From 9d82cfdd646bf36fe753689f38a093e537711133 Mon Sep 17 00:00:00 2001
From: Hannes Janetzek <hannes.janetzek@gmail.com>
Date: Sat, 15 Jun 2013 16:55:00 +0200
Subject: [PATCH] move labeling to separate package

---
 src/org/oscim/layers/labeling/Debug.java      |  75 ++
 src/org/oscim/layers/labeling/Label.java      |  60 ++
 .../LabelLayer.java}                          |  15 +-
 .../layers/labeling/TextRenderLayer.java      | 698 ++++++++++++++++++
 4 files changed, 840 insertions(+), 8 deletions(-)
 create mode 100644 src/org/oscim/layers/labeling/Debug.java
 create mode 100644 src/org/oscim/layers/labeling/Label.java
 rename src/org/oscim/layers/{overlay/LabelingOverlay.java => labeling/LabelLayer.java} (82%)
 create mode 100644 src/org/oscim/layers/labeling/TextRenderLayer.java

diff --git a/src/org/oscim/layers/labeling/Debug.java b/src/org/oscim/layers/labeling/Debug.java
new file mode 100644
index 00000000..f4af5e73
--- /dev/null
+++ b/src/org/oscim/layers/labeling/Debug.java
@@ -0,0 +1,75 @@
+/*
+ * Copyright 2013
+ *
+ * This program is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.oscim.layers.labeling;
+
+import org.oscim.graphics.Color;
+import org.oscim.renderer.sublayers.Layers;
+import org.oscim.renderer.sublayers.LineLayer;
+import org.oscim.renderer.sublayers.TextItem;
+import org.oscim.theme.renderinstruction.Line;
+
+public class Debug {
+
+	private final static float[] mDebugPoints = new float[4];
+
+	static void addDebugBox(Layers dbg, Label l, TextItem ti, int overlaps, boolean prev,
+			float scale) {
+
+		LineLayer ll;
+		if (prev) {
+			if (overlaps == 1)
+				ll = dbg.getLineLayer(4);
+			else
+				ll = dbg.getLineLayer(5);
+
+		} else {
+			if (ti.width > ti.length * scale) {
+				ll = dbg.getLineLayer(1);
+				overlaps = 3;
+			}
+			else if (overlaps == 1)
+				ll = dbg.getLineLayer(0);
+			else if (overlaps == 2)
+				ll = dbg.getLineLayer(3);
+			else
+				ll = dbg.getLineLayer(2);
+		}
+		float[] points = mDebugPoints;
+		float width = (ti.x2 - ti.x1) / 2f;
+		float height = (ti.y2 - ti.y1) / 2f;
+		points[0] = (l.x - width * scale);
+		points[1] = (l.y - height * scale);
+		points[2] = (l.x + width * scale);
+		points[3] = (l.y + height * scale);
+		ll.addLine(points, null, false);
+
+		if (l.bbox != null && overlaps != 3) {
+			ll.addLine(l.bbox.corner, null, true);
+		}
+	}
+
+	static void addDebugLayers(Layers dbg) {
+		int alpha = 0xaaffffff;
+
+		dbg.clear();
+		dbg.addLineLayer(0, new Line((Color.BLUE & alpha), 2));
+		dbg.addLineLayer(1, new Line((Color.RED & alpha), 2));
+		dbg.addLineLayer(3, new Line((Color.YELLOW & alpha), 2));
+		dbg.addLineLayer(2, new Line((Color.GREEN & alpha), 2));
+		dbg.addLineLayer(4, new Line((Color.CYAN & alpha), 2));
+		dbg.addLineLayer(5, new Line((Color.MAGENTA & alpha), 2));
+	}
+
+}
diff --git a/src/org/oscim/layers/labeling/Label.java b/src/org/oscim/layers/labeling/Label.java
new file mode 100644
index 00000000..5136f544
--- /dev/null
+++ b/src/org/oscim/layers/labeling/Label.java
@@ -0,0 +1,60 @@
+/*
+ * Copyright 2013 Hannes Janetzek
+ *
+ * This program is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.oscim.layers.labeling;
+
+import org.oscim.layers.tile.MapTile;
+import org.oscim.renderer.sublayers.TextItem;
+import org.oscim.utils.OBB2D;
+
+class Label extends TextItem {
+	TextItem item;
+
