Added maxRotation parameter.

lib/scatter.js

@@ -268,7 +268,8 @@ export class AbstractScatter extends Throwable {
         onThrowFinished = null,
         scaleAutoClose = false,
         scaleCloseThreshold = 0.10,
-        scaleCloseBuffer = 0.05
+        scaleCloseBuffer = 0.05,
+        maxRotation = 5
     } = {}) {
         if (rotationDegrees != null && rotation != null) {
             throw new Error('Use rotationDegrees or rotation but not both')
@@ -300,6 +301,7 @@ export class AbstractScatter extends Throwable {
         this.startScale = startScale // Needed to reset object
         this.minScale = minScale
         this.maxScale = maxScale
+        this.maxRotation = maxRotation
         this.overdoScaling = overdoScaling
         this.translatable = translatable
         if (!translatable) {
@@ -311,6 +313,7 @@ export class AbstractScatter extends Throwable {
         this.resizable = resizable
         this.mouseZoomFactor = mouseZoomFactor
         this.autoBringToFront = autoBringToFront
+        
         this.dragging = false
         this.onTransform = onTransform != null ? [onTransform] : null
         this.onClose = onClose != null ? [onClose] : null
@@ -345,10 +348,16 @@ export class AbstractScatter extends Throwable {
 
     gesture(interaction) {
         let delta = interaction.delta()
-        //console.log("gesture", delta)
+        console.log("gesture", delta.rotate)
         if (delta != null) {
             this.addVelocity(delta)
-            this.transform(delta, delta.zoom, delta.rotate, delta.about)
+            let alpha = delta.rotate
+            if (this.maxRotationPerStep != null) {
+                if (Math.abs(alpha) > this.maxRotationPerStep) {
+                    alpha = 0
+                }
+            }
+            this.transform(delta, delta.zoom, alpha, delta.about)
             if (delta.zoom != 1) this.interactionAnchor = delta.about
         }
     }