Polygon label position (minor improvements) (#204), #80

vtm-themes/resources/assets/styles/default.xml

@@ -402,7 +402,8 @@
     <m e="way">
         <m closed="yes" k="natural" v="water">
             <area use="water" />
-            <caption k="name" fill="#777744" size="16" stroke="#aaffffff" stroke-width="2.0" area-size="0.4" />
+            <caption area-size="0.4" fill="#777744" k="name" size="16" stroke="#aaffffff"
+                stroke-width="2.0" />
             <!--<line use="water:outline" />-->
         </m>
 
@@ -527,8 +528,8 @@
                     <area fill="#e8ecde" />
                 </m>
                 <m zoom-min="12">
-                    <caption dy="18" fill="#000000" k="name" priority="5" size="19" stroke="#ffffff"
+                    <caption area-size="0.1" dy="18" fill="#000000" k="name" priority="5" size="19"
-                        stroke-width="2.0" area-size="0.1"/>
+                        stroke="#ffffff" stroke-width="2.0" />
                 </m>
                 <m zoom-max="11">
                     <caption dy="18" fill="#000000" k="ref" priority="5" size="19" stroke="#ffffff"
@@ -997,7 +998,7 @@
 
         <!-- place -->
         <m k="place">
-            <circle radius="5.0" fill="#ff0000"/>
+            <circle fill="#ff0000" radius="5.0" />
             <m v="suburb" zoom-max="14">
                 <caption style="italic" fill="#606060" k="name" priority="4" size="17"
                     stroke="#ffffff" stroke-width="2.0" />

vtm/src/org/oscim/core/GeometryBuffer.java

@@ -426,9 +426,9 @@ public class GeometryBuffer {
         int n = index[0];
 
         for (int i = 0; i < n - 2; i += 2) {
-            area = area + (points[i] * points[i+3]) - (points[i+1] * points[i+2]);
+            area = area + (points[i] * points[i + 3]) - (points[i + 1] * points[i + 2]);
         }
-        area = area + (points[n-2] * points[1]) - (points[n-1] * points[0]);
+        area = area + (points[n - 2] * points[1]) - (points[n - 1] * points[0]);
 
         return 0.5f * area;
     }

vtm/src/org/oscim/core/MapElement.java

@@ -1,5 +1,6 @@
 /*
  * Copyright 2012 Hannes Janetzek
+ * Copyright 2016 Andrey Novikov
  *
  * This file is part of the OpenScienceMap project (http://www.opensciencemap.org).
  *
@@ -26,6 +27,8 @@ package org.oscim.core;
  */
 public class MapElement extends GeometryBuffer {
 
+    public PointF labelPosition;
+
     /**
      * layer of the element (0-10) overrides the theme drawing order
      */
@@ -33,8 +36,6 @@ public class MapElement extends GeometryBuffer {
 
     public final TagSet tags = new TagSet();
 
-    public PointF labelPosition;
-
     public MapElement() {
         super(1024, 16);
     }
@@ -43,14 +44,14 @@ public class MapElement extends GeometryBuffer {
         super(points, indices);
     }
 
-    public void setLayer(int layer) {
-        this.layer = layer;
-    }
-
     public void setLabelPosition(float x, float y) {
         labelPosition = new PointF(x, y);
     }
 
+    public void setLayer(int layer) {
+        this.layer = layer;
+    }
+
     @Override
     public MapElement clear() {
         layer = 5;

vtm/src/org/oscim/layers/tile/vector/labeling/LabelTileLoaderHook.java

@@ -86,7 +86,7 @@ public class LabelTileLoaderHook implements TileLoaderThemeHook {
 
                 PointF label = element.labelPosition;
                 if (label == null)
-                    label = PolyLabel.get(element, 5f);
+                    label = PolyLabel.get(element);
 
                 if (label.x < 0 || label.x > Tile.SIZE || label.y < 0 || label.y > Tile.SIZE)
                     return false;

vtm/src/org/oscim/utils/geom/PolyLabel.java

@@ -1,15 +1,14 @@
 /**
  * Copyright 2016 Andrey Novikov
- * Java implementation of
+ * Java implementation of https://github.com/mapbox/polylabel
- * https://github.com/mapbox/polylabel
+ * <p>
- *
  * ISC License
  * Copyright (c) 2016 Mapbox
- *
+ * <p>
  * Permission to use, copy, modify, and/or distribute this software for any purpose
  * with or without fee is hereby granted, provided that the above copyright notice
  * and this permission notice appear in all copies.
- *
+ * <p>
  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH REGARD TO
  * THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
  * IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
@@ -27,15 +26,20 @@ import java.util.Comparator;
 import java.util.PriorityQueue;
 
 public class PolyLabel {
-    private static float SQRT2 = (float) Math.sqrt(2);
+    /**
+     * Calculation precision.
+     */
+    public static float PRECISION = 5f;
+
+    private static final float SQRT2 = (float) Math.sqrt(2);
 
     /**
      * Returns pole of inaccessibility, the most distant internal point from the polygon outline.
+     *
      * @param polygon polygon geometry
-     * @param precision calculation precision
      * @return optimal label placement point
      */
-    public static PointF get(GeometryBuffer polygon, float precision) {
+    public static PointF get(GeometryBuffer polygon) {
         // find the bounding box of the outer ring
         float minX = Float.MAX_VALUE, minY = Float.MAX_VALUE, maxX = Float.MIN_VALUE, maxY = Float.MIN_VALUE;
 
@@ -81,7 +85,7 @@ public class PolyLabel {
                 bestCell = cell;
 
             // do not drill down further if there's no chance of a better solution
-            if (cell.max - bestCell.d <= precision) continue;
+            if (cell.max - bestCell.d <= PRECISION) continue;
 
             // split the cell into four cells
             h = cell.h / 2;
@@ -94,8 +98,7 @@ public class PolyLabel {
         return new PointF(bestCell.x, bestCell.y);
     }
 
-    private static class MaxComparator implements Comparator<Cell>
+    private static class MaxComparator implements Comparator<Cell> {
-    {
         @Override
         public int compare(Cell a, Cell b) {
             return Float.compare(b.max, a.max);
@@ -132,10 +135,10 @@ public class PolyLabel {
                 continue;
 
             for (int i = 0, n = polygon.index[k], j = n - 2; i < n; j = i, i += 2) {
-                float ax = polygon.points[pos+i];
+                float ax = polygon.points[pos + i];
-                float ay = polygon.points[pos+i+1];
+                float ay = polygon.points[pos + i + 1];
-                float bx = polygon.points[pos+j];
+                float bx = polygon.points[pos + j];
-                float by = polygon.points[pos+j+1];
+                float by = polygon.points[pos + j + 1];
 
                 if (((ay > y) ^ (by > y)) &&
                         (x < (bx - ax) * (y - ay) / (by - ay) + ax)) inside = !inside;
@@ -157,9 +160,9 @@ public class PolyLabel {
 
         for (int i = 0, n = polygon.index[0], j = n - 2; i < n; j = i, i += 2) {
             float ax = polygon.points[i];
-            float ay = polygon.points[i+1];
+            float ay = polygon.points[i + 1];
             float bx = polygon.points[j];
-            float by = polygon.points[j+1];
+            float by = polygon.points[j + 1];
             float f = ax * by - bx * ay;
             x += (ax + bx) * f;
             y += (ay + by) * f;