CODEWITHSUNDEEP
javascriptopenseadragon
user1690146
user1690146

Reputation: 393

Custom Tile Source Multiple Image Hosts?

In experimenting with a custom tile source in OpenSeadragon, I was wondering if there is a way to cycle multiple image hosts, to improve the async way in which the browser retrieves resources?

In the 

getTileUrl: function(level, x, y){
  return "imagecdn1.example.com/" + 
    level + "/" + x + "_" + "y" + ".png"

..can I put a %d or some sort of cycling value (of '1' in this example) so that I get the following round-robin set of calls for tiles?

Example sequence:

imagecdn1.example.com
imagecdn2.example.com
imagecdn3.example.com

Is this possible?

As a follow-up if it is not possible, does this really improve the performance anyway in the browser, in that should I even be doing it at a URL level?

Upvotes: 0

Views: 168

Answers (1)

avandecreme
avandecreme

Reputation: 979

This is not possible however you can do that yourself in your getTileUrl method:

var inc = 0;
getTileUrl: function(level, x, y){
  inc++;
  inc = inc % 3 + 1; //number of cdn you have
  return "imagecdn" + inc + ".example.com/" + 
    level + "/" + x + "_" + "y" + ".png"

I doubt that would be really beneficial though.

One disadvantage I can think of is that if a tile is already cached at one URL, it will be redownloaded anyway if getTileUrl return a different URL.

Upvotes: 2

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