tile generation algo added

map_tile_renderer.py

@@ -3,11 +3,11 @@
 try:
     from xml.etree.ElementTree import SubElement, parse as parse_xml
     from mapnik import Map, load_map, render_to_file, Box2d
-    from os import unlink
     from sys import argv
-    from os.path import exists
+    from os import getcwd, unlink, mkdir
+    from os.path import exists, join
     from subprocess import run
-    from tile_extent_determinator import get_tile_extent, tiles_required_at_certain_zoom_level
+    from tile_extent_determinator import get_tile_extent
 except ImportError as e:
     print('[!]Module Unavailable : {}'.format(str(e)))
     exit(1)
@@ -16,100 +16,93 @@
 def format_style_sheet(xml_doc, layer_name, element_name, element_attrs, element_text, target_xml):
     # formats template XML stylesheet during runtime.
     et = parse_xml(xml_doc)  # parsing XML document
-    target_elem = None
     for i in et.getroot().findall('Layer'):
-        # iterates over all available layers in XML and selects one using layer_name attribute
-        if(i.attrib.get('name') == layer_name):
+        # iterates over all available layers in XML and selects those which is mentioned in layer_name parameter
+        if(not layer_name):
+            break  # if layer_name is exhausted, just break loop
+        if(i.attrib.get('name') in layer_name):
+            # remove that layer which is found and to be processed
+            layer_name.remove(i.attrib.get('name'))
             target_elem = i.find('Datasource')  # this is our target element
-            break  # in case of success, just break loop
-    if(not target_elem):
-        # if something goes wrong with target Layer Name, denote failure
-        return False
-    # creating a new element, which is child of our target `Datasource` element
-    subelement = SubElement(target_elem, element_name)
-    subelement.text = element_text  # setting text for newly added element
-    subelement.set(*element_attrs)  # sets attribute of new element
+            if(not target_elem):
+                # if something goes wrong with target Layer Name, denote failure
+                return False
+            # creating a new element, which is child of our target `Datasource` element
+            subelement = SubElement(target_elem, element_name)
+            subelement.text = element_text  # setting text for newly added element
+            subelement.set(*element_attrs)  # sets attribute of new element
     if(exists(target_xml)):
         unlink(target_xml)
     et.write(target_xml)  # writes to another XML stylesheet
     return True
 
 
-def tile_generator(x_val, y_val, zoom_lvl, degree_along_x, degree_along_y, num_of_tiles_to_start_with, tile_width, tile_height, style_sheet, output_file):
-    num_of_tiles = tiles_required_at_certain_zoom_level(
-        num_of_tiles_to_start_with, zoom_lvl)
-    print('[+]No.of tiles required => {}'.format(num_of_tiles))
-    extent = get_tile_extent(zoom_lvl, (-180, +90), tile_width, tile_height,
-                             degree_along_x, degree_along_y).get('{},{}'.format(x_val, y_val), [])
-    print(extent)
-    return True
-    if(not extent):
+def tile_generator(zoom_lvl, tile_width, tile_height, style_sheet, target_storage_path):
+    print('\t[+]Generating tiles in zoom level -- {}'.format(zoom_lvl))
+    tiles = get_tile_extent(zoom_lvl, (-180, +90), tile_width, tile_height,
+                            360, 180)
+    if(not tiles):
         return False
-    map_obj = Map(tile_width, tile_height,
-                  '+proj=longlat +datum=WGS84 +no_defs ')
-    if(not format_style_sheet(style_sheet, 'layer1', 'Parameter', [
-            'name', 'extent'], 'something', 'tmp.xml')):
-        return False
-    load_map(map_obj, 'tmp.xml')  # loads XML style sheet
-    map_obj.zoom_to_box(Box2d(*extent))
-    render_to_file(map_obj, output_file, 'png')
+    for key, value in tiles.items():
+        map_obj = Map(tile_width, tile_height,
+                      '+proj=longlat +datum=WGS84 +no_defs ')
+        if(not format_style_sheet(style_sheet, ['layer1'], 'Parameter', [
+                'name', 'extent'], '{}, {}, {}, {}'.format(*value), 'tmp.xml')):
+            return False
+        print(
+            '\t\t[+]Rendering tile {} - {} - {} ...'.format(zoom_lvl, *key.split(',')))
+        load_map(map_obj, 'tmp.xml')  # loads generated XML style sheet
+        map_obj.zoom_to_box(Box2d(*value))
+        render_to_file(map_obj, join(target_storage_path, '{}_{}_{}.png'.format(
+            zoom_lvl, *key.split(','))), 'png')
     # removes temporary XML file, which was generated from template XML
     unlink('tmp.xml')
     return True
 
