From 3bca09bf272ee9d77da972cd85a2615063e0ae09 Mon Sep 17 00:00:00 2001
From: Antonio Scandurra <as-cii@github.com>
Date: Thu, 20 Apr 2017 19:47:03 +0200
Subject: [PATCH] Schedule update when setting scroll top row or scroll left
 column

---
 spec/text-editor-component-spec.js | 16 ++++++++++++++--
 src/text-editor-component.js       | 24 ++++++++++++++++--------
 2 files changed, 30 insertions(+), 10 deletions(-)

diff --git a/spec/text-editor-component-spec.js b/spec/text-editor-component-spec.js
index bf9c20c6e..2d5c88edc 100644
--- a/spec/text-editor-component-spec.js
+++ b/spec/text-editor-component-spec.js
@@ -2837,28 +2837,40 @@ describe('TextEditorComponent', () => {
       await component.getNextUpdatePromise()
 
       expect(component.getMaxScrollTop() / component.getLineHeight()).toBe(9)
+      expect(component.refs.verticalScrollbar.element.scrollTop).toBe(0 * component.getLineHeight())
 
       editor.setFirstVisibleScreenRow(1)
       expect(component.getFirstVisibleRow()).toBe(1)
+      await component.getNextUpdatePromise()
+      expect(component.refs.verticalScrollbar.element.scrollTop).toBe(1 * component.getLineHeight())
 
       editor.setFirstVisibleScreenRow(5)
       expect(component.getFirstVisibleRow()).toBe(5)
+      await component.getNextUpdatePromise()
+      expect(component.refs.verticalScrollbar.element.scrollTop).toBe(5 * component.getLineHeight())
 
       editor.setFirstVisibleScreenRow(11)
       expect(component.getFirstVisibleRow()).toBe(9)
+      await component.getNextUpdatePromise()
+      expect(component.refs.verticalScrollbar.element.scrollTop).toBe(9 * component.getLineHeight())
     })
 
     it('delegates setFirstVisibleScreenColumn and getFirstVisibleScreenColumn to the component', async () => {
       const {component, element, editor} = buildComponent({rowsPerTile: 3, autoHeight: false})
       element.style.width = 30 * component.getBaseCharacterWidth() + 'px'
       await component.getNextUpdatePromise()
-
       expect(editor.getFirstVisibleScreenColumn()).toBe(0)
-      component.setScrollLeft(5.5 * component.getBaseCharacterWidth())
+      expect(component.refs.horizontalScrollbar.element.scrollLeft).toBe(0 * component.getBaseCharacterWidth())
+
+      setScrollLeft(component, 5.5 * component.getBaseCharacterWidth())
       expect(editor.getFirstVisibleScreenColumn()).toBe(5)
+      await component.getNextUpdatePromise()
+      expect(component.refs.horizontalScrollbar.element.scrollLeft).toBe(Math.round(5.5 * component.getBaseCharacterWidth()))
 
       editor.setFirstVisibleScreenColumn(12)
       expect(component.getScrollLeft()).toBe(Math.round(12 * component.getBaseCharacterWidth()))
+      await component.getNextUpdatePromise()
+      expect(component.refs.horizontalScrollbar.element.scrollLeft).toBe(Math.round(12 * component.getBaseCharacterWidth()))
     })
   })
 })
diff --git a/src/text-editor-component.js b/src/text-editor-component.js
index 0990d4c20..88b52ddcc 100644
--- a/src/text-editor-component.js
+++ b/src/text-editor-component.js
@@ -1728,13 +1728,13 @@ class TextEditorComponent {
   flushPendingLogicalScrollPosition () {
     let changedScrollTop = false
     if (this.pendingScrollTopRow > 0) {
-      changedScrollTop = this.setScrollTopRow(this.pendingScrollTopRow)
+      changedScrollTop = this.setScrollTopRow(this.pendingScrollTopRow, false)
       this.pendingScrollTopRow = null
     }
 
     let changedScrollLeft = false
     if (this.pendingScrollLeftColumn > 0) {
-      changedScrollLeft = this.setScrollLeftColumn(this.pendingScrollLeftColumn)
+      changedScrollLeft = this.setScrollLeftColumn(this.pendingScrollLeftColumn, false)
       this.pendingScrollLeftColumn = null
     }
 
@@ -2466,13 +2466,17 @@ class TextEditorComponent {
     return this.setScrollLeft(scrollRight - this.getScrollContainerClientWidth())
   }
 
-  setScrollTopRow (scrollTopRow) {
+  setScrollTopRow (scrollTopRow, scheduleUpdate = true) {
     if (this.measurements) {
-      return this.setScrollTop(this.pixelPositionBeforeBlocksForRow(scrollTopRow))
+      const didScroll = this.setScrollTop(this.pixelPositionBeforeBlocksForRow(scrollTopRow))
+      if (didScroll && scheduleUpdate) {
+        this.scheduleUpdate()
+      }
+      return didScroll
     } else {
       this.pendingScrollTopRow = scrollTopRow
+      return false
     }
-    return false
   }
 
   getScrollTopRow () {
@@ -2483,13 +2487,17 @@ class TextEditorComponent {
     }
   }
 
-  setScrollLeftColumn (scrollLeftColumn) {
+  setScrollLeftColumn (scrollLeftColumn, scheduleUpdate = true) {
     if (this.measurements && this.getLongestLineWidth() != null) {
-      return this.setScrollLeft(scrollLeftColumn * this.getBaseCharacterWidth())
+      const didScroll = this.setScrollLeft(scrollLeftColumn * this.getBaseCharacterWidth())
+      if (didScroll && scheduleUpdate) {
+        this.scheduleUpdate()
+      }
+      return didScroll
     } else {
       this.pendingScrollLeftColumn = scrollLeftColumn
+      return false
     }
-    return false
   }
 
   getScrollLeftColumn () {