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GeoPointUtils: calculate scale to display a BoundingBox #396

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Emux 2017-11-20 10:48:16 +02:00
parent 4f7675d2a8
commit 8ad2036ec1
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1 changed files with 25 additions and 0 deletions
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vtm/src/org/oscim/utils/GeoPointUtils.java
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@ -15,8 +15,11 @@
*/ */
package org.oscim.utils; package org.oscim.utils;
import org.oscim.core.BoundingBox;
import org.oscim.core.GeoPoint; import org.oscim.core.GeoPoint;
import org.oscim.core.MercatorProjection;
import org.oscim.core.Point; import org.oscim.core.Point;
import org.oscim.core.Tile;
/** /**
* The coordinate validation functions come from Mapsforge <a href="https://github.com/mapsforge/mapsforge/blob/master/mapsforge-core/src/main/java/org/mapsforge/core/util/LatLongUtils.java">LatLongUtils</a> class. * The coordinate validation functions come from Mapsforge <a href="https://github.com/mapsforge/mapsforge/blob/master/mapsforge-core/src/main/java/org/mapsforge/core/util/LatLongUtils.java">LatLongUtils</a> class.
@ -97,6 +100,28 @@ public final class GeoPointUtils {
return new Point(startX + t * (endX - startX), startY + t * (endY - startY)); return new Point(startX + t * (endX - startX), startY + t * (endY - startY));
} }
/**
* Calculates the scale that allows to display the {@link BoundingBox} on a view with width and
* height.
*
* @param bbox the {@link BoundingBox} to display.
* @param viewWidth the width of the view.
* @param viewHeight the height of the view.
* @return the scale that allows to display the {@link BoundingBox} on a view with width and
* height.
*/
public static double scaleForBounds(BoundingBox bbox, int viewWidth, int viewHeight) {
double minx = MercatorProjection.longitudeToX(bbox.getMinLongitude());
double miny = MercatorProjection.latitudeToY(bbox.getMaxLatitude());
double dx = Math.abs(MercatorProjection.longitudeToX(bbox.getMaxLongitude()) - minx);
double dy = Math.abs(MercatorProjection.latitudeToY(bbox.getMinLatitude()) - miny);
double zx = viewWidth / (dx * Tile.SIZE);
double zy = viewHeight / (dy * Tile.SIZE);
return Math.min(zx, zy);
}
/** /**
* @param latitude the latitude coordinate in degrees which should be validated. * @param latitude the latitude coordinate in degrees which should be validated.
* @return the latitude value * @return the latitude value