Package org.geotools.renderer.lite

Class StreamingRenderer

Object
StreamingRenderer
All Implemented Interfaces:
GTRenderer
public class StreamingRenderer extends Object implements GTRenderer
A streaming implementation of the GTRenderer interface.
  • Uses as little memory as possible by processing features as they come from the data source, instead of accumulating them up-front
Use this class if you need a stateless renderer that provides low memory footprint and decent rendering performance on the first call but don't need good optimal performance on subsequent calls on the same data.

The streaming renderer is not thread safe

Author:
James Macgill, dblasby, jessie eichar, Simone Giannecchini, Andrea Aime, Alessio Fabiani

  • Field Details

    • SCALE_ACCURATE

      public static final String SCALE_ACCURATE
      Computes the scale as the ratio between map distances and real world distances, assuming 90dpi and taking into consideration projection deformations and actual earth shape.
      Use this method only when in need of accurate computation. Will break if the data extent is outside of the currenct projection definition area.
      See Also:

    • SCALE_OGC

      public static final String SCALE_OGC
      Very simple and lenient scale computation method that conforms to the OGC SLD specification 1.0, page 26.
      This method is quite approximative, but should never break and ensure constant scale even on lat/lon unprojected maps (because in that case scale is computed as if the area was along the equator no matter what the real position is).
      See Also:

    • RENDERING_BUFFER

      public static final String RENDERING_BUFFER
      The rendering buffer grows the query area to account for features that are contributing to the requested area due to their large symbolizer, or long label
      See Also:

    • filterFactory

      protected static final FilterFactory filterFactory
      Filter factory for creating bounding box filters

    • STYLE_FACTORY

      protected static final StyleFactory STYLE_FACTORY

    • scaleDenominator

      protected double scaleDenominator
      The ratio required to scale the features to be rendered so that they fit into the output space.

    • labelCache

      protected LabelCache labelCache

    • painter

      protected StyledShapePainter painter
      The painter class we use to depict shapes onto the screen

    • TEXT_RENDERING_STRING

      public static final String TEXT_RENDERING_STRING
      Text will be rendered using the usual calls gc.drawString/drawGlyphVector. This is a little faster, and more consistent with how the platform renders the text in other applications. The downside is that on most platform the label and its eventual halo are not properly centered.

    • TEXT_RENDERING_OUTLINE

      public static final String TEXT_RENDERING_OUTLINE
      Text will be rendered using the associated GlyphVector outline, that is, a Shape. This ensures perfect centering between the text and the halo, but introduces more text aliasing.

    • TEXT_RENDERING_ADAPTIVE

      public static final String TEXT_RENDERING_ADAPTIVE
      Will use STRING mode for horizontal labels, OUTLINE mode for all other labels. Works best when coupled with RenderingHints.VALUE_FRACTIONALMETRICS_ON

    • TEXT_RENDERING_KEY

      public static final String TEXT_RENDERING_KEY
      The text rendering method, either TEXT_RENDERING_OUTLINE or TEXT_RENDERING_STRING
      See Also:

    • LINE_WIDTH_OPTIMIZATION_KEY

      public static final String LINE_WIDTH_OPTIMIZATION_KEY
      Whether the thin line width optimization should be used, or not.

      When rendering non antialiased lines adopting a width of 0 makes the java2d renderer get into a fast path that generates the same output as a 1 pixel wide line

      Unfortunately for antialiased rendering that optimization does not help, and disallows controlling the width of thin lines. It is provided as an explicit option as the optimization has been hard coded for years, removing it when antialiasing is on by default will invalidate lots of existing styles (making lines appear thicker).

      See Also:

    • OPTIMIZE_FTS_RENDERING_KEY

      public static final String OPTIMIZE_FTS_RENDERING_KEY
      Boolean flag controlling a memory/speed trade off related to how multiple feature type styles are rendered.

      When enabled (by default) multiple feature type styles against the same data source will be rendered in separate memory back buffers in a way that allows the source to be scanned only once (each back buffer is as big as the image being rendered).

      When disabled no memory back buffers will be used but the feature source will be scanned once for every feature type style declared against it

      See Also:

    • ADVANCED_PROJECTION_HANDLING_KEY

      public static final String ADVANCED_PROJECTION_HANDLING_KEY
      Enables advanced reprojection handling. Geometries will be sliced to fit into the area of definition of the rendering projection.
      See Also:

    • CONTINUOUS_MAP_WRAPPING

      public static final String CONTINUOUS_MAP_WRAPPING
      Enabled continuous cartographic wrapping for projections that can wrap around their edges (e.g., Mercator): this results in a continous horizontal map much like Google Maps
      See Also:

