Class MapCanvas.StaticGraphics

Object

StaticGraphics

Enclosing class:

Map­Canvas

public static class MapCanvas.StaticGraphics
extends Object

JavaFX nodes rendered using a snapshot of the objective to display transform. This object provides a way to show shapes more easily than adding them as floating­Pane children, but at the expanse of quality. This object is easier to use because it allows to ignore the dynamic nature of the transform managed by the enclosing canvas. Instead, users can add shapes with coordinate values computed with a snapshot of the transform at the time when this instance is obtained, then ignore all changes in the enclosing canvas that may happen afterward.

While this object allows a much easier strategy than adding shapes into floating­Pane and tracking objective to display changes, the result is rougher (especially after zooms). For this reason, this object should be used for short-lived shapes such as animation effects, when the high-quality strategy is not worth the effort. The nodes added through this object may disappear at any time, for example after a change of objective CRS.

Since:

1.7

Field Summary

Fields

Modifier and Type	Field	Description
final Coordinate­Reference­System	objective­CRS	The CRS which is the source of the objective to display transform.
final Linear­Transform	objective­To­Display	The (usually affine) conversion from objective CRS to display coordinate system.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	Static­Graphics(Map­Canvas canvas)	Creates a snapshot of the objective to display transform from the given canvas.

Method Summary

Modifier and Type	Method	Description
Observable­List<Node>	get­Children()	Returns children to show with coordinates computed from the objective to display snapshot.
protected Map­Canvas.Static­Graphics	unique()	Returns a unique instance of this snapshot.

Methods inherited from class Object

clone, equals, finalize, get­Class, hash­Code, notify, notify­All, to­String, wait, wait, wait

Field Details

objectiveCRS

public final CoordinateReferenceSystem objectiveCRS

The CRS which is the source of the objective to display transform. This is the value of Canvas.get­Objective­CRS() at the time when this Static­Graphics instance has been obtained. May be null if the snapshot was created before Canvas was initialized with data.

See Also:

• Canvas.get­Objective­CRS()

objectiveToDisplay

public final LinearTransform objectiveToDisplay

The (usually affine) conversion from objective CRS to display coordinate system. This is the value of Canvas.get­Objective­To­Display() at the time when this Static­Graphics instance has been obtained. This is never null.

See Also:

• Canvas.get­Objective­To­Display()

Constructor Details

StaticGraphics

protected StaticGraphics(MapCanvas canvas)

Creates a snapshot of the objective to display transform from the given canvas. This constructor is made available for Map­Canvas subclasses wanting to override their Map­Canvas.using­Fixed­Transform() method. This constructor should be used in a code equivalent to the following snippet:

@Override
public StaticGraphics usingFixedTransform() {
    return new MySubclass(this).unique();
}

Parameters:

canvas - the enclosing canvas.

See Also:

• Map­Canvas.using­Fixed­Transform()

Method Details

unique

protected MapCanvas.StaticGraphics unique()

Returns a unique instance of this snapshot. If the canvas specified at construction time already contains an Static­Graphics of the same class as this and with equal objective­CRS and objective­To­Display transform, then that snapshot is returned and this should be discarded. Otherwise, this method returns this.

Returns:

a unique instance of this snapshot.

getChildren

public ObservableList<Node> getChildren()

Returns children to show with coordinates computed from the objective to display snapshot. The shapes added in the children list should use an animation effect such as Fade­Transition and be removed from the list after a few seconds. This method shall be invoked from the JavaFX thread.

Returns:

children to show using the objective to display snapshot.