Package com.luciad.layers.features

Class FeatureCanvas.LabelDrawCommand

java.lang.Object
com.luciad.layers.features.FeatureCanvas.LabelDrawCommand
All Implemented Interfaces:
AutoCloseable
Enclosing class:
FeatureCanvas
public static final class FeatureCanvas.LabelDrawCommand extends Object implements AutoCloseable
Command to draw labels for a feature.

It is mandatory to specify at least the following:

Label content
The label content can be

It is mandatory to call at least one of these methods. If not, an exception will be thrown when submitting this label draw command. If these methods are called multiple times, only the last one is used.

Label positions
It is possible to explicitly specify a label position. This can be done using one of the following methods:
  • the pointPositions method: to anchor a label to a Point geometry
  • the onPath method: to place a label along a line
  • the inPath method: to place a label inside an area

If these methods are called multiple times, only the last one is used. If none of these methods is called, a default label positions is chosen using the LabelDrawCommand#anchor geometry.

Label decluttering
Labels that are added using this class are automatically decluttered:
  • Multiple label locations are tried to avoid overlapping labels
  • Labels for which no good location can be found (i.e. that would always overlap with an other label) are dropped.

See the related guide for a more extensive overview of the labeling API.

  • Method Details

    • finalize

      protected void finalize()
      Overrides:
      finalize in class Object

    • close

      public void close()
      Specified by:
      close in interface AutoCloseable

    • text

      @NotNull public FeatureCanvas.LabelDrawCommand text(@NotNull String text)
      Sets the text to use for the label.

      This property is optional, though it is mandatory that at least one method is used to specify the label content. See the class documentation for more info.

      Parameters:
      text - the text to use for the label.
      Returns:
      this

    • text

      @NotNull public FeatureCanvas.LabelDrawCommand text(@NotNull TextBlock text)
      Sets the text block to use for the label.

      A text block is composed of multiple texts with different styling each. See TextBlock and TextBlock.Builder.

      This property is optional, though it is mandatory that at least one method is used to specify the label content. See the class documentation for more info.

      Parameters:
      text - the text block to use for the label.
      Returns:
      this

    • text

      @NotNull public FeatureCanvas.LabelDrawCommand text(@NotNull List<@NotNull String> text, @NotNull HorizontalAlignment alignment)
      Sets the text to use for the label.

      Each string in this vector is rendered as a separate line.

      This property is optional, though it is mandatory that at least one method is used to specify the label content. See the class documentation for more info.

      Parameters:
      text - the text to use for the label.
      alignment - side where text is aligned. By default text is aligned on the left.
      Returns:
      this

    • text

      @NotNull public FeatureCanvas.LabelDrawCommand text(@NotNull List<@NotNull String> text)
      Sets the text to use for the label.

      Each string in this vector is rendered as a separate line.

      This property is optional, though it is mandatory that at least one method is used to specify the label content. See the class documentation for more info.

      Parameters:
      text - the text to use for the label.
      Returns:
      this

    • textStyle

      @NotNull public FeatureCanvas.LabelDrawCommand textStyle(@NotNull TextStyle textStyle)
      Sets the styling for the text.

      This property is optional. See the text style builder for the default values.

      Parameters:
      textStyle - the styling for the text.
      Returns:
      this

    • pinStyle

      @NotNull public FeatureCanvas.LabelDrawCommand pinStyle(@NotNull PinStyle pinStyle)
      This method enables pins for labels and defines their styling.

      By default, there's no pin for labels.

      Pins are only supported when a label is attached to a point. No pin will be painted when onPath or inPath label positioning is used.

      Parameters:
      pinStyle - the styling for the pin. See PinStyle#newBuilder. This property is optional. By default, there's no pin for labels.
      Returns:
      this

    • icon

      @NotNull public FeatureCanvas.LabelDrawCommand icon(@NotNull IIcon icon) throws NullPointerException
      Sets the icon to use for the label.

      This property is optional, though it is mandatory that at least one method is used to specify the label content. See the class documentation for more info.

      Parameters:
      icon - the icon to use for the label, cannot be null
      Returns:
      this
      Throws:
      NullPointerException - when the icon is null.

    • anchor

      @NotNull public FeatureCanvas.LabelDrawCommand anchor(@NotNull Geometry anchor) throws NullPointerException
      Sets the anchor of the label.

      This property is mandatory.

      Parameters:
      anchor - the anchor of the label, cannot be null.
      Returns:
      this
      Throws:
      NullPointerException - if the anchor is null.

    • anchorDraped

      @NotNull public FeatureCanvas.LabelDrawCommand anchorDraped(boolean draped)
      Specify whether the anchor is draped or not.

      If this method is not invoked, the draping status will be the same as when rendering the anchor: if all Z components equal to 0, draping is enabled and the label will be on the ground. Otherwise, the label will be placed at anchor elevation.

