org.osmdroid.views

Class Projection

java.lang.Object

org.osmdroid.views.Projection

All Implemented Interfaces:

IProjection, MapViewConstants

public class Projection
extends Object
implements IProjection, MapViewConstants

A Projection serves to translate between the coordinate system of x/y on-screen pixel coordinates and that of latitude/longitude points on the surface of the earth. You obtain a Projection from MapView.getProjection(). You should not hold on to this object for more than one draw, since the projection of the map could change.

Note: This class will "wrap" all pixel and lat/long values that overflow their bounds (rather than clamping to their bounds).

Author:

Marc Kurtz, Nicolas Gramlich, Manuel Stahl

Field Summary

Fields

Modifier and Type	Field and Description
protected float	mMultiTouchScale
protected int	mOffsetX
protected int	mOffsetY

Fields inherited from interface org.osmdroid.views.util.constants.MapViewConstants

ANIMATION_DURATION_DEFAULT, ANIMATION_DURATION_LONG, ANIMATION_DURATION_SHORT, ANIMATION_SMOOTHNESS_DEFAULT, ANIMATION_SMOOTHNESS_HIGH, ANIMATION_SMOOTHNESS_LOW, DEBUGMODE, MINIMUM_ZOOMLEVEL, NOT_SET

Method Summary

Methods

Modifier and Type	Method and Description
protected android.graphics.Point	adjustForDateLine(int x, int y, android.graphics.Point reuse)
IGeoPoint	fromPixels(int x, int y) Create a new GeoPoint from pixel coordinates relative to the top-left of the MapView that provided this PixelConverter.
IGeoPoint	fromPixels(int x, int y, GeoPoint reuse)
BoundingBoxE6	getBoundingBox()
android.graphics.Rect	getIntrinsicScreenRect()
android.graphics.Matrix	getInvertedScaleRotateCanvasMatrix() This will provide a Matrix that will revert the current map's scaling and rotation.
float	getMapOrientation()
IGeoPoint	getNorthEast() Get the coordinates of the most north-easterly visible point of the map.
android.graphics.Rect	getScreenRect()
IGeoPoint	getSouthWest() Get the coordinates of the most south-westerly visible point of the map.
int	getZoomLevel()
float	metersToEquatorPixels(float meters) Converts a distance in meters (along the equator) to one in (horizontal) pixels at the current zoomlevel.
float	metersToPixels(float meters) Converts a distance in meters to one in (horizontal) pixels at the current zoomlevel and at the current latitude at the center of the screen.
android.graphics.Point	rotateAndScalePoint(int x, int y, android.graphics.Point reuse) This will apply the current map's scaling and rotation for a point.
android.graphics.Point	toMercatorPixels(int x, int y, android.graphics.Point reuse)
android.graphics.Point	toPixels(IGeoPoint in, android.graphics.Point reuse) Converts the given IGeoPoint to onscreen pixel coordinates, relative to the top-left of the MapView that provided this Projection.
android.graphics.Point	toPixelsFromMercator(int x, int y, android.graphics.Point reuse)
android.graphics.Point	toPixelsFromProjected(android.graphics.Point in, android.graphics.Point reuse) Performs the second computationally light part of the projection.
android.graphics.Point	toProjectedPixels(GeoPoint geoPoint, android.graphics.Point reuse) A wrapper for toProjectedPixels(int, int, Point)
android.graphics.Point	toProjectedPixels(int latituteE6, int longitudeE6, android.graphics.Point reuse) Performs only the first computationally heavy part of the projection.
android.graphics.Point	unrotateAndScalePoint(int x, int y, android.graphics.Point reuse) This will revert the current map's scaling and rotation for a point.

Methods inherited from class java.lang.Object

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

Field Detail

mOffsetX

protected final int mOffsetX

mOffsetY

protected final int mOffsetY

mMultiTouchScale

protected final float mMultiTouchScale

Method Detail

getZoomLevel

public int getZoomLevel()

getBoundingBox

public BoundingBoxE6 getBoundingBox()

getScreenRect

public android.graphics.Rect getScreenRect()

getIntrinsicScreenRect

public android.graphics.Rect getIntrinsicScreenRect()

getMapOrientation

public float getMapOrientation()

fromPixels

public IGeoPoint fromPixels(int x,
                   int y)

Description copied from interface: IProjection

Create a new GeoPoint from pixel coordinates relative to the top-left of the MapView that provided this PixelConverter.

