XmDrawingArea

The DrawingArea widget class

Format

#include <Xm/DrawingA.h>

DESCRIPTION

DrawingArea is an empty widget that is easily adaptable to a variety of purposes. It does no drawing and defines no behavior except for invoking callbacks. Callbacks notify the application when graphics need to be drawn (exposure events or widget resize) and when the widget receives input from the keyboard or mouse.

Applications are responsible for defining appearance and behavior as needed in response to DrawingArea callbacks.

DrawingArea is also a composite widget and subclass of XmManager that supports minimal geometry management for multiple widget or gadget children.

DrawingArea uses the XmNinitialFocus resource of XmManager to define whether or not DrawingArea will receive focus when it is traversed to, even if it has traversable children. If XmNinitialFocus is NULL, DrawingArea receives focus only if it does not have any traversable children. If XmNinitialFocus is not NULL, then DrawingArea receives focus when traversed to. In the latter case, the application first needs to be able to realize that the DrawingArea will receive focus, then, as appropriate, needs to either call the XmProcessTraversal function for the desired child, or to navigate across the private DrawingArea graphics objects.

The following resources are not currently used by the DrawingArea widget: XmNshadowThickness, XmNtopShadowPixmap, XmNbottomShadowPixmap, XmNtopShadowColor, and XmNbottomShadowColor

Data Transfer Behavior

DrawingArea has no widget class conversion or destination procedure. Subclasses and the XmNconvertCallback procedures are responsible for any conversion of selections. Subclasses and the XmNdestinationCallback procedures are responsible for any data transfers to the widget.

Classes

DrawingArea inherits behavior and resources from the Core, Composite, Constraint, and XmManager classes.

The class pointer is xmDrawingAreaWidgetClass.

The class name is XmDrawingArea.

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).

Inherited Resources

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

Callback Information

A pointer to the following structure is passed to the XmNexposeCallback, XmNinputCallback, and XmNresizeCallback procedures:

typedef struct
{
        int 
reason;
        XEvent 
* event;
        Window 
window;
} XmDrawingAreaCallbackStruct;

typedef struct
{
        int 
reason;
        XEvent *
event;
        Atom 
selection;
        Atom 
target;
        XtPointer 
source_data;
        XtPointer 
location_data;
        int 
flags;
        XtPointer 
parm;
        int 
parm_format;
        unsigned long 
parm_length;
        int 
status;
        XtPointer 
value;
        Atom 
type;
        int 
format;
        unsigned long 
length;
} XmConvertCallbackStruct;

typedef struct
{
        int 
reason;
        XEvent *
event;
        Atom 
selection;
        XtEnum 
operation;
        int 
flags;
        XtPointer 
transfer_id;
        XtPointer 
destination_data;
        XtPointer 
location_data;
        Time 
time;
} XmDestinationCallbackStruct;

Translations

XmDrawingArea inherits translations from XmManager. Before calling the XmManager actions, all events in the inherited translations except BtnMotion, EnterWindow, LeaveWindow, FocusIn, and FocusOut also call the DrawingAreaInput() action.

XmDrawingArea has the following additional translations. The following key names are listed in the X standard key event translation table syntax. This format is the one used by Motif to specify the widget actions corresponding to a given key. A brief overview of the format is provided under VirtualBindings (3). For a complete description of the format, please refer to the X Toolkit Instrinsics Documentation.

Action Routines

The XmDrawingArea action routines are

Additional Behavior

The XmDrawingArea widget has the following additional behavior:

Virtual Bindings

The bindings for virtual keys are vendor specific. For information about bindings for virtual buttons and keys, see VirtualBindings (3).

RELATED

Composite (3), Constraint (3), Core (3), XmCreateDrawingArea (3), and XmManager (3).