+	//Link blocking;
+	//Link blockedBy;
+	// shared list of all label for a tile
+	//Link siblings;
+
+	MapTile tile;
+
+	//public byte origin;
+	public int active;
+	public OBB2D bbox;
+
+	public TextItem move(TextItem ti, float dx, float dy, float scale) {
+		this.x = (dx + ti.x) * scale;
+		this.y = (dy + ti.y) * scale;
+		return this;
+	}
+
+	public void clone(TextItem ti) {
+		this.string = ti.string;
+		this.text = ti.text;
+		this.width = ti.width;
+		this.length = ti.length;
+	}
+
+	public void setAxisAlignedBBox() {
+		this.x1 = x - width / 2;
+		this.y1 = y - text.fontHeight / 2;
+		this.x2 = x + width / 2;
+		this.y2 = y + text.fontHeight / 2;
+	}
+
+	static int comparePriority(Label l1, Label l2){
+
+
+		return 0;
+	}
+}
\ No newline at end of file
diff --git a/src/org/oscim/layers/overlay/LabelingOverlay.java b/src/org/oscim/layers/labeling/LabelLayer.java
similarity index 82%
rename from src/org/oscim/layers/overlay/LabelingOverlay.java
rename to src/org/oscim/layers/labeling/LabelLayer.java
index 619e5b0b..7e7827bf 100644
--- a/src/org/oscim/layers/overlay/LabelingOverlay.java
+++ b/src/org/oscim/layers/labeling/LabelLayer.java
@@ -12,25 +12,24 @@
  * You should have received a copy of the GNU Lesser General Public License along with
  * this program. If not, see <http://www.gnu.org/licenses/>.
  */
-package org.oscim.layers.overlay;
+package org.oscim.layers.labeling;
 
 import org.oscim.core.MapPosition;
+import org.oscim.layers.InputLayer;
 import org.oscim.layers.tile.TileRenderLayer;
-import org.oscim.renderer.layers.TextRenderLayer;
 import org.oscim.view.MapView;
 
 import android.util.Log;
 import android.view.MotionEvent;
 
-/**
- * @author Hannes Janetzek
- */
-public class LabelingOverlay extends Overlay {
-	private final static String TAG = LabelingOverlay.class.getName();
+public class LabelLayer extends InputLayer {
+	private final static String TAG = LabelLayer.class.getName();
 	final TextRenderLayer mTextLayer;
 
-	public LabelingOverlay(MapView mapView, TileRenderLayer tileRenderLayer) {
+	public LabelLayer(MapView mapView, TileRenderLayer tileRenderLayer) {
 		super(mapView);
+
+		//mTextLayer = new org.oscim.renderer.layers.TextRenderLayer(mapView, tileRenderLayer);
 		mTextLayer = new TextRenderLayer(mapView, tileRenderLayer);
 		mLayer = mTextLayer;
 	}
diff --git a/src/org/oscim/layers/labeling/TextRenderLayer.java b/src/org/oscim/layers/labeling/TextRenderLayer.java
new file mode 100644
index 00000000..c9b3215a
--- /dev/null
+++ b/src/org/oscim/layers/labeling/TextRenderLayer.java
@@ -0,0 +1,698 @@
+/*
+ * Copyright 2012 Hannes Janetzek
+ *
+ * This program is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.oscim.layers.labeling;
+
+// TODO
+// 1. rewrite :)
+// 1.1 test if label is actually visible
+// 2. compare previous to current state
+// 2.1 test for new labels to be placed
+// 2.2 handle collisions
+// 2.3 try to place labels along a way
+// 2.4 use 4 point labeling
+// 3 join segments that belong to one feature
+// 4 handle zoom-level changes
+// 5 R-Tree might be handy
+//
+
+import org.oscim.core.MapPosition;
+import org.oscim.core.Tile;
+import org.oscim.layers.tile.MapTile;
+import org.oscim.layers.tile.TileRenderLayer;
+import org.oscim.layers.tile.TileSet;
+import org.oscim.renderer.GLRenderer.Matrices;
+import org.oscim.renderer.GLState;
