OpenSeaDragon not displaying multiple images in dzc_output.xml file

Question

I'm trying to display multiple images with OpenSeaDragon. I used Deep Zoom Composer to create the image files and it produced the following XML file (abridged):

dzc_output.xml:

<?xml version="1.0" encoding="utf-8"?>
<Collection MaxLevel="8" TileSize="256" Format="jpg" NextItemId="5" ServerFormat="Default" xmlns="http://schemas.microsoft.com/deepzoom/2009">
  <Items>
    <I Id="0" N="0" Source="dzc_output_images/ft1.xml">
      <Size Width="825" Height="584" />
      <Viewport Width="5.2402050398801272" X="-0" Y="-0" />
    </I>
    <I Id="1" N="1" Source="dzc_output_images/ft2.xml">
      <Size Width="824" Height="583" />
      <Viewport Width="5.2375806686733934" X="-1.0500455705877254" Y="-0" />
    </I>
    <!--3 more images not shown as not necessary-->
  </Items>
</Collection>

I created a very simple HTML page to display the viewer (I plan to use Django for the final project). I created the viewer with the following code:

var viewer = OpenSeadragon({
                id: "openseadragon1",
                prefixUrl: "openseadragon/images/",
                tileSources: "imagesources/dzc_output.xml",
                sequenceMode: true
            });

I'm using python -m http.server to serve the folder that the html page is in. It worked fine for single images. However, with this dzc_output.xml file containing multiple images, the viewer displays "Unable to open [object Object]: Unable to load TileSource" when I load the page. Scrolling through the images produces this error: "Unable to open [object Object]: HTTP 404 attempting to load TileSource"

I'm not sure what the problem is here. Any help would be good.

iangilman iangilman · Accepted Answer · 2019-11-14T23:21:22

Indeed... that's a "Deep Zoom Collection", which is a different format from "Deep Zoom Image" which is what OpenSeadragon supports. We have an issue for support DZCs: https://github.com/openseadragon/openseadragon/issues/67, but so far there hasn't been any action on it.

At this point you have a variety of options:

Export the images as DZIs from Deep Zoom Composer instead.
Write a script to convert the DZC output into a series of DZIs for use in OSD.
Help us implement DZC support natively to OSD.

Now that we have true multi-image, supporting DZC shouldn't be too hard. One aspect, as discussed in https://github.com/openseadragon/openseadragon/issues/67, is that DZC also includes an additional tile pyramid with thumbnails for the images (see https://docs.microsoft.com/en-us/previous-versions/windows/silverlight/dotnet-windows-silverlight/cc645077(v=vs.95)#collections for more info). That's a nice optimization (saves on network traffic), but we can skip it for starters and just use the DZC as a directory of DZIs.

Note that this issue is also discussed in https://github.com/openseadragon/openseadragon/issues/1735.

OpenSeaDragon not displaying multiple images in dzc_output.xml file

1 Answers