      Parameters:
      draped - whether the anchor is draped or not.
      Returns:
      this

    • priority

      @NotNull public FeatureCanvas.LabelDrawCommand priority(@NotNull Priority priority)
      Sets the priority that is used to determine the order in which labels are placed.

      • Using a high priority will make it more likely for a label to be placed.
      • Using a low priority will make it more likely for the label to be omitted during label placement, because other labels with a higher priority may already occupy its space.

      Label priorities work across layers. This means that it is possible to give a high priority to a label, regardless of where the layer is located in the Map's LayerList.

      This property is optional. The default is Priority#normal().

      Parameters:
      priority - the priority for this label
      Returns:
      this

    • pointPositions

      @NotNull public FeatureCanvas.LabelDrawCommand pointPositions(@NotNull List<@NotNull RelativePosition> positions) throws IllegalArgumentException
      Specifies the possible positions to place a Point label.

      If the anchor is not a point geometry, an exception is thrown in the submit method.

      Calling this method is optional. See LabelDrawCommand for more information.

      Parameters:
      positions - the possible positions for a point label. If empty, an exception is thrown.
      Returns:
      this LabelDrawCommand
      Throws:
      IllegalArgumentException - if the list of positions is empty.

    • inPath

      @NotNull public FeatureCanvas.LabelDrawCommand inPath()
      Configure the LabelDrawCommand to paint the label inside the anchor.

      The anchor is used as follows:

      • The anchor must be a closed ring or a surface, or contain one. If it's not the case, an exception is thrown in the submit method.
      • If the anchor is a multi geometry, only the biggest one is considered.
      • If the anchor is an extruded one, the base geometry is considered.
      • If the anchor is a Patch, the base geometry is considered.
      • For other geometries, the label is positioned in such a way that it's inside the anchor geometry.

      Calling this method is optional. See LabelDrawCommand for more information.

      Returns:
      this LabelDrawCommand

    • queryable

      @NotNull public FeatureCanvas.LabelDrawCommand queryable(boolean queryable)
      Indicates whether or not the label should be considered when a Map#queryFeatures is requested.

      The default is true.

      Parameters:
      queryable - true if the label should be considered.
      Returns:
      this TextDrawCommand.

    • onPath

      @NotNull public FeatureCanvas.LabelDrawCommand onPath(@NotNull PathLabelPosition verticalPosition, double additionalVerticalOffset)
      Configure the LabelDrawCommand to position a single label along a line.

      The label will also be placed within the view extent if possible.

      When this method is called, the anchor must be a Curve or consist of one in case of:

      Also Bounds geometries are supported.

      If an anchor is specified that is not supported by this labeling method, an exception will be thrown when the label command is submitted.

      Calling this method is optional. See LabelDrawCommand for more information.

      Parameters:
      verticalPosition - specifies where the label is placed wrt to a position on the line.
      additionalVerticalOffset - an additional perpendicular offset from the position on the line at which a label will be placed. This offset is expressed in pixels. If the value is positive, the label position is moved away from the line. If the value is negative, the label positions is moved towards the line. There is no maximum limit to the negative values, but keep in mind that large negative values will push the label to the opposite side of the line. The default offset is 0.
      Returns:
      this LabelDrawCommand

    • onPath

      @NotNull public FeatureCanvas.LabelDrawCommand onPath(@NotNull OnPathLabelStyle onPathLabelStyle)
      Configure the LabelDrawCommand to position a single label along a line.

      Depending on how the given OnPathLabelStyle is configured, it can be located

      • somewhere along the line, but also within the view extent
      • at a specific location along the line, for example exactly in the middle

      When this method is called, the anchor must be a Curve.

      If an anchor is specified that is not supported by this labeling method, an exception will be thrown when the label command is submitted.

      Calling this method is optional. See LabelDrawCommand for more information.

      Parameters:
      onPathLabelStyle - specifies all parameters needed to place the label at a specific location along the line, cannot be null.
      Returns:
      this LabelDrawCommand

    • labelGroup

      @NotNull public FeatureCanvas.LabelDrawCommand labelGroup(@NotNull LabelGroup labelGroup)
      Set the LabelGroup for label decluttering.

      A label declutter group is a collection of labels that are positioned independently from other label declutter groups. I.e. labels from one group will never affect labels from other groups. This also means that labels from different groups are allowed to overlap.

      Parameters:
      labelGroup - declutter group for this label. See LabelGroup for more information.
      Returns:
      this LabelDrawCommand

    • submit

      public void submit() throws IllegalStateException
      Submits this draw command.

      Nothing will be painted if the draw command is not submitted.

      Throws:
      IllegalStateException - if anchor is not a Point and the pointPositions method is used.