From 6742149599d0545dfe619e0a3e7f43c470eb298c Mon Sep 17 00:00:00 2001
From: ClemensFischer <fischer.clemens@gmail.com>
Date: Fri, 22 Aug 2025 16:10:03 +0200
Subject: [PATCH] TileCollection

---
 MapControl/Shared/MapTileLayer.cs        | 17 ++++-------
 MapControl/Shared/TileCollection.cs      | 36 ++++++++++++++----------
 MapControl/Shared/WmtsTileMatrixLayer.cs | 10 +------
 3 files changed, 27 insertions(+), 36 deletions(-)

diff --git a/MapControl/Shared/MapTileLayer.cs b/MapControl/Shared/MapTileLayer.cs
index 0e912e89..173b0abb 100644
--- a/MapControl/Shared/MapTileLayer.cs
+++ b/MapControl/Shared/MapTileLayer.cs
@@ -199,24 +199,17 @@ namespace MapControl
                     {
                         var numTiles = 1 << z;
                         var tileSize = 1 << (TileMatrix.ZoomLevel - z);
-                        var x1 = (int)Math.Floor((double)TileMatrix.XMin / tileSize); // may be negative
-                        var x2 = TileMatrix.XMax / tileSize; // may be greater than numTiles-1
-                        var y1 = Math.Max(TileMatrix.YMin / tileSize, 0);
-                        var y2 = Math.Min(TileMatrix.YMax / tileSize, numTiles - 1);
+                        var xMin = (int)Math.Floor((double)TileMatrix.XMin / tileSize); // may be negative
+                        var xMax = TileMatrix.XMax / tileSize; // may be greater than numTiles-1
+                        var yMin = Math.Max(TileMatrix.YMin / tileSize, 0);
+                        var yMax = Math.Min(TileMatrix.YMax / tileSize, numTiles - 1);
 
-                        for (var y = y1; y <= y2; y++)
-                        {
-                            for (var x = x1; x <= x2; x++)
-                            {
-                                tiles.Add(Tiles.GetTile(z, x, y, numTiles));
-                            }
-                        }
+                        tiles.FillMatrix(Tiles, z, xMin, yMin, xMax, yMax, numTiles);
                     }
                 }
             }
 
             Tiles = tiles;
-
             Children.Clear();
 
             foreach (var tile in tiles)
diff --git a/MapControl/Shared/TileCollection.cs b/MapControl/Shared/TileCollection.cs
index e65a38a7..d13d4935 100644
--- a/MapControl/Shared/TileCollection.cs
+++ b/MapControl/Shared/TileCollection.cs
@@ -6,27 +6,33 @@ namespace MapControl
     public class TileCollection : List<Tile>
     {
         /// <summary>
-        /// Get a matching Tile from a TileCollection or create a new one.
+        /// Adds existing Tiles from the source collection or newly created Tiles to fill the specified tile matrix.
         /// </summary>
-        public Tile GetTile(int zoomLevel, int x, int y, int columnCount)
+        public void FillMatrix(TileCollection source, int zoomLevel, int xMin, int yMin, int xMax, int yMax, int columnCount)
         {
-            var tile = this.FirstOrDefault(t => t.ZoomLevel == zoomLevel && t.X == x && t.Y == y);
-
-            if (tile == null)
+            for (var y = yMin; y <= yMax; y++)
             {
-                tile = new Tile(zoomLevel, x, y, columnCount);
-
-                var equivalentTile = this.FirstOrDefault(
-                    t => t.Image.Source != null && t.ZoomLevel == tile.ZoomLevel && t.Column == tile.Column && t.Row == tile.Row);
-
-                if (equivalentTile != null)
+                for (var x = xMin; x <= xMax; x++)
                 {
-                    tile.IsPending = false;
-                    tile.Image.Source = equivalentTile.Image.Source; // no opacity animation
+                    var tile = source.FirstOrDefault(t => t.ZoomLevel == zoomLevel && t.X == x && t.Y == y);
+
+                    if (tile == null)
+                    {
+                        tile = new Tile(zoomLevel, x, y, columnCount);
+
+                        var equivalentTile = source.FirstOrDefault(
+                            t => t.Image.Source != null && t.ZoomLevel == tile.ZoomLevel && t.Column == tile.Column && t.Row == tile.Row);
+
+                        if (equivalentTile != null)
+                        {
+                            tile.IsPending = false;
+                            tile.Image.Source = equivalentTile.Image.Source; // no opacity animation
+                        }
+                    }
+
+                    Add(tile);
                 }
             }
-
-            return tile;
         }
     }
 }
diff --git a/MapControl/Shared/WmtsTileMatrixLayer.cs b/MapControl/Shared/WmtsTileMatrixLayer.cs
index 971e6e5b..e9199302 100644
--- a/MapControl/Shared/WmtsTileMatrixLayer.cs
+++ b/MapControl/Shared/WmtsTileMatrixLayer.cs
@@ -86,17 +86,9 @@ namespace MapControl
             TileMatrix = new TileMatrix(TileMatrix.ZoomLevel, xMin, yMin, xMax, yMax);
 
             var tiles = new TileCollection();
-
-            for (var y = yMin; y <= yMax; y++)
-            {
-                for (var x = xMin; x <= xMax; x++)
-                {
-                    tiles.Add(Tiles.GetTile(TileMatrix.ZoomLevel, x, y, WmtsTileMatrix.MatrixWidth));
-                }
-            }
+            tiles.FillMatrix(Tiles, TileMatrix.ZoomLevel, xMin, yMin, xMax, yMax, WmtsTileMatrix.MatrixWidth);
 
             Tiles = tiles;
-
             Children.Clear();
 
             foreach (var tile in tiles)