Improve multiple crop zone support

Amends handling of the 'crop' render option such that when multiple
crop zones are specified, one CroppedRegionSet with many crop zones
is used rather than many CroppedRegionSets each with one crop zone.
This resolves issues where crop zones within the same render
could clobber each others tiles if close enough and could be rendered
with a different number of zoom levels.

overviewer.py

@@ -531,20 +531,12 @@ def set_renderchecks(checkname, num):
 
         # If a crop is requested, wrap the regionset here
         if "crop" in render:
-            rsets = []
-            for zone in render['crop']:
-                rsets.append(world.CroppedRegionSet(rset, *zone))
-        else:
-            rsets = [rset]
+            rset = world.CroppedRegionSet(rset, render['crop'])
 
         # If this is to be a rotated regionset, wrap it in a RotatedRegionSet
         # object
         if (render['northdirection'] > 0):
-            newrsets = []
-            for r in rsets:
-                r = world.RotatedRegionSet(r, render['northdirection'])
-                newrsets.append(r)
-            rsets = newrsets
+            rset = world.RotatedRegionSet(rset, render['northdirection'])
 
         ###############################
         # Do the final prep and create the TileSet object
@@ -560,9 +552,8 @@ def set_renderchecks(checkname, num):
             "dimension", "changelist", "showspawn", "overlay", "base", "poititle", "maxzoom",
             "showlocationmarker", "minzoom", "center"])
         tileSetOpts.update({"spawn": w.find_true_spawn()})  # TODO find a better way to do this
-        for rset in rsets:
-            tset = tileset.TileSet(w, rset, assetMrg, tex, tileSetOpts, tileset_dir)
-            tilesets.append(tset)
+        tset = tileset.TileSet(w, rset, assetMrg, tex, tileSetOpts, tileset_dir)
+        tilesets.append(tset)
 
     # If none of the requested dimenstions exist, tilesets will be empty
     if not tilesets:

overviewer_core/world.py

@@ -1743,42 +1743,38 @@ def iterate_newer_chunks(self, filemtime):
             yield x,z,mtime
 
 class CroppedRegionSet(RegionSetWrapper):
-    def __init__(self, rsetobj, xmin, zmin, xmax, zmax):
+    def __init__(self, rsetobj, cropzones):
         super(CroppedRegionSet, self).__init__(rsetobj)
-        self.xmin = xmin//16
-        self.xmax = xmax//16
-        self.zmin = zmin//16
-        self.zmax = zmax//16
-
-    def get_chunk(self,x,z):
-        if (
-                self.xmin <= x <= self.xmax and
-                self.zmin <= z <= self.zmax
-                ):
-            return super(CroppedRegionSet, self).get_chunk(x,z)
+        newcropzones = []
+        for cz in cropzones:
+            # Crop zone format: (xmin, zmin, xmax, zmax)
+            newcropzones.append(tuple([x // 16 for x in cz]))
+        self.cropzones = newcropzones
+
+    def chunk_in_cropzone(self, x, z):
+        # Determines if chunk at (x, z) is within one of the defined crop zones
+        for cz in self.cropzones:
+            if cz[0] <= x <= cz[2] and cz[1] <= z <= cz[3]:
+                return True
+        return False
+
+    def get_chunk(self, x, z):
+        if self.chunk_in_cropzone(x, z):
+            return super(CroppedRegionSet, self).get_chunk(x, z)
         else:
             raise ChunkDoesntExist("This chunk is out of the requested bounds")
 
     def iterate_chunks(self):
-        return ((x,z,mtime) for (x,z,mtime) in super(CroppedRegionSet,self).iterate_chunks()
-                if
-                    self.xmin <= x <= self.xmax and
-                    self.zmin <= z <= self.zmax
-                )
+        return ((x, z, mtime) for (x, z ,mtime) in super(CroppedRegionSet,self).iterate_chunks()
+                if self.chunk_in_cropzone(x, z))
 
     def iterate_newer_chunks(self, filemtime):
-        return ((x,z,mtime) for (x,z,mtime) in super(CroppedRegionSet,self).iterate_newer_chunks(filemtime)
-                if
-                    self.xmin <= x <= self.xmax and
-                    self.zmin <= z <= self.zmax
-                )
+        return ((x, z, mtime) for (x, z, mtime) in super(CroppedRegionSet,self).iterate_newer_chunks(filemtime)
+                if self.chunk_in_cropzone(x, z))
 
     def get_chunk_mtime(self,x,z):
-        if (
-                self.xmin <= x <= self.xmax and
-                self.zmin <= z <= self.zmax
-                ):
-            return super(CroppedRegionSet, self).get_chunk_mtime(x,z)
+        if self.chunk_in_cropzone(x, z):
+            return super(CroppedRegionSet, self).get_chunk_mtime(x, z)
         else:
             return None