org.oscim.utils

Class ScanBox

java.lang.Object

org.oscim.utils.ScanBox

public abstract class ScanBox
extends java.lang.Object

Scan-line fill algorithm to retrieve tile-coordinates from Viewport.

ScanBox is used to calculate tile coordinates that intersect the box (or trapezoid) which is the projection of screen bounds to the map. Usage:

 Viewport.getMapViewProjection(box)
     ScanBox sb = new ScanBox(){
          protected void setVisible(int y, int x1, int x2) {
          }
    };
 sb.scan(pos.x, pos.y, pos.scale, * zoomLevel, coords);
 

where zoomLevel is the zoom-level for which tile coordinates should be calculated.

Field Summary

Fields

Modifier and Type	Field and Description
protected int	mZoom

Constructor Summary

Constructors

Constructor and Description
ScanBox()

Method Summary

Modifier and Type	Method and Description
void	scan(double x, double y, double scale, int zoom, float[] box)
protected abstract void	setVisible(int y, int x1, int x2)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

mZoom

protected int mZoom

Constructor Detail

ScanBox

public ScanBox()

Method Detail

setVisible

protected abstract void setVisible(int y,
                                   int x1,
                                   int x2)

Parameters:

y - the y-number of tile to be set visible.

x1 - the start x-number of tile to be set visible.

x2 - the end x-number of tile to be set visible (excluded).

scan

public void scan(double x,
                 double y,
                 double scale,
                 int zoom,
                 float[] box)

Parameters:

x - Projected map position x in 0..1.

y - Projected map position y in 0..1.

scale - Absolute scale.

zoom - Tile zoom level for current scale.

box - Current visible cut-out (8 floats).