Package org.geotools.renderer.lite

Interface LabelCache

  • All Known Implementing Classes:
    LabelCacheImpl, SynchronizedLabelCache
    public interface LabelCache
    Used to cache labels prior to their being drawn on the screen.

    Implementations exisit with different trade offs about what labels can fit where.

    Since:
    2.2
    Author:
    jeichar

    • Method Summary

      All Methods Instance Methods Abstract Methods 
      Modifier and Type Method Description
      void clear()
      Clears the cache completely
      void clear​(String layerId)
      Clears the cache of all information relating to the layer identified.
      void disableLayer​(String layerId)
      Leaves the label information in the cache but ignores it when calculating what labels are drawn.
      void enableLayer​(String layerId)
      Enable a layer after being disabled.
      void end​(Graphics2D graphics, Rectangle displayArea)
      Called to indicate that the map is done rendering.
      void endLayer​(String layerId, Graphics2D graphics, Rectangle displayArea)
      Called to indicate that a layer is done rendering.
      List orderedLabels()
      Return a list with all the values in priority order.
      void put​(Rectangle2D geometry)
      Reserve the provided geometry prior to sorting out where labels can go.
      void put​(String layerId, TextSymbolizer symbolizer, Feature feature, LiteShape2 shape, NumberRange<Double> scaleRange)
      Puts a Label in the cache.
      void start()
      Called by renderer to indicate that the rendering process is starting.
      void startLayer​(String layerId)
      Called by renderer to indication the start of rendering a layer.
      void stop()
      Tells the cache to stop labelling.

    • Method Detail

      • start

        void start()
        Called by renderer to indicate that the rendering process is starting.

      • startLayer

        void startLayer​(String layerId)
        Called by renderer to indication the start of rendering a layer. Will add the layer to the set of active layers.
        Parameters:
        layerId - an id for the layer

      • put

        void put​(String layerId,
         TextSymbolizer symbolizer,
         Feature feature,
         LiteShape2 shape,
         NumberRange<Double> scaleRange)
        Puts a Label in the cache.
        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

      • put

        void put​(Rectangle2D geometry)
        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...

        Parameters:
        geometry - The Area of the screen to reserve (in screen coordinates)

      • endLayer

        void endLayer​(String layerId,
              Graphics2D graphics,
              Rectangle displayArea)
        Called to indicate that a layer is done rendering. The method may draw labels if appropriate for the labeling algorithm
        Parameters:
        graphics - the graphics to draw on.
        displayArea - The size of the display area
        layerId - an id for the layer

      • end

        void end​(Graphics2D graphics,
         Rectangle displayArea)
        Called to indicate that the map is done rendering. The method may draw labels if appropriate for the labeling algorithm
        Parameters:
        graphics - the graphics to draw on.
        displayArea - The size of the display area.

      • stop

        void stop()
        Tells the cache to stop labelling.

      • clear

        void clear()
        Clears the cache completely

      • clear

        void clear​(String layerId)
        Clears the cache of all information relating to the layer identified.
        Parameters:
        layerId - id of the layer

      • disableLayer

        void disableLayer​(String layerId)
        Leaves the label information in the cache but ignores it when calculating what labels are drawn.
        Parameters:
        layerId - id of the layer to disable.

      • enableLayer

        void enableLayer​(String layerId)
        Enable a layer after being disabled. If startLayer is called this does not need to be called as start layer implicitely activates the layer.
        Parameters:
        layerId - layer to activate.

      • orderedLabels

        List orderedLabels()
        Return a list with all the values in priority order. Both grouped and non-grouped
        Returns:
        list with all values in priority order