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

Modifier and Type	Method and 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

Parameters:

labelCache -

Returns:

list with all values in priority order