+import org.oscim.renderer.layers.BasicRenderLayer;
+import org.oscim.renderer.sublayers.Layer;
+import org.oscim.renderer.sublayers.Layers;
+import org.oscim.renderer.sublayers.LineRenderer;
+import org.oscim.renderer.sublayers.PolygonRenderer;
+import org.oscim.renderer.sublayers.TextItem;
+import org.oscim.renderer.sublayers.TextLayer;
+import org.oscim.renderer.sublayers.TextureRenderer;
+import org.oscim.utils.FastMath;
+import org.oscim.utils.OBB2D;
+import org.oscim.utils.pool.LList;
+import org.oscim.utils.pool.Pool;
+import org.oscim.view.MapView;
+import org.oscim.view.MapViewPosition;
+
+import android.opengl.GLES20;
+import android.os.AsyncTask;
+import android.os.Handler;
+import android.os.Looper;
+
+public class TextRenderLayer extends BasicRenderLayer {
+	private final static String TAG = TextRenderLayer.class.getName();
+	private final static float MIN_CAPTION_DIST = 5;
+	private final static float MIN_WAY_DIST = 3;
+
+	private final static long MAX_RELABEL_DELAY = 200;
+
+	private final MapViewPosition mMapViewPosition;
+	private final TileSet mTileSet;
+
+	private MapPosition mTmpPos;
+
+	// TextLayer that is updating
+	private TextLayer mTmpLayer;
+	// TextLayer that is ready to be added to 'layers'
+	private TextLayer mNextLayer;
+
+	// thread local pool
+	class LabelPool extends Pool<TextItem> {
+		Label releaseAndGetNext(Label l) {
+			if (l.item != null)
+				TextItem.pool.release(l.item);
+
+			// drop references
+			l.item = null;
+			l.tile = null;
+			l.string = null;
+
+			Label ret = (Label) l.next;
+
+			super.release(l);
+
+			return ret;
+		}
+
+		@Override
+		protected TextItem createItem() {
+			return new Label();
+		}
+	}
+
+	private final LabelPool mPool = new LabelPool();
+
+	// list of previous labels
+	private Label mPrevLabels;
+
+	// list of current labels
+	private Label mLabels;
+
+	//private final float[] mTmpCoords = new float[8];
+
+	//private final HashMap<MapTile, LabelTile> mActiveTiles;
+
+	class LabelTile {
+		Tile tile;
+		LList<Label> labels;
+	}
+
+
+
+	//	class ActiveTile {
+	//		MapTile tile;
+	//		int activeLabels;
+	//		Label labels;
+	//	}
+
+	private float mSquareRadius;
+	private int mRelabelCnt;
+	private final TileRenderLayer mTileLayer;
+
+	public TextRenderLayer(MapView mapView, TileRenderLayer baseLayer) {
+		super(mapView);
+
+		mMapViewPosition = mapView.getMapViewPosition();
+		mTileLayer = baseLayer;
+		mTileSet = new TileSet();
+		layers.textureLayers = new TextLayer();
+		mTmpLayer = new TextLayer();
+
+		//mActiveTiles = new HashMap<MapTile, LabelTile>();
+		mTmpPos = new MapPosition();
+		mRelabelCnt = 0;
+	}
+
+	// remove Label l from mLabels and return l.next
+	private Label removeLabel(Label l) {
+		Label ret = (Label) l.next;
+		mLabels = (Label) mPool.release(mLabels, l);
+
+		return ret;
+	}
+
+	public void addLabel(Label l) {
+		TextItem ll = mLabels;
+
+		for (; ll != null; ll = ll.next) {
+			// find other label with same text style
+			if (l.text == ll.text) {
+				while (ll.next != null
+						// break if next item uses different text style
+						&& l.text == ll.next.text
+						// check same string instance
+						&& l.string != ll.string
+						// check same string
+						&& !l.string.equals(ll.string))
+					ll = ll.next;
+
+				// Note: this is required for 'packing test' in prepare to work!
+				TextItem.shareText(l, ll);
+
+				// insert after text of same type and/or before same string
+				l.next = ll.next;
+				ll.next = l;
+				return;
+			}
+		}
+
+		l.next = mLabels;
+		mLabels = l;
+	}
+
+	private byte checkOverlap(Label l) {
+
+		for (Label ll = mLabels; ll != null;) {
+			// check bounding box
+			if (!TextItem.bboxOverlaps(l, ll, 150)) {
+				ll = (Label) ll.next;
+				continue;
+			}
+
+			if (TextItem.shareText(l, ll)) {
+
+				// keep the label that was active earlier
+				if (ll.active <= l.active)
+					return 1;
+
+				// keep the label with longer segment
+				if (ll.length < l.length) {
+					ll = removeLabel(ll);
+					continue;
+				}
+
+				return 2;
+			}
+
+			boolean intersect = l.bbox.overlaps(ll.bbox);
+
+			if (intersect) {
+				if (ll.active <= l.active)
+					return 1;
+
+				//Log.d(TAG, "intersection " + lp.string + " <> " + ti.string
+				//		+ " at " + ti.x + ":" + ti.y);
+
+				if (!ll.text.caption
+						&& (ll.text.priority > l.text.priority || ll.length < l.length)) {
+
+					ll = removeLabel(ll);
+					continue;
+				}
+
+				return 1;
+			}
+			ll = (Label) ll.next;
+		}
+		return 0;
+	}
+
+	private boolean nodeIsVisible(TextItem ti) {
+		// rough filter
+		float dist = ti.x * ti.x + ti.y * ti.y;
+		if (dist > mSquareRadius)
+			return false;
+
+		return true;
+	}
+
+	private boolean wayIsVisible(TextItem ti) {
+		// rough filter
+		float dist = ti.x * ti.x + ti.y * ti.y;
+		if (dist < mSquareRadius)
+			return true;
+
+		dist = ti.x1 * ti.x1 + ti.y1 * ti.y1;
+		if (dist < mSquareRadius)
+			return true;
+
+		dist = ti.x2 * ti.x2 + ti.y2 * ti.y2;
+		if (dist < mSquareRadius)
+			return true;
+
+		return false;
+	}
+
+	private Layers mDebugLayer;
+
+	private Label getLabel() {
+		Label l = (Label) mPool.get();
+		l.active = Integer.MAX_VALUE;
+
+		return l;
+	}
+
+	private static float flipLongitude(float dx, int max) {
+		// flip around date-line
+		if (dx > max)
+			dx = dx - max * 2;
+		else if (dx < -max)
+			dx = dx + max * 2;
+
+		return dx;
+	}
+
+	boolean updateLabels() {
+		// nextLayer is not loaded yet
+		if (mTmpLayer == null)
+			return false;
+
+		// get current tiles
+		boolean changedTiles = mTileLayer.getVisibleTiles(mTileSet);
+		boolean changedPos;
+
+		if (mTileSet.cnt == 0) {
+			//Log.d(TAG, "no tiles "+ mTileSet.getSerial());
+			return false;
+		}
+		MapPosition pos = mTmpPos;
+
+		synchronized (mMapViewPosition) {
+			changedPos = mMapViewPosition.getMapPosition(pos);
+			//mMapViewPosition.getMapViewProjection(coords);
+		}
+
+		if (!changedTiles && !changedPos) {
+			//Log.d(TAG, "not changed " + changedTiles + " " + changedPos);
+			return false;
+		}
+
+		Layers dbg = null;
+		if (mMapView.getDebugSettings().debugLabels)
+			dbg = new Layers();
+
+		int mw = (mMapView.getWidth() + Tile.SIZE) / 2;
+		int mh = (mMapView.getHeight() + Tile.SIZE) / 2;
+		mSquareRadius = mw * mw + mh * mh;
+
+		MapTile[] tiles = mTileSet.tiles;
+
+		int zoom = tiles[0].zoomLevel;
+
