Fix tile range error in chunk scan

The chunk scan should have been checking tile bounds using the treedepth
value, not the world boundary. This was causing some tiles near the edge
to not get rendered. In the old version, the row/col boundaries were set
to the treedepth calculated bounds, so this wasn't a problem there.

overviewer_core/tileset.py

@@ -272,8 +272,8 @@ class TileSet(object):
         # not the workers)
 
         # Calculate the min and max column over all the chunks.
-        # This sets self.bounds to a Bounds namedtuple
+        # This returns a Bounds namedtuple
-        self.bounds = self._find_chunk_range()
+        bounds = self._find_chunk_range()
 
         # Calculate the depth of the tree
         for p in xrange(1,33): # max 32
@@ -285,14 +285,16 @@ class TileSet(object):
             # Y has 4 times as many chunks as tiles, then halved since this is
             # a radius
             yradius = 2*2**p
-            if xradius >= self.bounds.maxcol and -xradius <= self.bounds.mincol and \
+            if xradius >= bounds.maxcol and -xradius <= bounds.mincol and \
-                    yradius >= self.bounds.maxrow and -yradius <= self.bounds.minrow:
+                    yradius >= bounds.maxrow and -yradius <= bounds.minrow:
                 break
 
         if p >= 15:
             logging.warning("Just letting you know, your map requries %s zoom levels. This is REALLY big!",
                     p)
         self.treedepth = p
+        self.xradius = xradius
+        self.yradius = yradius
 
         # Do any tile re-arranging if necessary
         self._rearrange_tiles()
@@ -300,7 +302,6 @@ class TileSet(object):
         # Do the chunk scan here
         self.dirtytree = self._chunk_scan()
 
-
     def get_num_phases(self):
         """Returns the number of levels in the quadtree, which is equal to the
         number of phases of work that need to be done.
@@ -412,7 +413,6 @@ class TileSet(object):
             maxrow = max(maxrow, row)
             mincol = min(mincol, col)
             maxcol = max(maxcol, col)
-
         return Bounds(mincol, maxcol, minrow, maxrow)
 
     def _rearrange_tiles(self):
@@ -525,7 +525,10 @@ class TileSet(object):
         # See note at the top of this file about the rendercheck modes for an
         # explanation of what this method does in different situations.
 
+        # Local vars for slightly faster lookups
         depth = self.treedepth
+        xradius = self.xradius
+        yradius = self.yradius
 
         dirty = RendertileSet(depth)
 
@@ -600,14 +603,15 @@ class TileSet(object):
                     c = tilecol - 2*i
                     r = tilerow + 4*j
 
-                    # Make sure the tile is in the range according to the given
+                    # Make sure the tile is in the boundary we're rendering.
-                    # depth. This won't happen unless the user has given -z to
+                    # This can happen when rendering at lower treedepth than
-                    # render a smaller area of the map than everything
+                    # can contain the entire map, but shouldn't happen if the
+                    # treedepth is correctly calculated.
                     if (
-                            c < self.bounds.mincol or
+                            c < -xradius or
-                            c >= self.bounds.maxcol or
+                            c >= xradius or
-                            r < self.bounds.minrow or
+                            r < -yradius or
-                            r >= self.bounds.maxrow
+                            r >= yradius
                             ):
                         continue
 
@@ -649,7 +653,7 @@ class TileSet(object):
         return dirty
 
     def __str__(self):
-        return "<TileSet for %s>" % os.basename(self.outputdir)
+        return "<TileSet for %s>" % os.path.basename(self.outputdir)
 
     def _render_compositetile(self, dest, name):
         """