From deaf6d87f6f920d959b33a22750aae02c2fcf47c Mon Sep 17 00:00:00 2001
From: Richard Shine <richard.shine@shinenetservices.com>
Date: Mon, 13 Apr 2020 14:08:42 +0100
Subject: [PATCH] Have added pinch zoom ux #990, fix mobile device.

---
 src/dygraph-interaction-model.js | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/src/dygraph-interaction-model.js b/src/dygraph-interaction-model.js
index 8d644aa22..a50795f7e 100644
--- a/src/dygraph-interaction-model.js
+++ b/src/dygraph-interaction-model.js
@@ -418,12 +418,13 @@ DygraphInteraction.startTouch = function(event, g, context) {
   var touches = [];
   for (var i = 0; i < event.touches.length; i++) {
     var t = event.touches[i];
+    var rect = t.target.getBoundingClientRect();
     // we dispense with 'dragGetX_' because all touchBrowsers support pageX
     touches.push({
       pageX: t.pageX,
       pageY: t.pageY,
-      dataX: g.toDataXCoord(t.pageX),
-      dataY: g.toDataYCoord(t.pageY)
+      dataX: g.toDataXCoord(t.clientX-rect.left),
+      dataY: g.toDataYCoord(t.clientY-rect.top)
       // identifier: t.identifier
     });
   }
@@ -536,8 +537,8 @@ DygraphInteraction.moveTouch = function(event, g, context) {
   var didZoom = false;
   if (context.touchDirections.x) {
     g.dateWindow_ = [
-      c_init.dataX - swipe.dataX + (context.initialRange.x[0] - c_init.dataX) / xScale,
-      c_init.dataX - swipe.dataX + (context.initialRange.x[1] - c_init.dataX) / xScale
+      c_init.dataX - swipe.dataX / xScale + (context.initialRange.x[0] - c_init.dataX) / xScale,
+      c_init.dataX - swipe.dataX / xScale + (context.initialRange.x[1] - c_init.dataX) / xScale
     ];
     didZoom = true;
   }
@@ -550,8 +551,8 @@ DygraphInteraction.moveTouch = function(event, g, context) {
         // TODO(danvk): implement
       } else {
         axis.valueRange = [
-          c_init.dataY - swipe.dataY + (context.initialRange.y[0] - c_init.dataY) / yScale,
-          c_init.dataY - swipe.dataY + (context.initialRange.y[1] - c_init.dataY) / yScale
+          c_init.dataY - swipe.dataY / yScale + (context.initialRange.y[0] - c_init.dataY) / yScale,
+          c_init.dataY - swipe.dataY / yScale + (context.initialRange.y[1] - c_init.dataY) / yScale
         ];
         didZoom = true;
       }
@@ -591,9 +592,6 @@ DygraphInteraction.endTouch = function(event, g, context) {
         // no double-tap, pan or pinch so its a touchover
         event.isTouchOver = true;
         g.mouseMoveHandler_(event);
-        // g.mousemove(event);f
-        
-        
         
       }