From 08b94a0c4265c4cd2081f82a4fad2fb89b273836 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=D0=90=D0=BB=D0=B5=D0=BA=D1=81=D0=B0=D0=BD=D0=B4=D1=80?=
 <Blakfast@mail.ru>
Date: Mon, 17 May 2021 16:18:20 +0300
Subject: [PATCH] Distant labels rendering (#844)

---
 .../tile/vector/labeling/LabelPlacement.java   | 18 +++++++++++++++---
 vtm/src/org/oscim/utils/Parameters.java        |  5 +++++
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/vtm/src/org/oscim/layers/tile/vector/labeling/LabelPlacement.java b/vtm/src/org/oscim/layers/tile/vector/labeling/LabelPlacement.java
index 2097253e..68ec1526 100644
--- a/vtm/src/org/oscim/layers/tile/vector/labeling/LabelPlacement.java
+++ b/vtm/src/org/oscim/layers/tile/vector/labeling/LabelPlacement.java
@@ -2,6 +2,7 @@
  * Copyright 2013 Hannes Janetzek
  * Copyright 2016-2019 devemux86
  * Copyright 2018 Gustl22
+ * Copyright 2021 blakfast
  *
  * This file is part of the OpenScienceMap project (http://www.opensciencemap.org).
  *
@@ -31,6 +32,7 @@ import org.oscim.renderer.bucket.SymbolItem;
 import org.oscim.renderer.bucket.TextItem;
 import org.oscim.theme.styles.TextStyle;
 import org.oscim.utils.FastMath;
+import org.oscim.utils.Parameters;
 import org.oscim.utils.geom.OBB2D;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -49,6 +51,7 @@ public class LabelPlacement {
         return (LabelTileData) tile.getData(LabelLayer.LABEL_DATA);
     }
 
+    private static final float DISTANCE_COEFFICIENT = 3;
     private static final float MIN_CAPTION_DIST = 5;
     private static final float MIN_WAY_DIST = 3;
 
@@ -352,9 +355,18 @@ public class LabelPlacement {
         }
 
         /* estimation for visible area to be labeled */
-        int mw = (mMap.getWidth() + Tile.SIZE) / 2;
-        int mh = (mMap.getHeight() + Tile.SIZE) / 2;
-        mSquareRadius = mw * mw + mh * mh;
+        if (Parameters.DISTANT_LABELS) {
+            int mw = mMap.getWidth();
+            int mh = mMap.getHeight();
+            float k = pos.tilt / mMap.viewport().getMaxTilt() * DISTANCE_COEFFICIENT;
+            if (k < 0.5)
+                k = 0.5f;
+            mSquareRadius = (mw * mw + mh * mh) * k;
+        } else {
+            int mw = (mMap.getWidth() + Tile.SIZE) / 2;
+            int mh = (mMap.getHeight() + Tile.SIZE) / 2;
+            mSquareRadius = mw * mw + mh * mh;
+        }
 
         /* scale of tiles zoom-level relative to current position */
         double scale = pos.scale / (1 << zoom);
diff --git a/vtm/src/org/oscim/utils/Parameters.java b/vtm/src/org/oscim/utils/Parameters.java
index 2d72252b..ded22996 100644
--- a/vtm/src/org/oscim/utils/Parameters.java
+++ b/vtm/src/org/oscim/utils/Parameters.java
@@ -33,6 +33,11 @@ public final class Parameters {
      */
     public static boolean CUSTOM_TILE_SIZE = false;
 
+    /**
+     * Rendering of distant labels.
+     */
+    public static boolean DISTANT_LABELS = false;
+
     /**
      * If true the <code>MapEventLayer2</code> will be used instead of default <code>MapEventLayer</code>.
      */