com.yworks.yfiles.view.input

Interface IDragHandler

All Known Subinterfaces:

IHandle, IPositionHandler

All Known Implementing Classes:

ConstrainedDragHandler, ConstrainedHandle, ConstrainedPositionHandler, LabelPositionHandler, PortLocationModelParameterHandle, PortRelocationHandle, RectangleHandle, ReparentStripePositionHandler, ReshapeHandlerHandle

public interface IDragHandler

Interface for an object that can be used to drag something displayed in a CanvasControl.

Items can be dragged with the mouse and an instance of this class will modify their position accordingly. A drag will trigger the invocation of initializeDrag(IInputModeContext), zero or more handleMove(IInputModeContext, PointD, PointD) calls, and will be finalized by either dragFinished(IInputModeContext, PointD, PointD) or cancelDrag(IInputModeContext, PointD).

See Also:

IPositionHandler, IHandle, IInputModeContext

Method Summary

Modifier and Type	Method and Description
void	cancelDrag(IInputModeContext context, PointD originalLocation) Called by clients to indicate that the dragging has been canceled by the user.
void	dragFinished(IInputModeContext context, PointD originalLocation, PointD newLocation) Called by clients to indicate that the repositioning has just been finished.
IPoint	getLocation() Returns a view of the location of the item.
void	handleMove(IInputModeContext context, PointD originalLocation, PointD newLocation) Called by clients to indicate that the element has been dragged and its position should be updated.
void	initializeDrag(IInputModeContext context) Called by clients to indicate that the element is going to be dragged.

Method Detail

cancelDrag

void cancelDrag(IInputModeContext context,
                PointD originalLocation)

Called by clients to indicate that the dragging has been canceled by the user.

This method may be called after the initial initializeDrag(IInputModeContext) and zero or more invocations of handleMove(IInputModeContext, PointD, PointD). Implementations should reset the position of the items they modify to their initial state. Alternatively to this method the dragFinished(IInputModeContext, PointD, PointD) method might be called.

Parameters:

context - The context to retrieve information about the drag from.

originalLocation - The value of the coordinate of the Location property at the time of initializeDrag(IInputModeContext).

dragFinished

void dragFinished(IInputModeContext context,
                  PointD originalLocation,
                  PointD newLocation)

Called by clients to indicate that the repositioning has just been finished.

This method may be called after the initial initializeDrag(IInputModeContext) and zero or more invocations of handleMove(IInputModeContext, PointD, PointD). Alternatively to this method the cancelDrag(IInputModeContext, PointD) method might be called.

Parameters:

context - The context to retrieve information about the drag from.

newLocation - The coordinates in the world coordinate system that the client wants the handle to be at. Depending on the implementation the Location may or may not be modified to reflect the new value. This is the same value as delivered in the last invocation of handleMove(IInputModeContext, PointD, PointD)

originalLocation - The value of the Location property at the time of initializeDrag(IInputModeContext).

getLocation

IPoint getLocation()

Returns a view of the location of the item.

The point describes the current world coordinate of the element that can be modified by this handler.

Returns:

The Location.

handleMove

void handleMove(IInputModeContext context,
                PointD originalLocation,
                PointD newLocation)

Called by clients to indicate that the element has been dragged and its position should be updated.

This method may be called more than once after an initial initializeDrag(IInputModeContext) and will the final call will be followed by either one dragFinished(IInputModeContext, PointD, PointD) or one cancelDrag(IInputModeContext, PointD) call.

Parameters:

context - The context to retrieve information about the drag from.

originalLocation - The value of the Location property at the time of initializeDrag(IInputModeContext).

newLocation - The coordinates in the world coordinate system that the client wants the handle to be at. Depending on the implementation the Location may or may not be modified to reflect the new value.

initializeDrag

void initializeDrag(IInputModeContext context)

Called by clients to indicate that the element is going to be dragged.

This call will be followed by one or more calls to handleMove(IInputModeContext, PointD, PointD), and a final dragFinished(IInputModeContext, PointD, PointD) or cancelDrag(IInputModeContext, PointD).

Parameters:

context - The context to retrieve information about the drag from.