# OpenLayers.Handler.Drag

The drag handler is used to deal with sequences of browser events related to dragging. The handler is used by controls that want to know when a drag sequence begins, when a drag is happening, and when it has finished.

Controls that use the drag handler typically construct it with callbacks for ‘down’, ‘move’, and ‘done’. Callbacks for these keys are called when the drag begins, with each move, and when the drag is done. In addition, controls can have callbacks keyed to ‘up’ and ‘out’ if they care to differentiate between the types of events that correspond with the end of a drag sequence. If no drag actually occurs (no mouse move) the ‘down’ and ‘up’ callbacks will be called, but not the ‘done’ callback.

Create a new drag handler with the OpenLayers.Handler.Drag constructor.

#### Inherits from

- OpenLayers.Handler

Summary

OpenLayers.Handler.Drag | The drag handler is used to deal with sequences of browser events related to dragging.
Properties |
started | {Boolean} When a mousedown or touchstart event is received, we want to record it, but not set ‘dragging’ until the mouse moves after starting.
stopDown | {Boolean} Stop propagation of mousedown events from getting to listeners on the same element.
dragging | {Boolean}
last | {OpenLayers.Pixel} The last pixel location of the drag.
start | {OpenLayers.Pixel} The first pixel location of the drag.
lastMoveEvt | {Object} The last mousemove event that occurred.
oldOnselectstart | {Function}
interval | {Integer} In order to increase performance, an interval (in milliseconds) can be set to reduce the number of drag events called.
timeoutId | {String} The id of the timeout used for the mousedown interval.
documentDrag | {Boolean} If set to true, the handler will also handle mouse moves when the cursor has moved out of the map viewport.
documentEvents | {Boolean} Are we currently observing document events?
Constructor |
OpenLayers.Handler.Drag | Returns OpenLayers.Handler.Drag
Functions |
dragstart | This private method is factorized from mousedown and touchstart methods
dragmove | This private method is factorized from mousemove and touchmove methods
dragend | This private method is factorized from mouseup and touchend methods
down | This method is called during the handling of the mouse down event.
move | This method is called during the handling of the mouse move event.
up | This method is called during the handling of the mouse up event.
out | This method is called during the handling of the mouse out event.
mousedown | Handle mousedown events
touchstart | Handle touchstart events
mousemove | Handle mousemove events
touchmove | Handle touchmove events
removeTimeout | Private.
mouseup | Handle mouseup events
touchend | Handle touchend events
mouseout | Handle mouseout events
click | The drag handler captures the click event.
activate | Activate the handler.
deactivate | Deactivate the handler.
adjustXY | Converts event coordinates that are relative to the document body to ones that are relative to the map viewport.
addDocumentEvents | Start observing document events when documentDrag is true and the mouse cursor leaves the map viewport while dragging.
removeDocumentEvents | Stops observing document events when documentDrag is true and the mouse cursor re-enters the map viewport while dragging.

### Properties

### started

{Boolean} When a mousedown or touchstart event is received, we want to record it, but not set ‘dragging’ until the mouse moves after starting.

### stopDown

{Boolean} Stop propagation of mousedown events from getting to listeners on the same element. Default is true.

### dragging

{Boolean}

### last

{OpenLayers.Pixel} The last pixel location of the drag.

### start

{OpenLayers.Pixel} The first pixel location of the drag.

### lastMoveEvt

{Object} The last mousemove event that occurred. Used to position the map correctly when our “delay drag” timeout expired.

### oldOnselectstart

{Function}

### interval

{Integer} In order to increase performance, an interval (in milliseconds) can be set to reduce the number of drag events called. If set, a new drag event will not be set until the interval has passed. Defaults to 0, meaning no interval.

### timeoutId

{String} The id of the timeout used for the mousedown interval. This is “private”, and should be left alone.

### documentDrag

{Boolean} If set to true, the handler will also handle mouse moves when the cursor has moved out of the map viewport. Default is false.

### documentEvents

{Boolean} Are we currently observing document events?

### Constructor

### OpenLayers.Handler.Drag

Returns OpenLayers.Handler.Drag

#### Parameters

control | {OpenLayers.Control} The control that is making use of this handler. If a handler is being used without a control, the handlers setMap method must be overridden to deal properly with the map.
callbacks | {Object} An object containing a single function to be called when the drag operation is finished. The callback should expect to recieve a single argument, the pixel location of the event. Callbacks for ‘move’ and ‘done’ are supported. You can also speficy callbacks for ‘down’, ‘up’, and ‘out’ to respond to those events.
options | {Object}

### Functions

### dragstart

> dragstart: function ( | evt | )

This private method is factorized from mousedown and touchstart methods

#### Parameters

evt | {Event} The event

#### Returns

{Boolean} Let the event propagate.

### dragmove

> dragmove: function ( | evt | )

This private method is factorized from mousemove and touchmove methods

#### Parameters

evt | {Event} The event

#### Returns

{Boolean} Let the event propagate.

### dragend

> dragend: function ( | evt | )

This private method is factorized from mouseup and touchend methods

#### Parameters

evt | {Event} The event

#### Returns

{Boolean} Let the event propagate.

### down

> down: function( | evt | )

This method is called during the handling of the mouse down event. Subclasses can do their own processing here.

#### Parameters

evt | {Event} The mouse down event

### move

> move: function( | evt | )

This method is called during the handling of the mouse move event. Subclasses can do their own processing here.

#### Parameters

evt | {Event} The mouse move event

### up

> up: function( | evt | )

This method is called during the handling of the mouse up event. Subclasses can do their own processing here.

#### Parameters

evt | {Event} The mouse up event

### out

> out: function( | evt | )

This method is called during the handling of the mouse out event. Subclasses can do their own processing here.

#### Parameters

evt | {Event} The mouse out event

### mousedown

> mousedown: function( | evt | )

Handle mousedown events

#### Parameters

evt | {Event}

#### Returns

{Boolean} Let the event propagate.

### touchstart

> touchstart: function( | evt | )

Handle touchstart events

#### Parameters

evt | {Event}

#### Returns

{Boolean} Let the event propagate.

### mousemove

> mousemove: function( | evt | )

Handle mousemove events

#### Parameters

evt | {Event}

#### Returns

{Boolean} Let the event propagate.

### touchmove

> touchmove: function( | evt | )

Handle touchmove events

#### Parameters

evt | {Event}

#### Returns

{Boolean} Let the event propagate.

### removeTimeout

> removeTimeout: function()

Private. Called by mousemove() to remove the drag timeout.

### mouseup

> mouseup: function( | evt | )

Handle mouseup events

#### Parameters

evt | {Event}

#### Returns

{Boolean} Let the event propagate.

### touchend

> touchend: function( | evt | )

Handle touchend events

#### Parameters

evt | {Event}

#### Returns

{Boolean} Let the event propagate.

### mouseout

> mouseout: function ( | evt | )

Handle mouseout events

#### Parameters

evt | {Event}

#### Returns

{Boolean} Let the event propagate.

### click

> click: function ( | evt | )

The drag handler captures the click event. If something else registers for clicks on the same element, its listener will not be called after a drag.

#### Parameters

evt | {Event}

#### Returns

{Boolean} Let the event propagate.

### activate

> activate: function()

Activate the handler.

#### Returns

{Boolean} The handler was successfully activated.

### deactivate

> deactivate: function()

Deactivate the handler.

#### Returns

{Boolean} The handler was successfully deactivated.

### adjustXY

> adjustXY: function( | evt | )

Converts event coordinates that are relative to the document body to ones that are relative to the map viewport. The latter is the default in OpenLayers.

#### Parameters

evt | {Object}

### addDocumentEvents

> addDocumentEvents: function()

Start observing document events when documentDrag is true and the mouse cursor leaves the map viewport while dragging.

### removeDocumentEvents

> removeDocumentEvents: function()

Stops observing document events when documentDrag is true and the mouse cursor re-enters the map viewport while dragging.

This class represents a screen coordinate, in x and y coordinates

> dragstart: function ( | evt | )

This private method is factorized from mousedown and touchstart methods

> dragmove: function ( | evt | )

This private method is factorized from mousemove and touchmove methods

> dragend: function ( | evt | )

This private method is factorized from mouseup and touchend methods

> down: function( | evt | )

This method is called during the handling of the mouse down event.

> move: function( | evt | )

This method is called during the handling of the mouse move event.

> up: function( | evt | )

This method is called during the handling of the mouse up event.

> out: function( | evt | )

This method is called during the handling of the mouse out event.

> mousedown: function( | evt | )

Handle mousedown events

> touchstart: function( | evt | )

Handle touchstart events

> mousemove: function( | evt | )

Handle mousemove events

> touchmove: function( | evt | )

Handle touchmove events

> removeTimeout: function()

Private.

> mouseup: function( | evt | )

Handle mouseup events

> touchend: function( | evt | )

Handle touchend events

> mouseout: function ( | evt | )

Handle mouseout events

> click: function ( | evt | )

The drag handler captures the click event.

> activate: function()

Activate the handler.

> deactivate: function()

Deactivate the handler.

> adjustXY: function( | evt | )

Converts event coordinates that are relative to the document body to ones that are relative to the map viewport.

> addDocumentEvents: function()

Start observing document events when documentDrag is true and the mouse cursor leaves the map viewport while dragging.

> removeDocumentEvents: function()

Stops observing document events when documentDrag is true and the mouse cursor re-enters the map viewport while dragging.
Returns OpenLayers.Handler.Drag
Base class to construct a higher-level handler for event sequences.
Controls affect the display or behavior of the map.
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