From bac2cab8e948f54d24af09e5be94712dacca8daa Mon Sep 17 00:00:00 2001
From: thejohnhoffer <hoffexi@gmail.com>
Date: Wed, 2 Nov 2016 20:45:33 -0400
Subject: [PATCH 01/10] document tiledImage.preload

---
 src/openseadragon.js |  4 ++++
 src/tiledimage.js    | 20 +++++++++++++++++++-
 src/viewer.js        |  7 ++++++-
 3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/src/openseadragon.js b/src/openseadragon.js
index bd252e1c..fac2dc98 100644
--- a/src/openseadragon.js
+++ b/src/openseadragon.js
@@ -187,6 +187,9 @@
   * @property {Number} [opacity=1]
   *     Default opacity of the tiled images (1=opaque, 0=transparent)
   *
+  * @property {Boolean} [preload=false]
+  *     If true, tiles in image load without drawing. Defaults to false, so tiles are loaded and drawn.
+  *
   * @property {String} [compositeOperation=null]
   *     Valid values are 'source-over', 'source-atop', 'source-in', 'source-out',
   *     'destination-over', 'destination-atop', 'destination-in',
@@ -1081,6 +1084,7 @@ function OpenSeadragon( options ){
 
             // APPEARANCE
             opacity:                    1,
+            preload:                    false,
             compositeOperation:         null,
             placeholderFillStyle:       null,
 
diff --git a/src/tiledimage.js b/src/tiledimage.js
index e8092083..4f3d477c 100644
--- a/src/tiledimage.js
+++ b/src/tiledimage.js
@@ -71,6 +71,7 @@
  * @param {Number} [options.smoothTileEdgesMinZoom] - See {@link OpenSeadragon.Options}.
  * @param {Boolean} [options.iOSDevice] - See {@link OpenSeadragon.Options}.
  * @param {Number} [options.opacity=1] - Opacity the tiled image should be drawn at.
+ * @param {Boolean} [options.preload=false] - If true, tiles in image load without drawing. Defaults to false, so tiles are loaded and drawn.
  * @param {String} [options.compositeOperation] - How the image is composited onto other images; see compositeOperation in {@link OpenSeadragon.Options} for possible values.
  * @param {Boolean} [options.debugMode] - See {@link OpenSeadragon.Options}.
  * @param {String|CanvasGradient|CanvasPattern|Function} [options.placeholderFillStyle] - See {@link OpenSeadragon.Options}.
@@ -162,6 +163,7 @@ $.TiledImage = function( options ) {
         crossOriginPolicy:      $.DEFAULT_SETTINGS.crossOriginPolicy,
         placeholderFillStyle:   $.DEFAULT_SETTINGS.placeholderFillStyle,
         opacity:                $.DEFAULT_SETTINGS.opacity,
+        preload:                $.DEFAULT_SETTINGS.preload,
         compositeOperation:     $.DEFAULT_SETTINGS.compositeOperation
     }, options );
 
@@ -290,7 +292,7 @@ $.extend($.TiledImage.prototype, $.EventSource.prototype, /** @lends OpenSeadrag
      * Draws the TiledImage to its Drawer.
      */
     draw: function() {
-        if (this.opacity !== 0) {
+        if (this.opacity !== 0 && !this.preload) {
             this._midDraw = true;
             this._updateViewport();
             this._midDraw = false;
@@ -767,6 +769,22 @@ $.extend($.TiledImage.prototype, $.EventSource.prototype, /** @lends OpenSeadrag
         this._needsDraw = true;
     },
 
