001// License: GPL. For details, see LICENSE file.
002package org.openstreetmap.josm.data.projection.proj;
003
004/**
005 * A {@link Proj} implements this interface, if it derives the scale factor
006 * value from it's other input parameters.
007 *
008 * (Normally the scale factor is projection input parameter and the Proj
009 * class does not deal with it.)
010 *
011 * @see Proj
012 * @since  9565 (creation)
013 * @since 10600 (functional interface)
014 */
015@FunctionalInterface
016public interface IScaleFactorProvider {
017    /**
018     * Get the scale factor.
019     * Will be multiplied by the scale factor parameter, if supplied by the user
020     * explicitly.
021     * @return the scale factor
022     */
023    double getScaleFactor();
024}