From ef51842e6a8b9feaf8c631f8d30851c6038f15d6 Mon Sep 17 00:00:00 2001
From: Nolan Lawson <nolan@nolanlawson.com>
Date: Thu, 22 Mar 2018 17:33:42 -0700
Subject: [PATCH] calculate listOffset to avoid profile offset issue

---
 .../_components/virtualList/VirtualList.html   | 18 +++++++++++++++++-
 .../virtualList/virtualListStore.js            | 14 ++++++++------
 routes/_pages/accounts/[accountId].html        |  1 -
 routes/_utils/getRectFromEntry.js              | 16 ++++++++++------
 4 files changed, 35 insertions(+), 14 deletions(-)

diff --git a/routes/_components/virtualList/VirtualList.html b/routes/_components/virtualList/VirtualList.html
index 1061b761..3257a6a3 100644
--- a/routes/_components/virtualList/VirtualList.html
+++ b/routes/_components/virtualList/VirtualList.html
@@ -1,5 +1,7 @@
 <VirtualListContainer :realm :containerQuery >
-  <div class="virtual-list {{shown ? '' : 'hidden'}}" style="height: {{$height}}px;">
+  <div class="virtual-list {{shown ? '' : 'hidden'}}"
+       style="height: {{$height}}px;"
+       ref:node >
     <VirtualListHeader component="{{headerComponent}}" virtualProps="{{headerProps}}" shown="{{$showHeader}}"/>
     {{#if $visibleItems}}
       {{#each $visibleItems as visibleItem @key}}
@@ -85,6 +87,7 @@
         if (scrollTop === 0) {
           this.fireScrollToTop()
         }
+        this.calculateListOffset()
       })
     },
     data: () => ({
@@ -104,6 +107,19 @@
       scrollTop: ($scrollTop) => $scrollTop,
       // TODO: bug in svelte store, shouldn't need to do this
       allVisibleItemsHaveHeight: ($allVisibleItemsHaveHeight) => $allVisibleItemsHaveHeight,
+    },
+    methods: {
+      calculateListOffset() {
+        // TODO: better way to get the offset top?
+        let node = this.refs.node
+        if (!node) {
+          return
+        }
+        mark('calculateListOffset')
+        let listOffset = node.offsetParent.offsetTop
+        this.store.setForRealm({listOffset})
+        stop('calculateListOffset')
+      }
     }
   }
 </script>
\ No newline at end of file
diff --git a/routes/_components/virtualList/virtualListStore.js b/routes/_components/virtualList/virtualListStore.js
index d5b5f6db..e76cb79f 100644
--- a/routes/_components/virtualList/virtualListStore.js
+++ b/routes/_components/virtualList/virtualListStore.js
@@ -2,7 +2,7 @@ import { mark, stop } from '../../_utils/marks'
 import { RealmStore } from '../../_utils/RealmStore'
 import { reselect } from '../../_utils/reselect'
 
-const RENDER_BUFFER_FACTOR = 5
+const RENDER_BUFFER_FACTOR = 1.5
 
 class VirtualListStore extends RealmStore {
   constructor (state) {
@@ -20,16 +20,18 @@ virtualListStore.computeForRealm('headerHeight', 0)
 virtualListStore.computeForRealm('scrollTop', 0)
 virtualListStore.computeForRealm('scrollHeight', 0)
 virtualListStore.computeForRealm('offsetHeight', 0)
+virtualListStore.computeForRealm('listOffset', 0)
 virtualListStore.computeForRealm('itemHeights', {})
 
 virtualListStore.compute('rawVisibleItems',
-    ['items', 'scrollTop', 'itemHeights', 'offsetHeight', 'showHeader', 'headerHeight'],
-    (items, scrollTop, itemHeights, offsetHeight, showHeader, headerHeight) => {
+    ['items', 'scrollTop', 'itemHeights', 'offsetHeight', 'showHeader', 'headerHeight', 'listOffset'],
+    (items, scrollTop, itemHeights, offsetHeight, showHeader, headerHeight, listOffset) => {
       window.rawVisibleItemsComputed = (window.rawVisibleItemsComputed || 0) + 1
       mark('compute visibleItems')
       if (!items) {
         return null
       }
+      let effectiveScrollTop = scrollTop - listOffset
       let renderBuffer = RENDER_BUFFER_FACTOR * offsetHeight
       let visibleItems = []
       let totalOffset = showHeader ? headerHeight : 0
@@ -40,13 +42,13 @@ virtualListStore.compute('rawVisibleItems',
         let height = itemHeights[key] || 0
         let currentOffset = totalOffset
         totalOffset += height
-        let isAboveViewport = (currentOffset < scrollTop)
+        let isAboveViewport = (currentOffset < effectiveScrollTop)
         if (isAboveViewport) {
-          if ((scrollTop - height - renderBuffer) > currentOffset) {
+          if ((effectiveScrollTop - height - renderBuffer) > currentOffset) {
             continue // above the area we want to render
           }
         } else {
-          if (currentOffset > (scrollTop + offsetHeight + renderBuffer)) {
+          if (currentOffset > (effectiveScrollTop + offsetHeight + renderBuffer)) {
             break // below the area we want to render
           }
         }
diff --git a/routes/_pages/accounts/[accountId].html b/routes/_pages/accounts/[accountId].html
index c11c481b..879a681b 100644
--- a/routes/_pages/accounts/[accountId].html
+++ b/routes/_pages/accounts/[accountId].html
@@ -30,7 +30,6 @@
   export default {
     oncreate() {
       let accountId = this.get('params').accountId
-      let instanceName = this.store.get('currentInstance')
       updateProfileAndRelationship(accountId)
     },
     store: () => store,
diff --git a/routes/_utils/getRectFromEntry.js b/routes/_utils/getRectFromEntry.js
index 8a0837a1..d45006da 100644
--- a/routes/_utils/getRectFromEntry.js
+++ b/routes/_utils/getRectFromEntry.js
@@ -3,16 +3,20 @@
 
 let hasBoundingRectBug
 
+function rectsAreEqual (rectA, rectB) {
+  return rectA.height === rectB.height &&
+  rectA.top === rectB.top &&
+  rectA.width === rectB.width &&
+  rectA.bottom === rectB.bottom &&
+  rectA.left === rectB.left &&
+  rectA.right === rectB.right
+}
+
 export function getRectFromEntry (entry) {
   if (typeof hasBoundingRectBug !== 'boolean') {
     const boundingRect = entry.target.getBoundingClientRect()
     const observerRect = entry.boundingClientRect
-    hasBoundingRectBug = boundingRect.height !== observerRect.height ||
-      boundingRect.top !== observerRect.top ||
-      boundingRect.width !== observerRect.width ||
-      boundingRect.bottom !== observerRect.bottom ||
-      boundingRect.left !== observerRect.left ||
-      boundingRect.right !== observerRect.right
+    hasBoundingRectBug = !rectsAreEqual(boundingRect, observerRect)
   }
   return hasBoundingRectBug ? entry.target.getBoundingClientRect() : entry.boundingClientRect
 }