 
 def input_validator():
     # validates input, which was provided during invokation of function
-    zoom_lvl, x_val, y_val, num_of_tiles_to_start_with, style_sheet, image_file = argv[1:]
+    max_zoom_lvl = argv[1]
     try:
-        zoom_lvl = int(zoom_lvl)
-        x_val = int(x_val)
-        y_val = int(y_val)
-        num_of_tiles_to_start_with = int(num_of_tiles_to_start_with)
+        max_zoom_lvl = int(max_zoom_lvl)
     except ValueError as e:
         print('[!]Error : {}'.format(str(e)))
-        return ()
-    if(zoom_lvl < 0 or zoom_lvl > 10):
-        print('[!]Zoom level value should be in range of 0 to 10')
-        return ()
-    t = True
-    i = 0
-    while(t):
-        tmp = 2**i
-        if(tmp == num_of_tiles_to_start_with):
-            t = False
-        if(tmp > num_of_tiles_to_start_with):
-            t = False
-            i = -1
-        i += 1
-    if(i < 1):
-        print('[!]Minimum number of tiles required to cover World at zoomed out condition needs to be 2^x where x=0,1,2,3 ....\n')
-        return ()
-    if(not exists(style_sheet) or not style_sheet.endswith('.xml')):
-        print('[!]Style Sheet not available !\n')
-        return ()
-    return (zoom_lvl, x_val, y_val, num_of_tiles_to_start_with, style_sheet, image_file)
+        return None
+    if(max_zoom_lvl < 0 or max_zoom_lvl > 10):
+        print('[!]Max Zoom level value should be in range of 0 to 10')
+        return None
+    for i in range(max_zoom_lvl+1):
+        if(not exists('map_tile_renderer_style_sheet_{}.xml'.format(i))):
+            print('[!]Style Sheet not available for zoom-level -- {} !\n'.format(i))
+            return None
+    return max_zoom_lvl
 
 
-def main(tile_width, tile_height):
-    if(len(argv) != 7):
-        print('[+]Usage : ./{} zoom-level x-value y-value number-of-tiles-to-start-with style-sheet image-file-name\n\t[*] zoom-level = 0 to 10\n\t[*] number-of-tiles-to-start-with = 2^x , where x= 0,1,2,3 .... \n'.format(argv[0]))
+def app(tile_width, tile_height):
+    if(len(argv) != 2):
+        print(
+            '[+]Usage : ./{} max-zoom-level \n\t[*] max-zoom-level = 0 to 10\n'.format(argv[0]))
         return
-    try:
-        # if some argument is not okay, it'll fail simply
-        zoom_lvl, x_val, y_val, num_of_tiles_to_start_with, style_sheet, image_file = input_validator()
-    except ValueError:
+    # if command line input argument is not okay, it'll fail simply
+    max_zoom_lvl = input_validator()
+    if(not max_zoom_lvl):
         return
-    print('[+]Generating tile ({},{}) with zoom level {} ...'.format(x_val, y_val, zoom_lvl))
-    if(not tile_generator(x_val, y_val, zoom_lvl, 360, 180, num_of_tiles_to_start_with, tile_width, tile_height, style_sheet, image_file)):
-        print('[!]Illegal Tile extent value !')
+    target_storage_path = join(getcwd(), 'tiles')
+    if(not exists(target_storage_path)):
+        mkdir(target_storage_path)
+    print('[+]Generating all tiles with max zoom level {} ...'.format(max_zoom_lvl))
+    for i in range(max_zoom_lvl+1):
+        if(not tile_generator(i, tile_width, tile_height, 'map_tile_renderer_style_sheet_{}.xml'.format(i), target_storage_path)):
+            print('\t[!]Illegal Tile extent value !')
+            return
+    print('[+]Success')
     return
 
 
 if __name__ == '__main__':
     run('clear')
     try:
-        main(256, 144)
+        app(256, 128)
     except KeyboardInterrupt:
         print('\n[!]Terminated')
     finally: