Add simple render script.

demo/simple-renderer/render.py

@@ -0,0 +1,23 @@
+#!/usr/bin/env python
+
+import sys
+import mapnik
+
+def render(input_file, output_file, width=800, height=800, bbox=None):
+    m = mapnik.Map(width, height)
+    mapnik.load_map(m, input_file, False)
+    if bbox is not None:
+        m.zoom_to_box(bbox)
+    else:
+        m.zoom_all()
+    mapnik.render_to_file(m, output_file)
+
+if len(sys.argv) == 2:
+    render(sys.argv[1], "output.png")
+elif len(sys.argv) == 3:
+    render(sys.argv[1], sys.argv[2])
+elif len(sys.argv) == 5:
+    render(sys.argv[1], sys.argv[2], int(sys.argv[3]), int(sys.argv[4]))
+else:
+    print "usage: %s style_file [output_file] [width height]" % sys.argv[0]
+    sys.exit(1)