Package com.luciad.view.lightspeed.label.algorithm

Class TLspFixedOnPathLabelLocationProvider

java.lang.Object
com.luciad.view.lightspeed.label.algorithm.ALspLabelLocationProvider
com.luciad.view.lightspeed.label.algorithm.TLspFixedOnPathLabelLocationProvider
public class TLspFixedOnPathLabelLocationProvider extends ALspLabelLocationProvider

This label location provider positions points on a specific location on a line. This algorithm works for all shapes that implement ILcdCurve. To retrieve this curve, the anchor object of a label is used.

When the anchor object of the label is a composite shape, like an ILcdShapeList or ILcdComplexPolygon, this label location provider first tries to find the largest sub-shape and then finds a location for this sub-shape.

This label location provider only calculates a single label location. So if this label overlaps with an other label, no alternative locations are available. If this functionality is needed, it can be done by creating a composite TLspFixedOnPathLabelLocationProvider.

Unlike TLspOnPathLabelingAlgorithm, this label location provider doesn't try to keep the label inside the view. When navigating away from the label location, no label location within the view bounds is calculated. Because of this, this labeling location provider works more efficiently CPU-wise. On top of that, this label location provider works by specifying a specific location on the line.

The used label painter must be an ILspStampLocationLabelPainter. If not, the label will not be placed. The placed label location will be a ALspStampLabelLocation.

To use this label location provider to create a labeling algorithm, the following code can be used:


 TLspFixedOnPathLabelLocationProvider provider = new TLspFixedOnPathLabelLocationProvider();
 TLspLabelingAlgorithm algorithm = new TLspLabelingAlgorithm(provider);
Since:
2016.0

  • Constructor Details

    • TLspFixedOnPathLabelLocationProvider

      public TLspFixedOnPathLabelLocationProvider(double aRelativeLocation, TLspFixedOnPathLabelLocationProvider.VerticalAlignment aVerticalAlignment, TLspFixedOnPathLabelLocationProvider.HorizontalAlignment aHorizontalAlignment, double aVerticalOffset, double aHorizontalOffset)
      Creates a new TLspFixedOnPathLabelLocationProvider.
      Parameters:
      aRelativeLocation - the location of the label, relative on the line. Values should lie in the interval [0, 1]. If not, an IllegalArgumentException is thrown.
      aVerticalAlignment - the alignment of the label perpendicular to the line
      aHorizontalAlignment - the alignment of the label with respect to the location on the line (parallel to the line):
      aVerticalOffset - vertical space between the location on the line and the label in pixels
      aHorizontalOffset - horizontal space between the location and the label in pixels

  • Method Details

    • isAllowUpsideDown

      public boolean isAllowUpsideDown()
      Returns if it is allowed for this location provider to place labels upside down.
      Returns:
      if it is allowed for this location provider to place labels upside down.
      Since:
      2022.0
      See Also:

    • setAllowUpsideDown

      public void setAllowUpsideDown(boolean aAllowUpsideDown)
      Sets if it is allowed for this location provider to place labels upside down. If set to true, there is no restriction on the rotation of the labels. If set to false, labels that are rotated upside down are rotated 180 degrees around their center. In this context, upside down means that the rotation of the label lies between 90 and 270 degrees, assuming that 0 degrees lies at 3 'o clock.

      The default value is false.

      Parameters:
      aAllowUpsideDown - true to allow labels being painted upside done, and false otherwise.
      Since:
      2022.0
      See Also:

    • getMaxLocationCount

      public int getMaxLocationCount(TLspLabelID aLabel, TLspPaintState aPaintState, ILspLabelingAlgorithm.LabelContext aLabelContext, ILspView aView)
      Description copied from class: ALspLabelLocationProvider
      Returns the maximal number of locations to be tried for the given label. Override this method to return a custom number of locations. When overriding this method, one should also make sure that the getLocation method can create the same number of locations as returned by this method. By default, this method returns 1.
      Overrides:
      getMaxLocationCount in class ALspLabelLocationProvider
      Parameters:
      aLabel - the label.
      aPaintState - the paint state.
      aLabelContext - provides context information, such as priorities, PaintState, ...
      aView - the view.
      Returns:
      the maximal number of locations to be tried.

    • isValidLocation

      public boolean isValidLocation(TLspLabelPlacement aLocation, ALspLabelLocations aCurrentLabelLocations, TLspPaintState aPaintState, ILspLabelingAlgorithm.LabelContext aLabelContext, ILspView aView)
      Description copied from class: ALspLabelLocationProvider
      Checks if the given location is a valid location. This check should be used if this label location provider is capable of producing the given location. Labeling algorithms may use this method for previous label locations. I.e. when using a previous label locations, this method can be used to verify if the previous label location can be used.

      By default, this method returns true.

      Overrides:
      isValidLocation in class ALspLabelLocationProvider
      Parameters:
      aLocation - the location to check.
      aCurrentLabelLocations - an ALspLabelLocations object containing locations for the currently placed labels.
      aPaintState - the paint state.
      aLabelContext - provides context information, such as priorities, PaintState, ...
      aView - the view.
      Returns:
      if the given location is a valid location.

    • getLocation

      public TLspLabelPlacement getLocation(TLspLabelID aLabel, int aLocationIndex, ALspLabelLocations aCurrentLabelLocations, TLspPaintState aPaintState, ILspLabelingAlgorithm.LabelContext aLabelContext, ILspView aView)
      Description copied from class: ALspLabelLocationProvider
      This method returns a location for the given label using the given location index. Override this method to create custom locations for a label.
      Specified by:
      getLocation in class ALspLabelLocationProvider
      Parameters:
      aLabel - a label.
      aLocationIndex - the location index.
      aCurrentLabelLocations - an ALspLabelLocations object containing locations for the currently placed labels.
      aPaintState - the paint state
      aLabelContext - provides context information, such as priorities, PaintState, ...
      aView - the view.
      Returns:
      the label location for the given label and index, or null if no location could be calculated.

    • toString

      public String toString()
      Overrides:
      toString in class Object