ScreenSelector (NASA World Wind)

java.lang.Object
- gov.nasa.worldwind.avlist.AVListImpl
- - gov.nasa.worldwind.WWObjectImpl
  - - gov.nasa.worldwindx.examples.util.ScreenSelector

All Implemented Interfaces:

AVList, MessageListener, SelectListener, WWObject, MouseListener, MouseMotionListener, PropertyChangeListener, EventListener
```
public class ScreenSelector
extends WWObjectImpl
implements MouseListener, MouseMotionListener, SelectListener
```
ScreenSelector is an application utility that provides interactive screen rectangle selection with visual feedback, and tracks the list of objects intersecting the screen rectangle. The screen rectangle is displayed on a layer created by ScreenSelector, and is used as the WorldWindow's pick rectangle to perform object selection. Objects intersecting the screen rectangle can be accessed by calling getSelectedObjects().

Using ScreenSelector

To use ScreenSelector in an application, create a new instance of ScreenSelector and specify the application's WorldWindow as the sole parameter. When the user wants to define a screen selection, call enable() and the ScreenSelector then translates mouse events to changes in the selection rectangle. The selection rectangle is displayed as a filled rectangle with a 1-pixel wide border drawn in the interiorColor and borderColor. The ScreenSelector consumes mouse events it responds in order to suppress navigation events while the user is performing a selection. When the user selection is complete, call disable() and the ScreenSelector stops responding to mouse events.
While the ScreenSelector is enabled it keeps track of the objects intersecting the selection rectangle, which can be accessed by calling getSelectedObjects. When the list of selected objects changes, SceneSelector sends SELECTION_STARTED, SELECTION_CHANGED, and SELECTION_ENDED messages to its message listeners. These three messages correspond to the user starting a selection, changing what's in the selection, and completing the selection. To receive a notification when the list of selected objects changes, register a MessageListener with the SceneSelector by calling addMessageListener(gov.nasa.worldwind.event.MessageListener).
Note that enabling or disabling the ScreenSelector does not change its list of selected objects. The list of selected objects only changes in response to user input when the ScreenSelector is enabled.

User Input

When ScreenSelector is enabled, pressing the first mouse button causes ScreenSelector to set its selection to a rectangle at the cursor with zero width and height, then clear the list of selected objects. Subsequently dragging the mouse causes ScreenSelector to update its selection rectangle to include the starting point and the current cursor point, then update the list of objects intersecting that rectangle. Finally, releasing the first mouse button causes ScreenSelector to stop displaying the selection rectangle, but does not change the list of selected objects. Keeping the list of selected object available after the selection is complete enables applications to access the user's final selection by calling getSelectedObjects.
To customize ScreenSelector's response to mouse events, create a subclass of ScreenSelector and override the methods mousePressed, mouseReleased, and mouseDragged. To customize ScreenSelector's response to screen rectangle select events, override the method selected.
ScreenSelector translates its raw mouse events to the methods selectionStarted, selectionEnded, and selectionChanged. To customize how ScreenSelector responds to these semantic events without changing the user input model, create a subclass of ScreenSelector and override any of these methods.

Screen Rectangle Appearance

To customize the appearance of the rectangle displayed by ScreenRectangle, call setInteriorColor(java.awt.Color) and setBorderColor(java.awt.Color) to specify the rectangle's interior and border colors, respectively. Setting either value to null causes ScreenRectangle to use the default values: 25% opaque white interior, 100% opaque white border.
To further customize the displayed rectangle, create a subclass of ScreenSelector, override the method createSelectionRectangle, and return a subclass of the internal class ScreenSelector.SelectionRectangle.

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

protected static class ScreenSelector.SelectionRectangle

Nested Classes
Modifier and Type	Class and Description
`protected static class`	`ScreenSelector.SelectionRectangle`

Field Summary

Fields
Modifier and Type	Field and Description
`protected boolean`	`armed`
`protected Layer`	`layer`
`protected List<MessageListener>`	`messageListeners`
`protected List<Object>`	`selectedObjects`
`static String`	`SELECTION_CHANGED` Message type indicating that the list of selected objects has changed.
`static String`	`SELECTION_ENDED` Message type indicating that the user has completed their selection.
`static String`	`SELECTION_STARTED` Message type indicating that the user has started their selection.
`protected ScreenSelector.SelectionRectangle`	`selectionRect`
`protected WorldWindow`	`wwd`

Constructor Summary

Constructors
Constructor and Description

ScreenSelector(WorldWindow worldWindow)

Constructors
Constructor and Description
`ScreenSelector(WorldWindow worldWindow)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`addMessageListener(MessageListener listener)`
`protected Layer`	`createLayer()`
`protected ScreenSelector.SelectionRectangle`	`createSelectionRectangle()`
`void`	`disable()`
`void`	`enable()`
`Color`	`getBorderColor()`
`Color`	`getInteriorColor()`
`Layer`	`getLayer()`
`List<?>`	`getSelectedObjects()`
`WorldWindow`	`getWwd()`
`protected Point`	`limitPointToWorldWindow(Point point)` Limits the specified point's x and y coordinates to the World Window's viewport, and returns a new point with the limited coordinates.
`void`	`mouseClicked(MouseEvent mouseEvent)`
`void`	`mouseDragged(MouseEvent mouseEvent)`
`void`	`mouseEntered(MouseEvent mouseEvent)`
`void`	`mouseExited(MouseEvent mouseEvent)`
`void`	`mouseMoved(MouseEvent mouseEvent)`
`void`	`mousePressed(MouseEvent mouseEvent)`
`void`	`mouseReleased(MouseEvent mouseEvent)`
`void`	`removeMessageListener(MessageListener listener)`
`void`	`selected(SelectEvent event)`
`protected void`	`selectionChanged(MouseEvent mouseEvent)`
`protected void`	`selectionEnded(MouseEvent mouseEvent)`
`protected void`	`selectionStarted(MouseEvent mouseEvent)`
`protected void`	`selectObjects(List<?> list)`
`protected void`	`sendMessage(Message message)`
`void`	`setBorderColor(Color color)`
`void`	`setInteriorColor(Color color)`

Methods inherited from class gov.nasa.worldwind.WWObjectImpl
onMessage, propertyChange

Methods inherited from class gov.nasa.worldwind.avlist.AVListImpl
addPropertyChangeListener, addPropertyChangeListener, clearList, copy, firePropertyChange, firePropertyChange, getBooleanValue, getBooleanValue, getChangeSupport, getDoubleValue, getDoubleValue, getEntries, getIntegerValue, getIntegerValue, getLongValue, getLongValue, getRestorableStateForAVPair, getStringValue, getStringValue, getStringValue, getValue, getValues, hasKey, removeKey, removePropertyChangeListener, removePropertyChangeListener, setValue, setValues

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface gov.nasa.worldwind.avlist.AVList
addPropertyChangeListener, addPropertyChangeListener, clearList, copy, firePropertyChange, firePropertyChange, getEntries, getStringValue, getValue, getValues, hasKey, removeKey, removePropertyChangeListener, removePropertyChangeListener, setValue, setValues

- Field Detail
  - armed
```
protected boolean armed
```
  - layer
```
protected Layer layer
```
  - messageListeners
```
protected List<MessageListener> messageListeners
```
  - selectedObjects
```
protected List<Object> selectedObjects
```
  - SELECTION_CHANGED
```
public static final String SELECTION_CHANGED
```
    Message type indicating that the list of selected objects has changed. This may be followed by one or more SELECTION_CHANGED events before the final SELECTION_ENDED event.
    
    See Also:
    
    Constant Field Values
  - SELECTION_ENDED
```
public static final String SELECTION_ENDED
```
    Message type indicating that the user has completed their selection. The ScreenSelector's list of selected objects does not changes until a subsequent SELECTION_STARTED event, if any.
    
    See Also:
    
    Constant Field Values
  - SELECTION_STARTED
```
public static final String SELECTION_STARTED
```
    Message type indicating that the user has started their selection. The ScreenSelector's list of selected objects is empty, and does not change until a subsequent SELECTION_CHANGED event, if any. If this is followed by a SELECTION_ENDED event without any SELECTION_CHANGED event in between, then the user has selected nothing.
    
