From 1fd37af4a10e318e13c2688b7ff3402584beea9a Mon Sep 17 00:00:00 2001
From: Ian Gilman <ian@iangilman.com>
Date: Tue, 19 Mar 2019 11:16:28 -0700
Subject: [PATCH] Brought changes over from
 https://github.com/paaddyy/openseadragon and cleaned up whitespace

---
 src/imageloader.js   | 25 +++++++++++++++++++++++--
 src/openseadragon.js |  4 +++-
 src/viewer.js        |  4 +++-
 3 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/src/imageloader.js b/src/imageloader.js
index 14eb576b..2a4dc6f3 100644
--- a/src/imageloader.js
+++ b/src/imageloader.js
@@ -46,12 +46,14 @@
  * @param {Function} [options.callback] - Called once image has been downloaded.
  * @param {Function} [options.abort] - Called when this image job is aborted.
  * @param {Number} [options.timeout] - The max number of milliseconds that this image job may take to complete.
+ * @param {Number} [options.tries] - Actual number of the current try.
  */
 function ImageJob (options) {
 
     $.extend(true, this, {
         timeout: $.DEFAULT_SETTINGS.timeout,
-        jobId: null
+        jobId: null,
+        tries: 0
     }, options);
 
     /**
@@ -70,6 +72,8 @@ ImageJob.prototype = {
      * @method
      */
     start: function(){
+        this.tries++;
+
         var self = this;
         var selfAbort = this.abort;
 
@@ -180,6 +184,7 @@ $.ImageLoader = function(options) {
         jobLimit:       $.DEFAULT_SETTINGS.imageLoaderLimit,
         timeout:        $.DEFAULT_SETTINGS.timeout,
         jobQueue:       [],
+        failedTiles:    [],
         jobsInProgress: 0
     }, options);
 
@@ -244,7 +249,8 @@ $.ImageLoader.prototype = {
 };
 
 /**
- * Cleans up ImageJob once completed.
+ * Cleans up ImageJob once completed. Restarts job after 2.5 seconds
+ * if it failed loading but max three times.
  * @method
  * @private
  * @param loader - ImageLoader used to start job.
@@ -252,6 +258,10 @@ $.ImageLoader.prototype = {
  * @param callback - Called once cleanup is finished.
  */
 function completeJob(loader, job, callback) {
+    if (job.errorMsg != '' && job.image === null && job.tries < 1 + loader.tileRetryMax) {
+        loader.failedTiles.push(job);
+    }
+
     var nextJob;
 
     loader.jobsInProgress--;
@@ -262,6 +272,17 @@ function completeJob(loader, job, callback) {
         loader.jobsInProgress++;
     }
 
+    if (loader.tileRetryMax > 0 && loader.jobQueue.length === 0) {
+        //SAME AS ABOVE => REFACTOR
+        if ((!loader.jobLimit || loader.jobsInProgress < loader.jobLimit) && loader.failedTiles.length > 0) {
+            nextJob = loader.failedTiles.shift();
+            setTimeout(function () {
+                nextJob.start();
+            }, loader.tileRetryDelay);
+            loader.jobsInProgress++;
+        }
+    }
+
     callback(job.image, job.errorMsg, job.request);
 }
 
diff --git a/src/openseadragon.js b/src/openseadragon.js
index fd3fe809..d5f9c012 100644
--- a/src/openseadragon.js
+++ b/src/openseadragon.js
@@ -1156,7 +1156,9 @@ function OpenSeadragon( options ){
             imageLoaderLimit:       0,
             maxImageCacheCount:     200,
             timeout:                30000,
-            useCanvas:              true,  // Use canvas element for drawing if available
+            useCanvas:              true, // Use canvas element for drawing if available
+            tileRetryMax:           0,
+            tileRetryDelay:         2500,
 
             //INTERFACE RESOURCE SETTINGS
             prefixUrl:              "/images/",
diff --git a/src/viewer.js b/src/viewer.js
index 51b22756..b1f5f071 100644
--- a/src/viewer.js
+++ b/src/viewer.js
@@ -377,7 +377,9 @@ $.Viewer = function( options ) {
     // Create the image loader
     this.imageLoader = new $.ImageLoader({
         jobLimit: this.imageLoaderLimit,
-        timeout: options.timeout
+        timeout: options.timeout,
+        tileRetryMax: this.tileRetryMax,
+        tileRetryDelay: this.tileRetryDelay
     });
 
     // Create the tile cache