Recent change in map visualization code?

[ndoggac]

It seems like a recent update has made loading offline mbtile maps very clunky.  The whole feel of the app is different.  Maps fade in to view slowly, zooms in/out are very slow.  When I have one mbtile at 50% opacity, overlayed on another mbtile, zooming in/out makes the overlay temporarily 100% opacity, then it fades back to its opacity setting.

Everything mentioned above used to be buttery smooth, now its borderline unusable.  What has changed?

[Menion]

Hi,
thanks for the feedback.
I'm testing a few MBT maps I have on the device and all seems to be correct, so there has to be some difference. What if you disable your overlay layer? What about settings > maps > offline > automatic map loading, does it make any difference?

Problem with a temporarily visible overlay when zooming simulated, thanks. I'll fix this for sure.

And what has changed? Our tool tells me that around 350.000 lines of code ... so really a lot.

[ndoggac]

350.000 lines of code

Amazing work menion!  Thanks for all your efforts, it really shows.  Best money I've ever spent on an app.

Thank you for the recognition of the zoom level opacity issue, and upcoming fix.

Speed issues are independent of "automatic map loading" setting, tried all three options with no effect.

Disabling overlay layer definitely sped things up, but overall things are slower in either mode.  I have used this option a lot in the past and was used to (and understood) the speed diffs with it on/off.

MBT with either JPG or PNG underlying imagery is affected.

Also now getting errors with no imagery shown where I know there is some in the MBT, and the message "Map of this area is not available".  This is happening with several MBT files.

Speed issue is recognizable across multiple devices.

[Menion]

Hmm, I have three MBT maps on the device and see no difference.
Is it possible to download any map you use to check if there isn't anything special that may slow things down? Thanks.

[ndoggac]

I think if I shutdown/close LM with the overlayed MBT off, viewing only the underlying MBT imagery, then start the app back up performance seems normal.  As soon as I turn on overlayed MBT, performance is terrible.  Then turn it back off, performance is still hindered although not as bad as with overlay off but definitely worse than normal, until I restart the app.  Once app is restarted (w. overlay off), performance seems normal again.  This behavior is independent of which MBT file I utilize.

This is the MBTILE file that is not displaying correctly, southern half does not appear when zoomed in.  It loads fine in QGIS 3, and previously in LM.  (~13MB)
https://drive.google.com/file/d/0B8HbMSWXSoZEaGxzaHhaTk5jckU/view?usp=sharing

[Menion]

Hello, thanks for the map, it helped a lot. I probably found the reason for both issues.
Slowness is caused by a new system that tries to fill gaps in certain zoom by searching for useful map tile from zoom above and below. In your case, where not all zooms have full coverage, the app spends a lot of time on this task. So I've disabled it now and will invest more time to find a more performant way.

Missing half of the map was caused by incorrect detection of map border, fixed hopefully as well.

If you will have a moment, will you try a special version if I made one? Just to be sure, it works better then before.

[ndoggac]

Thanks again menion!  I can try the special version.  PM me the link?

[Menion]

Hello,
fine thanks. I've just published new Beta version 3.38.0.1 so give it a try if you will have a free moment, thank you.

[ndoggac]

Holiday weekend, so didn't get to the beta version. 3.38.2 came tonight through normal upgrade process. Performance back to its normal feel when moving around with MBT overlay on and off. MBT previously linked loads up just fine, as do others I had issues with.

Only comment left would be that the MBT overlay still comes into view after moving in delayed, stepped opacities. Maybe that's expected though? Personal opinion, I preferred it the old way.

Thanks so much for the fixes!!

[ndoggac]

If you're interested, here's the MBT I overlaid on top of the MBT linked above.  When you zoom in/out, the overlay seems to run through several opacity variations before coming into full view.  Perhaps this is expected behavior?

https://drive.google.com/file/d/1OP3LparlGBzm9hWlBa3YyAERN6f4b5N0/view