }