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.

Multi-threading

Planar­Canvas is not thread-safe. Synchronization, if desired, must be done by the caller. Another common strategy is to interact with Planar­Canvas from a single thread, for example the Swing or JavaFX event queue.
Since:
1.1

  • Field Details

  • 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 Canvas, before data are added and canvas is configured. It should not be null anymore once a Canvas 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:

    • 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:

    • 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: