# Panner Widget

    Application header file	<X11/Xaw/Panner.h>

    Class header file	<X11/Xaw/PannerP.h>

    Class		pannerWidgetClass

    Class Name	Panner

    Superclass	Simple

A Panner widget is a rectangle, called the ``canvas,'' on which another rectangle, the ``slider,'' moves in two dimensions. It is often used with a Porthole widget to move, or ``scroll,'' a third widget in two dimensions, in which case the slider's size and position gives feedback as to what portion of the third widget is visible.

The slider may be scrolled around the canvas by pressing, dragging, and releasing Button1; the default translation also enables scrolling via arrow keys and some other keys. While scrolling is in progress, the application receives notification through callback procedures. Notification may be done either continuously whenever the slider moves or discretely whenever the slider has been given a new location.

## Resources

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

Name | Class | Type | Notes | Default Value
--- | --- | --- | --- | ---
accelerators | Accelerators | AcceleratorTable |  | NULL
allowOff | AllowOff | Boolean |  | False
ancestorSensitive | AncestorSensitive | Boolean | D | True
background | Background | Pixel |  | XtDefaultBackground
backgroundPixmap | Pixmap | Pixmap |  | XtUnspecifiedPixmap
backgroundStipple | BackgroundStipple | String |  | NULL
borderColor | BorderColor | Pixel |  | XtDefaultForeground
borderPixmap | Pixmap | Pixmap |  | XtUnspecifiedPixmap
borderWidth | BorderWidth | Dimension |  | 1
canvasHeight | CanvasHeight | Dimension |  | 0
canvasWidth | CanvasWidth | Dimension |  | 0
colormap | Colormap | Colormap |  | Parent's Colormap
cursor | Cursor | Cursor |  | None
cursorName | Cursor | String |  | NULL
defaultScale | DefaultScale | Dimension |  | 8
depth | Depth | int | C | Parent's Depth
destroyCallback | Callback | XtCallbackList |  | NULL
foreground | Foreground | Pixel |  | XtDefaultForeground
height | Height | Dimension | A | depends on orientation
internalSpace | InternalSpace | Dimension |  | 4
international | International | Boolean | C | False
lineWidth | LineWidth | Dimension |  | 0
mappedWhenManaged | MappedWhenManaged | Boolean |  | True
pointerColor | Foreground | Pixel |  | XtDefaultForeground
pointerColorBackground | Background | Pixel |  | XtDefaultBackground
reportCallback | ReportCallback | Callback |  | NULL
resize | Resize | Boolean |  | True
rubberBand | RubberBand | Boolean |  | False
screen | Screen | Screen | R | Parent's Screen
sensitive | Sensitive | Boolean |  | True
shadowColor | ShadowColor | Pixel |  | XtDefaultForeground
shadowThickness | ShadowThickness | Dimension |  | 2
sliderX | SliderX | Position |  | 0
sliderY | SliderY | Position |  | 0
sliderHeight | SliderHeight | Dimension |  | 0
sliderWidth | SliderWidth | Dimension |  | 0
translations | Translations | TranslationTable |  | See below
width | Width | Dimension | A | depends on orientation
x | Position | Position |  | 0
y | Position | Position |  | 0

`allowOff`

  Whether to allow the edges of the slider to go off the edges of the canvas.

`backgroundStipple`

  The name of a bitmap pattern to be used as the background for the area representing the canvas.

`canvasHeight`

`canvasWidth`

  The size of the canvas.

`defaultScale`

  The percentage size that the Panner widget should have relative to the size of the canvas.

`foreground`

  A pixel value which indexes the widget's colormap to derive the color used to draw the slider.

`internalSpace`

  The width of internal border in pixels between a slider representing the full size of the canvas and the edge of the Panner widget.

`lineWidth`

  The width of the lines in the rubberbanding rectangle when rubberbanding is in effect instead of continuous scrolling. The default is 0.

`reportCallback`

  All functions on this callback list are called when the `notify` action is invoked. See the `Panner Actions` section for details.

`resize`

  Whether or not to resize the panner whenever the canvas size is changed so that the `defaultScale` is maintained.

`rubberBand`

  Whether or not scrolling should be discrete (only moving a rubberbanded rectangle until the scrolling is done) or continuous (moving the slider itself). This controls whether or not the `move` action procedure also invokes the `notify` action procedure.

`shadowColor`

  The color of the shadow underneath the slider.

`shadowThickness`

  The width of the shadow underneath the slider.

`sliderX`

`sliderY`

  The location of the slider in the coordinates of the canvas.

`sliderHeight`

`sliderWidth`

  The size of the slider.

## Panner Actions

The actions supported by the Panner widget are:

`start`()

  This action begins movement of the slider.

`stop`()

  This action ends movement of the slider.

`abort`()

  This action ends movement of the slider and restores it to the position it held when the `start` action was invoked.

`move`()

  This action moves the outline of the slider (if the `rubberBand` resource is True) or the slider itself (by invoking the `notify` action procedure).

`page`(`xamount`,`yamount`)

  This action moves the slider by the specified amounts. The format for the amounts is a signed or unsigned floating-point number (e.g., +1.0 or \-.5) followed by either `p` indicating pages (slider sizes), or `c` indicating canvas sizes. Thus, page(+0,+.5p) represents vertical movement down one-half the height of the slider and page(0,0) represents moving to the upper left corner of the canvas.

`notify`()

  This action informs the application of the slider's current position by invoking the `reportCallback` functions registered by the application.

`set`(`what`,`value`)

  This action changes the behavior of the Panner. The what argument must currently be the string `rubberband` and controls the value of the `rubberBand` resource. The `value` argument may have one of the values `on`, `off`, or `toggle`.

The default bindings for Panner are:

    	<Btn1Down>:	start(\|)
    	<Btn1Motion>:	move(\|)
    	<Btn1Up>:	notify(\|) stop(\|)
    	<Btn2Down>:	abort(\|)
    	<Key>KP_Enter:	set(rubberband,toggle)
    	<Key>space:	page(+1p,+1p)
    	<Key>Delete:	page(\-1p,\-1p)
    	<Key>BackSpace:	page(\-1p,\-1p)
    	<Key>Left:	page(\-.5p,+0)
    	<Key>Right:	page(+.5p,+0)
    	<Key>Up:	page(+0,\-.5p)
    	<Key>Down:	page(+0,+.5p)
    	<Key>Home:	page(0,0)

## Panner Callbacks

The functions registered on the `reportCallback` list are invoked by the `notify` action as follows:

      void ReportProc
      Widget panner
      XtPointer client_data
      XtPointer report

panner

  Specifies the Panner widget.

panner

  Specifies the client data.

panner

  Specifies a pointer to an `XawPannerReport` structure containing the location and size of the slider and the size of the canvas.