Class PlanarCanvas

Object

Observable

Canvas

PlanarCanvas

All Implemented Interfaces:

Localized

Direct Known Subclasses:

Map­Canvas

public abstract class PlanarCanvas
extends Canvas

A canvas for two-dimensional display device using a Cartesian coordinate system. Data are reduced to a two-dimensional slice before to be displayed.

Thread safety

Planar­Canvas is not thread-safe. A single thread should be used for interactions with all instances of Planar­Canvas that are linked together by Canvas­Follower or other listeners. External synchronization is generally not sufficient because listeners may create a graph of canvases, and it is difficult to ensure that a lock is kept during all the graph traversal.

Since:

1.1

Field Summary

Fields

Modifier and Type	Field	Description
protected static final int	BIDIMENSIONAL	The 2 constant for identifying code specific to bi-dimensional case.
protected final Affine­Transform	objective­To­Display	The conversion from objective CRS to the display coordinate system as a Java2D affine transform.

Fields inherited from class Canvas

DISPLAY_BOUNDS_PROPERTY, OBJECTIVE_CRS_PROPERTY, OBJECTIVE_TO_DISPLAY_PROPERTY, POINT_OF_INTEREST_PROPERTY

Modifier and Type	Field	Description
static final String	DISPLAY_BOUNDS_PROPERTY	The "displayBounds" property name, used for notifications about changes in bounds of display device.
static final String	OBJECTIVE_CRS_PROPERTY	The "objectiveCRS" property name, used for notifications about changes in objective CRS.
static final String	OBJECTIVE_TO_DISPLAY_PROPERTY	The "objectiveToDisplay" property name, used for notifications about changes in objective to display conversion.
static final String	POINT_OF_INTEREST_PROPERTY	The "pointOfInterest" property name, used for notifications about changes in point of interest.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	Planar­Canvas(Locale locale)	Creates a new two-dimensional canvas.

Method Summary

Modifier and Type	Method	Description
Envelope2D	get­Display­Bounds()	Returns the size and location of the display device.
void	transform­Display­Coordinates(Affine­Transform after)	Updates the objective to display transform as if the given transform was applied after the current transform.
void	transform­Objective­Coordinates(Affine­Transform before)	Updates the objective to display transform as if the given transform was applied before the current transform.

Methods inherited from class Canvas

get­Display­CRS, get­Geographic­Area, get­Grid­Geometry, get­Locale, get­Objective­CRS, get­Objective­To­Display, get­Point­Of­Interest, get­Spatial­Resolution, set­Display­Bounds, set­Grid­Geometry, set­Objective­CRS, set­Objective­To­Display, set­Point­Of­Interest

Modifier and Type	Method	Description
final Engineering­CRS	get­Display­CRS()	Returns the Coordinate Reference System of the display device.
Optional<Geographic­Bounding­Box>	get­Geographic­Area()	Returns the geographic bounding box encompassing the area shown on the display device.
Grid­Geometry	get­Grid­Geometry()	Returns canvas properties (CRS, display bounds, conversion) encapsulated in a grid geometry.
Locale	get­Locale()	Returns the locale used for texts or for producing some error messages.
Coordinate­Reference­System	get­Objective­CRS()	Returns the Coordinate Reference System in which all data are transformed before displaying.
Linear­Transform	get­Objective­To­Display()	Returns the (usually affine) conversion from objective CRS to display coordinate system.
Direct­Position	get­Point­Of­Interest(boolean objective)	Returns the coordinates of a point considered representative of the data.
Optional­Double	get­Spatial­Resolution()	Returns an estimation of the resolution (in metres) at the point of interest.
void	set­Display­Bounds(Envelope new­Value)	Sets the size and location of the display device.
void	set­Grid­Geometry(Grid­Geometry new­Value)	Sets canvas properties from the given grid geometry.
void	set­Objective­CRS(Coordinate­Reference­System new­Value, Direct­Position anchor)	Sets the Coordinate Reference System in which all data are transformed before displaying.
void	set­Objective­To­Display(Linear­Transform new­Value)	Sets the conversion from objective CRS to display coordinate system.
void	set­Point­Of­Interest(Direct­Position new­Value)	Sets the coordinates of a representative point inside the data bounding box.

Methods inherited from class Observable

add­Property­Change­Listener, fire­Property­Change, fire­Property­Change, has­Property­Change­Listener, remove­Property­Change­Listener

Modifier and Type	Method	Description
final void	add­Property­Change­Listener(String property­Name, Property­Change­Listener listener)	Registers a listener for the property of the given name.
protected void	fire­Property­Change(Property­Change­Event event)	Notifies all registered listeners that a property changed its value.
protected void	fire­Property­Change(String property­Name, Object old­Value, Object new­Value)	Notifies all registered listeners that a property of the given name changed its value.
protected final boolean	has­Property­Change­Listener(String property­Name)	Returns true if the given property has at least one listener.
final void	remove­Property­Change­Listener(String property­Name, Property­Change­Listener listener)	Unregisters a property listener.

Methods inherited from class Object

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

Field Details

BIDIMENSIONAL

protected static final int BIDIMENSIONAL

The 2 constant for identifying code specific to bi-dimensional case.

See Also:

• Constant Field Values

objectiveToDisplay

protected final AffineTransform objectiveToDisplay

The conversion from objective CRS to the display coordinate system as a Java2D affine transform. This transform will be modified in-place when user applies zoom, translation or rotation on the view area. Subclasses should generally not modify this affine transform directly; invoke one of the transformFooCoordinates(Affine­Transform) methods instead.

See Also:

• Canvas.get­Objective­To­Display()
• transform­Objective­Coordinates(Affine­Transform)
• transform­Display­Coordinates(Affine­Transform)

Constructor Details

PlanarCanvas

protected PlanarCanvas(Locale locale)

Creates a new two-dimensional canvas.

Parameters:

locale - the locale to use for labels and some messages, or null for default.

Method Details

getDisplayBounds

public Envelope2D getDisplayBounds()

Returns the size and location of the display device. The unit of measurement is Units.PIXEL and coordinate values are usually (but not necessarily) integers.

This value may be null on newly created Planar­Canvas, before data are added and canvas is configured. It should not be null anymore once a Planar­Canvas is ready for displaying.

The returned envelope is a copy: display changes happening after this method invocation will not be reflected in the returned envelope.

Overrides:

get­Display­Bounds in class Canvas

Returns:

size and location of the display device in pixel coordinates.

See Also:

• Canvas.set­Display­Bounds(Envelope)

transformObjectiveCoordinates

public void transformObjectiveCoordinates(AffineTransform before)

Updates the objective to display transform as if the given transform was applied before the current transform. For example if the given before transform is a translation, then the translation vector is in units of the objective CRS (typically metres on the map).

This method does nothing if the given transform is identity. Otherwise an "objectiveToDisplay" property change event will be sent with the Transform­Change­Event.Reason.OBJECTIVE_NAVIGATION reason after the change became effective. Depending on the implementation, the change may not take effect immediately. For example, subclasses may do the rendering in a background thread.

Parameters:

before - coordinate conversion to apply before the current objective to display transform.

See Also:

• Transform­Change­Event.get­Objective­Change()

transformDisplayCoordinates

public void transformDisplayCoordinates(AffineTransform after)

Updates the objective to display transform as if the given transform was applied after the current transform. For example if the given after transform is a translation, then the translation vector is in pixel units.

This method does nothing if the given transform is identity. Otherwise an "objectiveToDisplay" property change event will be sent with the Transform­Change­Event.Reason.DISPLAY_NAVIGATION reason after the change became effective. Depending on the implementation, the change may not take effect immediately. For example, subclasses may do the rendering in a background thread.

Parameters:

after - coordinate conversion to apply after the current objective to display transform.

See Also:

• Transform­Change­Event.get­Display­Change()