+    /**
+     * @returns {Boolean} whether the tiledImage is set to load tiles without drawing them.
+     */
+    getPreload: function() {
+        return this.preload;
+    },
+
+    /**
+     * Set true to load without drawing. Set false for default loading and drawing.
+     * @param {Boolean} whether to load tiles without drawing in this tiledImage.
+     */
+    setPreload: function(preload) {
+        this.preload = Boolean(preload);
+        this._needsDraw = true;
+    },
+
     /**
      * Get the current rotation of this tiled image in degrees.
      * @returns {Number} the current rotation of this tiled image in degrees.
diff --git a/src/viewer.js b/src/viewer.js
index 06b224e0..4d2a7358 100644
--- a/src/viewer.js
+++ b/src/viewer.js
@@ -1227,7 +1227,8 @@ $.extend( $.Viewer.prototype, $.EventSource.prototype, $.ControlDock.prototype,
      * @param {OpenSeadragon.Rect} [options.clip] - An area, in image pixels, to clip to
      * (portions of the image outside of this area will not be visible). Only works on
      * browsers that support the HTML5 canvas.
-     * @param {Number} [options.opacity] Opacity the tiled image should be drawn at by default.
+     * @param {Number} [options.opacity=1] Opacity the tiled image should be drawn at by default.
+     * @param {Boolean} [options.preload=false]  If true, tiles in image load without drawing by default.
      * @param {Number} [options.degrees=0] Initial rotation of the tiled image around
      * its top left corner in degrees.
      * @param {String} [options.compositeOperation] How the image is composited onto other images.
@@ -1265,6 +1266,9 @@ $.extend( $.Viewer.prototype, $.EventSource.prototype, $.ControlDock.prototype,
         if (options.opacity === undefined) {
             options.opacity = this.opacity;
         }
+        if (options.preload === undefined) {
+            options.preload = this.preload;
+        }
         if (options.compositeOperation === undefined) {
             options.compositeOperation = this.compositeOperation;
         }
@@ -1371,6 +1375,7 @@ $.extend( $.Viewer.prototype, $.EventSource.prototype, $.ControlDock.prototype,
                     clip: queueItem.options.clip,
                     placeholderFillStyle: queueItem.options.placeholderFillStyle,
                     opacity: queueItem.options.opacity,
+                    preload: queueItem.options.preload,
                     degrees: queueItem.options.degrees,
                     compositeOperation: queueItem.options.compositeOperation,
                     springStiffness: _this.springStiffness,

From 1baf086e1bd7c4251c436fe5ab84454c5962c244 Mon Sep 17 00:00:00 2001
From: thejohnhoffer <hoffexi@gmail.com>
Date: Thu, 3 Nov 2016 17:11:22 -0400
Subject: [PATCH 02/10] setting booleans the easy way

---
 src/tiledimage.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/tiledimage.js b/src/tiledimage.js
index 4f3d477c..bff8603a 100644
--- a/src/tiledimage.js
+++ b/src/tiledimage.js
@@ -781,7 +781,7 @@ $.extend($.TiledImage.prototype, $.EventSource.prototype, /** @lends OpenSeadrag
      * @param {Boolean} whether to load tiles without drawing in this tiledImage.
      */
     setPreload: function(preload) {
-        this.preload = Boolean(preload);
+        this.preload = (true == preload);
         this._needsDraw = true;
     },
 

From 3fc1948a4446fdf57c066f40adecfd3589ccda18 Mon Sep 17 00:00:00 2001
From: thejohnhoffer <hoffexi@gmail.com>
Date: Thu, 3 Nov 2016 17:12:44 -0400
Subject: [PATCH 03/10] setting booleans the shortest way

---
 src/tiledimage.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/tiledimage.js b/src/tiledimage.js
index bff8603a..99a7c1f6 100644
--- a/src/tiledimage.js
+++ b/src/tiledimage.js
@@ -781,7 +781,7 @@ $.extend($.TiledImage.prototype, $.EventSource.prototype, /** @lends OpenSeadrag
      * @param {Boolean} whether to load tiles without drawing in this tiledImage.
      */
     setPreload: function(preload) {
-        this.preload = (true == preload);
+        this.preload = !!preload;
         this._needsDraw = true;
     },
 

From 0a44585457a53a564e94e5b486aa3a378a1e480c Mon Sep 17 00:00:00 2001
From: thejohnhoffer <hoffexi@gmail.com>
Date: Thu, 3 Nov 2016 22:39:00 -0400
Subject: [PATCH 04/10] documentation of opacity and preload relations

