Update 2020-06-27: Qlik sense has changed since I originally wrote this, up to date version of using a Promise can be found here:
One of the great new features in Qlik Sense is snapshots and storytelling. It allows you to create a snapshot of your visualizations, with the current selection state, and then include the snapshot in a story. Behind the scenes Qlik Sense also uses snapshot for export to PDF, PowerPoint and image. This makes it even more important for you to make your extension work well with snapshots. Sometimes this is however not easy…
The basics
To turn snapshots on, you need to include a few lines in your extension:
This will give you a context menu in the client with alternatives to create snapshot and export the visualization. That might be enough, but it might not be enough. To verify it you should:
- create a snapshot of your extension, include it in a story and verify that it works
- export your extension to PDF and/or PowerPoint (possibly also image)
- and export the story to Powerpoint/PDF
You visualization is actually used in three contexts, that are somewhat different:
- the normal analyse mode, with live data, affected by changes in selection state
- the snapshot/story mode with a snapshot of data and the selection state as it was when the snapshot was created
- the export mode, which is also based on a snapshot, but run in a separate service on the server
To make it actually work in all, you might need to do some more work.
Make Qlik Sense wait for your extension
One problem, mainly in export, is to let Qlik Sense know when your extension actually is ready with the rendering. You might get just an empty area in your powerpoint, or just the header but no content. This might be because the image is taken before your extension is ready.
The mechanism to fix this is a javascript concept called a Promise. Your paint method should return a Promise, that resolves when the rendering is ready. Qlik Sense will then wait until the Promise is resolved and then grab the image.
This is described where briefly in Qlik Sense help under ‘Set up “finished rendering” notification, like this:
This will return a Promise, that immediately resolves. This might not be good enough, since you might want to wait for something until you resolve. In my case, I used highcarts and highcharts has a callback function that will be called when rendering is ready. The final solution is like this:
So, I create a deferred object before calling the Highcharts rendering method. I can then return the promise that belongs to the deferred, but I do not resolve it until Highcharts tells me that rendering is complete, actually I had to add an additional delay of 1 second to make sure. There is currently no documentation of qlik.Promise in Qlik Sense help, but you can look in the angularjs documentation.
Turn animations off
If it’s still not working, you should take a look at animations. Animations in analyse mode are good (if used the right way…) and might help the user discover insights in their data, but in export they should be turned off.
In Highcharts there are actually two flags you should turn off to diable animations. It might be enough to turn off just one of them, but why not both:
The isSnapshot flag which I use to determine if we are in analyse mode or in snapshot (story or export) is undocumented, so this solution might break in future Qlik Sense versions, but in September 2017 it works.