    • VECTOR_RENDERING_KEY

      public static final String VECTOR_RENDERING_KEY
      Boolean flag indicating whether vector rendering should be preferred when painting graphic fills. See SLDStyleFactory.isVectorRenderingEnabled() for more details.
      See Also:

    • ADVANCED_PROJECTION_DENSIFICATION_KEY

      public static final String ADVANCED_PROJECTION_DENSIFICATION_KEY
      Boolean flag indicating whether advanced projection densification should be used when needed.
      See Also:

    • ADVANCED_PROJECTION_DENSIFICATION_TOLERANCE_KEY

      public static final String ADVANCED_PROJECTION_DENSIFICATION_TOLERANCE_KEY
      Densification Tolerance, to be used when densification is enabled.
      See Also:

    • DATELINE_WRAPPING_HEURISTIC_KEY

      public static final String DATELINE_WRAPPING_HEURISTIC_KEY
      Boolean flag indicating whether advanced projection wrapping heuristic should be used or nto.
      See Also:

    • LABEL_CACHE_KEY

      public static final String LABEL_CACHE_KEY
      See Also:

    • FORCE_EPSG_AXIS_ORDER_KEY

      public static final String FORCE_EPSG_AXIS_ORDER_KEY
      See Also:

    • DPI_KEY

      public static final String DPI_KEY
      See Also:

    • DECLARED_SCALE_DENOM_KEY

      public static final String DECLARED_SCALE_DENOM_KEY
      See Also:

    • SCALE_COMPUTATION_METHOD_KEY

      public static final String SCALE_COMPUTATION_METHOD_KEY
      See Also:

    • BYLAYER_INTERPOLATION

      public static final String BYLAYER_INTERPOLATION
      See Also:

  • Constructor Details

    • StreamingRenderer

      public StreamingRenderer()
      Creates a new instance of LiteRenderer without a context. Use it only to gain access to utility methods of this class or if you want to render random feature collections instead of using the map context interface

  • Method Details

    • setThreadPool

      public void setThreadPool(ExecutorService threadPool)
      Sets a thread pool to be used in parallel rendering

    • setConcatTransforms

      public void setConcatTransforms(boolean flag)
      Sets the flag which controls behaviour for applying affine transformation to the graphics object.
      Parameters:
      flag - If true then the transform will be concatenated to the existing transform. If false it will be replaced.

    • getConcatTransforms

      public boolean getConcatTransforms()
      Flag which controls behaviour for applying affine transformation to the graphics object.
      Returns:
      a boolean flag. If true then the transform will be concatenated to the existing transform. If false it will be replaced.

    • addRenderListener

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

    • removeRenderListener

      public void removeRenderListener(RenderListener listener)
      Removes a render listener.
      Specified by:
      removeRenderListener in interface GTRenderer
      Parameters:
      listener - the listener to remove.
      See Also:

    • stopRendering

      public void stopRendering()
      If you call this method from another thread than the one that called paint or render the rendering will be forcefully stopped before termination
      Specified by:
      stopRendering in interface GTRenderer

    • paint

      public void paint(Graphics2D graphics, Rectangle paintArea, AffineTransform worldToScreen)
      Renders features based on the map layers and their styles as specified in the map context using setContext .

      This version of the method assumes that the size of the output area and the transformation from coordinates to pixels are known. The latter determines the map scale. The viewport (the visible part of the map) will be calculated internally.

      Specified by:
      paint in interface GTRenderer
      Parameters:
      graphics - The graphics object to draw to.
      paintArea - The size of the output area in output units (eg: pixels).
      worldToScreen - A transform which converts World coordinates to Screen coordinates.
      TODO:
      Need to check if the Layer CoordinateSystem is different to the BoundingBox rendering CoordinateSystem and if so, then transform the coordinates.

    • paint

      public void paint(Graphics2D graphics, Rectangle paintArea, Envelope mapArea)
      Renders features based on the map layers and their styles as specified in the map context using setContext .

      This version of the method assumes that the area of the visible part of the map and the size of the output area are known. The transform between the two is calculated internally.

      Specified by:
      paint in interface GTRenderer
      Parameters:
      graphics - The graphics object to draw to.
      paintArea - The size of the output area in output units (eg: pixels).
      mapArea - the map's visible area (viewport) in map coordinates.

    • paint

      public void paint(Graphics2D graphics, Rectangle paintArea, ReferencedEnvelope mapArea)
      Renders features based on the map layers and their styles as specified in the map context using setContext .

      This version of the method assumes that the area of the visible part of the map and the size of the output area are known. The transform between the two is calculated internally.

      Specified by:
      paint in interface GTRenderer
      Parameters:
      graphics - The graphics object to draw to.
      paintArea - The size of the output area in output units (eg: pixels).
      mapArea - the map's visible area (viewport) in map coordinates.

