Improve smoothness by protecting visible tiles

PBMap.pb

@@ -1423,6 +1423,53 @@ Module PBMap
     LockMutex(*PBMap\MemoryCacheAccessMutex) ; Prevents threads to start or finish
     Protected CacheSize = MapSize(*PBMap\MemCache\Images()) * Pow(*PBMap\TileSize, 2) * 4 ; Size of a tile = TileSize * TileSize * 4 bytes (RGBA) 
     Protected CacheLimit = *PBMap\Options\MaxMemCache * 1024
+    Protected EnabledLayers.i
+    Protected MinTiles.i
+    Protected MinCacheBytes.i
+    Protected nx.i = DesktopScaledX(GadgetWidth(*PBMap\Gadget)) / 2 / *PBMap\TileSize
+    Protected ny.i = DesktopScaledY(GadgetHeight(*PBMap\Gadget)) / 2 / *PBMap\TileSize
+    Protected NewMap ProtectedTiles.i()
+    Protected TileCoords.Coordinates
+    Protected tx.i, ty.i, tilex.i, tiley.i, x.i, y.i
+    Protected kq.q
+    Protected key.s
+    Protected tilemax.i = 1 << *PBMap\Zoom
+
+    ForEach *PBMap\LayersList()
+      If *PBMap\LayersList()\Enabled
+        EnabledLayers + 1
+      EndIf
+    Next
+
+    If EnabledLayers > 0
+      MinTiles = (2 * nx + 3) * (2 * ny + 3) * EnabledLayers
+      MinCacheBytes = MinTiles * Pow(*PBMap\TileSize, 2) * 4
+      CacheLimit = Max(CacheLimit, MinCacheBytes)
+
+      LatLon2TileXY(@*PBMap\GeographicCoordinates, @TileCoords, *PBMap\Zoom)
+      tx = Int(TileCoords\x)
+      ty = Int(TileCoords\y)
+
+      ForEach *PBMap\LayersList()
+        If *PBMap\LayersList()\Enabled
+          For y = -ny - 1 To ny + 1
+            For x = -nx - 1 To nx + 1
+              tilex = (tx + x) % tilemax
+              If tilex < 0
+                tilex + tilemax
+              EndIf
+              tiley = ty + y
+              If tiley >= 0 And tiley < tilemax
+                kq = (*PBMap\Zoom << 8) | (tilex << 16) | (tiley << 36)
+                key = *PBMap\LayersList()\Name + Str(kq)
+                ProtectedTiles(key) = 1
+              EndIf
+            Next
+          Next
+        EndIf
+      Next
+    EndIf
+
     MyDebug(*PBMap, "Cache size : " + Str(CacheSize/1024) + " / CacheLimit : " + Str(CacheLimit/1024), 5)
     If CacheSize > CacheLimit    
       MyDebug(*PBMap, " Cache full. Trying cache cleaning", 5)
@@ -1432,6 +1479,7 @@ Module PBMap
         Protected CacheMapKey.s = *PBMap\MemCache\ImagesTimeStack()\MapKey
         ; Is the loading over
         If *PBMap\MemCache\Images(CacheMapKey)\Tile <= 0 ;TODO Should not verify this var directly
+          If FindMapElement(ProtectedTiles(), CacheMapKey) = 0
             MyDebug(*PBMap, "  Delete " + CacheMapKey, 5)
             If *PBMap\MemCache\Images(CacheMapKey)\nImage;IsImage(*PBMap\MemCache\Images(CacheMapKey)\nImage)
               FreeImage(*PBMap\MemCache\Images(CacheMapKey)\nImage)
@@ -1440,6 +1488,7 @@ Module PBMap
             EndIf
             DeleteMapElement(*PBMap\MemCache\Images(), CacheMapKey)
             DeleteElement(*PBMap\MemCache\ImagesTimeStack(), 1)
+          EndIf
           ;           ElseIf *PBMap\MemCache\Images(CacheMapKey)\Tile = 0 
           ;             MyDebug(*PBMap, "  Delete " + CacheMapKey, 5)
           ;             DeleteMapElement(*PBMap\MemCache\Images(), CacheMapKey)
@@ -3313,9 +3362,9 @@ EndModule
  
 
 
-; IDE Options = PureBasic 6.21 (Windows - x64)
+; IDE Options = PureBasic 6.12 LTS (Windows - x86)
-; CursorPosition = 53
+; CursorPosition = 484
-; FirstLine = 40
+; FirstLine = 468
 ; Folding = ---------------------
 ; EnableThread
 ; EnableXP