From bd9d4bce7436ba442d329ae54a4ada4ef3c14f2a Mon Sep 17 00:00:00 2001
From: Quincy Morgan <2046746+quincylvania@users.noreply.github.com>
Date: Fri, 24 Jul 2020 17:43:52 -0400
Subject: [PATCH] Fix issue with reversed bounding box coordinate order in WMS
 1.3 for EPSG:4326 CRS (close #7557)

---
 modules/renderer/background_source.js | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/modules/renderer/background_source.js b/modules/renderer/background_source.js
index 6d39bb270..b3bf00701 100644
--- a/modules/renderer/background_source.js
+++ b/modules/renderer/background_source.js
@@ -112,7 +112,7 @@ export function rendererBackgroundSource(data) {
         // Guess a type based on the tokens present in the template
         // (This is for 'custom' source, where we don't know)
         if (!source.type) {
-            if (/\{(proj|wkid|bbox)\}/.test(_template)) {
+            if (/SERVICE=WMS|\{(proj|wkid|bbox)\}/.test(_template)) {
                 source.type = 'wms';
                 source.projection = 'EPSG:3857';  // guess
             } else if (/\{(x|y)\}/.test(_template)) {
@@ -159,23 +159,30 @@ export function rendererBackgroundSource(data) {
               switch (key) {
                 case 'width':
                 case 'height':
-                  return tileSize;
+                    return tileSize;
                 case 'proj':
-                  return projection;
+                    return projection;
                 case 'wkid':
-                  return projection.replace(/^EPSG:/, '');
+                    return projection.replace(/^EPSG:/, '');
                 case 'bbox':
-                  return minXmaxY.x + ',' + maxXminY.y + ',' + maxXminY.x + ',' + minXmaxY.y;
+                    // WMS 1.3 flips x/y for some coordinate systems including EPSG:4326 - #7557
+                    if (projection === 'EPSG:4326' &&
+                        // The CRS parameter implies version 1.3 (prior versions use SRS)
+                        /VERSION=1.3|CRS={proj}/.test(source.template())) {
+                        return maxXminY.y + ',' + minXmaxY.x + ',' + minXmaxY.y + ',' + maxXminY.x;
+                    } else {
+                        return minXmaxY.x + ',' + maxXminY.y + ',' + maxXminY.x + ',' + minXmaxY.y;
+                    }
                 case 'w':
-                  return minXmaxY.x;
+                    return minXmaxY.x;
                 case 's':
-                  return maxXminY.y;
+                    return maxXminY.y;
                 case 'n':
-                  return maxXminY.x;
+                    return maxXminY.x;
                 case 'e':
-                  return minXmaxY.y;
+                    return minXmaxY.y;
                 default:
-                  return token;
+                    return token;
               }
             });