    See Also:
    
    Constant Field Values
  - selectionRect
```
protected ScreenSelector.SelectionRectangle selectionRect
```
  - wwd
```
protected WorldWindow wwd
```
- Constructor Detail
  - ScreenSelector
```
public ScreenSelector(WorldWindow worldWindow)
```
- Method Detail
  - addMessageListener
```
public void addMessageListener(MessageListener listener)
```
  - createLayer
```
protected Layer createLayer()
```
  - createSelectionRectangle
```
protected ScreenSelector.SelectionRectangle createSelectionRectangle()
```
  - disable
```
public void disable()
```
  - enable
```
public void enable()
```
  - getBorderColor
```
public Color getBorderColor()
```
  - getInteriorColor
```
public Color getInteriorColor()
```
  - getLayer
```
public Layer getLayer()
```
  - getSelectedObjects
```
public List<?> getSelectedObjects()
```
  - getWwd
```
public WorldWindow getWwd()
```
  - limitPointToWorldWindow
```
protected Point limitPointToWorldWindow(Point point)
```
    Limits the specified point's x and y coordinates to the World Window's viewport, and returns a new point with the limited coordinates. For example, if the World Window's viewport rectangle is x=0, y=0, width=100, height=100 and the point's coordinates are x=50, y=200 this returns a new point with coordinates x=50, y=100. If the specified point is already inside the World Window's viewport, this returns a new point with the same x and y coordinates as the specified point.
    
    Parameters:
    
    point - the point to limit.
    
    Returns:
    
    a new Point representing the specified point limited to the World Window's viewport rectangle.
  - mouseClicked
```
public void mouseClicked(MouseEvent mouseEvent)
```
    Specified by:
    
    mouseClicked in interface MouseListener
  - mouseDragged
```
public void mouseDragged(MouseEvent mouseEvent)
```
    Specified by:
    
    mouseDragged in interface MouseMotionListener
  - mouseEntered
```
public void mouseEntered(MouseEvent mouseEvent)
```
    Specified by:
    
    mouseEntered in interface MouseListener
  - mouseExited
```
public void mouseExited(MouseEvent mouseEvent)
```
    Specified by:
    
    mouseExited in interface MouseListener
  - mouseMoved
```
public void mouseMoved(MouseEvent mouseEvent)
```
    Specified by:
    
    mouseMoved in interface MouseMotionListener
  - mousePressed
```
public void mousePressed(MouseEvent mouseEvent)
```
    Specified by:
    
    mousePressed in interface MouseListener
  - mouseReleased
```
public void mouseReleased(MouseEvent mouseEvent)
```
    Specified by:
    
    mouseReleased in interface MouseListener
  - removeMessageListener
```
public void removeMessageListener(MessageListener listener)
```
  - selected
```
public void selected(SelectEvent event)
```
    Specified by:
    
    selected in interface SelectListener
  - selectionChanged
```
protected void selectionChanged(MouseEvent mouseEvent)
```
  - selectionEnded
```
protected void selectionEnded(MouseEvent mouseEvent)
```
  - selectionStarted
```
protected void selectionStarted(MouseEvent mouseEvent)
```
  - selectObjects
```
protected void selectObjects(List<?> list)
```
  - sendMessage
```
protected void sendMessage(Message message)
```
  - setBorderColor
```
public void setBorderColor(Color color)
```
  - setInteriorColor
```
public void setInteriorColor(Color color)
```

Class ScreenSelector

Using ScreenSelector

User Input

Screen Rectangle Appearance

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class gov.nasa.worldwind.WWObjectImpl

Methods inherited from class gov.nasa.worldwind.avlist.AVListImpl

Methods inherited from class java.lang.Object

Methods inherited from interface gov.nasa.worldwind.avlist.AVList

Field Detail

armed

layer

messageListeners

selectedObjects

SELECTION_CHANGED

SELECTION_ENDED

SELECTION_STARTED

selectionRect

wwd

Constructor Detail

ScreenSelector

Method Detail

addMessageListener

createLayer

createSelectionRectangle

disable

enable

getBorderColor

getInteriorColor

getLayer

getSelectedObjects

getWwd

limitPointToWorldWindow

mouseClicked

mouseDragged

mouseEntered

mouseExited

mouseMoved

mousePressed

mouseReleased

removeMessageListener

selected

selectionChanged

selectionEnded

selectionStarted

selectObjects

sendMessage

setBorderColor

setInteriorColor