+		// scale of tiles zoom-level relative to current position
+		double scale = pos.scale / (1 << zoom);
+
+		double angle = Math.toRadians(pos.angle);
+		float cos = (float) Math.cos(angle);
+		float sin = (float) Math.sin(angle);
+
+		int maxx = Tile.SIZE << (zoom - 1);
+
+		if (dbg != null)
+			Debug.addDebugLayers(dbg);
+
+		mRelabelCnt++;
+
+		double tileX = (pos.x * (Tile.SIZE << zoom));
+		double tileY = (pos.y * (Tile.SIZE << zoom));
+
+		for (Label l = mPrevLabels; l != null;) {
+			if (l.text.caption) {
+				l = mPool.releaseAndGetNext(l);
+				continue;
+			}
+
+			int diff = l.tile.zoomLevel - zoom;
+			if (diff > 1 || diff < -1) {
+				l = mPool.releaseAndGetNext(l);
+				continue;
+			}
+
+			float div = FastMath.pow(diff);
+			float sscale = (float) (pos.scale / (1 << l.tile.zoomLevel));
+
+			if (l.width > l.length * sscale) {
+				l = mPool.releaseAndGetNext(l);
+				continue;
+			}
+
+			float dx = (float) (l.tile.tileX * Tile.SIZE - tileX * div);
+			float dy = (float) (l.tile.tileY * Tile.SIZE - tileY * div);
+
+			dx = flipLongitude(dx, maxx);
+
+			l.move(l.item, dx, dy, sscale);
+
+			// set line endpoints relative to view to be able to
+			// check intersections with label from other tiles
+			float w = (l.item.x2 - l.item.x1) / 2f;
+			float h = (l.item.y2 - l.item.y1) / 2f;
+			l.x1 = l.x - w;
+			l.y1 = l.y - h;
+			l.x2 = l.x + w;
+			l.y2 = l.y + h;
+
+			if (!wayIsVisible(l)) {
+				l = mPool.releaseAndGetNext(l);
+				continue;
+			}
+
+			l.bbox.set(l.x, l.y, l.x1, l.y1,
+					l.width + MIN_WAY_DIST,
+					l.text.fontHeight + MIN_WAY_DIST);
+
+			byte overlaps = checkOverlap(l);
+
+			if (dbg != null)
+				Debug.addDebugBox(dbg, l, l.item, overlaps, true, sscale);
+
+			if (overlaps == 0) {
+				Label ll = l;
+				l = (Label) l.next;
+
+				ll.next = null;
+				addLabel(ll);
+				continue;
+			}
+			l = mPool.releaseAndGetNext(l);
+		}
+
+		Label l = null;
+
+		/* add way labels */
+		for (int i = 0, n = mTileSet.cnt; i < n; i++) {
+			MapTile t = tiles[i];
+			if (t.state != MapTile.STATE_READY)
+				continue;
+
+			float dx = (float) (t.tileX * Tile.SIZE - tileX);
+			float dy = (float) (t.tileY * Tile.SIZE - tileY);
+			dx = flipLongitude(dx, maxx);
+
+			for (TextItem ti = t.labels; ti != null; ti = ti.next) {
+
+				if (ti.text.caption)
+					continue;
+
+				// acquire a TextItem to add to TextLayer
+				if (l == null)
+					l = getLabel();
+
+				// check if path at current scale is long enough for text
+				if (dbg == null && ti.width > ti.length * scale)
+					continue;
+
+				l.clone(ti);
+				l.move(ti, dx, dy, (float) scale);
+
+				// set line endpoints relative to view to be able to
+				// check intersections with label from other tiles
+				float w = (ti.x2 - ti.x1) / 2f;
+				float h = (ti.y2 - ti.y1) / 2f;
+				l.bbox = null;
+				l.x1 = l.x - w;
+				l.y1 = l.y - h;
+				l.x2 = l.x + w;
+				l.y2 = l.y + h;
+
+				if (!wayIsVisible(l))
+					continue;
+
+				byte overlaps = -1;
+
+				if (l.bbox == null)
+					l.bbox = new OBB2D(l.x, l.y, l.x1, l.y1,
