add support for rendering an extra overlay on top of the base map

ocitysmap/__init__.py

@@ -111,6 +111,7 @@ def __init__(self):
         self.language        = None # str (locale)
 
         self.stylesheet      = None # Obj Stylesheet
+        self.overlay         = None # Obj Stylesheet
 
         self.paper_width_mm  = None
         self.paper_height_mm = None
@@ -181,11 +182,11 @@ def assign_if_present(key, cast_fn=str):
         return s
 
     @staticmethod
-    def create_all_from_config(parser):
-        styles = parser.get('rendering', 'available_stylesheets')
-        if not styles:
-            raise ValueError, \
-                    'OCitySMap configuration does not contain any stylesheet!'
+    def create_all_from_config(parser, type='stylesheets'):
+        try:
+            styles = parser.get('rendering', 'available_'+type)
+        except (ConfigParser.NoOptionError, ValueError):
+            return []
 
         return [Stylesheet.create_from_config_section(parser, name.strip())
                 for name in styles.split(',')]
@@ -202,6 +203,8 @@ class OCitySMap:
 
     STYLESHEET_REGISTRY = []
 
+    OVERLAY_REGISTRY = []
+
     def __init__(self, config_files=None):
         """Instanciate a new configured OCitySMap instance.
 
@@ -229,8 +232,14 @@ def __init__(self, config_files=None):
 
         # Read stylesheet configuration
         self.STYLESHEET_REGISTRY = Stylesheet.create_all_from_config(self._parser)
+        if not self.STYLESHEET_REGISTRY:
+            raise ValueError, \
+                    'OCitySMap configuration does not contain any stylesheet!'
         LOG.debug('Found %d Mapnik stylesheets.' % len(self.STYLESHEET_REGISTRY))
 
+        self.OVERLAY_REGISTRY = Stylesheet.create_all_from_config(self._parser, "overlays")
+        LOG.debug('Found %d Mapnik overlay styles.' % len(self.OVERLAY_REGISTRY))
+
     @property
     def _db(self):
         if self.__db:
@@ -391,6 +400,18 @@ def get_stylesheet_by_name(self, name):
                 return style
         raise LookupError, 'The requested stylesheet %s was not found!' % name
 
+    def get_all_overlay_configurations(self):
+        """Returns the list of all available overlay stylesheet configurations 
+           (list of overlay Stylesheet objects)."""
+        return self.OVERLAY_REGISTRY
+
+    def get_overlay_by_name(self, name):
+        """Returns a overlay stylesheet by its key name."""
+        for style in self.OVERLAY_REGISTRY:
+            if style.name == name:
+                return style
+        raise LookupError, 'The requested overlay stylesheet %s was not found!' % name
+
     def get_all_renderers(self):
         """Returns the list of all available layout renderers (list of
         Renderer classes)."""

ocitysmap/layoutlib/multi_page_renderer.py

@@ -265,6 +265,14 @@ def __init__(self, db, rc, tmpdir, dpi, file_prefix):
                                    self._usable_area_height_pt, dpi,
                                    extend_bbox_to_ratio=False)
 
+            # Create canvas for overlay on current page
+            overla_canvas = None
+            if self.rc.overlay:
+                overlay_canvas = MapCanvas(self.rc.overlay,
+                                           bb, self._usable_area_width_pt,
+                                           self._usable_area_height_pt, dpi,
+                                           extend_bbox_to_ratio=False)
+
             # Create the grid
             map_grid = Grid(bb_inner, map_canvas.get_actual_scale(), self.rc.i18n.isrtl())
             grid_shape = map_grid.generate_shape_file(
@@ -280,7 +288,11 @@ def __init__(self, db, rc, tmpdir, dpi, file_prefix):
                                       self.rc.stylesheet.grid_line_width)
 
             map_canvas.render()
-            self.pages.append((map_canvas, map_grid))
+
+            if overlay_canvas:
+		overlay_canvas.render()
+
+            self.pages.append((map_canvas, map_grid, overlay_canvas))
 
             # Create the index for the current page
             inside_contour_wkt = interior_contour.intersection(interior).wkt
@@ -673,13 +685,17 @@ def render(self, cairo_surface, dpi, osm_date):
 
         self._render_overview_page(ctx, cairo_surface, dpi)
 
