deepzoom-tile: Fix running viewer from local disk on Chrome

Author: bgilbert

examples/deepzoom/deepzoom-tile.py

@@ -20,6 +20,7 @@
 
 """An example program to generate a Deep Zoom directory tree from a slide."""
 
+import json
 from multiprocessing import Process, JoinableQueue
 from openslide import open_slide, ImageSlide
 from openslide.deepzoom import DeepZoomGenerator
@@ -110,7 +111,10 @@ def _tile_done(self):
 
     def _write_dzi(self):
         with open('%s.dzi' % self._basename, 'w') as fh:
-            fh.write(self._dz.get_dzi(self._format))
+            fh.write(self.get_dzi())
+
+    def get_dzi(self):
+        return self._dz.get_dzi(self._format)
 
 
 class DeepZoomStaticTiler(object):
@@ -126,6 +130,7 @@ def __init__(self, slidepath, basename, format, tile_size, overlap,
         self._queue = JoinableQueue(2 * workers)
         self._workers = workers
         self._with_viewer = with_viewer
+        self._dzi_data = {}
         for _i in range(workers):
             TileWorker(self._queue, slidepath, tile_size, overlap).start()
 
@@ -150,8 +155,10 @@ def _run_image(self, associated=None):
             image = ImageSlide(self._slide.associated_images[associated])
             basename = os.path.join(self._basename, self._slugify(associated))
         dz = DeepZoomGenerator(image, self._tile_size, self._overlap)
-        DeepZoomImageTiler(dz, basename, self._format, associated,
-                    self._queue).run()
+        tiler = DeepZoomImageTiler(dz, basename, self._format, associated,
+                    self._queue)
+        tiler.run()
+        self._dzi_data[self._url_for(associated)] = tiler.get_dzi()
 
     def _url_for(self, associated):
         if associated is None:
@@ -167,9 +174,13 @@ def _write_html(self):
         template = env.get_template('index.html')
         associated_urls = dict((n, self._url_for(n))
                     for n in self._slide.associated_images)
+        # Embed the dzi metadata in the HTML to work around Chrome's
+        # refusal to allow XmlHttpRequest from file:///, even when
+        # the originating page is also a file:///
         data = template.render(slide_url=self._url_for(None),
                     associated=associated_urls,
-                    properties=self._slide.properties)
+                    properties=self._slide.properties,
+                    dzi_data=json.dumps(self._dzi_data))
         with open(os.path.join(self._basename, 'index.html'), 'w') as fh:
             fh.write(data)
 

examples/deepzoom/templates/index.html

@@ -7,14 +7,16 @@
 
 <script type="text/javascript">
 $(document).ready(function() {
+    var dzi_data = {{ dzi_data|default('{}')|safe }};
     var viewer = new Seadragon.Viewer("view");
-    viewer.openDzi("{{ slide_url }}");
+    viewer.openDzi("{{ slide_url }}", dzi_data["{{ slide_url }}"]);
     viewer.config.animationTime = 0.5;
     viewer.config.blendTime = 0.1;
     $(".load-slide").click(function(ev) {
         $(".current-slide").removeClass("current-slide");
         $(this).parent().addClass("current-slide");
-        viewer.openDzi($(this).attr('data-url'));
+        var url = $(this).attr('data-url');
+        viewer.openDzi(url, dzi_data[url]);
         ev.preventDefault();
     });
 });