polylabel-java

A Java port of PolyLabel from MapBox.

Official repo: https://github.com/mapbox/polylabel

Article: https://blog.mapbox.com/a-new-algorithm-for-finding-a-visual-center-of-a-polygon-7c77e6492fbc

Requirements

• Java 8 or later
• Maven 3
• Git

Installation

Add polylabel-java to your local .m2 folder with the following commands:

git clone https://github.com/FreshLlamanade/polylabel-java
cd polylabel-java
mvn clean install

Then add the following dependency to your pom.xml:

<groupId>com.monst</groupId>
<artifactId>polylabel-java</artifactId>
<version>1.2.1</version>

Usage

Using default precision (1.0), no console messages:

PolyLabel result = PolyLabel.polyLabel(new Integer[][][] {{{0, 0}, {10, 0}, {0, 10}}})
// result.getCoordinates() -> {3.125, 3.125}

Using precision of 0.5, no console messages:

PolyLabel result = PolyLabel.polyLabel(new Integer[][][] {{{0, 0}, {10, 0}, {0, 10}}}, 0.5)
// result.getCoordinates() -> {2.8125, 2.8125}

Using precision of 0.5, with console messages:

PolyLabel result = PolyLabel.polyLabel(new Integer[][][] {{{0, 0}, {10, 0}, {0, 10}}}, 0.5, true)
//    Found best 2.50 after 5 probes
//
//    Found best 2.65 after 21 probes
//
//    Found best 2.81 after 25 probes
//
//    Num probes: 25
//    Best distance: 2.812500
//
// result.getCoordinates() -> {2.8125, 2.8125}