gov.nasa.worldwind.util.BasicDragger Maven / Gradle / Ivy
/*
* Copyright (C) 2016 United States Government as represented by the Administrator of the
* National Aeronautics and Space Administration.
* All Rights Reserved.
*/
package gov.nasa.worldwind.util;
import gov.nasa.worldwind.*;
import gov.nasa.worldwind.avlist.AVKey;
import gov.nasa.worldwind.drag.*;
import gov.nasa.worldwind.event.*;
import gov.nasa.worldwind.geom.*;
import gov.nasa.worldwind.globes.Globe;
import java.awt.*;
/**
* Interprets mouse input via the {@link DragSelectEvent} for notifying picked objects implementing the
* {@link Draggable} interface. This version uses the {@link Draggable} interface for dragging but retains the original
* behavior of the BasicDragger when the {@link gov.nasa.worldwind.pick.PickedObject} implements either the
* {@link Movable} or {@link Movable2} interface.
*
* For objects not yet implementing the {@link Draggable} interface the legacy dragging functionality will be used.
*/
public class BasicDragger implements SelectListener
{
/**
* The {@link WorldWindow} this dragger will utilize for the {@link Globe}, {@link View}, and
* {@link SceneController} objects.
*/
protected WorldWindow wwd;
/**
* Indicates if the dragger is currently dragging.
*/
protected boolean dragging = false;
/**
* The {@link DragContext} for dragging operations. Initialized on {@link AVKey#DRAG_BEGIN}.
*/
protected DragContext dragContext;
/**
* Creates a dragging controller which converts {@link SelectEvent}s to the {@link Draggable} interface.
*
* @param wwd the {@link WorldWindow} this drag controller should be associated with.
*
* @throws IllegalArgumentException if the provided {@link WorldWindow} is null.
*/
public BasicDragger(WorldWindow wwd)
{
if (wwd == null)
{
String msg = Logging.getMessage("nullValue.WorldWindow");
Logging.logger().severe(msg);
throw new IllegalArgumentException(msg);
}
this.wwd = wwd;
}
/**
* Ignores the useTerrain argument as it has been deprecated and utilizes the single parameter constructor.
*
* @deprecated the useTerrain property has been deprecated in favor of the {@link Draggable} interface which allows
* the object to define the drag behavior.
*/
public BasicDragger(WorldWindow wwd, boolean useTerrain)
{
this(wwd);
}
/**
* Returns if the dragger is currently executing a dragging operation.
*
* @return true if a drag operation is executing.
*/
public boolean isDragging()
{
return this.dragging;
}
/**
*
* @return false as this functionality has been deprecated.
* @deprecated the {@link Draggable} provides the object being dragged complete control over the dragging behavior.
*/
public boolean isUseTerrain()
{
return false;
}
/**
* @param useTerrain
*
* @deprecated definition of dragging behavior now defined by the object in the {@link Draggable} interface.
*/
public void setUseTerrain(boolean useTerrain)
{
// ignored - functionality deprecated
}
@Override
public void selected(SelectEvent event)
{
if (event == null)
{
String msg = Logging.getMessage("nullValue.EventIsNull");
Logging.logger().severe(msg);
throw new IllegalArgumentException(msg);
}
if (event.getEventAction().equals(SelectEvent.DRAG_END))
{
this.dragContext.setDragState(AVKey.DRAG_ENDED);
this.fireDrag((DragSelectEvent) event);
this.dragContext = null;
this.dragging = false;
}
else if (event.getEventAction().equals(SelectEvent.DRAG))
{
if (this.dragContext == null)
this.dragContext = new DragContext();
this.dragContext.setPoint(event.getPickPoint());
this.dragContext.setPreviousPoint(((DragSelectEvent) event).getPreviousPickPoint());
this.dragContext.setView(this.wwd.getView());
this.dragContext.setGlobe(this.wwd.getModel().getGlobe());
this.dragContext.setSceneController(this.wwd.getSceneController());
if (this.dragging)
{
this.dragContext.setDragState(AVKey.DRAG_CHANGE);
this.fireDrag((DragSelectEvent) event);
}
else
{
this.dragContext.setDragState(AVKey.DRAG_BEGIN);
this.dragContext.setInitialPoint(((DragSelectEvent) event).getPreviousPickPoint());
this.dragging = true;
this.fireDrag((DragSelectEvent) event);
}
}
event.consume();
}
/**
* Propagates the {@link DragContext} to the picked object if it implements {@link Draggable},
* {@link Movable}, or {@link Movable2}.
