Add zoom threshold (#317) (#347)

Co-authored-by: BolyavinMA <[email protected]>

Author: glemiron

README.md

@@ -103,6 +103,9 @@ plugins: {
 			// (percentage of zoom on a wheel event)
 			speed: 0.1,
 
+			// Minimal zoom distance required before actually applying zoom
+			threshold: 2,
+
 			// On category scale, minimal zoom level before actually applying zoom
 			sensitivity: 3,
 

src/plugin.js

@@ -482,7 +482,8 @@ var zoomPlugin = {
 			chartInstance.$zoom._dragZoomStart = null;
 			chartInstance.$zoom._dragZoomEnd = null;
 
-			if (dragDistanceX <= 0 && dragDistanceY <= 0) {
+			var zoomThreshold = options.zoom && options.zoom.threshold || 0;
+			if (dragDistanceX <= zoomThreshold && dragDistanceY <= zoomThreshold) {
 				return;
 			}