Add support for custom tile size to Zoomify layer.

https://github.com/openlayers/openlayers/issues/6608

externs/olx.js

@@ -7326,6 +7326,15 @@ olx.source.ZoomifyOptions.prototype.size;
 olx.source.ZoomifyOptions.prototype.transition;
 
 
+/**
+ * Tile size. Same tile size is used for all zoom levels. Default value is
+ * `OpenLayers.DEFAULT_TILE_SIZE`.
+ * @type {number|undefined}
+ * @api
+ */
+olx.source.ZoomifyOptions.prototype.tileSize;
+
+
 /**
  * Namespace.
  * @type {Object}

src/ol/imagetile.js

@@ -19,6 +19,7 @@ goog.require('ol.events.EventType');
  * @param {olx.TileOptions=} opt_options Tile options.
  */
 ol.ImageTile = function(tileCoord, state, src, crossOrigin, tileLoadFunction, opt_options) {
+  var options = opt_options || {};
 
   ol.Tile.call(this, tileCoord, state, opt_options);
 
@@ -51,6 +52,14 @@ ol.ImageTile = function(tileCoord, state, src, crossOrigin, tileLoadFunction, op
    */
   this.tileLoadFunction_ = tileLoadFunction;
 
+  var tileCoordZ = tileCoord[0];
+  var tileGridTileSize = (options.tileGrid ? options.tileGrid.getTileSize(tileCoordZ) : undefined);
+
+  /**
+   * @protected
+   * @type {number}
+   */
+  this.tileSize_ = tileGridTileSize || ol.DEFAULT_TILE_SIZE;
 };
 ol.inherits(ol.ImageTile, ol.Tile);
 

src/ol/source/tile.js

@@ -75,7 +75,10 @@ ol.source.Tile = function(options) {
    * @protected
    * @type {olx.TileOptions}
    */
-  this.tileOptions = {transition: options.transition};
+  this.tileOptions = {
+    transition: options.transition,
+    tileGrid: this.tileGrid
+  };
 
 };
 ol.inherits(ol.source.Tile, ol.source.Source);

src/ol/source/zoomify.js

@@ -33,25 +33,26 @@ ol.source.Zoomify = function(opt_options) {
   var imageWidth = size[0];
   var imageHeight = size[1];
   var tierSizeInTiles = [];
-  var tileSize = ol.DEFAULT_TILE_SIZE;
+  var tileSize = options.tileSize || ol.DEFAULT_TILE_SIZE;
+  var tileSizeForTierSizeCalculation = tileSize;
 
   switch (tierSizeCalculation) {
     case ol.source.Zoomify.TierSizeCalculation_.DEFAULT:
-      while (imageWidth > tileSize || imageHeight > tileSize) {
+      while (imageWidth > tileSizeForTierSizeCalculation || imageHeight > tileSizeForTierSizeCalculation) {
         tierSizeInTiles.push([
-          Math.ceil(imageWidth / tileSize),
+          Math.ceil(imageWidth / tileSizeForTierSizeCalculation),
-          Math.ceil(imageHeight / tileSize)
+          Math.ceil(imageHeight / tileSizeForTierSizeCalculation)
         ]);
-        tileSize += tileSize;
+        tileSizeForTierSizeCalculation += tileSizeForTierSizeCalculation;
       }
       break;
     case ol.source.Zoomify.TierSizeCalculation_.TRUNCATED:
       var width = imageWidth;
       var height = imageHeight;
-      while (width > tileSize || height > tileSize) {
+      while (width > tileSizeForTierSizeCalculation || height > tileSizeForTierSizeCalculation) {
         tierSizeInTiles.push([
-          Math.ceil(width / tileSize),
+          Math.ceil(width / tileSizeForTierSizeCalculation),
-          Math.ceil(height / tileSize)
+          Math.ceil(height / tileSizeForTierSizeCalculation)
         ]);
         width >>= 1;
         height >>= 1;
@@ -79,6 +80,7 @@ ol.source.Zoomify = function(opt_options) {
 
   var extent = [0, -size[1], size[0], 0];
   var tileGrid = new ol.tilegrid.TileGrid({
+    tileSize: tileSize,
     extent: extent,
     origin: ol.extent.getTopLeft(extent),
     resolutions: resolutions
@@ -113,7 +115,8 @@ ol.source.Zoomify = function(opt_options) {
           var tileIndex =
               tileCoordX +
               tileCoordY * tierSizeInTiles[tileCoordZ][0];
-          var tileGroup = ((tileIndex + tileCountUpToTier[tileCoordZ]) / ol.DEFAULT_TILE_SIZE) | 0;
+          var tileSize = tileGrid.getTileSize(tileCoordZ);
+          var tileGroup = ((tileIndex + tileCountUpToTier[tileCoordZ]) / tileSize) | 0;
           var localContext = {
             'z': tileCoordZ,
             'x': tileCoordX,
@@ -180,7 +183,7 @@ ol.source.Zoomify.Tile_.prototype.getImage = function() {
   if (this.zoomifyImage_) {
     return this.zoomifyImage_;
   }
-  var tileSize = ol.DEFAULT_TILE_SIZE;
+  var tileSize = this.tileSize_;
   var image = ol.ImageTile.prototype.getImage.call(this);
   if (this.state == ol.TileState.LOADED) {
     if (image.width == tileSize && image.height == tileSize) {