export history

src/c3nav/mapdata/cache.py

@@ -6,6 +6,7 @@ from itertools import chain
 import numpy as np
 from django.conf import settings
 from django.db.models.signals import m2m_changed, post_delete
+from PIL import Image
 from shapely import prepared
 from shapely.geometry import box
 from shapely.ops import unary_union
@@ -56,10 +57,13 @@ class MapHistory:
 
     def save(self, filename):
         with open(filename, 'wb') as f:
-            f.write(struct.pack('<BHHHHH', self.resolution, self.x, self.y, *reversed(self.data.shape),
-                                len(self.updates)))
-            f.write(struct.pack('<'+'II'*len(self.updates), *chain(*self.updates)))
-            f.write(self.data.tobytes('C'))
+            self.write(f)
+
+    def write(self, f):
+        f.write(struct.pack('<BHHHHH', self.resolution, self.x, self.y, *reversed(self.data.shape),
+                            len(self.updates)))
+        f.write(struct.pack('<'+'II'*len(self.updates), *chain(*self.updates)))
+        f.write(self.data.tobytes('C'))
 
     def add_new(self, geometry):
         prep = prepared.prep(geometry)
@@ -125,6 +129,18 @@ class MapHistory:
         self.y += miny
         self.data = self.data[miny:maxy+1, minx:maxx+1]
 
+    def to_image(self):
+        from c3nav.mapdata.models import Source
+        (miny, minx), (maxy, maxx) = Source.max_bounds()
+
+        height, width = self.data.shape
+        image_data = np.zeros((int(math.ceil((maxy-miny)/self.resolution)),
+                               int(math.ceil((maxx-minx)/self.resolution))), dtype=np.uint8)
+        visible_data = (self.data.astype(float)*255/(len(self.updates)-1)).clip(0, 255).astype(np.uint8)
+        image_data[self.y:self.y+height, self.x:self.x+width] = visible_data
+
+        return Image.fromarray(np.flip(image_data, axis=0), 'L')
+
 
 class GeometryChangeTracker:
     def __init__(self):

src/c3nav/mapdata/urls.py

@@ -1,7 +1,8 @@
 from django.conf.urls import url
 
-from c3nav.mapdata.views import tile
+from c3nav.mapdata.views import history, tile
 
 urlpatterns = [
     url(r'^(?P<level>\d+)/(?P<zoom>\d+)/(?P<x>-?\d+)/(?P<y>-?\d+).(?P<format>png|svg)$', tile, name='mapdata.tile'),
+    url(r'^history/(?P<level>\d+)/(?P<mode>base|render).(?P<format>png|data)$', history, name='mapdata.history'),
 ]

src/c3nav/mapdata/views.py

@@ -1,9 +1,12 @@
 import os
 
 from django.conf import settings
+from django.core.exceptions import PermissionDenied
 from django.http import Http404, HttpResponse, HttpResponseNotModified
+from django.shortcuts import get_object_or_404
 from shapely.geometry import box
 
+from c3nav.mapdata.cache import MapHistory
 from c3nav.mapdata.models import Level, MapUpdate, Source
 from c3nav.mapdata.render.svg import SVGRenderer
 
@@ -88,3 +91,23 @@ def tile(request, level, zoom, x, y, format):
     response['Cache-Control'] = 'no-cache'
 
     return response
+
+
+def history(request, level, mode, format):
+    if not request.user.is_superuser:
+        raise PermissionDenied
+    level = get_object_or_404(Level, pk=level)
+
+    if mode == 'render' and level.on_top_of_id is None:
+        raise Http404
+
+    history = MapHistory.open(os.path.join(settings.CACHE_ROOT, 'level_%s_%d' % (mode, level.pk)))
+    if format == 'png':
+        response = HttpResponse(content_type='image/png')
+        history.to_image().save(response, format='PNG')
+    elif format == 'data':
+        response = HttpResponse(content_type='application/octet-stream')
+        history.write(response)
+    else:
+        raise ValueError
+    return response