Updated png-it.py, now it has --autocrop option.

contrib/png-it.py

@@ -27,6 +27,9 @@ def main():
     parser.add_option('--center', '-e', help = 'Mark what will be the center of the image, two percentage values comma separated',\
         metavar = '<center>', type = str, dest = 'center', default = None)
 
+    parser.add_option('--autocrop', '-a', help = 'Calculates the center and crop vales automatically to show all the tiles in the minimun image size.Unless you want a very specific image this options is very recommendedable.',\
+         action = 'store_true', dest = 'autocrop', default = False)
+
     parser.add_option('--output', '-o', help = 'Path for the resulting PNG. It will save it as PNG, no matter what extension do you use.',\
         metavar = '<output>', type = str, dest = 'output', default = "output.png")
 
@@ -43,6 +46,9 @@ def main():
     if not options.zoom_level:
         parser.error("Error! The option zoom-level is mandatory.")
     
+    if options.autocrop and (options.center or options.crop):
+        parser.error("Error! You can't mix --autocrop with --center or --crop.")
+    
     # check for the output
     folder, filename = split(options.output)
     if folder != '' and not exists(folder):
@@ -54,8 +60,50 @@ def main():
     tile_size = (384,384)
     px_size = 4 # bytes
 
-    # the vector that joins the center tile with the new center tile in
-    # tile coords (tile coords is how many tile are on the left, x, and 
+    # create a list with all the images in the zoom level
+    path = tileset
+    for i in range(options.zoom_level):
+        path = join(path, "?")
+    path += ".png"
+    
+    all_images = glob(path)
+    if not all_images:
+        "Error! No images found in this zoom leve. Is this really an overviewer tile set directory?"
+        sys.exit(1)
+
+    # autocrop will calculate the center and crop values automagically
+    if options.autocrop:
+        min_x = min_y = length_in_tiles
+        max_x = max_y = 0
+        counter = 0
+        total = len(all_images)
+        print "Checking tiles for autocrop calculations:"
+        # get the maximun and minimun tiles coordinates of the map
+        for path in all_images:
+            t = get_tuple_coords(options, path)
+            c = get_tile_coords_from_tuple(options, t)
+            min_x = min(min_x, c[0])
+            min_y = min(min_y, c[1])
+            max_x = max(max_x, c[0])
+            max_y = max(max_y, c[1])
+            counter += 1
+            if (counter % 100 == 0 or counter == total or counter == 1): print "Checked {0} of {1}".format(counter, total)
+        
+        # the center of the map will be in the middle of the occupied zone
+        center = (int((min_x + max_x)/2.), int((min_y + max_y)/2.))
+        # see the next next comment to know what's center_vector
+        center_vector = (int(center[0] - (length_in_tiles/2. - 1)), int(center[1] - (length_in_tiles/2. - 1)))
+        # I'm not completely sure why, but the - 1 factor in  ^  makes everything nicer.
+        
+        # min_x - center_vector[0] will be the unused amount of tiles in
+        # the left and the right of the map (and this is true because we
+        # are in the actual center of the map)
+        crop = (min_x - center_vector[0], min_y - center_vector[1])
+        
+    else:
+        # center_vector is the vector that joins the center tile with
+        # the new center tile in tile coords
+        #(tile coords are how many tile are on the left, x, and 
         # how many above, y. The top-left tile has coords (0,0)
         if options.center:
             center_x, center_y = options.center.split(",")
@@ -67,6 +115,7 @@ def main():
         else:
             center_vector = (0,0)
 
+        # crop if needed
         tiles_to_crop = int(2**n*(options.crop/100.))
         crop = (tiles_to_crop, tiles_to_crop)
 
@@ -80,17 +129,6 @@ def main():
         print "Warning! The expected RAM usage exceeds the spicifyed limit. Exiting."
         sys.exit(1)
 
-    # create a list with all the images in the zoom level
-    path = tileset
-    for i in range(options.zoom_level):
-        path = join(path, "?")
-    path += ".png"
-    
-    all_images = glob(path)
-    if not all_images:
-        "Error! No images found in this zoom leve. Is this really an overviewer tile set directory?"
-        sys.exit(1)
-
     # Create a new huge image
     final_img = Image.new("RGBA", final_cropped_img_size, (26, 26, 26, 0))