---
 src/openseadragon.js |  5 +++--
 src/tiledimage.js    | 10 +++++-----
 src/viewer.js        |  4 ++--
 3 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/src/openseadragon.js b/src/openseadragon.js
index fac2dc98..cdaee4e5 100644
--- a/src/openseadragon.js
+++ b/src/openseadragon.js
@@ -185,10 +185,11 @@
   *     If 0, adjusts to fit viewer.
   *
   * @property {Number} [opacity=1]
-  *     Default opacity of the tiled images (1=opaque, 0=transparent)
+  *     Default proportional opacity of the tiled images (1=opaque, 0=hidden)
+  *     Hidden images do not draw and only load when preloading is allowed.
   *
   * @property {Boolean} [preload=false]
-  *     If true, tiles in image load without drawing. Defaults to false, so tiles are loaded and drawn.
+  *     Default switch for loading hidden images (true loads, false blocks)
   *
   * @property {String} [compositeOperation=null]
   *     Valid values are 'source-over', 'source-atop', 'source-in', 'source-out',
diff --git a/src/tiledimage.js b/src/tiledimage.js
index 99a7c1f6..11d96928 100644
--- a/src/tiledimage.js
+++ b/src/tiledimage.js
@@ -70,8 +70,8 @@
  * @param {Number} [options.minPixelRatio] - See {@link OpenSeadragon.Options}.
  * @param {Number} [options.smoothTileEdgesMinZoom] - See {@link OpenSeadragon.Options}.
  * @param {Boolean} [options.iOSDevice] - See {@link OpenSeadragon.Options}.
- * @param {Number} [options.opacity=1] - Opacity the tiled image should be drawn at.
- * @param {Boolean} [options.preload=false] - If true, tiles in image load without drawing. Defaults to false, so tiles are loaded and drawn.
+ * @param {Number} [options.opacity=1] - Set to draw at proportional opacity. If zero, images will not draw.
+ * @param {Boolean} [options.preload=false] - Set true to load even when the image is hidden by zero opacity.
  * @param {String} [options.compositeOperation] - How the image is composited onto other images; see compositeOperation in {@link OpenSeadragon.Options} for possible values.
  * @param {Boolean} [options.debugMode] - See {@link OpenSeadragon.Options}.
  * @param {String|CanvasGradient|CanvasPattern|Function} [options.placeholderFillStyle] - See {@link OpenSeadragon.Options}.
@@ -770,15 +770,15 @@ $.extend($.TiledImage.prototype, $.EventSource.prototype, /** @lends OpenSeadrag
     },
 
     /**
-     * @returns {Boolean} whether the tiledImage is set to load tiles without drawing them.
+     * @returns {Boolean} whether the tiledImage can load hidden tiles of zero opacity.
      */
     getPreload: function() {
         return this.preload;
     },
 
     /**
-     * Set true to load without drawing. Set false for default loading and drawing.
-     * @param {Boolean} whether to load tiles without drawing in this tiledImage.
+     * Set true to load even when hidden. Set false to block loading when hidden.
+     * @param {Boolean}  whether the tiledImage can load hidden tiles of zero opacity.
      */
     setPreload: function(preload) {
         this.preload = !!preload;
diff --git a/src/viewer.js b/src/viewer.js
index 4d2a7358..78357873 100644
--- a/src/viewer.js
+++ b/src/viewer.js
@@ -1227,8 +1227,8 @@ $.extend( $.Viewer.prototype, $.EventSource.prototype, $.ControlDock.prototype,
      * @param {OpenSeadragon.Rect} [options.clip] - An area, in image pixels, to clip to
      * (portions of the image outside of this area will not be visible). Only works on
      * browsers that support the HTML5 canvas.
-     * @param {Number} [options.opacity=1] Opacity the tiled image should be drawn at by default.
-     * @param {Boolean} [options.preload=false]  If true, tiles in image load without drawing by default.
+     * @param {Number} [options.opacity=1] Default proportional opacity of the tiled images (1=opaque, 0=hidden)
+     * @param {Boolean} [options.preload=false]  Default switch for loading hidden images (true loads, false blocks)
      * @param {Number} [options.degrees=0] Initial rotation of the tiled image around
      * its top left corner in degrees.
      * @param {String} [options.compositeOperation] How the image is composited onto other images.