+							l.width + MIN_WAY_DIST,
+							l.text.fontHeight + MIN_WAY_DIST);
+				else
+					l.bbox.set(l.x, l.y, l.x1, l.y1,
+							l.width + MIN_WAY_DIST,
+							l.text.fontHeight + MIN_WAY_DIST);
+
+				if (dbg == null || ti.width < ti.length * scale)
+					overlaps = checkOverlap(l);
+
+				if (dbg != null)
+					Debug.addDebugBox(dbg, l, ti, overlaps, false, (float) scale);
+
+				if (overlaps == 0) {
+					addLabel(l);
+					l.item = TextItem.copy(ti);
+					l.tile = t;
+					l.active = mRelabelCnt;
+					l = null;
+				}
+			}
+		}
+
+		/* add caption */
+		for (int i = 0, n = mTileSet.cnt; i < n; i++) {
+			MapTile t = tiles[i];
+			if (t.state != MapTile.STATE_READY)
+				continue;
+
+			float dx = (float) (t.tileX * Tile.SIZE - tileX);
+			float dy = (float) (t.tileY * Tile.SIZE - tileY);
+			dx = flipLongitude(dx, maxx);
+
+			for (TextItem ti = t.labels; ti != null; ti = ti.next) {
+				if (!ti.text.caption)
+					continue;
+
+				// acquire a TextItem to add to TextLayer
+				if (l == null)
+					l = getLabel();
+
+				l.clone(ti);
+				l.move(ti, dx, dy, (float) scale);
+				if (!nodeIsVisible(l))
+					continue;
+
+				//l.setAxisAlignedBBox();
+
+				if (l.bbox == null)
+					l.bbox = new OBB2D();
+
+				l.bbox.setNormalized(l.x, l.y, cos, -sin,
+						l.width + MIN_CAPTION_DIST,
+						l.text.fontHeight + MIN_CAPTION_DIST);
+
+				boolean overlaps = false;
+
+				for (Label lp = mLabels; lp != null;) {
+					if (l.bbox.overlaps(lp.bbox)) {
+						if (l.text.priority < lp.text.priority) {
+							lp = removeLabel(lp);
+							continue;
+						}
+
+						overlaps = true;
+						break;
+					}
+					lp = (Label) lp.next;
+				}
+				if (!overlaps) {
+					addLabel(l);
+					l.item = TextItem.copy(ti);
+					l.tile = t;
+					l.active = mRelabelCnt;
+					l = null;
+				}
+			}
+		}
+
+		for (Label ti = mLabels; ti != null; ti = (Label) ti.next) {
+			if (ti.text.caption)
+				continue;
+
+			// flip label upside-down
+			if (cos * (ti.x2 - ti.x1) - sin * (ti.y2 - ti.y1) < 0) {
+				float tmp = ti.x1;
+				ti.x1 = ti.x2;
+				ti.x2 = tmp;
+
+				tmp = ti.y1;
+				ti.y1 = ti.y2;
+				ti.y2 = tmp;
+			}
+		}
+
+		// temporarily used Label
+		mPool.release(l);
+
+		//reuse text layer
+		TextLayer tl = mTmpLayer;
+		mTmpLayer = null;
+
+		tl.labels = mLabels;
+		// draw text to bitmaps and create vertices
+		tl.prepare();
+
+		// after 'prepare' TextLayer does not need TextItems
+		mPrevLabels = mLabels;
+		mLabels = null;
+		tl.labels = null;
+
+		// remove tile locks
+		mTileLayer.releaseTiles(mTileSet);
+
+		// pass new labels for rendering
+		//synchronized (this) {
+		mNextLayer = tl;
+		mDebugLayer = dbg;
+		//}
+
+		return true;
+	}
+
+
+	@Override
+	public synchronized void update(MapPosition pos, boolean changed,
+			Matrices matrices) {
+
+		if (mNextLayer != null) {
+			// keep text layer, not recrating its canvas each time
+			mTmpLayer = (TextLayer) layers.textureLayers;
+
+			// clear textures and text items from previous layer
