From eb588d4c7c328488ff2fb9832ef1ac2810325b38 Mon Sep 17 00:00:00 2001
From: Nathan Sobo <nathan@github.com>
Date: Wed, 29 Mar 2017 20:51:24 -0600
Subject: [PATCH] Test and fix the `center` option to autoscroll

---
 spec/text-editor-component-spec.js | 12 ++++++++++++
 src/text-editor-component.js       |  4 ++--
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/spec/text-editor-component-spec.js b/spec/text-editor-component-spec.js
index 5866ea947..d18ba5213 100644
--- a/spec/text-editor-component-spec.js
+++ b/spec/text-editor-component-spec.js
@@ -523,6 +523,18 @@ describe('TextEditorComponent', () => {
       expect(component.getScrollBottom()).toBe((6 + 1 + scrollMarginInLines) * component.measurements.lineHeight)
     })
 
+    it('autoscrolls the given range to the center of the screen if the `center` option is true', async () => {
+      const {component, editor} = buildComponent({height: 50})
+      expect(component.getLastVisibleRow()).toBe(3)
+
+      editor.scrollToScreenRange([[4, 0], [6, 0]], {center: true})
+      await component.getNextUpdatePromise()
+
+      const actualScrollCenter = (component.getScrollTop() + component.getScrollBottom()) / 2
+      const expectedScrollCenter = Math.round((4 + 7) / 2 * component.getLineHeight())
+      expect(actualScrollCenter).toBe(expectedScrollCenter)
+    })
+
     it('automatically scrolls horizontally when the requested range is within the horizontal scroll margin of the right edge of the gutter or right edge of the scroll container', async () => {
       const {component, element, editor} = buildComponent()
       const {scrollContainer} = component.refs
diff --git a/src/text-editor-component.js b/src/text-editor-component.js
index c30f668a9..a49e7fd30 100644
--- a/src/text-editor-component.js
+++ b/src/text-editor-component.js
@@ -1472,8 +1472,8 @@ class TextEditorComponent {
     if (options && options.center) {
       const desiredScrollCenter = (screenRangeTop + screenRangeBottom) / 2
       if (desiredScrollCenter < this.getScrollTop() || desiredScrollCenter > this.getScrollBottom()) {
-        desiredScrollTop = desiredScrollCenter - this.measurements.clientHeight / 2
-        desiredScrollBottom = desiredScrollCenter + this.measurements.clientHeight / 2
+        desiredScrollTop = desiredScrollCenter - this.getScrollContainerClientHeight() / 2
+        desiredScrollBottom = desiredScrollCenter + this.getScrollContainerClientHeight() / 2
       }
     } else {
       desiredScrollTop = screenRangeTop - verticalScrollMargin