Add an additional level of zoom

Note that this *really* doesn't scale: tile generation has to manipulate
really large images (more than 3 GB RAM for large panorama), and it
produces a hell of a lot of tiles.  And this is for just one additional
level of zoom.

We should instead find a solution where the browser upscales the tiles
when we need more zoom than the base zoom level.

panorama/gen_tiles.py

@@ -19,14 +19,17 @@ import tempfile
 import PIL.Image
 
 
-def gen_tiles(image, output_path, min_scale=0, max_scale=8, crop_x=256, crop_y=256):
+def gen_tiles(image, output_path, min_scale=-1, max_scale=8, crop_x=256, crop_y=256):
     orig_im = PIL.Image.open(image)
     for scale in range(min_scale, max_scale + 1):
         if scale == 0:
             im = orig_im
-        else:
+        elif scale > 0:
             scaled_size = (orig_im.size[0] >> scale, orig_im.size[1] >> scale)
             im = orig_im.resize(scaled_size)
+        else:
+            scaled_size = (orig_im.size[0] << (-scale), orig_im.size[1] << (-scale))
+            im = orig_im.resize(scaled_size, resample=PIL.Image.BILINEAR)
         for x in range(0, im.size[0], crop_x):
             for y in range(0, im.size[1], crop_y):
                 geom = (x, y, min(im.size[0], x + crop_x),

panorama/models.py

@@ -157,9 +157,13 @@ class Panorama(ReferencePoint):
         """Hack to feed the current js code with tiles data (we should use the
         JSON API instead, and get rid of this function)"""
         data = dict()
-        for zoomlevel in range(9):
-            width = self.image_width >> zoomlevel
-            height = self.image_height >> zoomlevel
+        for zoomlevel in range(-1, 9):
+            if zoomlevel >= 0:
+                width = self.image_width >> zoomlevel
+                height = self.image_height >> zoomlevel
+            else:
+                width = self.image_width << (-zoomlevel)
+                height = self.image_height << (-zoomlevel)
             d = dict()
             d["tile_width"] = d["tile_height"] = 256
             # Python3-style division

panorama/static/panorama/js/pano.js

@@ -270,11 +270,19 @@ function erase_point() {
  * ex: 3 -> "003"
  */
 function zero_pad(number) {
-	var temp = number.toString(10);
-	while (temp.length < 3) {
-		temp = '0' + temp;
-	}
-	return temp;
+    var temp = Math.abs(number).toString(10);
+    var max_len;
+    if (number < 0)
+        max_len = 2;
+    else
+        max_len = 3;
+    while (temp.length < max_len) {
+	temp = '0' + temp;
+    }
+    if (number < 0)
+        return '-' + temp;
+    else
+        return temp;
 }
 
 function get_file_name(x, y, z) { // recherche du fichier correspondant au zoom et à la position

panorama/templates/panorama/view.html

@@ -46,7 +46,7 @@
     </canvas>
 
     <fieldset id="control"><legend>contrôle</legend>
-      <label>Zoom : <input type="range" min="0" max="2" value="2" id="zoom_ctrl"/></label>
+      <label>Zoom : <input type="range" min="-1" max="2" value="2" id="zoom_ctrl"/></label>
       <label>Cap : <input type="number" min="0" max="360" step="10" value="0" autofocus="" id="angle_ctrl"/></label>
       <label>Élévation : <input type="number" min="-90" max="90" step="1" value="0" autofocus="" id="elvtn_ctrl"/></label>
     </fieldset>