+			layers.clear();
+
+			if (mDebugLayer != null) {
+				layers.baseLayers = mDebugLayer.baseLayers;
+				mDebugLayer = null;
+			}
+
+			// set new TextLayer to be uploaded and rendered
+			layers.textureLayers = mNextLayer;
+			mNextLayer = null;
+
+			// make the 'labeled' MapPosition current
+			MapPosition tmp = mMapPosition;
+			mMapPosition = mTmpPos;
+			mTmpPos = tmp;
+
+			this.newData = true;
+		}
+
+		if (!mHolding)
+			postLabelTask((mLastRun + MAX_RELABEL_DELAY) - System.currentTimeMillis());
+	}
+
+	/* private */LabelTask mLabelTask;
+	/* private */long mLastRun;
+
+	class LabelTask extends AsyncTask<Void, Void, Integer> {
+
+		@Override
+		protected Integer doInBackground(Void... unused) {
+			boolean labelsChanged = false;
+
+			if (!isCancelled())
+				labelsChanged = updateLabels();
+
+			if (!isCancelled() && labelsChanged)
+				mMapView.render();
+
+			//Log.d(TAG, "relabel " + labelsChanged);
+
+			mLastRun = System.currentTimeMillis();
+			mLabelTask = null;
+			return null;
+		}
+
+		@Override
+		protected void onCancelled() {
+			cleanup();
+		}
+	}
+
+	/*private */void cleanup() {
+		mPool.releaseAll(mPrevLabels);
+		mPrevLabels = null;
+		mTileSet.clear();
+		mLabelTask = null;
+	}
+
+	private final Runnable mLabelUpdate = new Runnable() {
+		@Override
+		public void run() {
+
+			if (mLabelTask == null) {
+				mLabelTask = new LabelTask();
+				mLabelTask.execute();
+			} else {
+				postLabelTask(50);
+				//Log.d(TAG, "repost");
+			}
+		}
+	};
+	private Handler mLabelHandler;
+
+	/* private */void postLabelTask(long delay) {
+		if (mLabelHandler == null) {
+			mLabelHandler = new Handler(Looper.getMainLooper());
+		}
+
+		mLabelHandler.removeCallbacks(mLabelUpdate);
+
+		if (delay > 0)
+			mLabelHandler.postDelayed(mLabelUpdate, delay);
+		else
+			mLabelHandler.post(mLabelUpdate);
+	}
+
+	@Override
+	public synchronized void render(MapPosition pos, Matrices m) {
+
+		GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, layers.vbo.id);
+		GLState.test(false, false);
+
+		float scale = (float) (mMapPosition.scale / pos.scale);
+
+		if (layers.baseLayers != null) {
+			setMatrix(pos, m, true);
+
+			for (Layer l = layers.baseLayers; l != null;) {
+				if (l.type == Layer.POLYGON) {
+					l = PolygonRenderer.draw(pos, l, m, true, false);
+				} else {
+					float div = scale * (float) (pos.scale / (1 << pos.zoomLevel));
+					l = LineRenderer.draw(layers, l, pos, m, div, 0);
+				}
+			}
+		}
+
+		setMatrix(pos, m, false);
+
+		for (Layer l = layers.textureLayers; l != null;)
+			l = TextureRenderer.draw(l, scale, m);
+	}
+
+	private boolean mHolding;
+
+	/**
+	 * @param enable layer updates
+	 */
+	public synchronized void hold(boolean enable) {
+		//		mHolding = enable;
+		//		if (!enable)
+		//			runLabelTask();
+	}
+
+	public synchronized void clearLabels() {
+		if (mLabelHandler != null)
+			mLabelHandler.removeCallbacks(mLabelUpdate);
+
+		if (mLabelTask == null) {
+			cleanup();
+		} else {
+			mLabelTask.cancel(false);
+		}
+	}
+}