From baf27bf99a34db13e7d2750eef09d31e9147ef65 Mon Sep 17 00:00:00 2001
From: Antonio Scandurra <me@as-cii.com>
Date: Wed, 23 Sep 2015 17:40:48 +0200
Subject: [PATCH] Preserve un-rounded scroll positions

---
 src/text-editor-component.coffee |  8 ++++----
 src/text-editor-presenter.coffee | 16 ++++++++++++----
 2 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/src/text-editor-component.coffee b/src/text-editor-component.coffee
index 4db79e716..ef2af790a 100644
--- a/src/text-editor-component.coffee
+++ b/src/text-editor-component.coffee
@@ -809,10 +809,10 @@ class TextEditorComponent
     {clientX, clientY} = event
 
     linesClientRect ?= @linesComponent.getDomNode().getBoundingClientRect()
-    top = clientY - linesClientRect.top + @presenter.scrollTop
-    left = clientX - linesClientRect.left + @presenter.scrollLeft
-    bottom = linesClientRect.top + @presenter.scrollTop + linesClientRect.height - clientY
-    right = linesClientRect.left + @presenter.scrollLeft + linesClientRect.width - clientX
+    top = clientY - linesClientRect.top + @presenter.getRealScrollTop()
+    left = clientX - linesClientRect.left + @presenter.getRealScrollLeft()
+    bottom = linesClientRect.top + @presenter.getRealScrollTop() + linesClientRect.height - clientY
+    right = linesClientRect.left + @presenter.getRealScrollLeft() + linesClientRect.width - clientX
 
     {top, left, bottom, right}
 
diff --git a/src/text-editor-presenter.coffee b/src/text-editor-presenter.coffee
index 8dc9a90a9..9474e9c5f 100644
--- a/src/text-editor-presenter.coffee
+++ b/src/text-editor-presenter.coffee
@@ -830,6 +830,9 @@ class TextEditorPresenter
   getScrollTop: ->
     @scrollTop
 
+  getRealScrollTop: ->
+    @realScrollTop ? @scrollTop
+
   didStartScrolling: ->
     if @stoppedScrollingTimeoutId?
       clearTimeout(@stoppedScrollingTimeoutId)
@@ -865,6 +868,9 @@ class TextEditorPresenter
   getScrollLeft: ->
     @scrollLeft
 
+  getRealScrollLeft: ->
+    @realScrollLeft ? @scrollLeft
+
   getClientHeight: ->
     if @clientHeight
       @clientHeight
@@ -1542,15 +1548,17 @@ class TextEditorPresenter
         @setScrollRight(desiredScrollRight)
 
   commitPendingScrollLeftPosition: ->
-    scrollLeft = Math.round(@constrainScrollLeft(@pendingScrollLeft))
+    scrollLeft = @constrainScrollLeft(@pendingScrollLeft)
     if scrollLeft isnt @scrollLeft and not Number.isNaN(scrollLeft)
-      @scrollLeft = scrollLeft
+      @realScrollLeft = scrollLeft
+      @scrollLeft = Math.round(scrollLeft)
       @model.setScrollLeft(@scrollLeft)
 
   commitPendingScrollTopPosition: ->
-    scrollTop = Math.round(@constrainScrollTop(@pendingScrollTop))
+    scrollTop = @constrainScrollTop(@pendingScrollTop)
     if scrollTop isnt @scrollTop and not Number.isNaN(scrollTop)
-      @scrollTop = scrollTop
+      @realScrollTop = scrollTop
+      @scrollTop = Math.round(scrollTop)
       @model.setScrollTop(@scrollTop)
 
   updateScrollPosition: ->