    • paint

      public void paint(Graphics2D graphics, Rectangle paintArea, Envelope mapArea, AffineTransform worldToScreen)
      Renders features based on the map layers and their styles as specified in the map context using setContext .

      This version of the method assumes that paint area, envelope and worldToScreen transform are already computed. Use this method to avoid recomputation. Note however that no check is performed that they are really in sync!

      Specified by:
      paint in interface GTRenderer
      Parameters:
      graphics - The graphics object to draw to.
      paintArea - The size of the output area in output units (eg: pixels).
      mapArea - the map's visible area (viewport) in map coordinates.
      worldToScreen - A transform which converts World coordinates to Screen coordinates.

    • paint

      public void paint(Graphics2D graphics, Rectangle paintArea, ReferencedEnvelope mapArea, AffineTransform worldToScreen)
      Renders features based on the map layers and their styles as specified in the map context using setContext .

      This version of the method assumes that paint area, envelope and worldToScreen transform are already computed. Use this method to avoid recomputation. Note however that no check is performed that they are really in sync!

      Specified by:
      paint in interface GTRenderer
      Parameters:
      graphics - The graphics object to draw to.
      paintArea - The size of the output area in output units (eg: pixels).
      mapArea - the map's visible area (viewport) in map coordinates. Its associate CRS is ALWAYS 2D
      worldToScreen - A transform which converts World coordinates to Screen coordinates.

    • fillBackground

      protected void fillBackground(Graphics2D graphics, Rectangle paintArea, Style style)

    • getRequestsQueue

      protected BlockingQueue<StreamingRenderer.RenderingRequest> getRequestsQueue()
      Builds the blocking queue used to bridge between the data loading thread and the painting one

    • transformEnvelope

      protected ReferencedEnvelope transformEnvelope(ReferencedEnvelope envelope, CoordinateReferenceSystem crs) throws TransformException, FactoryException
      Throws:
      TransformException
      FactoryException

    • getMaxBackBufferMemory

      public int getMaxBackBufferMemory(int width, int height)
      When drawing in optimized mode a 32bit surface is created for each FeatureTypeStyle other than the first in order to draw features in parallel while respecting the feature draw ordering multiple FTS impose. This method allows to estimate how many megabytes will be needed, in terms of back buffers, to draw the current MapContent, assuming the feature type style optimizations are turned on (in the case they are off, no extra memory will be used).
      Parameters:
      width - the image width
      height - the image height

    • isInteractive

      public boolean isInteractive()
      Getter for property interactive.
      Returns:
      Value of property interactive.

    • setInteractive

      public void setInteractive(boolean interactive)
      Sets the interactive status of the renderer. An interactive renderer won't wait for long image loading, preferring an alternative mark instead
      Parameters:
      interactive - new value for the interactive property

    • getGeneralizationDistance

      public double getGeneralizationDistance()
      Returns the generalization distance in the screen space.

    • setGeneralizationDistance

      public void setGeneralizationDistance(double d)
      Sets the generalizazion distance in the screen space.

      Default value is 0.8, meaning that two subsequent points are collapsed to one if their on screen distance is less than one pixel

      Set the distance to 0 if you don't want any kind of generalization

    • setJava2DHints

      public void setJava2DHints(RenderingHints hints)
      Description copied from interface: GTRenderer
      Hints used to configure Java2D Graphics prior to rendering.
      Specified by:
      setJava2DHints in interface GTRenderer

    • getJava2DHints

      public RenderingHints getJava2DHints()
      Description copied from interface: GTRenderer
      Hints used to configure Java2D Graphics prior to rendering.
      Specified by:
      getJava2DHints in interface GTRenderer
      Returns:
      Hints

    • setRendererHints

      public void setRendererHints(Map<?,?> hints)
      Description copied from interface: GTRenderer
      Hints used to configure rendering process.
      Specified by:
      setRendererHints in interface GTRenderer

    • getRendererHints

      public Map<Object,Object> getRendererHints()
      Description copied from interface: GTRenderer
      Hints used to configure rendering process
      Specified by:
      getRendererHints in interface GTRenderer
      Returns:
      Hints used to configure rendering process

    • setMapContent

      public void setMapContent(MapContent mapContent)
      Description copied from interface: GTRenderer
      Sets the MapContent which contains the data to be rendered.
      Specified by:
      setMapContent in interface GTRenderer
      Parameters:
      mapContent - the map content

    • getMapContent

      public MapContent getMapContent()
      Description copied from interface: GTRenderer
      Gets the MapContent instance which contains the data being rendered.
      Specified by:
      getMapContent in interface GTRenderer
      Returns:
      the MapContent instance

    • isCanTransform

      public boolean isCanTransform()

    • getMathTransform

      public static MathTransform getMathTransform(CoordinateReferenceSystem sourceCRS, CoordinateReferenceSystem destCRS)