How I solved a digiKam panorama hiccup

I've come across a stumble in digiKam panorama creation, but also found a way around it, too.

I've been preparing for an upcoming trip (it seems like I am always doing that...), and was trying to decide which notebook/netbook to take. My first choice was the lovely new Acer Aspire V3, because I just love the display. But I learned long ago to test everything as much as I could before leaving home, and for this kind of trip I expect to be making extensive use of digiKam, so that went onto the checklist.

digiKam Panorama Tool

As I was running through the various digiKam functions that I use, I got an unpleasant surprise when I tried to create a panorama: The "Stitch images into a panorama function" complained about a missing tool, something called pto2mk. That's not good. Although the tool offers to either find or install the missing bits, I had a strong suspicion that is not the real problem here, there is more likely something else wrong behind the scenes.

A bit of poking around on the web turned up the explanation. As I already knew, digiKam actually uses hugin to create a panorama, it just provides a nicer (or at least different) interface to the various steps involved in doing so. hugin, in turn, has been using pto2pk to assemble a batch job that actually performs the necessary tasks. Now there is a (relatively) new release of hugin which includes its own job execution utility (hugin_executor), so it no longer needs pto2mk, and thus it is no longer included.

The problem apparently is that digiKam (at least up to version 4.13) hasn't caught up with that situation. The panorama utility in digiKam tries to be intelligent and looks around to make sure that all the necessary bits are available, and when it can't find pto2mk it complains.

I have tried to work around this problem in a couple of different ways. First, I just linked hugin_executor to pto2nk, on the hope that digiKam would see a binary with the correct name and not complain. No luck. Then I tried using the find option offered by digiKam, and then pointing to hugin_executor, in hopes this would be the equivalent of saying "here, use this..." Still no joy.

hugin stand-alone

I finally realized there is another way around this.It is possible to run hugin as a stand-alone program; it's not in the normal Linux menus (any more - I think I recall that it once was), but if you just type the name at the KDE menus, it will come up and you can run it. Using it this way is a bit more tedious than via the digiKam panorama creator, but it's not rocket science. There is an assistant included, which helps you walk through the simplest possible creation process. Using that, it's not too difficult to merge multiple images (eight in this example) into one nice panorama:

Alpine View

Once you have gone through the assisted process, you can poke around and look at the other functions and possibilities - and you will discover there is actually even more available than digiKam offers through its panorama creator tool!

I am quite sure that this is a temporary problem, and it will be worked out between the maintainers of digiKam and hugin before too long. But until then, knowing that you can use hugin stand-alone can save the day, and it can even turn into a fun learning experience if you want!

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