Specified by:

fromPixels in interface IProjection

fromPixels

public IGeoPoint fromPixels(int x,
                   int y,
                   GeoPoint reuse)

toPixels

public android.graphics.Point toPixels(IGeoPoint in,
                              android.graphics.Point reuse)

Description copied from interface: IProjection

Converts the given IGeoPoint to onscreen pixel coordinates, relative to the top-left of the MapView that provided this Projection.

Specified by:

toPixels in interface IProjection

Parameters:

in - The latitude/longitude pair to convert.

reuse - A pre-existing object to use for the output; if null, a new Point will be allocated and returned.

adjustForDateLine

protected android.graphics.Point adjustForDateLine(int x,
                                       int y,
                                       android.graphics.Point reuse)

toProjectedPixels

public android.graphics.Point toProjectedPixels(GeoPoint geoPoint,
                                       android.graphics.Point reuse)

A wrapper for toProjectedPixels(int, int, Point)

toProjectedPixels

public android.graphics.Point toProjectedPixels(int latituteE6,
                                       int longitudeE6,
                                       android.graphics.Point reuse)

Performs only the first computationally heavy part of the projection. Call toPixelsFromProjected(Point, Point) to get the final position.

Parameters:

latituteE6 - the latitute of the point

longitudeE6 - the longitude of the point

reuse - just pass null if you do not have a Point to be 'recycled'.

Returns:

intermediate value to be stored and passed to toMapPixelsTranslated.

toPixelsFromProjected

public android.graphics.Point toPixelsFromProjected(android.graphics.Point in,
                                           android.graphics.Point reuse)

Performs the second computationally light part of the projection.

Parameters:

in - the Point calculated by the toProjectedPixels(int, int, Point)

reuse - just pass null if you do not have a Point to be 'recycled'.

Returns:

the Point containing the coordinates of the initial GeoPoint passed to the toProjectedPixels(int, int, Point).

toPixelsFromMercator

public android.graphics.Point toPixelsFromMercator(int x,
                                          int y,
                                          android.graphics.Point reuse)

toMercatorPixels

public android.graphics.Point toMercatorPixels(int x,
                                      int y,
                                      android.graphics.Point reuse)

metersToEquatorPixels

public float metersToEquatorPixels(float meters)

Description copied from interface: IProjection

Converts a distance in meters (along the equator) to one in (horizontal) pixels at the current zoomlevel. In the default Mercator projection, the actual number of pixels for a given distance will get higher as you move away from the equator.

Specified by:

metersToEquatorPixels in interface IProjection

Parameters:

meters - the distance in meters

Returns:

The number of pixels corresponding to the distance, if measured along the equator, at the current zoom level. The return value may only be approximate.

metersToPixels

public float metersToPixels(float meters)

Converts a distance in meters to one in (horizontal) pixels at the current zoomlevel and at the current latitude at the center of the screen.

Parameters:

meters - the distance in meters

Returns:

The number of pixels corresponding to the distance, if measured at the center of the screen, at the current zoom level. The return value may only be approximate.

getNorthEast

public IGeoPoint getNorthEast()

Description copied from interface: IProjection

Get the coordinates of the most north-easterly visible point of the map.

Specified by:

getNorthEast in interface IProjection

getSouthWest

public IGeoPoint getSouthWest()

Description copied from interface: IProjection

Get the coordinates of the most south-westerly visible point of the map.

Specified by:

getSouthWest in interface IProjection

getInvertedScaleRotateCanvasMatrix

public android.graphics.Matrix getInvertedScaleRotateCanvasMatrix()

This will provide a Matrix that will revert the current map's scaling and rotation. This can be useful when drawing to a fixed location on the screen.

unrotateAndScalePoint

public android.graphics.Point unrotateAndScalePoint(int x,
                                           int y,
                                           android.graphics.Point reuse)

This will revert the current map's scaling and rotation for a point. This can be useful when drawing to a fixed location on the screen.

rotateAndScalePoint

public android.graphics.Point rotateAndScalePoint(int x,
                                         int y,
                                         android.graphics.Point reuse)

This will apply the current map's scaling and rotation for a point. This can be useful when converting MotionEvents to a screen point.