*
* @param dragEvent the {@link DragContext} to deliver to the selected object.
*
* @throws IllegalArgumentException if the {@link DragContext} is null.
*/
protected void fireDrag(DragSelectEvent dragEvent)
{
if (dragEvent == null || dragEvent.getTopObject() == null)
{
String msg = Logging.getMessage("nullValue.ObjectIsNull");
Logging.logger().severe(msg);
throw new IllegalArgumentException(msg);
}
Object dragObject = dragEvent.getTopObject();
if (dragObject instanceof Draggable)
{
((Draggable) dragObject).drag(this.dragContext);
}
else if ((dragObject instanceof Movable2) || (dragObject instanceof Movable))
{
// Utilize the existing behavior
this.dragLegacy(dragEvent);
}
}
//////////////////////////////////////////////////////////
// Legacy Properties
//////////////////////////////////////////////////////////
protected Vec4 dragRefObjectPoint;
protected Point dragRefCursorPoint;
protected double dragRefAltitude;
/**
* Legacy drag approach, provided for objects not yet implementing the {@link Draggable} interface.
*
* @param event the current {@link SelectEvent}.
*/
protected void dragLegacy(SelectEvent event)
{
DragSelectEvent dragEvent = (DragSelectEvent) event;
Object dragObject = dragEvent.getTopObject();
if (dragObject == null)
return;
View view = wwd.getView();
Globe globe = wwd.getModel().getGlobe();
// Compute dragged object ref-point in model coordinates.
// Use the Icon and Annotation logic of elevation as offset above ground when below max elevation.
Position refPos = null;
if (dragObject instanceof Movable2)
refPos = ((Movable2) dragObject).getReferencePosition();
else if (dragObject instanceof Movable)
refPos = ((Movable) dragObject).getReferencePosition();
if (refPos == null)
return;
Vec4 refPoint = globe.computePointFromPosition(refPos);
if (this.dragContext.getDragState().equals(AVKey.DRAG_BEGIN)) // Dragging started
{
// Save initial reference points for object and cursor in screen coordinates
// Note: y is inverted for the object point.
this.dragRefObjectPoint = view.project(refPoint);
// Save cursor position
this.dragRefCursorPoint = dragEvent.getPreviousPickPoint();
// Save start altitude
this.dragRefAltitude = globe.computePositionFromPoint(refPoint).getElevation();
}
// Compute screen-coord delta since drag started.
int dx = dragEvent.getPickPoint().x - this.dragRefCursorPoint.x;
int dy = dragEvent.getPickPoint().y - this.dragRefCursorPoint.y;
// Find intersection of screen coord (refObjectPoint + delta) with globe.
double x = this.dragRefObjectPoint.x + dx;
double y = event.getMouseEvent().getComponent().getSize().height - this.dragRefObjectPoint.y + dy - 1;
Line ray = view.computeRayFromScreenPoint(x, y);
Position pickPos = null;
// Use intersection with sphere at reference altitude.
Intersection inters[] = globe.intersect(ray, this.dragRefAltitude);
if (inters != null)
pickPos = globe.computePositionFromPoint(inters[0].getIntersectionPoint());
if (pickPos != null)
{
// Intersection with globe. Move reference point to the intersection point,
// but maintain current altitude.
Position p = new Position(pickPos, refPos.getElevation());
if (dragObject instanceof Movable2)
((Movable2) dragObject).moveTo(globe, p);
else
((Movable) dragObject).moveTo(p);
}
}
}