Package org.geotools.renderer.label

Class LabelCacheImpl

Object
LabelCacheImpl
All Implemented Interfaces:
LabelCache
public class LabelCacheImpl extends Object implements LabelCache
Default LabelCache Implementation.

The label cache sports a number of features that are enabled depending on the programmatic configuration and the TextSymbolizer options.

The basic functionality of the label cache consist in finding the best label position for each Feature according to the TextSymbolizer specifications, and drawing it, provided it does not overlap with other labels.

This basic behaviour can be customised in a number of ways.

Priority

TextSymbolizer.getPriority() OGC Expression controls a label priority.

A label with high priority will be drawn before others, increasing its likeliness to appear on the screen

Author:
jeichar, dblasby, Andrea Aime - OpenGeo

  • Field Details

    • DISABLE_LETTER_LEVEL_CONFLICT

      public static boolean DISABLE_LETTER_LEVEL_CONFLICT

    • DEFAULT_PRIORITY

      public double DEFAULT_PRIORITY

    • DEFAULT_DISPLACEMENT_ANGLES

      public static final int[] DEFAULT_DISPLACEMENT_ANGLES

    • MIN_CURVED_DELTA

      public static double MIN_CURVED_DELTA
      The angle delta at which we switch from curved rendering to straight rendering

    • groupedLabelsLookup

      protected Map<LabelCacheItem,LabelCacheItem> groupedLabelsLookup
      Used to locate grouped labels quickly

    • labelCache

      protected ArrayList<LabelCacheItem> labelCache
      labels get thrown in here, in insertion order

    • labelRenderingMode

      protected LabelCacheImpl.LabelRenderingMode labelRenderingMode

    • styleFactory

      protected SLDStyleFactory styleFactory

  • Constructor Details

    • LabelCacheImpl

      public LabelCacheImpl()

  • Method Details

    • enableLayer

      public void enableLayer(String layerId)
      Description copied from interface: LabelCache
      Enable a layer after being disabled. If startLayer is called this does not need to be called as start layer implicitely activates the layer.
      Specified by:
      enableLayer in interface LabelCache
      Parameters:
      layerId - layer to activate.

    • getLabelRenderingMode

      public LabelCacheImpl.LabelRenderingMode getLabelRenderingMode()

    • setLabelRenderingMode

      public void setLabelRenderingMode(LabelCacheImpl.LabelRenderingMode mode)
      Sets the text rendering mode.

    • setConstructPainter

      public void setConstructPainter(BiFunction<Graphics2D,LabelCacheImpl.LabelRenderingMode,LabelPainter> constructPainter)
      Change the method used to construct LabelPainters. Defaults to LabelPainter(java.awt.Graphics2D, org.geotools.renderer.label.LabelCacheImpl.LabelRenderingMode).

    • stop

      public void stop()
      Description copied from interface: LabelCache
      Tells the cache to stop labelling.
      Specified by:
      stop in interface LabelCache

    • start

      public void start()
      Description copied from interface: LabelCache
      Called by renderer to indicate that the rendering process is starting.
      Specified by:
      start in interface LabelCache
      See Also:

    • clear

      public void clear()
      Description copied from interface: LabelCache
      Clears the cache completely
      Specified by:
      clear in interface LabelCache

    • clear

      public void clear(String layerId)
      Description copied from interface: LabelCache
      Clears the cache of all information relating to the layer identified.
      Specified by:
      clear in interface LabelCache
      Parameters:
      layerId - id of the layer

    • disableLayer

      public void disableLayer(String layerId)
      Description copied from interface: LabelCache
      Leaves the label information in the cache but ignores it when calculating what labels are drawn.
      Specified by:
      disableLayer in interface LabelCache
      Parameters:
      layerId - id of the layer to disable.

    • startLayer

      public void startLayer(String layerId)
      Description copied from interface: LabelCache
      Called by renderer to indication the start of rendering a layer. Will add the layer to the set of active layers.
      Specified by:
      startLayer in interface LabelCache
      Parameters:
      layerId - an id for the layer
      See Also:

    • getPriority

      public double getPriority(TextSymbolizer symbolizer, Feature feature)
      get the priority from the symbolizer its an expression, so it will try to evaluate it: 1. if its missing --> DEFAULT_PRIORITY 2. if its a number, return that number 3. if its not a number, convert to string and try to parse the number; return the number 4. otherwise, return DEFAULT_PRIORITY

    • put

      public void put(String layerId, TextSymbolizer symbolizer, Feature feature, LiteShape2 shape, NumberRange scaleRange)
      Description copied from interface: LabelCache
      Puts a Label in the cache.
      Specified by:
      put in interface LabelCache
      Parameters:
      layerId - id indicating the layer the feature is part of
      symbolizer - The symbolizer containing the style information
      feature - the feature that has the information required for the symbolizer to calculate the required render information.
      shape - the shape to be labeled. This is in screen coordinates.
      scaleRange - the scaleRange that the symbolizer is legal
      See Also:

    • put

      public void put(Rectangle2D area)
      Description copied from interface: LabelCache
      Reserve the provided geometry prior to sorting out where labels can go.

      This facility is used to reserve an area so that labels do not end up overlapping on screen constructs like scalebars or north arrows etc...

      Specified by:
      put in interface LabelCache
      Parameters:
      area - The Area of the screen to reserve (in screen coordinates)

    • endLayer

      public void endLayer(String layerId, Graphics2D graphics, Rectangle displayArea)
      Description copied from interface: LabelCache
      Called to indicate that a layer is done rendering. The method may draw labels if appropriate for the labeling algorithm
      Specified by:
      endLayer in interface LabelCache
      Parameters:
      layerId - an id for the layer
      graphics - the graphics to draw on.
      displayArea - The size of the display area
      See Also:

    • orderedLabels

      public List<LabelCacheItem> orderedLabels()
      Return a list with all the values in priority order. Both grouped and non-grouped
      Specified by:
      orderedLabels in interface LabelCache
      Returns:
      list with all values in priority order

    • getActiveLabels

      public List<LabelCacheItem> getActiveLabels()
      Returns a list of all active labels

    • end

      public void end(Graphics2D graphics, Rectangle displayArea)
      Description copied from interface: LabelCache
      Called to indicate that the map is done rendering. The method may draw labels if appropriate for the labeling algorithm
      Specified by:
      end in interface LabelCache
      Parameters:
      graphics - the graphics to draw on.
      displayArea - The size of the display area.
      See Also:

    • clipLineString

      public MultiLineString clipLineString(LineString line)
      try to be more robust dont bother returning points

      This will try to solve robustness problems, but read code as to what it does. It might return the unclipped line if there's a problem!

    • clipPolygon

      public MultiPolygon clipPolygon(Polygon poly, Polygon bbox, Envelope displayGeomEnv)
      try to do a more robust way of clipping a polygon to a bounding box. This might return the orginal polygon if it cannot clip TODO: this is a bit simplistic, there's lots more to do.
      Returns:
      a MutliPolygon

    • processNodes

      public List<LineString> processNodes(List<LineString> edges, Map<Coordinate,List<LineString>> nodes)
      pull a line from the list, and: 1. if nothing connects to it (its issolated), add it to "result" 2. otherwise, merge it at the start/end with the LONGEST line there. 3. remove the original line, and the lines it merged with from the hashtables 4. go again, with the merged line

    • removeFromHash

      public void removeFromHash(Map<Coordinate,List<LineString>> nodes, LineString ls)

    • addRenderListener

      public void addRenderListener(RenderListener listener)
      adds a listener that responds to error events of feature rendered events.
      Parameters:
      listener - the listener to add.
      See Also: