Label layer: use ZoomLimiter for overzoom (#544)

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

@@ -1,8 +1,9 @@
 /*
  * Copyright 2012, 2013 Hannes Janetzek
  * Copyright 2017 Wolfgang Schramm
- * Copyright 2017 devemux86
+ * Copyright 2017-2018 devemux86
  * Copyright 2017 Andrey Novikov
+ * Copyright 2018 Gustl22
  *
  * This file is part of the OpenScienceMap project (http://www.opensciencemap.org).
  *
@@ -24,13 +25,16 @@ import org.oscim.event.Event;
 import org.oscim.layers.Layer;
 import org.oscim.layers.tile.MapTile;
 import org.oscim.layers.tile.TileManager;
+import org.oscim.layers.tile.ZoomLimiter;
 import org.oscim.layers.tile.vector.VectorTileLayer;
 import org.oscim.map.Map;
+import org.oscim.map.Viewport;
 import org.oscim.utils.async.SimpleWorker;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-public class LabelLayer extends Layer implements Map.UpdateListener, TileManager.Listener {
+public class LabelLayer extends Layer implements Map.UpdateListener, TileManager.Listener,
+        ZoomLimiter.IZoomLimiter {
 
     static final Logger log = LoggerFactory.getLogger(LabelLayer.class);
 
@@ -38,19 +42,31 @@ public class LabelLayer extends Layer implements Map.UpdateListener, TileManager
 
     private static final long MAX_RELABEL_DELAY = 100;
 
+    // Sane default to allow render themes to work
+    private static final int ZOOM_LIMIT = Viewport.MAX_ZOOM_LEVEL;
+
     private final LabelPlacement mLabelPlacer;
     private final Worker mWorker;
+    private final ZoomLimiter mZoomLimiter;
 
     public LabelLayer(Map map, VectorTileLayer l) {
         this(map, l, new LabelTileLoaderHook());
     }
 
     public LabelLayer(Map map, VectorTileLayer l, VectorTileLayer.TileLoaderThemeHook h) {
+        this(map, l, h, ZOOM_LIMIT);
+    }
+
+    public LabelLayer(Map map, VectorTileLayer l, VectorTileLayer.TileLoaderThemeHook h,
+                      int zoomLimit) {
         super(map);
         l.getManager().events.bind(this);
         l.addHook(h);
 
-        mLabelPlacer = new LabelPlacement(map, l.tileRenderer());
+        mZoomLimiter = new ZoomLimiter(l.getManager(), map.viewport().getMinZoomLevel(),
+                map.viewport().getMaxZoomLevel(), zoomLimit);
+
+        mLabelPlacer = new LabelPlacement(map, l.tileRenderer(), mZoomLimiter);
         mWorker = new Worker(map);
         mRenderer = new TextRenderer(mWorker);
     }
@@ -86,6 +102,16 @@ public class LabelLayer extends Layer implements Map.UpdateListener, TileManager
         }
     }
 
+    @Override
+    public void addZoomLimit() {
+        mZoomLimiter.addZoomLimit();
+    }
+
+    @Override
+    public void removeZoomLimit() {
+        mZoomLimiter.removeZoomLimit();
+    }
+
     public void clearLabels() {
         mWorker.cancel(true);
     }

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

@@ -1,5 +1,7 @@
 /*
+ * Copyright 2013 Hannes Janetzek
  * Copyright 2016 devemux86
+ * Copyright 2018 Gustl22
  *
  * This file is part of the OpenScienceMap project (http://www.opensciencemap.org).
  *
@@ -21,7 +23,9 @@ import org.oscim.core.Tile;
 import org.oscim.layers.tile.MapTile;
 import org.oscim.layers.tile.TileRenderer;
 import org.oscim.layers.tile.TileSet;
+import org.oscim.layers.tile.ZoomLimiter;
 import org.oscim.map.Map;
+import org.oscim.map.Viewport;
 import org.oscim.renderer.bucket.SymbolBucket;
 import org.oscim.renderer.bucket.SymbolItem;
 import org.oscim.renderer.bucket.TextItem;
@@ -31,6 +35,9 @@ import org.oscim.utils.geom.OBB2D;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.util.HashSet;
+import java.util.Set;
+
 import static org.oscim.layers.tile.MapTile.State.NEW_DATA;
 import static org.oscim.layers.tile.MapTile.State.READY;
 
@@ -53,6 +60,7 @@ public class LabelPlacement {
     private final TileSet mTileSet = new TileSet();
     private final TileRenderer mTileRenderer;
     private final Map mMap;
+    private final ZoomLimiter mZoomLimiter;
 
     /**
      * list of current labels
@@ -67,9 +75,13 @@ public class LabelPlacement {
      */
     private int mRelabelCnt;
 
-    public LabelPlacement(Map map, TileRenderer tileRenderer) {
+    /* Zoom level of current tiles (initial value doesn't matter) */
+    private Integer mZoom = Viewport.MIN_ZOOM_LEVEL;
+
+    public LabelPlacement(Map map, TileRenderer tileRenderer, ZoomLimiter zoomLimiter) {
         mMap = map;
         mTileRenderer = tileRenderer;
+        mZoomLimiter = zoomLimiter;
     }
 
     /**
@@ -294,7 +306,13 @@ public class LabelPlacement {
     boolean updateLabels(LabelTask work) {
 
         /* get current tiles */
-        boolean changedTiles = mTileRenderer.getVisibleTiles(mTileSet);
+        int lastZoom = mZoom;
+        mZoom = mTileRenderer.getVisibleTiles(mTileSet, true);
+        boolean changedTiles = mZoom != null;
+
+        // set to last zoom in case of tiles didn't change
+        if (!changedTiles)
+            mZoom = lastZoom;
 
         if (mTileSet.cnt == 0) {
             return false;
@@ -307,10 +325,31 @@ public class LabelPlacement {
         if (!changedTiles && !changedPos)
             return false;
 
+        if (mZoom < mZoomLimiter.getMinZoom() || mZoom > mZoomLimiter.getMaxZoom())
+            return false;
+
         mRelabelCnt++;
 
-        MapTile[] tiles = mTileSet.tiles;
+        int cnt = mTileSet.cnt;
-        int zoom = tiles[0].zoomLevel;
+        MapTile[] tiles;
+        int zoom;
+        if (mZoom > mZoomLimiter.getZoomLimit()) {
+            // render from zoom limit tiles (avoid duplicates and null)
+            Set<MapTile> hashTiles = new HashSet<>();
+            for (int i = 0; i < cnt; i++) {
+                MapTile t = mZoomLimiter.getTile(mTileSet.tiles[i]);
+                if (t == null)
+                    continue;
+                hashTiles.add(t);
+            }
+
+            cnt = hashTiles.size();
+            tiles = hashTiles.toArray(new MapTile[cnt]);
+            zoom = mZoomLimiter.getZoomLimit();
+        } else {
+            tiles = mTileSet.tiles;
+            zoom = mZoom;
+        }
 
         /* estimation for visible area to be labeled */
         int mw = (mMap.getWidth() + Tile.SIZE) / 2;
@@ -398,7 +437,7 @@ public class LabelPlacement {
         }
 
         /* add way labels */
-        for (int i = 0, n = mTileSet.cnt; i < n; i++) {
+        for (int i = 0; i < cnt; i++) {
             MapTile t = tiles[i];
             if (!t.state(READY | NEW_DATA))
                 continue;
@@ -411,7 +450,7 @@ public class LabelPlacement {
         }
 
         /* add caption */
-        for (int i = 0, n = mTileSet.cnt; i < n; i++) {
+        for (int i = 0; i < cnt; i++) {
             MapTile t = tiles[i];
             if (!t.state(READY | NEW_DATA))
                 continue;
@@ -453,7 +492,7 @@ public class LabelPlacement {
         }
 
         /* add symbol items */
-        for (int i = 0, n = mTileSet.cnt; i < n; i++) {
+        for (int i = 0; i < cnt; i++) {
             MapTile t = tiles[i];
             if (!t.state(READY | NEW_DATA))
                 continue;