From c402a7bfdd92b8f8e0da62e19e6a4b3202b439b4 Mon Sep 17 00:00:00 2001
From: thejohnhoffer <hoffexi@gmail.com>
Date: Fri, 4 Nov 2016 09:11:46 -0400
Subject: [PATCH 05/10] underscores to preload

---
 src/tiledimage.js | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/src/tiledimage.js b/src/tiledimage.js
index 11d96928..dbb2e4fe 100644
--- a/src/tiledimage.js
+++ b/src/tiledimage.js
@@ -163,7 +163,7 @@ $.TiledImage = function( options ) {
         crossOriginPolicy:      $.DEFAULT_SETTINGS.crossOriginPolicy,
         placeholderFillStyle:   $.DEFAULT_SETTINGS.placeholderFillStyle,
         opacity:                $.DEFAULT_SETTINGS.opacity,
-        preload:                $.DEFAULT_SETTINGS.preload,
+        _preload:               $.DEFAULT_SETTINGS.preload,
         compositeOperation:     $.DEFAULT_SETTINGS.compositeOperation
     }, options );
 
@@ -292,7 +292,7 @@ $.extend($.TiledImage.prototype, $.EventSource.prototype, /** @lends OpenSeadrag
      * Draws the TiledImage to its Drawer.
      */
     draw: function() {
-        if (this.opacity !== 0 && !this.preload) {
+        if (this.opacity !== 0 && !this._preload) {
             this._midDraw = true;
             this._updateViewport();
             this._midDraw = false;
@@ -773,15 +773,14 @@ $.extend($.TiledImage.prototype, $.EventSource.prototype, /** @lends OpenSeadrag
      * @returns {Boolean} whether the tiledImage can load hidden tiles of zero opacity.
      */
     getPreload: function() {
-        return this.preload;
+        return this._preload;
     },
 
     /**
      * Set true to load even when hidden. Set false to block loading when hidden.
-     * @param {Boolean}  whether the tiledImage can load hidden tiles of zero opacity.
      */
     setPreload: function(preload) {
-        this.preload = !!preload;
+        this._preload = !!preload;
         this._needsDraw = true;
     },
 

From 171591a7a37e9f8b6414f9e90bad4470f2f1beb7 Mon Sep 17 00:00:00 2001
From: thejohnhoffer <hoffexi@gmail.com>
Date: Fri, 4 Nov 2016 09:21:04 -0400
Subject: [PATCH 06/10] new opacity flag

---
 src/tiledimage.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/tiledimage.js b/src/tiledimage.js
index dbb2e4fe..5a763ecd 100644
--- a/src/tiledimage.js
+++ b/src/tiledimage.js
@@ -1533,7 +1533,7 @@ function compareTiles( previousBest, tile ) {
 }
 
 function drawTiles( tiledImage, lastDrawn ) {
-    if (lastDrawn.length === 0) {
+    if (this.opacity == 0 || lastDrawn.length === 0) {
         return;
     }
     var tile = lastDrawn[0];

From 9548ad6a27601365e837616d484405deb782ccd8 Mon Sep 17 00:00:00 2001
From: thejohnhoffer <hoffexi@gmail.com>
Date: Fri, 4 Nov 2016 09:24:08 -0400
Subject: [PATCH 07/10] using the strict === comparison

---
 src/tiledimage.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/tiledimage.js b/src/tiledimage.js
index 5a763ecd..18ca5917 100644
--- a/src/tiledimage.js
+++ b/src/tiledimage.js
@@ -1533,7 +1533,7 @@ function compareTiles( previousBest, tile ) {
 }
 
 function drawTiles( tiledImage, lastDrawn ) {
-    if (this.opacity == 0 || lastDrawn.length === 0) {
+    if (this.opacity === 0 || lastDrawn.length === 0) {
         return;
     }
     var tile = lastDrawn[0];

From 2915ee09c5d953942afbf6f8a9bc5c8e8d33bf09 Mon Sep 17 00:00:00 2001
From: thejohnhoffer <hoffexi@gmail.com>
Date: Fri, 4 Nov 2016 09:26:34 -0400
Subject: [PATCH 08/10] correct logic for call to _updateViewport

---
 src/tiledimage.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/tiledimage.js b/src/tiledimage.js
index 18ca5917..d9067229 100644
--- a/src/tiledimage.js
+++ b/src/tiledimage.js
@@ -292,7 +292,7 @@ $.extend($.TiledImage.prototype, $.EventSource.prototype, /** @lends OpenSeadrag
      * Draws the TiledImage to its Drawer.
      */
     draw: function() {
-        if (this.opacity !== 0 && !this._preload) {
+        if (!(this.opacity === 0 && !this._preload)) {
             this._midDraw = true;
             this._updateViewport();
             this._midDraw = false;

From cf5825d1fa3a223c4504ce0e7395a649bf6e8144 Mon Sep 17 00:00:00 2001
From: thejohnhoffer <hoffexi@gmail.com>
Date: Fri, 4 Nov 2016 10:03:04 -0400
Subject: [PATCH 09/10] better underscores in preload term handling

---
 src/tiledimage.js | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/tiledimage.js b/src/tiledimage.js
index d9067229..f6337c59 100644
--- a/src/tiledimage.js
+++ b/src/tiledimage.js
@@ -163,10 +163,13 @@ $.TiledImage = function( options ) {
         crossOriginPolicy:      $.DEFAULT_SETTINGS.crossOriginPolicy,
         placeholderFillStyle:   $.DEFAULT_SETTINGS.placeholderFillStyle,
         opacity:                $.DEFAULT_SETTINGS.opacity,
-        _preload:               $.DEFAULT_SETTINGS.preload,
+        preload:                $.DEFAULT_SETTINGS.preload,
         compositeOperation:     $.DEFAULT_SETTINGS.compositeOperation
     }, options );
 
+    this._preload = this.preload;
+    delete this.preload;
+
     this._fullyLoaded = false;
 
     this._xSpring = new $.Spring({

From 7a4fda37b57808720454fcaab9780a2eea4caf25 Mon Sep 17 00:00:00 2001
From: thejohnhoffer <hoffexi@gmail.com>
Date: Tue, 30 May 2017 12:00:43 -0500
Subject: [PATCH 10/10] setPreload correctly treats both Primatives and Objects
 as Boolean Primatives

---
 src/tiledimage.js | 8 ++++----
 src/viewer.js     | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/tiledimage.js b/src/tiledimage.js
index f6337c59..bfedc96d 100644
--- a/src/tiledimage.js
+++ b/src/tiledimage.js
@@ -295,7 +295,7 @@ $.extend($.TiledImage.prototype, $.EventSource.prototype, /** @lends OpenSeadrag
      * Draws the TiledImage to its Drawer.
      */
     draw: function() {
-        if (!(this.opacity === 0 && !this._preload)) {
+        if (this.opacity !== 0 || this._preload) {
             this._midDraw = true;
             this._updateViewport();
             this._midDraw = false;
@@ -773,7 +773,7 @@ $.extend($.TiledImage.prototype, $.EventSource.prototype, /** @lends OpenSeadrag
     },
 
     /**
-     * @returns {Boolean} whether the tiledImage can load hidden tiles of zero opacity.
+     * @returns {Boolean} whether the tiledImage can load its tiles even when it has zero opacity.
      */
     getPreload: function() {
         return this._preload;
@@ -783,7 +783,7 @@ $.extend($.TiledImage.prototype, $.EventSource.prototype, /** @lends OpenSeadrag
      * Set true to load even when hidden. Set false to block loading when hidden.
      */
     setPreload: function(preload) {
-        this._preload = !!preload;
+        this._preload = new Boolean(preload).valueOf();
         this._needsDraw = true;
     },
 
@@ -1536,7 +1536,7 @@ function compareTiles( previousBest, tile ) {
 }
 
 function drawTiles( tiledImage, lastDrawn ) {
-    if (this.opacity === 0 || lastDrawn.length === 0) {
+    if (tiledImage.opacity === 0 || lastDrawn.length === 0) {
         return;
     }
     var tile = lastDrawn[0];
diff --git a/src/viewer.js b/src/viewer.js
index 78357873..2c97d31a 100644
--- a/src/viewer.js
+++ b/src/viewer.js
@@ -1227,7 +1227,7 @@ $.extend( $.Viewer.prototype, $.EventSource.prototype, $.ControlDock.prototype,
      * @param {OpenSeadragon.Rect} [options.clip] - An area, in image pixels, to clip to
      * (portions of the image outside of this area will not be visible). Only works on
      * browsers that support the HTML5 canvas.
-     * @param {Number} [options.opacity=1] Default proportional opacity of the tiled images (1=opaque, 0=hidden)
+     * @param {Number} [options.opacity=1] Proportional opacity of the tiled images (1=opaque, 0=hidden)
      * @param {Boolean} [options.preload=false]  Default switch for loading hidden images (true loads, false blocks)
      * @param {Number} [options.degrees=0] Initial rotation of the tiled image around
      * its top left corner in degrees.