* Understanding Layers is key to understanding how geoTools works and if * you plan to add a new type of geographic feature then the layer interface is the place to * start.
* Layers are held in one or more themes which in turn are held in one or more * viewers.
* If you do write your own type of layer then extending simpleLayer will make
* life easyer for you.
*/
public interface Layer
{
public static final int LOADING = 1;
public static final int PENDING = 2;
public static final int ERRORED = 4;
public static final int ABORTED = 8;
public static final int COMPLETED = 16;
/**
* Paints the layer to the screen.
* The very hart of the layer mechanism, paintScaled is where layers
* have to do most of their work.
* Calling and filling in of this method is handled by the theme to which
* the layer has been added.
* The GeoGraphics object should provide you with everything
* needed to plot a feature onto the screen.
* Inside gg you can use or not use the facilies provided as you see fit.
* gg.getGraphics() A Graphics object to which you should direct all of your output.
* gg.getScale() A Scaler which you can use to convert real world(tm) co-ordinates
* into on screen co-ordinates for use with the Graphics g object.
* gg.getShade() shade A Shader, if you want to color your features based on a value (perhaps from the data peramiter) then
* use shade.getColor(double value); to obtain the colours.
* gg.getGeoData() A GeoData object, use this if your features have id's then you can obtain a coresponding value
* from data.
* gg.getStyle() style A style with hints on how to display the features
*/
public void paintScaled(GeoGraphics gg);
/**
* Highligts the specified feature.
* A simple version of paintScaled, this is used to paint a single feature
* in some way that make it stand out from the other features.
* Todate, this has been by using a bright red colour, a more user-definable
* system maybe implemented in later versions.
* Again the only thing that sould call this is a Theme
* @param g A Graphics object to paint the highlighted feature to.
* @param scale A scaler that can be used to scale the feature.
* @param id An int for the ID of the feature to be highlighted.
* @param style A style with hints on how to display the highlight
* @see uk.ac.leeds.ccg.geotools.Theme
*/
public void paintHighlight(Graphics g,Scaler scale,int id,ShadeStyle style);
/**
* Dispays the specified features.
* A simple version of paintScaled, this is used to paint a group of features
* in some way that make it stand out from the other features.
* Todate, this has been by using a bright red colour, a more user-definable
* system maybe implemented in later versions.
* Again the only thing that sould call this is a Theme
* @param g A Graphics object to paint the selected features to.
* @param scale A scaler that can be used to scale the feature.
* @param ids An int[] for the IDs of the features to be shown as selected.
* @param style A style with hints on how to display the selection
* @see uk.ac.leeds.ccg.geotools.Theme
*/
public void paintSelection(Graphics g,Scaler scale,int ids[],ShadeStyle style);
/**
* Gets the smallest GeoRectangle that will contain all of this layers features.
* When implementing this, set up a new GeoRectangle that will define the region of interest for your
* layer.
* @return GeoRectangle A GeoRectangle that will contain all of the features in the layer; For layers without geographic bounds it should return a null e.g. a scale bar or a norh arrow.
*/
public GeoRectangle getBounds();
/**
* Gets the smallest GeoRectangle that will contain the feature identified by the given ID.
* @since 0.6.5
* @param id The id of the feature to fetch the bounds of
* @return GeoRectangle The bounds of the requested feature
*/
public GeoRectangle getBoundsOf(int id);
/**
* Gets the smallest GeoRectangle that will contain the features identified by the given IDs.
* @since 0.6.5
* @param id[] The ids of the features to fetch the bounding rectangle
* @return GeoRectangle The bounds of the requested feature
*/
public GeoRectangle getBoundsOf(int id[]);
/**
* gets the ID of the feature that can be assosiated with a given point.
* For example, the ID of a feature that contains the point.
* @param p The GeoPoint of a location to test for a feature.
* @return int The id of the feature assosiated with this point; return 0 if no feature is associated.
*/
public int getID(GeoPoint p);
/**
* gets the ID of the features that can be assosiated with a given region.
* For example, the IDs of all features that are within the rectangle.
* @param box The GeoGeoractangle of the region of the query.
*
* @return int[] The ids of the features assosiated with this region; returns new int[0] if no features are selected.
*/
public int[] getIDs(GeoRectangle box,int mode);
/**
* A convinence method that is the same as getID(GeoPoint) but witout having to construct a geoPoint.
* @param x a double, the x co-ordinate.
* @param y a double, the y co-ordinate.
* @return int The id of the feature assosiated with this point; return 0 if no feature is associated.
*/
public int getID(double x,double y);
/*{
GeoPoint p = new GeoPoint(x,y);
return getID(p);
}*/
/**
* get the status of this layer: in most cases this should be
* Layer.COMPLETED to show that the layer is ready to paint.
* Where a layer has posponed loading it can be
* Layer.PENDING, Layer.LOADING, Layer.ERRORED or Layer.ABORTED
*/
public int getStatus();
/**
* set the status of this layer: in most cases this should be
* Layer.COMPLETED to show that the layer is ready to paint.
* Where a layer has posponed loading it can be
* Layer.PENDING, Layer.LOADING, Layer.ERRORED or Layer.ABORTED
* When the status becomes COMPLETED for the first time, a
* LayerChangedEvent is sent.
* Should only be called by the Layer Producer or
* the Layer itself
*/
public void setStatus(int status);
/**
* Adds a LayerChangedListener to the layer, typicaly called by Theme
* writen for you if you extend simpleLayer();
*/
public void addLayerChangedListener(LayerChangedListener lcl);
/**
* Removes a LayerChangedListener to the layer, typicaly called by Theme
* writen for you if you extend simpleLayer();
*/
public void removeLayerChangedListener(LayerChangedListener lcl);
/**
* Notifis all LayerChangedListener's that this layer has been modified.
* It should only normaly be called by the layer itself.
* To make life easyer it has been writen for you if you extend simpleLayer.
* Make sure you call it if some aspect of your feature changes such that you would like it
* to be re-painted.
* @param reason An int code indicating what type of change has occured; LayerChangedEvent provides GEOGRAPHY and DATA as two * constants to use as reason codes. * @see LayerChangedListener */ public void notifyLayerChangedListeners(int reason); /** Set the name of this layer so it can be viewed in toString() and * getName() later on. * @param n the name of the layer */ public void setName(String n); /** * Get the name of this layer. If it has not been set in setName(), then * the layer will be called "Unknown". */ public String getName(); /** * Get the name of this layer. If it has not been set in setName(), then * the layer will be called "Unknown". */ public String toString(); }