These are chat archives for openseadragon/openseadragon

15th
May 2017
Ian Gilman
@iangilman
May 15 2017 16:56
@avandecreme Very cool!
rmcloughlin
@rmcloughlin
May 15 2017 21:04
I noticed that if my tile size is 254 then OSD starts out loading images at a sensible level (level 9). However if my tile size is 1024 then OSD starts all the way down at level zero and loads all levels up from there. Is this to be expected? I don't see why it needs 0/0_0.jpeg given that it's 1x1 pixel.
Ian Gilman
@iangilman
May 15 2017 21:06
@rmcloughlin I'm guessing it's #1020. The patch for it is #1193. Would you mind building that branch and verifying that it fixes your issue?
(the difference between 254 and 1024 being just enough to change the timing)
Btw, if you have your DZI overlap set to 1, I recommend 1022 for your tile size (so with both overlaps it comes out to 1024 which is a nice power of 2)
rmcloughlin
@rmcloughlin
May 15 2017 21:09
Sure, I will give it a try.
Ian Gilman
@iangilman
May 15 2017 21:10
Thank you :)
rmcloughlin
@rmcloughlin
May 15 2017 21:10
Also is there any technical benefit to the "nice power of 2"?
Ian Gilman
@iangilman
May 15 2017 21:12
GPUs sometimes require power of 2 textures, so if you're just over (e.g. 1026) they have to pad it into the next bigger power of 2. OSD uses canvas, which presumably involves the GPU on at least some browser/OS combinations, so it may be relevant for performance in those situations.
...but I don't know for sure. At any rate, it's easy to do, so it's okay if it's a "just in case"
rmcloughlin
@rmcloughlin
May 15 2017 21:13
Got it, thank you!
Ian Gilman
@iangilman
May 15 2017 21:13
:)
rmcloughlin
@rmcloughlin
May 15 2017 21:51
It did not seem to help. But I'm not 100% confident that I've built it correctly. The MD5 sum of my openseadragon.min.js is 139f4b66ece9e38c7f255e786734a374
rmcloughlin
@rmcloughlin
May 15 2017 22:01
Please let me know if there's anything I can do to help debug it (e.g. trying at different tile sizes)
Ian Gilman
@iangilman
May 15 2017 22:50
@rmcloughlin Interesting; Well, can you make a simple repro and share it?