-        for map_number, (canvas, grid) in enumerate(self.pages):
+        for map_number, (canvas, grid, overlay) in enumerate(self.pages):
 
             rendered_map = canvas.get_rendered_map()
             LOG.debug('Mapnik scale: 1/%f' % rendered_map.scale_denominator())
             LOG.debug('Actual scale: 1/%f' % canvas.get_actual_scale())
             mapnik.render(rendered_map, ctx)
 
+            if overlay:
+		rendered_overlay = overlay.get_rendered_map()
+                mapnik.render(rendered_overlay, ctx)
+
             # Place the vertical and horizontal square labels
             ctx.save()
             ctx.translate(commons.convert_pt_to_dots(self.grayed_margin_pt),

ocitysmap/layoutlib/single_page_renderers.py

@@ -41,6 +41,7 @@
 from indexlib.indexer import StreetIndex
 from indexlib.commons import IndexDoesNotFitError, IndexEmptyError
 import draw_utils
+from ocitysmap.maplib.map_canvas import MapCanvas
 
 LOG = logging.getLogger('ocitysmap')
 
@@ -143,6 +144,14 @@ def __init__(self, db, rc, tmpdir, dpi, file_prefix,
             float(self._map_coords[3]),  # H
             dpi )
 
+        # Prepare map overlay
+        if self.rc.overlay:
+            self._overlay_canvas = MapCanvas(self.rc.overlay,
+                                             self.rc.bounding_box,
+                                             float(self._map_coords[2]),  # W
+                                             float(self._map_coords[3]),  # H
+                                             dpi)
+
         # Prepare the grid
         self.grid = self._create_grid(self._map_canvas)
 
@@ -157,6 +166,11 @@ def __init__(self, db, rc, tmpdir, dpi, file_prefix,
         # Commit the internal rendering stack of the map
         self._map_canvas.render()
 
+        if self.rc.overlay:
+           self._overlay_canvas.render()
+
+
+
 
     def _create_index_rendering(self, on_the_side):
         """
@@ -402,11 +416,20 @@ def render(self, cairo_surface, dpi, osm_date):
         # Draw the rescaled Map
         ctx.save()
         rendered_map = self._map_canvas.get_rendered_map()
+        LOG.debug('Map:')
         LOG.debug('Mapnik scale: 1/%f' % rendered_map.scale_denominator())
         LOG.debug('Actual scale: 1/%f' % self._map_canvas.get_actual_scale())
         mapnik.render(rendered_map, ctx)
         ctx.restore()
 
+        # Draw the rescaled Overlay
+        if self.rc.overlay:
+            ctx.save()
+            rendered_overlay = self._overlay_canvas.get_rendered_map()
+            LOG.debug('Overlay:')
+            mapnik.render(rendered_overlay, ctx)
+            ctx.restore()
+
         # Draw a rectangle around the map
         ctx.rectangle(0, 0, map_coords_dots[2], map_coords_dots[3])
         ctx.stroke()

render.py

@@ -83,6 +83,10 @@ def main():
                       metavar='NAME',
                       help='specify which stylesheet to use. Defaults to the '
                       'first specified in the configuration file.')
+    parser.add_option('--overlay', dest='overlay',
+                      metavar='NAME',
+                      help='specify which overlay stylesheet to use. '
+                      'Defaults to none')
     parser.add_option('-l', '--layout', dest='layout',
                       metavar='NAME',
                       default=KNOWN_RENDERERS_NAMES[0].split()[0],
@@ -156,6 +160,17 @@ def main():
                  % (ex, ', '.join(map(lambda s: s.name,
                       mapper.STYLESHEET_REGISTRY))))
 
+    # Parse overlay stylesheet (defaults to none)
+    if options.overlay is None:
+        overlay = None
+    else:
+        try:
+            overlay = mapper.get_overlay_by_name(options.overlay)
+        except LookupError, ex:
+            parser.error("%s. Available overlay stylesheets: %s."
+                 % (ex, ', '.join(map(lambda s: s.name,
+                      mapper.OVERLAY_REGISTRY))))
+
     # Parse rendering layout
     if options.layout is None:
         cls_renderer = ocitysmap.layoutlib.renderers.get_renderers()[0]
@@ -226,6 +241,7 @@ def main():
     rc.bounding_box = bbox
     rc.language     = options.language
     rc.stylesheet   = stylesheet
+    rc.overlay      = overlay
     if options.orientation == 'portrait':
         rc.paper_width_mm  = paper_descr[1]
         rc.paper_height_mm = paper_descr[2]