From 4b13cf32fd19a417054492a867c4e20270c300f5 Mon Sep 17 00:00:00 2001
From: Alistair Buxton <a.j.buxton@gmail.com>
Date: Fri, 30 Oct 2020 23:27:26 +0000
Subject: [PATCH] Introduce getTileBounds method for tiledImage

This wraps the implementation in tileSource but provides support for
wrapping. It does not support getting the source bounds.

Using this function instead of the tileSource version allows the
viewport clipping optimization to work with wrapping.
---
 src/tiledimage.js | 33 +++++++++++++++++++++------------
 1 file changed, 21 insertions(+), 12 deletions(-)

diff --git a/src/tiledimage.js b/src/tiledimage.js
index 74ffacef..b89a0d8e 100644
--- a/src/tiledimage.js
+++ b/src/tiledimage.js
@@ -392,6 +392,23 @@ $.extend($.TiledImage.prototype, $.EventSource.prototype, /** @lends OpenSeadrag
         return bounds.rotate(this.getRotation(current), this._getRotationPoint(current));
     },
 
+    /**
+     * @function
+     * @param {Number} level
+     * @param {Number} x
+     * @param {Number} y
+     * @returns {OpenSeadragon.Rect} Where this tile fits (in normalized coordinates).
+     */
+    getTileBounds: function( level, x, y ) {
+        var numTiles = this.source.getNumTiles(level);
+        var xMod    = ( numTiles.x + ( x % numTiles.x ) ) % numTiles.x;
+        var yMod    = ( numTiles.y + ( y % numTiles.y ) ) % numTiles.y;
+        var bounds = this.source.getTileBounds(level, xMod, yMod);
+        bounds.x += (x - xMod) / numTiles.x;
+        bounds.y += (this._worldHeightCurrent / this._worldWidthCurrent) * ((y - yMod) / numTiles.y);
+        return bounds;
+    },
+
     /**
      * @returns {OpenSeadragon.Point} This TiledImage's content size, in original pixels.
      */
@@ -1258,14 +1275,9 @@ function updateLevel(tiledImage, haveDrawn, drawLevel, level, levelOpacity,
     for (var x = topLeftTile.x; x <= bottomRightTile.x; x++) {
         for (var y = topLeftTile.y; y <= bottomRightTile.y; y++) {
 
-            // Optimisation disabled with wrapping because getTileBounds does not
-            // work correctly with x and y outside of the number of tiles
-            if (!tiledImage.wrapHorizontal && !tiledImage.wrapVertical) {
-                var tileBounds = tiledImage.source.getTileBounds(level, x, y);
-                if (drawArea.intersection(tileBounds) === null) {
-                    // This tile is outside of the viewport, no need to draw it
-                    continue;
-                }
+            if (drawArea.intersection(tiledImage.getTileBounds(level, x, y)) === null) {
+                // This tile is outside of the viewport, no need to draw it
+                continue;
             }
 
             best = updateTile(
@@ -1450,7 +1462,7 @@ function getTile(
     if ( !tilesMatrix[ level ][ x ][ y ] ) {
         xMod    = ( numTiles.x + ( x % numTiles.x ) ) % numTiles.x;
         yMod    = ( numTiles.y + ( y % numTiles.y ) ) % numTiles.y;
-        bounds  = tileSource.getTileBounds( level, xMod, yMod );
+        bounds  = tiledImage.getTileBounds( level, x, y );
         sourceBounds = tileSource.getTileBounds( level, xMod, yMod, true );
         exists  = tileSource.tileExists( level, xMod, yMod );
         url     = tileSource.getTileUrl( level, xMod, yMod );
@@ -1469,9 +1481,6 @@ function getTile(
         context2D = tileSource.getContext2D ?
             tileSource.getContext2D(level, xMod, yMod) : undefined;
 
-        bounds.x += ( x - xMod ) / numTiles.x;
-        bounds.y += (worldHeight / worldWidth) * (( y - yMod ) / numTiles.y);
-
         tile = new $.Tile(
             level,
             x,