From cf88c31c704788ffad24f8e92103087677355d3c Mon Sep 17 00:00:00 2001
From: Michael Barry <msbarry@users.noreply.github.com>
Date: Mon, 12 Nov 2018 13:57:50 -0500
Subject: [PATCH] begin touch zoom immediately when rotation disabled (#7582)

---
 src/ui/handler/touch_zoom_rotate.js           |  5 ++-
 .../unit/ui/handler/touch_zoom_rotate.test.js | 40 +++++++++++++++++++
 2 files changed, 44 insertions(+), 1 deletion(-)

diff --git a/src/ui/handler/touch_zoom_rotate.js b/src/ui/handler/touch_zoom_rotate.js
index 7d33cb5044a..ff5a0a30a7b 100644
--- a/src/ui/handler/touch_zoom_rotate.js
+++ b/src/ui/handler/touch_zoom_rotate.js
@@ -51,7 +51,10 @@ function makeMovement(map, { rotationDisabled, aroundCenter }, e) {
 
         if (!gestureIntent) {
             const scale =  vector.mag() / startVector.mag();
-            if (Math.abs(1 - scale) > SIGNIFICANT_SCALE_THRESHOLD) {
+            if (rotationDisabled && scale !== 1) {
+                // when rotation is disabled, any scale change triggers the zoom gesture to start
+                gestureIntent = 'zoom';
+            } else if (Math.abs(1 - scale) > SIGNIFICANT_SCALE_THRESHOLD) {
                 gestureIntent = 'zoom';
             }
         }
diff --git a/test/unit/ui/handler/touch_zoom_rotate.test.js b/test/unit/ui/handler/touch_zoom_rotate.test.js
index 6789f1c9210..d2e96eccc08 100644
--- a/test/unit/ui/handler/touch_zoom_rotate.test.js
+++ b/test/unit/ui/handler/touch_zoom_rotate.test.js
@@ -108,3 +108,43 @@ test('TouchZoomRotateHandler does not begin a gesture if preventDefault is calle
     map.remove();
     t.end();
 });
+
+test('TouchZoomRotateHandler starts zoom immediately when rotation disabled', (t) => {
+    const map = createMap(t);
+    map.touchZoomRotate.disableRotation();
+
+    const zoomstart = t.spy();
+    const zoom      = t.spy();
+    const zoomend   = t.spy();
+
+    map.on('zoomstart', zoomstart);
+    map.on('zoom',      zoom);
+    map.on('zoomend',   zoomend);
+
+    simulate.touchstart(map.getCanvas(), {touches: [{clientX: 0, clientY: -5}, {clientX: 0, clientY: 5}]});
+    map._renderTaskQueue.run();
+    t.equal(zoomstart.callCount, 0);
+    t.equal(zoom.callCount, 0);
+    t.equal(zoomend.callCount, 0);
+
+    simulate.touchmove(map.getCanvas(), {touches: [{clientX: 0, clientY: -5}, {clientX: 0, clientY: 6}]});
+    map._renderTaskQueue.run();
+    t.equal(zoomstart.callCount, 1);
+    t.equal(zoom.callCount, 1);
+    t.equal(zoomend.callCount, 0);
+
+    simulate.touchmove(map.getCanvas(), {touches: [{clientX: 0, clientY: -5}, {clientX: 0, clientY: 5}]});
+    map._renderTaskQueue.run();
+    t.equal(zoomstart.callCount, 1);
+    t.equal(zoom.callCount, 2);
+    t.equal(zoomend.callCount, 0);
+
+    simulate.touchend(map.getCanvas(), {touches: []});
+    map._renderTaskQueue.run();
+    t.equal(zoomstart.callCount, 1);
+    t.equal(zoom.callCount, 2);
+    t.equal(zoomend.callCount, 1);
+
+    map.remove();
+    t.end();
+});