From 29b813457c7a185c41e050d358b001fadd2498e4 Mon Sep 17 00:00:00 2001
From: cpsdqs <cpsdqs@gmail.com>
Date: Sun, 1 Oct 2017 11:15:58 +0200
Subject: [PATCH] Improve smooth scrolling

---
 js/term/screen.js | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/js/term/screen.js b/js/term/screen.js
index 98ff13d..4a28355 100644
--- a/js/term/screen.js
+++ b/js/term/screen.js
@@ -268,10 +268,20 @@ module.exports = class TermScreen extends EventEmitter {
       }
     })
 
+    let aggregateWheelDelta = 0
     this.canvas.addEventListener('wheel', e => {
       if (this.mouseMode.clicks) {
-        this.input.onMouseWheel(...this.screenToGrid(e.offsetX, e.offsetY),
-          e.deltaY > 0 ? 1 : -1)
+        if (Math.abs(e.wheelDeltaY) === 120) {
+          // mouse wheel scrolling
+          this.input.onMouseWheel(...this.screenToGrid(e.offsetX, e.offsetY), e.deltaY > 0 ? 1 : -1)
+        } else {
+          // smooth scrolling
+          aggregateWheelDelta -= e.wheelDeltaY
+          if (Math.abs(aggregateWheelDelta) >= 40) {
+            this.input.onMouseWheel(...this.screenToGrid(e.offsetX, e.offsetY), aggregateWheelDelta > 0 ? 1 : -1)
+            aggregateWheelDelta = 0
+          }
+        }
 
         // prevent page scrolling
         e.preventDefault()